Texas State - Physical Geology - GEOL 1410 - Wernette - Final Exam Review

deformation

bending, breaking, or folding of the crust results from stresses (force) on it

drip curtains (cave deposit)

vertical sheet of rock formed by the dripping of water from a cracks in the cave ceiling

longshore current (longshore drift)

"along the shore current" transports sediment parallel to the shore: - migrates a long direction - barrier islands (currents smear sediment along beaches) sediment comes up on the shore at an angle and back out perpendicular to the beach - water follows the steepest path down reshapes shorelines - moving features around - eroding some and depositing others spit: land sticking out

composite volcano (stratovolcano)

"classic volcano" - conical shape with a steep summit area and gradually sloping flanks product of silica-rich magma having an andesitic composition alternating layers of ash/pyroclastic material and andesitic lava flows (steep sided layers built up by flows) intermediate composition explosive common at subduction zones: - continental volcanic arcs (ocean-continent convergence) - driven by water induced melting associated with the ring of fire forms mountains anatomy: conduit: - pipeline opening by which magma moves toward earth's surface vent: - opening to the surface volcanic cone: - cone-shaped structure created by successive events crater: - funnel shaped depression at the top of the cone fumarole: - vent in a volcanic area from which fumes or gases escape

borax

cleaner

guyots

flat topped seamounts volcano that went extinct - erosion produced the flat top surface

graphite

pencil led

metamorphic zones

zones: regions of equal metamorphic intensity/grade temperature & pressure conditions slate: low gneiss: high isograds: lines connecting points of the same grade (boundaries between zones) high-grade metamorphic center is flanked by lower grade metamorphic zones

earth's formation 5) earth's layers form

~4.6ga: earth formed as an independent planet that had out-competed other rocky chunks in its sector of the solar system (stabilized and started differentiating) gasses formed the atmosphere: atmosphere helped burn up the meteorites that were still bombarding earth back in the hadean very heavy elements (especially iron) sank to form the core less heavy elements (iron and magnesium) stayed in the middle to form the mantle light elements (silicon, aluminum, oxygen, etc.) formed the crust

uniformitarianism

"the present is the key to the past" geological, physical, and chemical processes that occur on the earth today work the same as they have throughout earth's history processes are consistent throughout time

cooling rates & crystal size

(nearly) instantaneously freeze - results in glass - obsidian cool quickly (not instantaneously) - results in many, small crystals cool slowly - results in fewer, larger crystals - granite cool very slowly: - results in massive crystals

glacier velocity

- fastest in the upper center - slowest against walls/floor depends on: - slope/gradient - temperature

oceans

- saltwater - larger - open exchange with other oceans - overlie oceanic crust divided into different layers - deeper as you go further down

seas

- saltwater - smaller - restricted connectivity to the ocean - may or may not overlie oceanic crust (could be on continents)

carbonates (mineral class)

...CO32- covalent bonds 1 carbon + 3 oxygens covalently bonded in triangles (don't link with each other) CaCO3 (calcite) & CaMg(CO3)2 (dolomite) triangles arranged in sheets with cations in between many react (fizz) with acid

sulfates (mineral class)

...SO42- covalent bonds 1 sulfur + 4 oxygen covalently bonded in a tetrahedron CaSO4 • 2H2O (gypsum) anhydrite (dry wall) when dehydrated

silicates (mineral class)

...SiO44- most abundant minerals in the crust covalent bonds include: potassium, sodium, aluminum, iron, and/or magnesium iron & magnesium-rich: - ferromagnesian (dark) silicates - oceanic crust - heavier & dark black or green - olivine (found in basalt), pyroxene (augite), hornblende (amphibole) sodium, potassium, and aluminum-rich: - non-ferromagnesian (light) silicates - continental crust - less dense & lighter color - quartz, muscovite, potassium feldspar silicate tetrahedron: - silicon & 4 oxygen bonded covalently (SiO44-) - tetrahedron (-4 net charge) bonds ionically with cations - building block of all silicate minerals subdivisions: when silicates break or dissolve, the surrounding bonds (not the tetrahedra) break and results in a unique set of properties for each silicate subclass 1. nesosilicates (isolated tetrahedra): olivine - covalent bonds (tetrahedra) - ionic bonds (break easily) - 4 oxygen ions for every silicon ion 2. inosilicates (single-chain): pyroxene - silicates are bonded (share oxygen) - oxygen-to-silicon ratio is 3:1 3. inosilicate (double-chain): amphibole - share up to 3 oxygens - every 2 chains connect at oxygen 4. phyllosilicate (sheet): mica/clay/talc - infinite 2D image - 3 of the 4 oxygen atoms being shared by adjacent tetrahedrons 5. tectosilicate (framework): feldspar/quartz - infinite 3D image - covalent bonds in 3 directions (stronger) - oxygen-to-silicon. ratio is 2:1

halides (mineral class)

...group 7 ionic bonds cation(s) ionically bonded with group 7 anion(s) NaCl (halite) & CaF2 (fluorite)

radioactive decay (example)

1) find the number of parent isotopes (P) in the rock 2) find the number of daughter isotopes (D) 3) use P:D to calculate the number of half-lives that have passed 4) multiply the number of half-lives that have passed by the half-life for that isotope after 1 half-life: - 50 left | 100 years - 50% parent & 50% daughter after 2 half-lives: - 25 left | 200 years - 25% parent & 57% daughter after 3 half-live: - 12.5 left | 300 years - 12.5% parent & 87.5% daughter

elastic rebound theory

1) strain builds up by bending the crust 2) when strain reaches the elastic limit, the crust breaks with brittle strain elastic limit: the farthest extent of strain before breaking - build up of strain - hits elastic limit - snaps (earthquake) - bounces back

minerals *

1. inorganic - does not contain organic molecules 2. naturally occurring 3. solid 4. orderly crystalline structure - made up of atoms (or ions) that are arranged in an orderly, repetitive manner 5. definable (definite) chemical composition that allows for some variation can be described by chemical formula: - SiO2 = quartz - Fe2O3 = hematite substitutions are allowed: - cations (+ve charge) have similar size/charge - anion (-ve charge) substitutions: new mineral (Mg,Fe)2SiO4 = olivine K(Mg,Fe)3(AlSi3O10)(OH,F)2 = biotite polymorphs: two minerals may have the same chemical formula - CaCO3: calcite & aragonite - C: diamond & graphite usually made of a combination of ionic and covalent bonds (olivine)

convergent boundary (continent-continent)

1. no subduction - buoyancy of continental material inhibits it from being subducted 2. mountain building - formation of a new mountain belt composed of deformed sedimentary and metamorphic rocks that contain slivers of oceanic lithosphere

classifying mass wasting

1. rate of movement: - rapid or slow fast movement: sudden trigger of visible movement slow movement: steady, imperceptible rate of movement noted by effects accumulated over time (tilted trees or poles) 2. type of movement: - falling, sliding, or flowing 3. type of material - rock, soil, debris

where do we find volcanoes?

1. subduction zones: - convergent plate boundaries - ocean-ocean & ocean-continent - water-induced melting - more than 60% of the world's volcanoes are on the ring of fire - volcanic island arcs & continental island arcs 2. divergent plate boundaries: - decompression melting - active lava extrusions to form new crust (boundaries) - where the greatest volume of magma erupts along - spreading centers decompression melting: - melting that occurs as rock ascends due to a drop in confining pressure - hot, solid mantle rock ascends and moves into regions of lower pressure - ascending mantel plumes reach the uppermost mantle 3. hot spots: - oceanic & continental - mantle plumes bringing heat - intraplate volcanism

volcanic hazards: gases

50-80% water vapor carbon dioxide, sulfuric gases, some nitrogen may cause significant fatalities if higher in toxic gases fumarole: volcanic vent that lets gas escape (degassing can help delay an eruption)

(plate-mantle convection) layer cake model

2 zones of convection: - thin, dynamic layer in the upper mantle - thick, larger, sluggish layer located below downward convective flow is also driven by the subduction of cold, dense oceanic lithosphere upper layer: contains recycled oceanic lithosphere of various ages lower mantle: sluggish and does not provide material to support volcanism at the surface

igneous textures (grain size)*

3 factors influence the textures of igneous rocks: - rate at which the molten rock cools (dominant) - amount of silica in the magma - amount of dissolved gasses in the magma pegmatitic: (intrusive) - crystals larger than 1cm (may be much larger) - coarse - formed in deep earth - pegmatitic granite, pegmatitic diorite, pegmatitic gabbro phaneritic: (intrusive) - crystals consistently visible (less than 1cm) - crystals are roughly equal in size - granite, diorite, gabbro, peridiotite porphyritic: (intrusive & extrusive) - visible phenocrysts (large, visible crystals in an igneous rock) set in fine-grained groundmass (fine-grained crystals around a phenocryst, matrix) - formed in the magma chamber then erupted - porphyritic rhyolite, porphyritic andesite, porphyritic basalt aphanitic: (extrusive) - crystals very small (fine-grained) - crystals are not visible to the naked eye - formed at the surface - rhyolite, andesite, basalt glassy: (extrusive) - no crystals - formed at the surface quickly - smooth - obsidian vesicular: (extrusive) - contains air bubbles left from gas bubbles - contain many small cavities (vesicles) - formed at the surface - pumice, scoria, vesicular basalt pyroclastic: (extrusive) - made of broken rock fragments - formed at the surface during eruptions - volcanic breccia (fragments >2mm) - volcanic tuff (fragments <2mm) - felsic explosion

soil horizons

5 horizons (O, A, E, B, and C) differ in texture, composition, structure, and color soil profile: how well the different horizons are developed for that area topsoil: horizons O & A subsoil: horizon B true soil (solum): horizons O, A, E, and B

soil horizon: horizon B*

B = subsouil zone of accumulation: all the clay and chemical components leached/eluviated from E horizon few organisms and little organic matter hardpans: impermeable clay layers O + A + E + B = true soil (solum) solum: living roots and other plant and animal life are largely confined to this zone

ice sheets (continental glaciers)

Covers vast areas and are unconfined by topography builds up (center) flows out (outer edges) subsidence: warps the land underneath (emergent coasts) ice cap: dome-shaped masses of glacial ice that are smaller than continental glaciers ice shelves: part of the glacier floating in the sea but still connected to land

soil evolution

O horizon is always the uppermost few cm of loose organics as new sediment enters the system: - the A and O layers migrate upward - the bottom part of A is leached/eluviated (becomes E with mostly sandy quartz left) B grows as it accumulates more clay and soluble chemicals leached/eluviated from above C grows increasingly slowly as the underlying material is weathered (grows downward) as soil accumulates on top, it will shield the parent material, slowing weathering

artesian systems

a confined groundwater system with high hydrostatic pressure that causes water to rise above the level of the aquifer develops if: - the aquifer is confined above and below by aquicludes - the rock sequence is tilted to build up hydrostatic pressure - the aquifer is exposed at the surface and can be recharged flowing artesian well - flows freely because the wellhead is below the artesian pressure surface artesian well - doesn't flow freely because the wellhead is above the artesian pressure surface

viscosity

a fluid's resistance to flow depends on: - temperature - silica content high: thick & sticky: felsic - steeper slopes (stratovolcano) - more ash & pyroclastic material - more violent/explosive eruptions (super volcanoes) - yellowstone - more dangerous - conical & piled up low: thin & runny: mafic - faster lava flow - greater lava flow area (flood basalts & shield volcano) - hawaii - low, rounded, gentle slope eruption type/shape is determined by viscosity silicate structure: - well-connected (high, felsic) - less connected (low, mafic) temperature: - cold (high, felsic) - hot (low, mafic) gas content (water vapor and carbon dioxide): - high (high, felsic) - low (low, mafic)

geysers

a hot spring that periodically ejects hot water and steam steam builds up (pressurizes) and ejects water - hotter than hot springs - caused by magma - have the room/time for water to expand into stream

permeability

a material's capacity to transmit fluid (dependent on porosity) how connected pore spaces are low permeability (clay) - small pores with molecular attraction between particle and water high permeability (gravel) - highly fractured rock with fractures interconnected

headlands (shoreline formations)

a part of the shoreline that sticks out and is typically bounded by cliffs good beaches may form between headlands happens because some parts of the shoreline are made of harder materials and more resistant to erosion

effusive eruption

a quiescent eruption that produces mainly outpourings of fluid lava mafic magmas hawaii

braided streams

a stream with multiple dividing and rejoining channels less developed intricate network of dividing and rejoining broad and shallow channels separated from another by sand and gravel bars develop where: sediment supply exceeds the transport capacity of running water (sediment > water)

unconformity

a surface in the rock record representing a period of missing time due to a lack of deposition during that time or, later removal of that material interruption to deposition (erosion) 3 types: - disconformity - angular unconformity - nonconformity

rounding

abrasion reduces the size of the particle by rounding off sharp corners and edges during transport degree of rounding indicates the distance or time involved in transportation of sediment angular vs. rounded

magma migration: stoping

absorbs surrounding brittle rock rock surrounding magma chamber is cracked up and falls in goes through surrounding rock without melting country rock may persist as xenoliths (bits of unmelted country rock)

soil & soil types

accumulation of weathered material, water, air, & humus that can support vegetation regolith + humus + air + water forms in layers (horizons) with different compositions residual soil: - forms when parent material weathers in place - bedrock transplanted soil: - develops when weathered material was eroded and transported to a new location - common around rivers - clay and organic rich (agriculture) - unconsolidated sediment

volcano classification: activity level

active: has erupted recently and is likely to do so again (past 10,000 years) dormant: has not erupted recently but might do so again extinct: is not likely to erupt again indicators: - frequency/recency of past eruptions - geophysical indications of ongoing activity

melt a rock (3) change the composition

adding water induces melting - results in a compositional change subduction zones (convergent boundaries) - water in the subducting plate goes into the mantle with the plate - escaping water induces melting and changes the composition of the mantle

elements

all atoms with the same number of protons have the same chemical and physical properties over 100 elements are known (92 naturally occurring) vertical columns: similar size/charge atomic number: how many protons are in the atom (unique for each element) atomic weight: - about the number of protons + neutrons - changes depending on the number of neutrons - different isotopes have different atomic weights

ionic bonds

all or nothing weaker dissolve in water (halite) atom will give up electrons or steal them from others to complete its shell atoms with usually give or take 1-2 electrons ion: atom with unequal numbers of protons and electrons (charged) positively and negatively charged ions attract each other in order to balance the charge an atom that only has a couple of electrons in its outer shell will give them up (cation) cation + : positively charged (more protons than electrons) atom that is close to having a full outer shell will take electrons from others (anion) anion - : negatively charged (more electrons than protons ex. NaCl - Na: cation (gave 1) - Cl: anion (took 1) charge strength: bigger charge = stronger attraction - NaCl: weaker (+1/-1) - CaCO3: stronger (+2/-2) bond strength decreases with atom's size - small atoms = stronger attraction - negative ion: large - positive ion: small bond strength increases with packing efficiency - tighter packing = stronger attraction

domes

all the rocks dip away from the center (anticline) underlying intusion swelling the earth (pushes upwards) oldest rock/sediment in the center igneous

basins

all the rocks dip towards the center (syncline) sediment piling up overtime (piles up and sinks) youngest rock/sediment in the center depositional

regolith

all the sediment, residue, and other material left in place after weathering ex. sand dunes add decomposing organic matter (humus) → soil

deltas

alluvial deposit where a river flows into a lake or ocean and causes the shoreline to build outward into the lake or sea progradation: moving out into the water shape depends on which processes dominate: - streams - tidal - waves

disconformity

an erosional surface between two parallel rock units (above and below) between 2 separate sets of disposition represents a short interval of time (but may indicate a long one) easiest to recognize if there is a distinct change in rock type

angular unconformity

an erosional surface between two rock units that are not parallel - layers below are at a different angle than the ones below lower units were tilted or folded and eroded prior to the deposition of the upper units a large gap in time during which burial, folding, and erosion all took place deposition ➤ tilting ➤ erosion ➤ deposition

folds (compressional stress)

anticline: oldest layers in the middle syncline: youngest layers in the middle

compressive mountain building

anticlines & synclines (including overturned folds) reverse & thrust faults - compresses land into a small area shallow & deep marine rocks thrust far above sea level - rocks moved significantly from where they should be - evidence of mountain building granitic & dioritic plutons from subduction - pushes up on layers and adds more materials - volcanism and subduction zones regional metamorphism

beaches

any deposit of sediment extending from the low-tide line to a notable change in topography (dunes/cliffs) or the line of permanent vegetation (grassy field)

law of cross-cutting relationships

any event that causes rock units to be cut or split must have occurred after the deposition of all affected units cross-cutting events: - faults - dikes - large intrusions (plutons)

fossils

any evidence of prehistoric life body fossils: - remains of the organism - bones, shells, and other body materials that have been fossilized - sometimes these are washed in/not representative of the environment trace fossils: - indication of the organism's activity - tracks/burrows, fossilized poop, bite marks - more informative - burrows (bioturbation) - footprints (lived/moved through that location)

sedimentary structures

any feature in a sedimentary rock that formed at or shortly after the time of deposition not specific to any specific environment informative about the physical processes occurring when the sediment was deposited - strata/beds - cross-bedding - ripple marks - graded bedding - mud cracks

magma

any mass of molten rock generated within earth that has not breached the surface formed by partial melting at various levels within the crust and upper mantle partial melting of ultramafic rocks tends to yield mafic (basaltic) magmas partial melting of mafic rocks generally yields intermediate (andesitic) magmas partial melting of intermediate rocks can generate felsic (granitic) magmas generated by: - decompression melting (caused by a decrease in pressure as magma rises) - introduction of water (lowers the melting temperature of hot mantle rock) - heating of crustal rocks above their melting temperature magma bodies rises toward the surface because it is less dense than the surrounding rocks 3 components: - liquid component - solid component - gaseous component mantle: mostly solid with just pockets of magma magma from melting the crust: - aluminium (continental) - potassium (continental) - sodium (continental) - calcium (oceanic) - iron (oceanic) magma from melting the upper mantle: - iron - magnesium - some olivine origins: - almost all magma originates in the mantle (mantle plumes, subduction, & decompression melting) mantle: ultramafic oceanic crust: mafic continental crust: felsic

landslides

any or all relatively rapid forms of mass movement

native elements (mineral class)

any single element metallic or covalent bonds metals: - Au (gold) - Ag (silver) - As (arsenic) - Cu (copper) non-metals: - S (sulfur) - C (graphite) - C (diamond)

hot springs

any spring in which the temperature is higher than 98.6°F heated by: - proximity to magma - earth's geothermal gradient

shorelines

area between the average low tide and high tide levels affected by tides & storm waves intertidal zone: area covered during high time and exposed during low tide coastlines are the most rapidly changing part of the geosphere

special soils

aridisol: - soil formed in arid regions - little organic matter - slow soil development pedocals: - carbonate-rich soils - chemical weathering is less intense - develops into caliche caliche: - made from leached limestone that develops in the B/C horizon - hardened sedimentary rock of cemented by calcium carbonate - formed in arid regions

magnetic reversals

as lava cools, iron-rich grains become magnetized and align themselves in the direction of the existing magnetic lines of force paleomagnetism: the natural remnant magnetism in rock bodies earth's magnetic field reverses itself somewhat regularly over time (hundreds-thousands of years) causing magnetic north to become south and vice versa normal polarity (black): when rocks exhibit the same magnetism as the present magnetic field reverse polarity (white): when rocks exhibit the opposite magnetism as the present magnetic field as magma solidifies at the crest of an oceanic ridge, it is magnetized with the polarity of Earth's magnetic field at the time when earth's magnetic field reverses polarity, any newly formed seafloor having the opposite polarity would form in the middle of the old strip (two halves of the old strip are carried in opposite directions - symmetry) rocks can be dated based on amount of time between polarity reversals

wave refraction

as part of the wave encounters shallower areas, it will slow, causing bends in the wave obstacles that stick out will experience higher wave speeds and energy, and will therefore be eroded

detrital sedimentary rocks: shale

as silt and clay accumulate, they tend to form thin layers (laminae) clay and silt particles take on a nearly parallel alignment and become tightly packed shales are weak (poorly cemented and not well lithified) forms barriers to the subsurface movement of water and petroleum

fractional crystallization

as the magma starts to cool, mafic minerals crystallize out leaving the magma more felsic olivine: - first to crystallize (ultramafic) quartz: - last to crystallize (felsic) ultramafic to mafic (1st) - mantle mafic to intermediate (2nd) - rising toward the crust intermediate to felsic (3rd) - moves through continental crust happens at: - mid-ocean ridges (mafic magma cools to form mid-ocean crust) moho: boundary between ultramafic mantle (peridotite) and mafic oceanic crust (gabbro) the more magma has to migrate through the crust to approach the surface, the more partial melting drives it towards being felsic the longer a magma chamber has to sit and cool, the more fractional crystallization will make it felsic

refraction and reflection

at a boundary between different densities, seismic waves are reflected or refracted depending on the angle reflection: waves go down and bounce back up refraction: waves go down and bend "diving waves" - P-waves and S-waves refract as they go deeper into the mantle as density increases, waves slow and bend

principle of original horizontality

at the surface, rock layers are originally laid down flat (horizontal) if rocks are no longer flat: - a tilting event has caused them to become deformed - the event must have occurred after the rocks were deposited

fringing reef

attached to a continent or island's margins (around island)

glacial budget

balance between snow input and melting output that controls glacial expansion (advance) vs. contraction (retreat) zone of accumulation: - area where snow growth exceed loss - end point moves forward zone of wastage: - area where ice loss exceeds accumulation - end point moves backwards

scientific law

basic principle that describes a particular behavior of nature that is generally narrow in scope and can be stated briefly simple mathematical equation tend to be observations rather than explanations

volcanic hazards: volcanic blocks and bombs

because of their size and weight, bombs and blocks usually fall near the vent volcanic blocks: - large pieces of exploded material - made of hardened lava volcanic bombs: - bits of lava that cool into rocks while in the air (football shaped)

plunging fold

bent across the top and angled down into the earth (at the end)

nonoliated rocks: anthracite

black (or grayish) very shiny, lightweight rock with brittle fracture low-grade metamorphism of bituminous coal purer than other forms of coal (more carbon and less toxic volatiles)

caldera (super volcano)

bowl-shaped very felsic (thick) massive magma chambers extremely violent: - blows off top, cracks, collapses - pyroclastic material covers wide distances forms craters (wide valleys) rather than raised forms continental hot spots - yellowstone crater lake-type caldera: - collapse of the summit of a large composite volcano following an explosive eruption of silica-rich pumice and ash fragments hawaiian-type caldera: - collapse of the top of a shield volcano caused by subterranean drainage from a central magma chamber yellowstone-type caldera: - collapse of a large area, caused by the discharge of colossal volumes of silica-rich pumice and ash along ring fractures

physical weathering: ice/frost wedging

breakage of rock (clean, large breaks) water caught in rock cracks will expand when frozen: puts pressure against the rock takes repeated freezing and thawing to break open rock will be most aggressive in wet climates with strong temperature fluctuations

iceberg calving

breaking off chunks of ice at the edge of a glacier brittle deformation

u-shaped trough (valley glacier landform)

broad, rounded base with steep sides steep/vertical walls & broad, floors form from glaciers reshaping stream valleys

burial & subduction metamorphism

burial: - slow burial of sedimentary layers pushes lower layers into the earth - enough heat and pressure to trigger metamorphosis - sedimentary basins subduction: - subducting oceanic crust - high pressure, low temperature involves other metamorphic processes: - contact: around magma chamber - burial: subducting oceanic crust - hydrothermal: fluids release from the oceanic slab

oceanic trench

depression formed where the subducting slab warps downwards deepest part of ocean

transportation: gravity

can transport any sized sediment but only a short distance without another medium high movement (not much transported) helped by rain and/or earthquakes assists other transportation methods

transportation: ice (glaciers)

can transport very large sediments that get caught in the glacier

carbon cycle

carbon atoms are cycled between the biosphere, atmosphere, hydrosphere, and geosphere carbon reservoirs: - places that can trap carbon for a long time - limestone - coal/fossil fuels - forests (short time) the more carbon is trapped in a carbon reservoir, the less carbon dioxide is available for the atmosphere cultivating forests for agriculture = less carbon dioxide trapped carbon in reservoirs is released through burning & used in cement as limestone) - released back into the atmosphere - absorbed back into the ocean volcanoes - naturally cycle carbon dioxide between the atmosphere & geosphere - self-regulating (trap amount = release amount)

chemical weathering

chemical reactions can only take place at the surface: - relies on physical weathering to start the process increasing surface area increases reaction rate - increased by physical weathering water: the most important agent of chemical weathering

chemical rocks: carbonates

carbonate minerals - calcium carbonate: calcium + carbon dioxide - chalk - coquina - travertine - fossiliferous limestone made of chemicals produced by organisms or from accumulation of plant/animal debris parent rock: - calcium ions come from pyroxene, amphibole, & calcium-rich feldspar in intermediate & mafic rocks coquina: loosely cemented shell hash (broken shells) fossiliferous limestone: calcite cemented shells chalk: microscopic shells and clay ions are derived from ocean water (previously derived from weathering intermediate & mafic rocks) metamorphic alterations: - marble limestone - mineral component: - calcium carbonate & calcite - always react with acid - chemical (evaporate) - biochemical (produced by organisms) - bioclastic (make from seashell/coral remains) dolostone - mineral component: - reacts with acid when powdered - formed by secondary alteration of limestone infiltrated by magnesium-rich groundwater

chemical rocks: oolitic limestone

carbonate rock little grains of sand, shell, or other particles get coated in layers of calcite sand-sized spheres (ooids) oolitic limestone: ooids cemented together by calcite

chemical rocks: travertine

carbonate rock underground springs rich in calcium and carbonates surface and changes in pressure and/or temperature may cause limestone to precipitate ribboned, bubbly appearance: - light-colored and lacy texture formed in flowing water (not in oceans like most limestones)

stress & strain

cause and effect (stress results in strain) stress: - (ex. pulling of crust) - force applied per area strain: - (ex. thinning of crust) - resulting deformation continental crust: - flat over broad area - small stress & strain mountain build up: - concentrated - large stress & strain

reverse fault (compressional stress)

caused by compressive forces that squeeze and shorten a body hanging wall: moves upward compresses land into a small area older above younger

strike-slip faults (shearing stress)

caused by horizontal shearing forces that shear the body left-laterally or right-laterally no hanging or foot wall slip: - distance of offset (dies out toward tips) - amount of movement slip is based on divergence, not offset earthquakes may occur along entire length bend: mini compression/tension zone - left bend (local compression) - right bend (local extension) mid-ocean ridge: connected by transform boundaries trench to trench subduction: - transform boundary between subduction zones - offset consistent with slip direction

normal fault (tensional stress)

caused by tensional forces that stretch a body and tend to pull it apart hanging wall: moves downwards missing the middle-aged rocks basin and range province: - brittle upper crust (slides down) - ductile lower crust (thins under confining pressure)

nearshore currents

caused by wave refraction incoming waves cause currents in the nearshore zone (trend in the transport direction) nearshore zone: region between the upper shoreline (high tide line) and the place where the swells become breakers (the surf zone) swells don't transport water/sediment in and out, just up and down - breakers drag it in and out 2 types: - longshore currents - rip currents

sea caves (shoreline formations)

caves formed in the most weathering susceptible parts of the shoreline found in the intertidal interval form between high and low tides - flood when the tide comes in

caves & caverns

caves: natural subsurface opening generally connected to the surface and large enough for a person to enter cavern: very large caves or system of interconnected caves form by dissolution

metamorphism: fluid activity

chemically active fluids carry dissolved ions and are warm upper crust: water occurs as ground water depth: hot water is released into the surrounding rocks when a magma body cools and solidifies some minerals take in water as part of the chemical reaction hot water provides thermal energy which helps promote the reactions olivine + water = serpentine & magnesium oxide source of fluids: - pore fluids trapped in pore spaces (limestone, sandstone, coal, released by heat/pressure) - volatile fluid (steam/nonliquid fluid trapped in magma escapes and enters surrounding rock) - hydrous minerals (gypsum and some clays naturally contain water that can be released into liquid form during metamorphism)

sinkholes

circular depression in the ground that forms by the solution of the underlying carbonate rocks or by the collapse of a cave roof formation by solution: - soluble rock dissolves and washed out by seeping water - loose overlying sediments settle into the void spaces formation by collapse: - seeping water dissolves soluble rock - cave roof collapses (steep-sided crater)

kaolinite

clay facial products medical powders paint thickener food additive

fossil fuels

coal, oil, natural gas, bitumen from tar sands, and shale oil source rock: - organic-rich sediments in which hydrocarbons form - shales - marine, lacustrine (lake), or deltaic source rock → reservoir rock reservoir rock: - rock into which hydrocarbons migrate and collect - needs good porosity (pore space) and permeability (easy to flow through) - sandstones cap rock: overlying impermeable layer that prevents hydrocarbons from escaping to the surface - gas (least dense) - oil - water trap: structural feature of the rocks that forces hydrocarbons to collect against the impermeable cap rock anticline trap: - folds in a layer (dome) - rising oil and gas collect at the top of the fold (natural gas collects above the oil) fault trap: - sealed off by a nonporous layer (bend) - strata are displaced so that a dripping reservoir rock abuts as an impermeable bed oil shales: hydrocarbons are trapped in impermeable source rocks called tight formations hydraulic fracturing (fracking): - opening up pore spaces in impermeable rocks, permitting natural gas and oil to flow out into wells - horizontally drill through the layer

emergent coast

coastline along which the local sea level is falling due to: - falling sea levels - intense deposition at a delta (sediment build up) - tectonic uplift (land pushing up) - isostasy (weight is removed from the last and springs back) rising up rare in an age of globally rising sea levels requires: - active tectonic uplift - glacial isostatic rebound identified by intertidal features (caves and undercutting) being exposed and dry

submergent coast

coastline along which the local sea level is rising due to: - rising sea levels - subsidence (when an area loses elevation due to isostasy) subsidence: sinking land - no sediment coming in - sediment compacts - land collapses due to weight submerged louisiana - local sediment is compacting/settling & sea levels are rising - flat & deltas are blocked from dumping sediment miami - continual flooding during high tide galveston - barrier islands migrate landward as sea levels rise - not receiving sediment from the river (sand and mud that would stabilize the barrier island is dumped elsewhere and causes galveston to move backwards) galveston seawall - part not protected by the seawall has moved tremendously - artificially dump sand in front of the seawall

native gold, silver, copper

coins, jewelry, wiring

(plate-mantle convection) whole-mantle convection

cold oceanic lithosphere sinks to great depths and stirs the entire mantle ultimate burial ground for subducting lithospheric slabs is the core- mantle boundary downward flow of subducting slabs is balanced by buoyantly rising mantle plumes that transport hot mantle rock toward the surface heat for both narrow plumes and the mega-plumes is thought to arise mainly from Earth's core narrow tube-like plumes: long, narrow plumes originate from the core-mantle boundary and produce hot- spot volcanism (hawaiian Islands) giant upwellings, mega-plumes: occur beneath the pacific basins and southern africa

streak (physical property)

color of a mineral in powered form much more reliable than regular color diagnostic for some minerals no streak = harder than streak plate hematite - metallic (red streak) metallic luster: dense, dark streak nonmetallic luster: light-colored streak

volcanic hazards: pyroclastic flows

common for andesitic/rhyolitic volcanoes (felsic - intermediate) heated steam, gas, ash, and rocks (hot gasses infused with incandescent ash and larger lava fragments) burning, melting, asphyxiating, entrapment moves fast most deadly volcanic hazard & most destructive forces of nature

volcanic hazards: lahars

common for andesitic/rhyolitic volcanoes (felsic - intermediate) violent mudflow from gas and steam (very hot, boiling) results when unstable layers of ash and debris become saturated and flow downslope (following stream channels) volcanic debris becomes saturated with water and rapidly moves down steep volcanic slopes moves fast sediment heavy rivers can be triggered before an eruption

volcanic hazards: dome/sector collapse

common for andesitic/rhyolitic volcanoes (felsic - intermediate) - steep & explosive portion of volcano collapses under force of eruption large landslide moves fast happens near ocean = tsunami

volcanic hazards: lava flows

common for mafic volcanoes - basalt (common) - andesite (less common) - rhyolite (rare) dangers: melting & burning moves slow basaltic lava types: - pahoehoe lava (hot, ropy, folds on itself, flowy) - aa lava (thick, cooler, rocky, sharp, jagged) basaltic lava formations: pillow basalt: - the result of very fast outer cooling around a very hot center - indicates that the lava flow formed below the surface of a water body columnar basalt (forms in sills): - the result of contraction along joints while cooling (breaks along straight planes) lava tubes: - solid rock forming on the outside with a liquid flowing center - insulated pathways that allow lava to flow great distances from its source

nonoliated rocks: hornfels

common, non-descript fine-grained rock composition depends on the original rock clay-rich rocks (shale and mudstone) are intruded by a hot magma body wide variety of parent rocks (shale common)

intermediate (andesitic) magma

composition between felsic and mafic composite cones

compressional tectonics & original horizontality

compressional faulting ➤ significant uplift to form inclined beds uplift events are recorded in angular unconformities (original horizontality has been disturbed) angled rocks = uplift & tectonics

seafloor sedimentation

concentrated near margins pelagic sediment: - very fine sediment ends up in abyssal plains - sediment that slowly settles from suspension in the water column and is deposited far from land

materials become plastic under the right conditions

confining pressure: - on all sides during deformation - deeper rocks are more plastic/ductile - deep pressure keeps rocks from breaking/melting high temperatures: - hotter rocks are more plastic/ductile - deforms easily slower application of stress - slow deformation ➤ more plastic/ductile

quartz

consists entirely of silicon and oxygen 3D framework conchoidal fracture colored by inclusions of various ions (impurities) jewelry microchips abrasives (sandpaper) glass making (foundation) electronic insulation

compressive mountain building (3)

continent-continent subduction - no intrusion and lots of thrusting thrust faults of mountain building moves large volumes of material over a large distance

marine deposition: continental shelf

continental crust flooded by water shallow, low to moderate energy (some wave action) warm water (near equator) evaporation: - rock salt & rock gypsum carbonate factory: - warm waters produce limestone - takes carbon dioxide out of the atmosphere and locks it in the geosphere - ocean traps carbonate in limestone, helping slow the rise of carbon dioxide in the atmosphere & hydrosphere - too much carbonic acid = acidic waters (disturbs carbonate production) diverse life forms (coral reefs) characteristics: - shale (clays from delta), fossiliferous limestone, micritic (chemical) limestone, oolitic limestone - bioturbation (trace fossils in limestone - burrows) - marine fossils (clams, oysters, corals, shells)

glaciers in the hydrologic cycle

continuously adjust to changes in temperature, snowmelt, slope, and sea level large reservoirs of fresh water glaciers contribute to oceans - melt water flows to oceans (river/stream runoff) - glaciers melt directly into oceans (increase sea level) - icebergs break off into the ocean (increase sea level)

glacier distribution

controlled by: - amount of snowfall (enough snow) - temperature (cold enough to keep snow)

forces that drive plate motion

convection: - the transfer of heat by the mass movement or circulation of a substance (heating causes materials to become less dense and float to the surface, which cools, increases in density and sinks to the bottom: restarting the process) - driving force of plate movement slab drag: convection in the asthenosphere (whole mantle) drags overriding plates with the convection currents (arthur holmes, 1920s) ridge push: - magma extruding from mid ocean ridge pushes plates apart - elevated position of the oceanic ridge causes slabs of lithosphere to "slide" down the flanks of the ridge - contributes far less to plate motions than slab pull slab pull: - plate "falling down" at subduction zone pulls mid ocean ridge open after it - cool, dense oceanic crust sinks into the mantle and "pulls" the trailing lithosphere along - major contribution to plate movement trench/slab suction: overlying plate at subduction zone is pulled towards subducting plate, causing spreading further away from the trench subduction is some combination of these factors

oceanic crust

created at: mid-ocean ridges composition: - basalt (top) - gabbro (bottom, buried) ophiolites: bits of oceanic crust that get thrusted up onto continents moho: boundary within the lithosphere between ultramafic mantle and mafic crust youngest crust is near the spreading centers

earth's compositional layers (chemical)

crust: - aluminum silicates - oxygen, silicon, aluminum - some sodium and potassium - formation rates vary by ridge (1.8-15cm per year) - atlantic is very slow: ~2.5 cm/yr - pacific is very fast: up to 16 cm/yr continental crust: - 10-70km - less dense, thicker, rides high - rocks are older and lighter oceanic crust: - 5-7km - more iron, magnesium - denser, thinner, rides low - rocks are younger and denser mantle: - ferromagnesian silicates - iron, magnesium, silicon - dominate rock type in the uppermost mantle is peridotite core: - 3500km - iron, nickel - inner core mostly iron

chemical rocks: evaporites

crystalline limestone: - crystallization of calcite - nonclastic: fine to coarse crystalline - produced in warm, shallow seas rock gypsum: - crystallization of gypsum (68%) - nonclastic: fine to coarse crystalline - parent rock: calcium ions come from pyroxene, amphibole, & calcium-rich feldspar in intermediate & mafic rocks - sulfates produced from sulfur released from volcanoes (or burning coal) into the atmosphere rock salt: - crystallization of halite (88%) - nonclastic: fine to coarse crystalline water evaporates (causes dissolved ions to link up and form rocks) ion-rich water evaporates and ions concentrate/link up requires a warm, evaporating environment - desert & ocean maintains all the properties of the mineral component

lithification: cementation

crystals or other materials precipitate around grains and lock them together lithifies sand and gravel ions from water latch onto the side of mineral grains common cements: - quartz or microcrystalline silica (makes hard rocks - chert) - hematite (makes the rock red) - calcite (makes the rock react with acid) chemical sediment may also precipitate as a chemical sedimentary rock - pure cement (calcite rock)

earthquake hazards

damage to buildings damages to roads & bridges damage to utilities fire

soil horizon: horizon O*

dark humus/organic rich layer at the top of the profile first place organic matter lands (ex. leaves) critical for bringing nutrients to plants enhances moisture retention (absorption rates) few centimeters thick teeming with microscopic life (bacteria, fungi, algae, and insects) O for organic

foliated rocks: amphibolite

dark rock primarily composed of hornblende (amphibole) and plagioclase elongated minerals get rearranged slightly foliated texture (elongate amphibole) intermediate-high grade metamorphism of basalt/gabbro

sources of heat

deep burial: brings rocks closer to heat lava: brings heat to the surface magma: intrudes into surrounding rocks (heats country rock) subduction: moves cold ocean slabs to hot areas (water induced melting) friction: meteorites (quick transfer of kinetic to thermal energy) or convergence (boundaries and fault planes)

incised meanders

deep meandering canyon cut into bedrock by a stream or river after a rapid base level drop stream cannot erode laterally and occupies the entire width of the canyon floor river sediment cuts into deposits and later into bedrock

continental rise

deep water gentler slope that builds up as material is dumped down the continental slope and deposited on the oceanic crust "alluvial fan of the ocean"

continental slope

deep water steeply inclined part of the margin (erosive area) cross-cut by trenches and canyons submarine canyon: steep-walled canyon that starts on the continental slope but carves back into the continental shelf

anhydrite

dehydrated gypsum drywall

composition sorting

dense iron-based minerals/rocks fall out of transportation unstable minerals continue to weather away until only quartz is left after very long transport different minerals have different densities: - high = fall out fast (dense) - low = weather out (turn into clays)

specific gravity (physical property)

density heavier or lighter than you expected for its size most common minerals have a specific gravity between 2 and 4 galena (7.5): extremely dense magnetite & pyrite: pretty dense (iron-based)

deposition along shorelines

deposition concentrated in inlets and bays transport & deposition caused by: - longshore currents - tides - rip currents (in deeper water) mostly quartz sand

metamorphic grades

describe the extent of alteration and reflects increasing heat & pressure classifies how intensely metamorphic something is high grade: - high temperature & high pressure - masses may be deformed (by folding) low grade: - low temperature & low pressure - shale becomes the more compact metamorphic rock slate - transition is gradual and change is subtle

biostratigraphy

determining the relative age of a section using the superposition of fossils correlation of ages (using fossils to read relative ages of rocks) correlating (finding matching time intervals) separate sections with similar fossil assemblages

alluvium

detrital sediment transported and deposited by running water found in: - braided rivers - meandering rivers

volcanoes in space

different materials can be volcanic: sulfur & water olympus mons: largest shield volcano in the solar system moon, venus, mars, io, enceladus

metamorphic index minerals

different minerals form under different grades can be used to interpret the metamorphic grade of the rock in which it occurs used to distinguish different zones of regional metamorphism chlorite (1st): low-grade muscovite: low/intermediate-grade biotite: intermediate-grade garnet: intermediate/high-grade staurolite: intermediate/high-grade) sillimanite: high-grade

intermediate igneous rocks

diorite, andesite, scoria plagioclase feldspar & amphibole: - some pyroxene and biotite gray or salt & pepper (even composition of each) andesite (extrusive): - aphanitic or porphyritic - andes mountains diorite (intrusive): - phaneritic or pegmatitic - plagioclase feldspar and amphibole - intrusive equivalent of andesite scoria (extrusive): - vesicular - product of basaltic magma occur in: - ocean-continent subduction zones (andes) - newly forming continental divergent zones (scoria) source material: - melted mantle + felsic/continental material (magma) via partial melting - granite, sandstone, shale, gneiss (silica-rich rocks) weathering products: - sand/gravel (feldspar and amphibole) - clays (from silicate hydrolysis, abundant) - ions (potassium, sodium, aluminum, calcium, magnesium, and iron: abundant) ions + clays: form chemical sedimentary rocks metamorphic alterations: - gneiss (rarely schist)

dip & strike

dip: - the angle into the earth the beds are oriented - steepest direction down the slope dip angle: - angle between horizontal and the surface - 0° = horizontal - 90° = vertical strike: compass direction made by a horizontal line drawn on the bed anticline (dips to the outside) syncline (dips to the middle)

sediment transport

dissolved load: ions produced by chemical weathering at the source, in transport, and from the river-bank suspended load: (fast) fine particles floating in the water and always in active transport (mostly mud and silt, sometimes sand) bed load: (slow) acquired from a stream's bed and bank where soluble rock are present (limestones) solid load: - creates mechanical weathering opportunities abrasion: transport sediment impacts and abrades the underlying bedrock potholes: circular to oval depression formed where swirling currents with sand and gravel eroded the rock

syncline (fold)

downward bend middle is sinking - oldest rock (outside) - youngest rock (center) old ➤ young ➤ old

overturned fold

ductile material under high stress - lost of strain (warped/bent all the way over) axial plane: horizontal (pushed over) old rock/sediment on top of young rock/sediment ductile folding over a long period of time

monocline

ductile sediment on brittle bedrock - ductile: sedimentary rocks - brittle: igneous and metamorphic rocks sediment draped over brittle/faulted basement rock 1 area inclined between 2 flat layers folded sedimentary layers over a normally faulted basement faulted brittle bedrock: sediment pulled down (ductile & folds) hanging wall falls: sedimentary layer is pulled down (not break)

effects of weathering

dull surfaces & loss of features color changes structural disintegration (rocks break up - chemical) weathering rinds (product of weathering) spheroidal weathering (rounding)

flows

during movement: material flows as a viscous (thick) fluid or with plastic movement start as falls, slumps, or slides and become flows as rocks or sediments break up down slope

bowen's reaction series*

each mineral melts or crystallizes in a specific order - except plagioclase feldspar olivine: - ultramafic - last to melt - first to crystallize pyroxene (augite): - mafic amphibole (hornblende): - intermediate - mafic biotite mica: - intermediate plagioclase feldspar: - variable - white with striations potassium feldspar: - felsic - pink with lamella muscovite mica: - felsic quartz: - felsic - first to melt - last to crystallize ultramafic: green - oceanic crust madic: black - green intermediate: gray (black & white) felsic: white - pink - red - continental crust

plates & plate boundaries

earthquakes outline otherwise calm regions into distinct plates plates are assumed to be rigid with activity only happening on the edges plates: areas of the crust that are rigid with plate tectonics activity 7 major lithospheric plates: - north american - south american - pacific (largest) - african - eurasian - australian-indian - antarctic some are mostly continental (some are all oceanic) the amount of oceanic crust affixed to each plate changes through time (continents are relatively stable)

oceanic ridges

elevated centers of seafloor spreading where young basaltic oceanic crust appears mid-ocean ridges

drumlin (glacial deposit - till)

elongated hills of till reshaped by a moving continental glacier glacier moves over an irregularity in bedrock: - deposits material as it picks it up - retreat = drops material in a mounded shape

seismic waves

energy moving through earth - help track earthquakes and where they happened - help understand the interior of the Earth

erosion

erosion: movement of sediment away from the source area requires external forces: - wind - rainwater - water flow (stream/river) - ice (glacier) - gravity increases rates: - more exposure to the elements - faster flow (wind or water) - steeper slopes

stream terrace

erosional remnant of a floodplain that formed when the stream was flowing at a higher level after a relative base level drop occurs due to base level drop or regional uplift river carves out different levels - leaves cliff of floodplain deposits around new river channel uplifted river and building up of floodplains

continental deposition: deserts

experience temperature extremes (hot or cold) 2 primary desert environments: - sand dunes (dune deposition) - interdune playas (flat areas between dunes or other places in the desert) ephemeral lakes: - forms after a flood event - dry out fast - mud cracks and evaporates (rock salt) characteristics: - well sorted, rounded (quartz) sandstone - scarce fossils - cross-bedded/ripples - mudstone & claystone - mud cracks

milankovitch cycles

explains ice ages theory: earth's rotation, axial tilt, and orbit all vary slightly over thousands of years, altering how much solar radiation earth gets 1. orbital eccentricity: earth's orbit varies from nearly circular to strongly elliptical in ~100,000 year cycles 2. change in obliquity: change in axial tilt in ~41,000 year cycles 3. precession: change in orientation of the earth's axis in ~26,000 year cycles

fjord (valley glacier landform)

extensions of the sea flooding below-sea level glacial valleys carved down to the ocean (flooded)

tensional stress

external forces act in opposite directions stretching the material brittle deformation divergent boundaries

compressional stress

external forces are directed towards each other squeezing the material convergent boundaries: - uplift & mountain building - folding and warping tectonics: mountain belts (thrust faults) examples: himalayas, alp's, andes

metamorphic facies*

facies: groupings of metamorphic rock based on a prescribed range of pressure & temperature conditions each facies is named after a characteristic mineral eclogite: moderate temperature + high pressure blueschist (subduction zones): low temperature + high pressure granulite: high temperature + moderate pressure hornfels (contact metamorphism): high temperature + low pressure different protoliths may produce different metamorphic rocks under the same facies - limestone (amphibolite facies) = calcite - sandstone (amphibolite facies) = garnet the same protolith may produce different metamorphic rocks under different facies - shale (hornfels facies) = slate - shale (amphibolite facies) = garnet porphyroblast: - larger crystal within a finer grained metamorphic groundmass - schists

size sorting

far from source: - very well sorted - beach sand close to source: - very poorly sorted - alluvial fan well sorted: all the grains in a sample of sandstone are about the same size poorly sorted: - contains mixed large and small particles - result when particles are transported for a short time and then rapidly deposited improves with: - distance of transport - energy variation of transport

dome volcano

felsic - intermediate - rhyolite (extrusive felsic) - andesite (extrusive intermediate) produced when thick lava is slowly squeezed from the vent steeper sided version of a shield volcano small felsic lava flows are thicker and pile up more "plug" vents inside larger volcanoes forms mountains Collapsing lava domes produce powerful pyroclastic flows

shear stress

forces are in opposite directions and different planes twisting the material transform boundaries

igneous compositions

felsic: white/pink/red - light-colored silicates - solidifies to form granite (granitic composition) intermediate: gray - contains at least 25% dark silicate minerals - solidifies to form andesite (andesitic composition) mafic: black - dark-colored silicates - solidifies to form basalt (basaltic composition) ultramafic: green - contains olivine and pyroxene - main constituent of the upper mantle

magma migration: void filling

fills rifts, cracks, and fissures magma moves into cracks and fills voids divergent boundaries

magma migration: forceful injection

fills thin sheets (sheets/dikes) pressurized magma pushes itself into cracks and weak points causes major uplift of overriding strata (laccoliths)

varves (glacial deposit - stratified drift)

finely laminated, alternating light and dark mud deposits in glacial lakes heavy (wet) summer runoff: light layer (silt and clay) sluggish (cold) winter runoff: dark layer (clay + organic matter)

locating earthquakes

first S-wave will come at some interval after the first P-wave length of that interval depends on travel distance finding the interval time will give the distance from the seismograph to the earthquake's epicenter but not the direction triangulation

cleavage (physical property)

flat planes made by a mineral breaking tendency of a mineral to break (cleave) along planes of weak bonding notable: micas (one direction - cleaves to form thin, flat sheets) described by the number of planes and angles between them lots of surfaces all in the same direction count as 1 plane cleavage (breakage pattern) vs. crystal form (growth shape) breaks weak ionic bonds and leaves covalent characterized in terms of: - quality: excellent (micas), poor, good - direction - angle of intersection stair steps = cleavage

ductile (plastic) strain

flow "plastically" when stress is applied resultant strain is irreversible will fold and stretch significantly without breaking - upright folds - plunging folds - anticlines (compression) - synclines (compression) - overturned folds (compression) - monocline (tension) - domes - basins

channel flow (running water)

flow confined to depressions (channels) picks up water along the way (turns into rivers) receive water from: - sheet flows - soil moisture - groundwater - rain or snow falls

texture: foliated vs nonfoliated

foliated: - rock has notable foliation/banding (layers) - results from differential pressure (one direction) - pressed elongated (platy) minerals into orientation - schist nonfoliated: - rock lacks foliation/banding - results from confining or lithospheric pressure (or compositional homogeneity of spherical grains) - quartzite

triggering mechanisms

forces that disturb the slope's equilibrium water: over-saturation from winter snow melt or heavy rainstorm earthquakes: ground shaking

valleys

form and develop in response to erosion by running water and mass wasting downcutting: deepening of the valley young: straight and cuts down into (uplifted) rock mature: evens and smooths our gradient old: carves out laterally (forms streams and valleys)

accretionary prism/wedge

form due to the scraping of material (loose debris and well-consolidated rock) off the subducting oceanic crust onto the overriding oceanic or continental crust much of the wedge may be under the overriding plate

shield volcano

form on oceanic crust - begin on the ocean floor as seamounts hawaiian Islands - mauna loa: earth's largest shield volcano - kilauea: hawaii's most active volcano low, broad, and round very runny basalt flows (mafic) - mostly lava flows - very little ejection besides lava accumulation of fluid basaltic lavas hotspots forms mountains

column (cave deposit)

form when a stalactite meets a stalagmite

law of faunal succession

fossil species appear and disappear in a set order throughout history index fossil: a fossil group that is geographically widespread and exists in a narrow time window (used to date the rocks) faunal succession predates the theory of evolution & does not require evolution to be true to work basis of the geologic time scale

faults (brittle strain)

fractures across which the rock has moved evidence of brittle strain/breakage footwall: the rock surface immediately below a fault hanging wall: the rock surface immediately above a fault fault scarp: a cliff created by movement along a fault if a sequence of rock repeats itself (older rocks on top of younger rocks), you can infer a fault is present

water on earth

fresh water is used for: - agriculture - industry - domestic usage - recreation 8% of all electricity is hydroelectric where: - 97% of water is in the oceans - 2% frozen in glaciers on land - 1% in atmosphere, groundwater, lakes, swamp, bogs, stream and river channels running water: - surface of water that moves from higher to lower areas - sheet flow - channel flow

fault metamorphism

friction on fault zones (heat and pressure) loosely coherent rock (fault breccia) composed of broken and crushed rock fragments forms thin layers of metamorphic minerals

magma migration: assimilation

full melt of surrounding material country rock heated to melting point: - surrounding rock becomes part of magma (incorporated in which increases the rate of partial melting) promotes composition change through partial melting melting causes heat loss, advancing fractional crystallization plutons and batholiths

polar wander

further evidence for continental drift came when a pole-wandering path was constructed for north america paths for north america and europe were found to be similar in direction but separated by 5000km explanation for the curves: north america and europe were joined until the mesozoic (when the atlantic began to open) when north america and europe are moved back to their pre-drift positions, the paths of polar wandering coincide

nonoliated rocks: quartzite

fused grains from quartz sandstone very hard (scratches glass) & hard to break due to fused quartz crystals waxy and flecked appearance from where it has been struck moderate- to high-grade metamorphism sedimentary features (cross-bedding) are preserved and creates a banded appearance iron oxide may produce reddish or pinkish stains

mafic igneous rocks

gabbro & basalt gabbro (intrusive): - phaneritic or pegmatitic - significant percentage of oceanic crust basalt (extrusive): - aphanitic or porphyritic - most common extrusive igneous rock pyroxene, plagioclase, and olivine: - some amphibole dark & crystalline (shiny) occur in: - lower oceanic crust (gabbro) - upper oceanic crust (basalt) - oceanic hotspots - ocean-ocean subduction zones source material: - melted mantle + oceanic crust - basalt and gabbro (as well as serpentinite & mafic metamorphic rocks) weathering products: - sand/gravel: minor component (plagioclase feldspar & amphibole; locally olivine & pyroxene) - clays (from silicate hydrolysis, abundant) - ions (magnesium, iron, some calcium: abundant) sand/gravel: little amount because mafic minerals are unstable and don't stick around as physical particles metamorphic alterations: - schist and some gneiss

controls on tidal height

gentle slope: - floods a broad area - slow - spreads out - shallow broad, gently sloping areas have smaller vertical tidal fluctuations but land area changes drastically steep slope: - deep - fast - floods narrowly steep shorelines have greater vertical rise/fall of tides but little effect on land area

ice ages

geologic intervals during which thick ice sheets cover large areas of land current: quaternary ice age each ice age has cycles of glacial periods during which ice is more extensive and interglacial periods during which ice retreats result from: - plate tectonic activity - changes in atmospheric and oceanic circulation patterns

glacial deposits

glacial drift: sediment from glacial ice (till) and meltwater streams (outwash, stratified drift) till: unsorted by particle size and density, no stratification (random) stratified drift: stratified & size/compositionally sorted

isostasy

glaciers cause the land to sink due to their weight when glaciers melt, the weight decreases and the land rebounds mountains: - height = deeper roots - roots keep mountains elevated after mountain building and weathering/erosion take place

glacial erosion & transport

glaciers erode, transport, and deposit huge quantities of sediment and soil glacial ice moving over bedrock: - weathers by abrasion - erodes by plucking glacial polish: smooth surface that glistens in reflected light glacial striations: straight scratches few mm deep on rock surface

scientific method

goal: disprove that which is wrong, not prove what we think is right 1. make an abundance of observations 2. ask a question 3. make a falsifiable/testable hypothesis (falsifiable: could be proven false) 4. conduct an experiment / test whether predictions are reliable 5. analyse results 6. reject / reformulate hypothesis or test more of the hypothesis' predictions 7. after the hypothesis has been tested repeatedly, it can be considered a theory

felsic igneous rocks

granite, rhyolite, obsidian, and pumice quartz & potassium feldspar: - some muscovite, biotite, amphibole & plagioclase feldspar white, light gray, or pink granite (intrusive): - phaneritic or pegmatitic - quartz, potassium feldspar, some biotite, amphibole, and muscovite - abundant in the continental crust rhyolite (extrusive): - aphanitic or porphyritic - light-colored silicates - contains glass fragments and voids (cooled rapidly at the surface) obsidian (extrusive): - volcanic glass - glassy - felsic (dark color caused by impurities) - high silica content - conchoidal fracture pumice (extrusive): - glassy vesicular rock with granitic composition - floats in water - granitic composition occur in: - continental hotspots - continental convergence (intrusive only) source material: - melted felsic/continental material (magma) via partial melting - granite, sandstone, shale, gneiss (silica-rich rocks) weathering products: - sand/gravel (quartz and feldspar) - clays (from silicate hydrolysis of micas and feldspar) - ions (potassium, sodium - rock aalt, aluminum) ions + clays: deposited in the ocean (shale) metamorphic alterations: - gneiss (rarely schist) - burial + pressure (continental convergence)

earth's formation 4) planets form

gravity causes space debris to clump up clumps smash into each other forming even bigger clumps until there are planets (some protoplanets got smashed and/or merged in the process) left as the dust settled: - the Sun - 8 Planets (4 inner rocky & 4 outer gassy) - dwarf Planets (like Pluto) - >101 moons/natural satellites (most around outer planets) - asteroids - comets and meteorites

nonoliated rocks: serpentine (greenstone)

green/dark colored from chlorite, epidote, and amphibole product of mafic rocks low grade metamorphism

sulfur

gun powder matches health spas skin treatments

crust differentiation: oceanic vs continental plates

hadean-archaean transition: ~4Ga (4 billion years ago) continental crust: - granitic - old (3.9-2 ga) - very difficult to destroy - thick (10-70km) - low density (granite, 2.7g/cm3) - silica, potassium, and sodium - forms the core (craton) of continents with thick units of newer rocks surrounding it - roots (average 30km and mountain belts reach 60km) oceanic crust: - basaltic - young-ish (up to jurassic, 200 ma) - getting destroyed all the time - thin (5-10km) - thinnest at mid-ocean ridges - high density (basalt, 2.9g/cm3) - iron & magnesium - forms the bottom the oceans with a thin covering of younger rock on top of it

hardness (physical property)

hard things can scratch soft things most useful diagnostic property mohs scale - relative only - based on strength & arrangement of bonds - more ionic bonds = softer (weak bonds) - more covalent bonds = harder (strong bonds) talc, 1 gypsum, 2 *fingernail: 2.5 calcite, 3 *copper penny: 3.5 fluorite, 4 *wire nail, 4.5 apatite, 5 *piece of glass: 5.5 orthoclase feldspar, 6 *streak plate, 6.5 quartz, 7 topaz, 8 corundum, 9 diamond, 10 fingernail: 2.5 copper penny: 3.5 piece of glass: 5.5 two (talc, 1) girls (gypsum, 2) coming (calcite, 3) from (fluorite, 4) alaska (apatite, 5) on (orthoclase feldspar, 6) quick (quartz, 7) trains (topaz, 8) carrying (corundum, 9) diamonds (diamond, 10)

diamond

harder tools high pressure experiments

seafloor spreading

harry hess, 1960s: new oceanic crust is produced at the crests of mid-ocean ridges (sites of divergence) new magma pushes up from the mantle at mid-ocean ridges, creating new crust as new crust is created the old crust spreads apart explains: - earthquakes (grinding movement) - valleys between ridges - new crust in the middle of ridges - magnetic reversals (flipped polarity has symmetry)

metamorphism: magmatic & lava heat

heat: - most important driving factor of metamorphism - provides energy needed to produce the chemical reactions that result in the recrystallization of existing minerals heat is highest close to the magma chamber and decreases with distance further from heat = less metamorphism (less heat) closer to heat = more metamorphism (more heat)

mountain glacier (valley glacier)

high elevation glacier flows downslope through mountain valleys/channels controlled by topography (flows around objects)

shock metamorphism

high pressure and temperature from meteorite impacts (happens quickly) energy of the once rapidly moving meteorite is transformed into heat energy and shock waves that pass through the surrounding rocks

regional metamorphism

high pressures over broad areas at convergent boundaries associated with large-scale mountain building continents come together and compress together sediments and crustal rocks that form the margins of the colliding continents are folded and faulted deep burial of large quantities of rock as one crustal block is thrusted beneath another deeply buried rocks become heated beyond their melting points (producing magma) shale: produces slate, phyllite, schist, and gneiss quartz sandstone: produces quartzite limestone: produced marble

hydrothermal metamorphism

high temperatures and hydrothermal fluids fluids are headed by local heat sources hot, ion-rich water circulates through fractures (pore spaces) in rock swap out ions & undergo chemical reactions with rock enhances the recrystallization of existing minerals common at: - mid-ocean ridges (seawater percolating through the young, hot oceanic crust is heated and chemically reacts with the newly formed basaltic rocks) - sources of heat with fluids greenstone and greenschist

contact (thermal) metamorphism

high temperatures around igneous intrusions occurs in the earth's upper crust (low pressure) when rocks immediately surrounding a molten igneous body are "baked" (high temperature) contact with heat source (lava/magma chamber) aureole: - metamorphosed region surrounding an intrusion - consist of distinct zones of metamorphism close to the magma body, high-temperature minerals form (garnet) further away, low-grade metamorphism minerals form (chlorite)

sea cliffs & wave-cut platforms

high tide aggressively carves out an overhanging area and scours the seafloor at the wave base low tide exposes a beveled, gently sloping surface where high tide didn't erode sea cliffs retreat backward over time

transitional deposition: beaches

high transport energy well sorted sediment (mostly quartz) home to abundant life forms green/black hawaiian beaches: - olivine/pyroxene/basalt weathered from the island's rock - mafic islands and ocean-ocean subduction zones characteristics: - quartz rich sandstones; coquina - calcite cement - shells, bones, etc. - symmetrical ripples (differs from deltas)

turbidity currents

high-density flows of water that carve out the canyons and deposit the material on the continental rise as submarine fans bottom: cold, extra salty, mud- and sediment-rich water graded bedding high-density sediment-rich water moving fast - abrasion & erosion triggered by earthquakes

luster (physical property)

how light reflects/refracts on a surface nonmetallic (descriptions are qualitative and subjective): - dull/earthy - waxy - pearly/satiny - adamantine (transparent & refracts light - fluorite) - resinous (dull shine) - greasy (shiny/oily - graphite) - vitreous/glassy (quartz, halite, calcite) metallic - most are shiny like a metal - some are duller metal looking like horseshoes, rebar, or cast iron *graphite: light weight, nonmetallic mineral that looks very shiny metallic

saltwater incursion (human impact)

human impact on groundwater coastal areas - saltwater contamination drop in level of fresh water - less pressure on salt water (rises and causes contamination) process: - excess pumping - cone of depression in the fresh groundwater - cone of ascension in the saltwater - contamination of the well with saltwater

subsidence (human impact)

human impact on groundwater lowering of the ground surface groundwater helps limit the compaction of sediment - water keeps sediment open and prevents compaction (better aquifer) if poorly consolidated sediment loses its water, it can compact - irreversible (aquifer turns into an aquiclude)

contamination (human impact)

human impact on groundwater pollution & sewage once pollutants get into the groundwater system, they spread wherever groundwater travels - difficult to contain (water is always flowing) sewage: septic tanks slowly release sewage into the ground where it is decomposed by oxidation and microorganisms and filtered by the sediment landfills: rainwater carries dissolved chemicals and other pollutants into groundwater reservoir toxic waste sites: dangerous chemicals buried or pumped underground fracking concerns: fracking could potentially rupture aquicludes (allowing contaminants to seep through)

lowering of the water table (human impact)

human impact on groundwater withdrawing groundwater faster than nature can recharge it pumping > recharge rate

overloading (slopes)

humans may dump or add lots of material to slopes added weight leads to mass wasting (even if angle of repose is constant)

chemical weathering: silicate hydrolysis

hydrolysis (water-losen): chemical reaction with acidic water alters a substance cations (potassium, sodium, aluminum): replaced with hydrogen in acidic water after reacting with carbonic acid breaks down silicates: turns silicates into clay and releases ions

glacier origination

ice: mineral glacial ice: metamorphic rock fresh snow: 20% solid & 80% air glacial ice: 90% solid & 10% air

stalactite (cave deposit)

icicle-shaped structures hanging from cave ceiling as the result of precipitation of dripping water

principle of inclusions

if there are cohesive chunks of rock included in but separate from a unit of rock, the chunks must have formed before the rest of the rock unit indicates which rock is older - inclusion rock formed first

rock cycle

igneous: melting sedimentary: weathering metamorphic: heat & pressure

aquicludes

impermeable rock layers or structures that prevents the movement of ground water shales, igneous and metamorphic rocks

vegetation (slopes)

improves slope stability - absorb water (prevents over saturation) - roots bind sediment in place

earth's spheres

interacting, interdependent components of the earth system biosphere: - all life - primitive life first appeared in the oceans about 4 billion years ago atmosphere: all the gasses from earth's surface until the vacuum of outer space hydrosphere: - all water on and beneath earth's surface - cryosphere: solid, icy parts - includes freshwater found underground, and in streams, lakes, and glaciers geosphere: - the solid, earth from the earth's surface to the planet's center - largest of earth's 4 spheres and extends from surface to the center of the planet

nonoliated rocks: marble

interlocked crystals of calcite from limestone (sometimes dolomite from dolostone) consists of intergrown calcite crystals that lack banding reacts with acid susceptible to chemical weathering fine-grained "sugary" look to coarsely granular

volcanic neck (volcanic plug)

isolated, steep-sided, erosional remnant consisting of lava that once occupied the vent of a volcano

subduction (convergent boundaries)

isostasy: denser plate rides lower in the asthenosphere plates collide: denser plate slips under the less dense one denser plate now has the force of even more material above it (pushing it deeper into the asthenosphere) angle at which oceanic lithosphere subducts depends on its: - age and density (young and buoyant subducting lithosphere results in a low angle of descent) rules: continents don't subduct - both are shortened and thickened (mountains) oceanic crust always subducts below continental older (denser) ocean always slips under younger deep earthquakes: - earthquakes only occur in the lithosphere - as the lithosphere subducts, earthquakes occur at increasing depths - at some depth, the lithosphere is heated enough that earthquakes can no longer occur - very large earthquakes (megathrust) at shallow to intermediate depths

diamond, corundum, beryl, topaz

jewelry

topography

land (continents) elevation of the land's surface 2D representation using contour lines (or a color spectrum)

karst topography

landscape formed from the dissolution of soluble rocks limestone (also dolomite or gypsum) characterized by underground drainage systems with: - sinkholes - solution valleys - caves - springs - disappearing streams

mass movement

large amounts of material is moved downhill at once - aided by weathering - upper layers of sediment - speed ranges from imperceptibly slow to extremely fast happens if: - force of gravity exceeds the friction between the sediment and the layer it's resting on influenced by: - water - earthquakes - over-steepened slopes - removal of vegetation - overloading

physical weathering: thermal expansion & contraction

melted materials expand & cooled materials contract rapid cooling causes fractures differences in temperature between night and day pore water may help accelerate the process

abyssal plain

large, flat area on the sea floor adjacent to a passive continental margin flatter than other oceanic places - old with accumulated "drape" of sediment covering up marine features

glaciers

large, permanent bodies of ice flowing downslope or outward over land covers 10% of earth's surface involved in erosion, sediment transport, and deposition produce distinctive landforms massive freshwater reservoir for hydrologic cycle glaciation: process of glacier origination, expansion (movement), and retreat (shrinkage)

dropstones (glacial deposit - stratified drift)

larger sediment clasts dropped in finer ocean or lake sediment as floating ice melts

sheet flow (running water)

laterally continuous film/sheet of water flowing over the surface not confined to depressions or stream beds (unchannelized) responsible for sheet-like (continuous) erosion notable after high rains (landscapes turn into a river) almost always temporary (period of heavy rainfall)

fissure eruption

lava flows out gently through long cracks in the crust emit fuild basaltic lavas that blanket wide areas mid-ocean ridges (fissure at boundary & flows out) flood basalts (mafic) pyroclastic deposits & ash flows (felsic) basalt plateau: - broad and extensive accumulation of lava from a succession of flows emanating from fissure eruptions flood basalt: - flow of basaltic lava that issues from numerous cracks or fissures and commonly covers extensive areas to thickness of hundreds of meters - deccan plateau

sedimentary structures: cross-bedding

layers form at an angle to the primary bed surface points downward in the direction the sediment was being transported requires wind/water currents in 1 direction (unidirectional) sand dunes, river deltas, and certain stream channel deposits results when sediment does not accumulate in horizontal beds

folds (ductile strain)

layers of rock become warped stay warped after stress is removed (plastic deformation) hinge line (fold axis): - line made along the crest/trough of a fold - where curvature of a fold is greatest limb: sides of a fold on either side of the hinge line axial plane: surface that connects hinge lines you don't always have to see a fold axis directly to infer its existence: - 2 sides dipping in different directions = fold limbs - mirrored areas = fold

continental glacier landforms

leaves a smooth, rounded surface exposed bedrock that is polished or striated numerous lakes/swamps (deranged drainage) little soil buildup (barren landscape)

melt a rock (2) reduce the pressure

less pressure on rocks divergent boundaries: - continental thinning - mid-ocean ridges

ultramafic magma

less than 45% silica (least) mostly olivine mantle

mafic (basaltic) magma

less than 52% silica (least) gas content (least) eruption temperature (highest) low viscosity pyroclastics (few) shield volcanoes, basalt plateaus, cinder cones calcium, iron, magnesium - ferromagnesian (produce heavy, green and/or black rocks) oceanic crust darker in color

felsic (granitic) magma

less than 70% silica (most) gas content (most) eruption temperature (lowest) high viscosity pyroclastics (lots) pyroclastic flow deposits, lava domes rhyolite: extrusive equivalent of granite

soil horizon: horizon E*

lighter colored layer with little organic matter zone of eluviation & leaching eluviation: "washing out" fine particles (clay & silt) leaching: dissolution and removal of "soluble materials (ions and unstable chemicals) water flowing through O and A picks up carbonic acid as it washes downward: making for effective dissolution/hydrolysis in E sand and gravel left E for eluviation

p-wave shadow zone

liquids have 0 rigidity - P-wave velocity drops P-wave shadows suggest the outer core is liquid

s-wave shadow zone

liquids have 0 rigidity - S-waves cannot pass through liquid S-wave shadows suggest the outer core is liquid

earth's mechanical layers (physical)

lithosphere: - 10-200km - strong, rigid solid (breaks) - crust + uppermost mantle - rocks get hotter and weaker with depth - mechanically detached from asthenosphere due to a small about of melting in the upper asthenosphere (able to move independently from the asthenosphere) oceanic lithosphere: - 100km thick in the deep-ocean - thinner along the crest of the oceanic ridge system - composed of basalt (rich iron and magnesium) - older (cooler) is gets, the greater its thickness continental lithosphere: - 150km thick (may extend to depths of 200 kilometers+ beneath the interiors of continents) - composed of less dense granitic rocks asthenosphere: - weak, plastic solid - upper mantle - convection - weak solid mesosphere: - stiffer plastic solid - mantle outer core: - liquid - movement of metallic iron within this zone generates Earth's magnetic field inner core: - solid due to immense pressures in the center of the planet outer + inner core = geodynamo

jetties

longshore drift (coastal engineering) designed to block sediment from filling up a channel keep sediment from entering an area (shipping channel)

groins

longshore drift (coastal engineering) designed to break up longshore drift and keep sediment in place as sediment migrates, groins trap sediment moving in that direction (keeps sediment in place)

carbonate compensation depth

lowermost limit at which calcareous material can be deposited high pressure & low temperatures: dissolves back into the water silica does not dissolve in deep water chert can form deeper than chalk

base level

lowest limit to which a stream can erode - ultimate base level: sea level - local base level: a lake, another stream, a reservoir too flat: - slows down, deposits sediment, and builds up too steep: - water erodes down and makes gullies and channels if the local level changes, the stream will adjust to regain balance - erodes a steeper stream channel - deposits to build the stream channel up

geologic time

ma (my): million years ga: billion years earth: 4.6 billion years old (~4.6ga)

water wells

made by digging or drilling into the zone of saturation may cause a cone of depression: - locally lowers the water table - water level lowered around the well because water withdrawal exceed the rate of water inflow cone of depression steepness depends on the permeability - low permeability steep cone - high permeability gentle gradient cone

chemical sedimentary rocks

made of minerals dissolved in water and precipitated out in a mineral or mineraloid (microcrystalline) form biochemical: chemical sediment that forms when material dissolved in water is precipitates by water-dwelling organisms (shells) types: - evaporites - carbonates - chert

detrital sedimentary rocks

made of solid particles of gravel, sand, silt, or clay/mud lithified through compaction/cementation main constituents: - clay minerals and quartz - other minerals are feldspars and micas magma produced (by melting): - felsic parent rock: any other rock conglomerate - grain size: gravel - rounded grains - parent rock: anything - metamorphic: metaconglomerate breccia - grain size: gravel - angular grains - parent rock: anything - metamorphic: metaconglomerate quartz sandstone - grain size: sand - mostly quartz - parent rock: granite, gneiss, quartzite - metamorphic: quartzite arkosic sandstone - grain size: sand - mostly feldspar - parent rock: granite, gneiss, diorite - metamorphic: schist/gneiss siltstone - grain size: mud/silt - breaks into blocks claystone - grain size: silt/mud/clay - crumbles and breaks into blocks shale - grain size: silt/mud/clay - fissile (splits easily) - parent rock: clays of silicates (any silicate except quartz) - metamorphic: slate, phyllite, schist, gneiss fissile: describes a rock that splits into well developed closely spaced planes

lava

magma that reaches earth's surface (exposed to air)

variably occurring mineral properties

magnetism - magnetite (can be picked up with a magnet) acid reactivity - carbonates (calcite & dolomite) lamellae - potassium feldspar - inside minerals striations - plagioclase & pyrite - physical grooves taste - halite (salty) smell - sulfur (rotten eggs) twinning - habit feel - graphite (greasy) - talc (soapy) elasticity flexibility - muscovite malleability - copper fluorescence - fluorite, halite (some), apatite

hematite & magnetite

magnets iron (ore) hematite jewelry

mantle plumes and hot spots

mantle plume: - a mass of hotter-than- typical mantle material that ascends toward the surface - surface manifestation of this activity is a hot spot hot spot: - concentration of heat in the mantle, capable of producing magma that extrudes onto Earth's surface - hawaiian islands

rockslides (type of mass movement)

material: rock motion: slide/fall velocity: moderate movement of internally in-tact blocks on a nearly planar slope triggered by water pressure between the block and slope common with thinly bedded rocks (slate and shale)

rockfalls (type of mass movement)

material: rock motion: slide/fall velocity: fast rocks fall through the air - extremely rapid result from physical cracks/dissolution seams breaking the rock into blocks - joints, bedding planes, frost wedging, carbonate dissolution triggered by natural or human undercutting of slopes or earthquake

debris flow (type of mass movement)

material: unconsolidated sediment motion: flow velocity: moderate bits of rocks move independently to each other triggers: - little bit of water and earthquakes - steep slopes

mudflow (type of mass movement)

material: unconsolidated sediment motion: flow velocity: moderate most fluid and the fastest type of movement silt and clay sized (fine) material and water common in: - arid and semiarid environments - mountain regions - areas covered by volcanic ash

creep (type of mass movement)

material: unconsolidated sediment motion: flow velocity: very slow - tilted objects and/or trees - rocks bend and warp (slow application of force)

slumps (type of mass movement)

material: unconsolidated sediment motion: slide/fall velocity: slow to moderate movement on curved slope scarp: steep cutoff place at the top

ductile (plastic) solids

materials that bend and flow for any given stress, strain is: - slow (take time to respond) - increases with time as long as stress is being applied - non-recoverable (remove stress ➤ no bounce back)

elastic/brittle solids

materials that stretch until they snap for any given stress, strain is: - finite (can only go so far with a given force) - instantaneous (moves quickly as force is applied) - reversible (remove force ➤ bounce back) if stressed past its elastic limit, a brittle solid will break elastic behavior: more force = more stretch

drainage systems

may take different shapes depending on the: - topography - sediment to water ratio - underlying rock

velocity (channel flow)

measure of distance traveled per unit of time (m/sec) water drags on the channel's sides and bottom (friction) velocity is greatest in the upper center (only flowing against water) shape of river channel controls how fast water moves - smooth, semicircular channels have the fastest flow more surface area = more drag = slower a smooth channel has less drag (faster) average flow velocity increases downstream - rough upper part of the channel (high drag) - Smooth semicircular downstream segment (low drag) number of smaller stream joining the main stream increases downstream

migmatite: a "mixed rock"

melted felsic minerals + metamorphosed mafic minerals temperature high enough to melt felsic minerals bands of granite & gneiss, amphibolite, or other mafic metamorphic rock

convergent boundary (ocean-continent)

melting is triggered within the wedge of hot asthenosphere that lies above it "wet" rock in a high-pressure environment melts at substantially lower temperatures than does "dry" rock of the same composition 1. ocean plate subducts - old oceanic lithosphere is more dense than the underlying asthenosphere, causing it to sink 2. ocean trench - produced where oceanic lithosphere bends as it descends into the mantle along subduction zones 3. continental volcanic arc - mountains formed in part by igneous activity associated with the subduction of oceanic lithosphere beneath a continent (andes)

muscovite

member of the mica family breaks into single planes (excellent cleavage) glitter window glass (replaced by quartz)

oxides (mineral class)

metal + O (oxygen) ionic bonds Fe2O3 (hematite)

sulfides (mineral class)

metal or H (hydrogen) + S2- ionic bonds PbS (galena)

metallic bonds

metallic elements can pack together as cations, sharing electrons freely among themselves free electron sharing bond that holds them together results from each atom contributing its valence electrons to a common pool of electrons that move freely throughout the entire metallic structure gives electrical/thermal properties to metallic minerals (conductors) iron, gold, silver, etc.

foliated rocks: gneiss

metamorphosed rock with gneissic banding gneissic banding: alternating bands of light (felsic) and dark (mafic) minerals many different parent rocks possible (shale, granite, and diorite) high-grade metamorphic rock

foliated rocks: schist

metamorphosed rock with schistose foliation schistose foliation: texture with more than 50% elongated/platy minerals (visible micas) schistosity: - type of foliation that is characteristic in coarser-grained metamorphic rocks - platy minerals and deformed quartz and feldspar crystals appear flattened or lens shapes many different parent rocks possible (shale - common) subcategorized by primary mineralogy - chlorite schist - biotite schist - garnet schist (garnet) porphyroblasts intermediate grade metamorphism

foliated rocks: phyllite

metamorphosed shale with glossy/lustrous sheen but no visible minerals phyllitic cleavage: coarser than slate splits into layers (shiny wrinkled/wavy surface) low grade metamorphism: grades into slate and schist green = chlorite

foliated rocks: slate

metamorphosed shale with slatey cleavage slaty cleavage: - fine-grained (not visible) texture that breaks on flat surfaces - parallel arrangement of fine-grained metamorphic minerals excellent rock cleavage (tendency to break into flat slabs) lowest grade metamorphism - least metamorphosed foliated rock well consolidated & feels harder than shale (also brittle) chalkboards & roofing tiles

tenacity (physical property)

minerals resistance to breaking, bending, cutting, or other forms of deformation nonmetallic minerals (quartz) and minerals that are ionically bonded (fluorite & halite) tend to be brittle and fracture or exhibit cleavage when struck malleable: native metals (copper and gold) can be hammered without breaking sectile: minerals that can be cut into thin shavings (gypsum & talc) micas: elastic and bend and snap back to their original shape after stress is released

silicate weathering resistance

minerals with the lowest crystallization/melting temperatures are the most stable at the surface olivine: least stable & lease resistant quartz: most stable & most resistant decomposed granite: mostly quartz and feldspar

oceanic ridge offsets

mini transform boundaries break the mid-ocean ridges into segments fault scarps that are buried by sediment over time

monthly tide fluctuations

moon orbits earth 1 time a month - monthly cycle of the combined effect of the moon's and sun's gravitational fields each month has: - 2 spring tides - 2 neap tides 1 month: - spring (new moon) - neap (1st quarter) - spring (full moon) - neap (3rd quarter)

metamorphism: pressure

more force = more pressure confining pressure: applied uniformly from all directions lithostatic pressure: pressure exerted on rocks by weight of surrounding rocks (burial pressure) directed pressure (differential stress): - force exerted in a particular direction - associated with tectonic activity (convergent zones)

how soil forms: climate*

most important factor in soil formation long-term average of temperature & precipitation hot, wet climate: produces a thin layer of chemically weathered soil cold, dry climate: produces a thin mantle of mechanically weathered debris tropical: - very thick (large B layer, little topsoil - leaches fast) - more rain = more leaching temperate: - moderately thick (more organic-rich material, topsoil) - slow development of soil desert: very thin (usually no O/A layers and grows slowly) polar: very, very thin (little chemical weathering, slow decomposition of organic matter)

chemical rocks: coal

most organic rock (no minerals, only organic matter) carbon-based organic matter partial decomposition of plant remains in an oxygen-poor swamp: peat parent rock: - n/a (purely organic) leaves & wood settle to the ground in oxygen-deprived bogs heat and pressure decompress the water and break down plant material into purer carbon form lignite coal: some original plant matter (most moisture is driven out) bituminous coal: shiny & industrial grade metamorphic alterations: anthracite

recessional moraine (glacial deposit - till)

mounds made during pauses in the glacier's retreat forms a ridge

orogenesis

mountain building mountain range: linear set of peaks and ridges related in age and origin styles: - block faulting via normal faults (basin and range province) - hot-spot volcanism (hawaii) - compressive plate boundaries compressive plate boundaries: - ocean-ocean island arcs (philippines) - ocean-continent volcanic arcs (andes) - continent-continent uplift (himalayas)

orogeny

mountain building by tectonic forces through the folding and faulting of rock layers major global tectonic events caused by collisions between continents continent-continent thrust faulting

continental deposition: alluvial fans

mountains meets flatland rainfall in the mountains makes high energy drainage channels discharge lots of material hits flat areas at the base and drop out heavy materials due to a loss of energy characteristics: - breccia/conglomerate - poorly sorted (coarse) - graded bedding (lakes) - very thick beds (drops a lot at once) - distally may get arkose

transportation: wind (aeolian)

moves mostly only sand and smaller sediments (silt and clay) little to no chemical sediment is moved sand: - requires less energy to be transported - windblown dunes and river deposits, and beaches

continental deposition: glaciers

moving: form of erosion stopped: melts and forms a deposition environment trap sediment in and around the ice deposition: glacier reaches the extent of its growth and starts to melt, leaving behind a pile of sediment characteristics: - leaves behind breccia - poorly sorted - angular - large, coarse grains

gorges (valley)

narrow and deep canyon water carves out via a fault in the earth

sea arches (shoreline formations)

natural arches formed where two sea caves join across a headland sea cave that was worn out (through the other side)

flooding

natural behavior of a stream flow of a stream becomes so great that it exceeds the capacity of its channel and overflows its banks regional flooding - seasonal and weather related flash flooding - limited in extent than regional floods - occur with little warning and have extreme flow velocity - local flooding ice-jam flooding - as ice melts on a river, it can obstruct the flow - when the ice dam breaks, the release of water can cause considerable damage dam-break flooding - when dams break, the reservoirs behind them break loose, causing significant damage

rock

naturally occurring, solid aggregate of mineral or mineral-like matter aggregates of several different minerals some rocks are composed almost entirely of one mineral (limestone - calcite) some rocks are composed of nonmineral matter - obsidian & pumice (volcanic rock) - coal (solid organic debris)

how soil forms: time*

need to keep soil in place for it to develop rich nutrients and support vegetation is one reason erosion-control projects are important more time = more soil development the longer a soil has been forming, the thicker it becomes and less it resembles parent material as weathering continues, the influence of parent material on soil is overshadowed by other soil-forming factors (climate)

seamounts

never reached the surface (submerged) young volcano or a young volcano that was cut off from its heat source before emerging associated with: - mid-ocean ridges - hot spots

nonfoliated

no discernable preferred orientation in mineral alignment produced by: - contact or hydrothermal metamorphism - regional or burial metamorphism of rocks with no elongate/platy minerals (limestone & sandstone)

deep ocean basins

no light near-freezing temperatures high water pressure

passive margin

no tectonic (lithospheric) plate boundary, just 2 different types of crust

do all volcanic arcs indicate plate boundaries?

no: hotspot arcs form in the middle of a plate as the plate moves and cuts the volcano off from the mantle plume, the plate develops a tail of increasingly younger volcanoes hot-spot track: chain of volcanic structures produced as lithospheric plate moves over a mantle plume (age of each volcano indicates how much time has elapsed since it was situated over the mantle plume)

extensional fractures

not faults rock pulls apart across fracture: - no slip, so not a fault - vertical break then pull apart joints: no detectable displacement/movement (just a break) vein: mineral-filled fracture (quartz, calcite, and ore metals) dikes: magma-filled fracture fissure: air-filled fracture (close to surface)

james hutton

noticed that dirt and rock eroded from his fields and piled up (deposited) in the area below, forming hard layers of new "rock" (pre-lithified-rock) speculated that: - breaks between rock layers indicate a period of erosion and a shift in the earth - all layers of rock must have formed in the same way (erosion ➤ deposition) processes takes a very, very long time

aftershocks

occur after and close to the mainshock adjustments of the crust to the stress changes following the mainshock

where rocks melt - types of magma

ocean-ocean convergent zone: - mafic magma - water driven melting (subduction) - moves through less crust ocean hot spot: - mafic magma (ocean zone) - hawaii ocean-ocean divergent zone: - mafic magma - lithosphere thinning (mid-ocean ridge) - moves through less crust ocean-continent convergent zone: - intermediate magma - mountains (subduction) - moves through more continental crust continent-continent divergent zone: - mafic magma - thin boundary - begins as intermediate

silicate weathering products

olivine → serpentine pyroxene → clay + ions amphibole → clay + ions biotite → clay + ions feldspar → clay + ions muscovite → clay + ions quartz doesn't change (stable)

opacity/transparency (physical property)

opaque: - blocks all light - metallic minerals - pearly, waxy, resinous translucent: - allows some light - waxy, resinous transparent: - allows most light and detail - vitreous

fracture (physical property)

opposite of cleavage: all bonds are equal chemical bonds that are equally (or nearly equally) strong in all directions framework silicate: conchoidal fracture (bowl-shaped & found in silica-based minerals, quartz)

continental growth

original formation of cratons 3ga (billion) - cratons: part of the continental crust that has attained stability continental extension/thinning (nevada) accretion of islands & sediments during subduction magmatic addition: continental volcanic arcs & hotspots exotic terranes broken off during rifting (plymouth rock)

earth's formation 3) solar system forms

our sector of the Milky Way had a star go supernova only supernovas form elements heavier than iron supernova's leftover dust/gas form a spinning cloud (nebula) that collapses into a disk central burning gasses turn into the sun heavy, rocky materials stay in the inner disk light gasses spin off toward the rim

redox weathering

oxidation + reduction oxidation: - removal of one or more electrons from an atom or ion - elements combine with oxygen - important in decomposing ferromagnesian minerals redox reactions: way of altering oxide minerals (both need water + oxygen) oxide = metal + oxygen (rusting process) changes iron-rich minerals (oxides) into different states magnetite → hematite combined with hydrolysis & dissolution: 1. iron is loosened up by hydrolysis 2. mixes with oxygen 3. creates different iron states

chemical rocks: chert

parent rock: any silicate (or siliceous organisms) microscopic crystals of silica has most properties of quartz but is opaque and microcrystalline - scratches glass - conchoidal fracture - hardness of 7 purely chemical or biological based grows as: - nodules/concretions within limestone as silica-rich ground water drops silica into vugs/holes - layers of siliceous ooze formed by phytoplankton (skeleton & shells) subgroups: - flint: reserved for the black version of chert (contains organic matter) - jasper: varieties that are red/brown because of hematite metamorphic alterations: - metachert (not one of our rocks)

soil horizon: horizon C*

partially altered parent material residual regolith & fragments grades downward to unaltered parent material

physical weathering: abrasion (water)

particles caught within water currents grind down whatever they flow past most common weathering factor

porosity

percentage of material's total volume that is pore space good (high) porosity - well-rounded - well-sorted - little cement pore space: space between particles in soil, sediment and sedimentary rock, cracks, fractures, faults, vesicles in volcanic rock open space in rock that could be filled with water detrital sedimentary rock: - well-sorted, well rounded (high porosity) - poorly sorted (low porosity) - well-sorted porous pebble (high porosity) - well sorted, but cemented (low porosity) massive sedimentary rock: - soluble rock (limestone) - low porosity increased by solution (weathering creates open spaces for more groundwater) metamorphic and igneous rock: - low porosity increased by fracturing (creates open spaces)

ultramafic igneous rocks

peridotite (intrusive): - phaneritic olivine - some pyroxene - little plagioclase feldspar usually green with black occurs in: - upper-most mantle (oceanic crust) source material: - mantle weathering products: - sand/gravel: minor component (olivine breaks down very easily) - clays (from silicate hydrolysis) - ions: most important component (magnesium and iron) metamorphic alterations: - serpentinite

aquifers

permeable layer transporting groundwater deposits of well-sorted, well-rounded sand and gravel limestones with fractures and bedding planes enlarged by solution

end moraine (glacial deposit - till)

pile or ridge of rubble deposited at the terminus (end) of a stationary glacier angular, unsorted rubble (till) valley glaciers: crescent shaped continental glacier: laterally extensive along the ice front

sea stacks (shoreline formations)

pillars left after sea arches collapse

deposition environment

place where deposition happens each has a characteristic set of biological (fossils), physical and chemical conditions (type of rock/sea structure) continental/terrestrial (on land): - dominated by clastic sedimentary rocks, largely because of their proximity to the source of the sediments - lakes - deserts - alluvial fans - glaciers - streams transitional (coastal): - anywhere that is directly affected by or periodically covered by marine waters - deltas - beaches - tidal flats - barrier islands - lagoons marine: - places permanently covered by ocean waters - continental shelf - continental slope - deep marine environments with no deposition: - mountains - tops of glaciers low energy = silt & clay high energy = gravel & sand rivers = cross-bedding beaches = symmetrical ripples dunes = cross-bedding

springs

place where groundwater flows or seeps out of the ground when percolating water reaches the water table or an impermeable layer: - it flows laterally

how soil forms: organic activity & organisms*

plants: - control how much organic matter accumulates - alter soil acidity/other chemistry - trees help promote more soil formation - help keep soil in place to build upwards (erosion control) bugs & fungi: - break down organic matter (into nutrients) - contribute to the organic matter - help aerate soil and redistribute nutrients good ecosystem = good soil

glacier movements

plastic flow: - ice flows and deforms without cracking - creeps downhill (ductile/plastic movement) - thick, viscous, very slow, rolls over self - polar environments basal slip: - ice slides over underlying surfaces - melt water at the base reduces friction (slides forward) - valley glaciers crevasse/fissure vs other faults depends on underlying topography upper: brittle flow lower: ductile flow

convergent boundaries

plates are colliding towards each other destructive margin: crust is destroyed trenches, mountains, arcs ocean-continent - ocean plate subducts - ocean trench - continental volcanic arc (created on a continental plate) ocean-ocean: - older plate subducts - deep ocean trench - oceanic island arc (volcanic island arc, created on a ocean plate) continent-continent: - no subduction - mountain building subduction: - old crust is recycled back into the mantle at subduction zones

divergent boundaries

plates are spreading apart from each other constructive margin: new crust is created upwelling of material from the mantle to create new seafloor ridges & rifts tensional stress = lithospheric thinning (continental or oceanic) and new oceanic crust thinned lithosphere = decompression melting of mantle melting = rising magma, lava flows, and spreading plates

transform boundaries

plates slide past each other without creation or destruction of crust byproduct of convergent and divergent faults acting on a spherical earth shearing tectonics: - side-to-side motion (friction = earthquakes) can be found on the ocean floor where they offset segments of the oceanic ridge system (step pattern) fracture zone: linear zone of irregular topography on the deep-ocean floor that follows transform faults and their inactive extensions most transform fault boundaries are located within the ocean basins (few cut through continent - san andreas fault) aligned parallel to the direction of spreading and measurements of transform faults reveal the direction of plate movement

compressive mountain building (2)

pluton emplacement - continental volcanism mountain building - moves material upwards contact metamorphism ocean-continent subduction

hydrologic (water) cycle

powered by solar radiation evaporation - vaporization of liquid - includes transpiration (evaporation of water from plant leaves) evaporation + transpiration = evapotranspiration condensation - cloud formation precipitation - rain or snow runoff - surface flows in streams and rivers

eons and eras

precambrian (eon, 4.6 billion years ago - beginning) - proterozoic: proto/almost animals - archaean: really old - hadean: early, molten Earth phanerozoic: big/visible animals (eon: 540 million years ago) - paleozoic: old life (era: 540 million years ago) - mesozoic: middle life (era: 250 million years ago) - cenozoic: modern life (era: 65 million years ago)

lithification: compaction

pressing sediment together (burial) drives out water and locks grains together weight of overlying material compresses more deeply buried sediment reduction in pore space (open space between particles) and water that was trapped in the sediments is driven out lithifies clay/mud (fine-grains)

recrystallization

primary process in metamorphism mineral grains break down into larger grains or new types of minerals reorder and rebind into new larger & new grains mineralogy may not change: sandstone (tiny grains) → quartzite (large grains) mineralogy may change: shale (clays) → schist (mica & garnet)

wilson cycle

process by which ocean basins open and close "supercontinent" cycle convergent and divergent plate boundaries combine oceanic crust opens and closes over time bringing continents together and apart 1. rifting within a continent splits the continent... 2. ...leading to the opening of a new ocean basin and creation of new oceanic crust, starting the cycle 3. as seafloor spreading continues and an ocean opens, passive margin cooling occurs and sediment accumulates 4. convergence begins; oceanic crust is subducted beneath a continent, creating a volcanic mountain belt at the active margin 5. terrane accretion (from the sedimentary accretionary wedge carried by the subducting plate) welds material to the continent 6. as continents collide, the crust thickens and builds mountain, forming a new supercontinent 7. the continent erodes, thinning the crust (eventually the process may begin again)

lithification

process of turning sediment into a rock methods: - compaction - cementation

petroleum & natural gas

product of deposited organic material (hydrocarbons) subjected to low-moderate heat & pressure forms easily in the deep ocean where oxygen can't destroy the organic material

tidewater glacier (valley glacier)

reach the ocean where valley glaciers flow downslope into the ocean

natural levee

ridge of sandy alluvium and organic debris deposited along the margins of a channel during a flood after each flood, rivers dump sand as it flows over the side: builds up and limit further flooding

wegener's hypothesis of continental drift *

proposed in 1912 after wegener started noticing the fit of continents suggested that all present continents once existed as a single supercontinent hypothesis: continents have separated slowly over time from a single continent (pangea, "all lands") to their current positions (beginning 200 million years ago) proposed that gravitational forces of the moon and sun that produce earth's tides were also capable of gradually moving the continents across the globe 4 lines of evidence: 1. jigsaw fit of continents - similarity between the coastlines on opposite sides of the Atlantic Ocean 2. distribution of fossils across oceans - mesosaurus (eastern south america and southwestern africa) - glossopteris (africa, australia, india, and south america, and antartica) 3. distribution of equivalent rock units across oceans - igneous rocks in brazil resembled similar rocks of the same age in africa 4. paleoclimate (ancient climate) records - discovery of evidence for a glacial period dating to the late paleozoic era in southern africa, south america, australia, and india (ice sheets form near the equator?) hypothesized mechanism: continents crash through oceanic crust, crumpling it up and pushing it out of the way (incorrectly suggested larger/sturdier continents broke through thinner oceanic crust) rejected: 1. the mechanism was highly implausible 2. gross overestimation of the rate of continental movement supported by arthur holmes (magma convects, dragging crust with it)

distance from the source

proximal: - sediments found close to the source - poor size sorting - angular - poor composition sorting distal: - sediments found far from the source - well size sorting - rounded - well composition sorting

absolute dating

putting a numerical date on the timing of a geological event

relative dating

putting events in order without indication of duration (no dates) sequence of events

melt a rock (1) raise the temperature

raising the temperature without raising the pressure results in melting mantle plumes: transfer heat from the core-mantle boundary hot spots: - heat migrates upwards and melts rocks - formed by plumes - as plates move, hot spots stay in one place leaving trail of older volcanoes - oceanic: hawaii - continental: yellowstone

active margins

reduced continental shelf & slope (no continental rise) - trench - accretionary wedge/prism - volcanoes lots of earthquakes (subduction zone) trenches: - old crust = steep trenches - young crust = narrow trenches

dating rocks & strata

relative dating: - older of the two types based on the sequence of events relative to each other - A is the oldest, B is in the middle, and C is the youngest absolute dating: - assigns quantitative ages to events - A is 2.5 years old and C is 6 months old combine relative dates with absolute dates to give age ranges to each event - B must be between 6 months and 2.5 years

radiometric dating

reliant on isotopes of different elements isotopes: - atoms of the same element with different number of neutrons carbon 12 (common) carbon 13 (1 extra neutron) carbon 14 (starts to decay)

Resources

renewable: a resource that is virtually inexhaustible or can be replenished over short time spans nonrenewable: a resource that forms or accumulates over such long time spans, it must be considered as fixed in total quantity mineral resource: all discovered and undiscovered deposits of a useful mineral that can be extracted now or at some time in the future ore deposit: a useful metallic mineral that can be mined at a profit

ground moraine (glacial deposit - till)

retreating glaciers leave a layer of sediment from the original end moraine backwards pushes sediment forward and piles up at the end moraine

kettle (continental glacier landform)

retreating glaciers leave blocks of ice behind when those blocks melt, they leave depressions

thrust fault (compressional stress)

reverse fault with a shallow-dipping fault plane (low-angle) hanging wall: moves upward compresses land into a small area older above younger

lateral moraine (glacial deposit - till)

ridge of sediment along the glacier's margin parallel, flanking outside (left behind) border of till debris

medial moraine (glacial deposit - till)

ridge of sediment where lateral moraines merged as glaciers came together

atoll

ring-shaped reef surrounding a lagoon on top of a seamount/guyot

transportation: water

rivers and waves the faster the flow, the bigger the pieces transported primary method of moving sediment gravels: moved by swiftly flowing rivers, landslides, and glaciers sand: - requires less energy to be transported - windblown dunes and river deposits, and beaches clay: - requires very little energy to be transported - settles very slowly (accumulations are associated quiet waters of lakes, lagoons, swamps, or marine environments) dissolved load: sodium & calcium suspended load: floating (silt/clay) bedload: larger materials saltation: bouncing traction: rolling

transitional deposition: deltas

rivers meet oceans unidirectional currents subcategories: - sands close to the river mouth (deposited 1st) - silts (deposited 2nd) - clays that are the lightest weight and float into ocean (deposited 3rd) characteristics: - quartz-rich sandstones, siltstones, and shales - well sorted and rounded - calcite cement (calcium carbonates) - organic rich = black clays - plant matter, shells, and vertebrate fossils

physical weathering: exhumation & unloading

rock is stable under confining pressure, but as soon as it has room to expand, it does exhumation (unbury) exfoliation: - sheets of rock break off - rocks swell under pressure (outer layers peel back) -parallel to the surface jointing: - cracks and fissures go down into the rock (rocks swell under pressure) - perpendicular to the surface - allows water to penetrate to depth and start the process of weathering long before the rock is exposed sheeting: mechanical weathering process that is characterized by the splitting off of slab-like sheets of rock exfoliation dome: large, dome-shaped structure (usually composed of granite) that is formed by sheeting

physical weathering: abrasion (glaciers & ice)

rocks caught at the base of a glacier scour striations into underlying rock

turning magma into rock

rocks formed directly from magma (inside earth): - intrusive (plutonic) - slow cooling rocks formed directly from lava (outside earth): - extrusive - fast cooling type of rock formed depends on: - magma's composition - speed of cooling (controls crystal size - texture)

metamorphic rocks

rocks formed from chemical/physical alteration of pre-existing rocks, caused by heat (without melting), pressure, and/or ion-rich fluids rocks may look similar to their parent rock (protolith), or they may have an entirely new appearance - similar (quartz sandstone to quartzite) - different (shale to blueschist) most of the crust is metamorphic: - continents: gneiss - oceans: schists produce economically important minerals and building materials requirements: - heat - pressure - chemically active fluids - time identified by: - composition & texture

igneous rocks

rocks produced from melted rocks that originated within the earth and solidify through cooling/crystallizing key: -melting & crystallization

biological weathering

root wedging (physical) lichen (physical) humic acid (chemical): - organic material decomposes and produce acids that contribute to chemical weathering burrowing (physical): - turns up rocks - break down rock by moving fresh material to the surface for physical and chemical processes

physical weathering: salt wedging

salty water gets into rock and evaporates leaving salt crystals behind salt crystals grow and break up more material

resources in sedimentary rocks

sand and gravel: construction industry pure clay deposit (kaolinite): ceramics limestone: manufacture of cement & building materials evaporates: table salt (rock salt) & dry wall (rock gypsum) uranium bearing sedimentary rock: energy bituminous coal, lignite: energy

earthquakes & liquefaction

saturated soil/poorly consolidated sediment gets shaken by an earthquake or other disturbance, and the clay & water mix

continental shelf

shallow marine impacted by tides & waves - causes diverse sedimentary structures (cross-bedding, ripples, strata layers) much broader in active regions than passive

geology

science that deals with the earth's (or other planets') physical structure and substance, its history, and the processes that act on it examines earth, its form and composition, and the changes it has undergone and is undergoing geo = earth logos = discourse physical geology: examines the materials composing earth and seeks to understand the processes operating within Earth and on its surface historical geology: examines the origin and evolution of earth and its inhabitants through time (continents, oceans, atmosphere and life through time)

outwash plains (glacial deposit - stratified drift)

sediment deposited by meltwater from a continental's glacier terminus valley trains: long, narrow deposit of stratified drift confined within a glacial valley

sediments

sediment: - chemical or physical products of weathering a rock - materials produced by weathering that are then subject to erosion and transportation detrital sediments: - solid particles coming from preexisting rock - clastic or physical - larger than 2mm = gravel - less than 2mm = sand chemical sediments: minerals that precipitate from solutions and are created by organisms to build their shells bioclastic sediments: remains of once living things (shells, plant matter, etc.)

information preserved in sedimentary rocks

sedimentary rocks contain numerous clues to help us interpret past conditions and environments on Earth sedimentary textures: - well sorted (quartz sandstone), well rounded sand-sized sediment may indicate a windblown dune - poorly sorted, large angular fragments may indicate a glacier fossils: any remains or evidence of ancient life including tracks, bones, shells, leaves, etc.

earth's interior

seismic wave velocities are determined by density & elasticity denser & rigid materials: waves travel through it faster P-waves travel faster than S-waves P-waves pass through liquid (S-waves don't) lithosphere: deeper = more rigid and denser (P- and S-Waves speed up) aesthenosphere: waves slow down (region is not as rigid) and speed up at depth mesosphere: P-waves and S-waves speed back up S-waves stop and P-waves slow down: evidence that the outer core is liquid

barrier reef

separated from the mainland by a lagoon protect the island from hurricanes (break up waves and currents) grows independent from the volcano no reef = erodes into a guyot

covalent bonds

sharing is caring stronger resistant to water & other materials (diamond) atoms that are neither close to finishing nor losing a shell share electrons so both atoms have a full set carbon bonds with itself infinitely

shoreline migration

shorelines migrate as: - global sea levels change - tidal fluctuations change - the local area subsides (loses elevation) or builds up (tectonics) coastlines are built on sediment: - if not building up more sediment, gravity causes sediment to compact and the top of the land falls (subsidence)

intrusive magma structures*

sill (tabular): - horizontal, thin sheet like intrusion between sedimentary layers (parallel) - concordant: intrusive igneous masses that form parallel to the bedding of the surrounding rock - form when magma exploits weaknesses between sedimentary beds or other rock structures - accumulates magma and increase in thickness laccolith: - sill-like feature that is swollen enough to cause a dome on the surface (shallow, bulging sill) dike (tabular): - sheet like vertical intrusion cutting across sedimentary layers and other magmatic bodies (vertical sill) - discordant: plutons that cut across existing rock structures - transport magma upward - more resistant and weather more slowly than the surrounding rock stock: - vertical intrusion that feeds a volcano (vent, neck, pipe) - portions of larger intrusive bodies that would be classified as batholiths if they were fully exposed pluton: - any large intrusive body that is slow cooling (most intrusive bodies) batholith: - a particularly large intrusive body >100km2 (large pluton) - enchanted rock - formed when magma was emplaced at depth, crystallized, and exposed by erosion - felsic (granitic) and intermediate rock types intrusions: - tabular: an igneous pluton that has two dimensions that are much longer than the third - massive: an igneous pluton that is not tabular (blob shaped) columnar jointing: - pattern of cracks that form during cooling of molten rock to generate columns - igneous rocks cool and develop shrinkage fractures that produce elongated, pillar-like columns

soil deterioration

soils are a non-renewable resource on human time scales (#1 economic resource) soil degradation: any process leading to loss of soil productivity (erosion, chemical pollution, compaction) practices contributing to erosion: - removing natural vegetation - overgrazing - over exploitation by firewood (removes decaying wood so it can't help develop soil) - deforestation

sedimentary structures: graded bedding

single layer that shows a decrease in grain size from bottom to top fluid experiences turbulence while flowing turbulent flow (underwater landslide) current experiences a rapid energy loss: largest particles settle first followed by successively smaller grains

meandering streams

single sinuous channel with broadly looping curves (meanders) less developed point bars: - deposition on inside curves - flow flows down - push toward the cut banks cut banks: - erosion of outside curves - flow speeds up - migrates further and further outward oxbow lakes: form when meanders cut each other off

magnitude (earthquake)

size of an earthquake indicated by: - amplitude & frequency of waves - duration of shaking - area of the fault & distance of slip richter scale - relies on amplitude and distance - every 1 point increase = 10x more shaking

slides

slope fails and material slips down (fully maintaining contact with the slope itself) material may internally break apart or remain internally in-tact 2 types: - slump/rotational slides (sediment and soil) - rock/block slides (rock)

gradient (channel flow)

slope over which a stream or river flows average slope from the highest to lowest point controls how fast water flows - steep = fast flow

foreshocks

small earthquakes that occur before the mainshock and close to its focus

gullies (valley)

small, steep-sided valleys young/immature stream valley water flows through soft sediment (forma a channel)

atoms

smallest unit of an element that retains the characteristics of that element combine in chemical reactions to form molecules nucleus: - center - mostly immutable portion of the atom inhabited by protons and neutrons proton: - positive charge - number of protons gives the element its identity - inside the nucleus neutron: - neutral charge - controls radioactive stability and some chemical signatures - inside the nucleus electron: - negative charge - outside the nucleus - controls how the atom bonds with others - occupy shells/levels - each shell can hold a certain number of electrons - innermost shells are filled first - outermost shell is left incomplete (except noble gasses) - atoms want to have a complete outer shell balanced atom: #protons = #electrons valence electrons: electrons involved in the bonding process

fluorite

soft abrasive toothpaste

foreshore (beach)

the intertidal part of the beach covered during high tide and exposed during low tide

soil horizon: horizon A*

some humus with more "mineral" matter (sand, silt, etc.) intense biological activity: - plant roots (anchor down) - bacteria & fungi - burrowing animals O + A = topsoil no topsoil: hard to grow plants

chemical weathering: carbonate dissolution

some minerals dissolve better in the presence of acid (boosts dissolution) much more effective than just water at dissolving rocks as water percolates, it picks up carbon dioxide carbonic acid - formed when carbon dioxide is dissolved in water - readily decompose many rocks and produce certain products that are water soluble causes marble statues to disintegrate karst topography: the caves and sinkholes associated with limestone dissolution

sedimentary rocks

source of information for what has happened outside the lithosphere throughout earth's history rock formed from the deposition and solidification of physical or chemical sediment any rock composed of physical, chemical, or bioclastic sediment rocks formed when fragments of pre-existing rock, biologically produced matter, or ions dissolved in water lithify at or near earth's surface lithification: process of turning lose material into a cohesive rock using cementation and compaction key: uplift - weathering - erosion - transportation - deposition - lithification clastic: - texture consisting of broken fragments of preexisting rock - detrital rocks (some chemical sedimentary rocks) nonclastic: - texture in which the minerals form a pattern of interlocking crystals - evaporites and some limestone

outlet glaciers

speed up when squeezed in narrower valley between mountains

cave deposits

speleothems (cave deposits) as water seeps into a cave: some of the dissolved carbon dioxide in the water escapes and a small amount of calcite is precipitated

cinder cone volcano

steep sided (piled up coarse material) small made of scoria, ash (tiny rock fragments), and pyroclastic material - not lava intermediate composition: andesitic (mafic over time) most are produced by a single, short-lived eruptive event forms mountains

cirques (valley glacier landform)

steep, bowl-shaped depressions in the mountainside at the upper end of a glacial valley opens on one side out into the glacial valley (flows out)

canyons (valley)

steep-walled, deep valleys of vast size tectonic uplift causes rivers to take a less steep path down to the ocean

old, subducting ocean crust

subducts easily colder and denser than new ocean crust lots of trapped water - mixes with rocks in the mantle during subduction - melts rocks to form magma

how soil forms: relief*

steeper slope = less soil development length and steepness of slopes significantly affect the amount of erosion and the water content of soil steep slopes: - soils are often poorly developed - due to rapid runoff, the quantity of water soaking in is slight optimum terrain for soil development: - a flat-to-undulating upland surface (good drainage, minimum erosion, and sufficient infiltration of water into the soil) exposure variables: - wind - rain (coast-facing slope receives more rain) - sun (north hemisphere north-facing slopes stay covered in snow longer)

angle of repose

steepest angle of the slope of a pile sediment can take collapsing fine sediment: low angle of repose coarse sediment: high angle of repose

slope

steepest angle that a slope can maintain without collapsing all slopes are in a state of dynamic equilibrium: constantly adjusting to new conditions processes that over steepen: - overloading (human or natural) - undercutting (by a stream or waves) - excavation (along road cuts or hillsides) the steeper the slope, the less stable it is (prone to failure)

making mass wasting less problematic

step 1) geologic investigation to identify hazards - identify former landslides - identify areas susceptible to mass movements step 2) intervene to minimize danger and damage - control surface sediment and pore pressure within sediment on hillsides - control water in slopes or sediment and building on the slope step 3) recognize that nature is vicious and any attempts to conquer it require long-term vigilance

elastic/brittle strain

strain immediately but only to a fixed, recoverable amount when stress is applied breaks if stressed beyond their limits take off stress (before elastic limit): bounce back - normal fault (hanging wall down) - reverse fault (hanging wall up) - strike/slip fault (side to side) - joints - dikes - fissures - veins

sedimentary structures: strata/beds

strata: layering in sedimentary rock bed: an individual layer of rock that indicates a single depositional event (may be any thickness) top = new | bottom = old change in rock types/characteristics through successive layers of strata record changes shale → limestone → shale: indicates fluctuating ocean depth (glacial cycles of shallow, deep, shallow) sandstone → shale → limestone: indicates rising sea levels sandstone → tuff→ sandstone: records a volcanic eruption (ash on beach after an eruption)

principles of stratigraphy

stratigraphy: the study of earth's layers, how they got there, and their relative ages principles of stratigraphy: 6 rules used to reconstruct the relative ages of an outcrop or series of outcrops 1. superposition 2. original horizontality 3. lateral continuity 4. cross-cutting relationships 5. inclusions 6. faunal succession

graded stream

stream with a profile in which a delicate balance exists among: - gradient - flow velocity - other channel characteristics neither deposition nor erosion takes place within its channel equilibrium point

stress

stress (solids) = force/area apply force on large area: little stress apply force on little area: large stress pressure (fluid and gas) is one form of stress

continental rifting

stretching phase: - faulting - magma rising (decompression melting) intermediate to mafic volcanoes (to basalt lava flows) continental rifting: rift valley develops and ocean crust starts forming as oceanic crust builds out, continents move apart ➤ small linear sea as it broadens into an open body of water, it becomes an ocean basin

flowstone (cave deposit)

structure formed by water flowing across cave's floor

hydrothermal activity

subsurface activity that results from the discharge of hot water hot springs & geysers - large quantities of dissolved minerals why: - subduction - decompression melting

earthquakes & tsunamis

sudden displacement of crust under the water causes water to be displaced - possibly triggering a tsunami major hazard at: - ocean-ocean subduction zones - ocean-continent subduction zones with low-elevation shorelines

earthquakes

sudden, instantaneous, violent release of strain on a fault accompanied by movement, rock fracture, and shaking stress: - causes strain - comes from tectonic processes (folding land to move in different directions) strain: - the deformation and bending experienced by rocks under stress - builds up then snaps (earthquake) focus (hypocenter): the point at which the earthquake starts within the earth epicenter: the point on the surface above the focus

drainage basin

surface area drained by a stream or river and its tributaries separated from an adjoining drainage basin by a divide (high topographic separating adjacent drainage basin) area of land that feeds into a river

nonconformity

surface between an igneous or metamorphic rock and later sedimentary rock sedimentary rock - on top (younger) igneous/metamorphic rock - underground (older)

factors enhancing weathering

surface exposure time: - short (less weathering) - long (more weathering) mineral stability: - stable (less weathering) - loose (more weathering) temperature: - more chemical (warm) - variable temperature better for physical amount of water - low (less weathering) - high (more weathering) acidity: - low (less weathering) - high (more weathering) biological activity - low (less weathering) - high (more weathering) slope steepness: - more physical and less chemical - steep: more exposure (less chemical weathering) vegetation: - low (less weathering) - high (more weathering) - slows down erosion rates

earth system science

system: group of interacting or interdependent parts forming a complex whole earth system: matter and energy are exchanged between biological components, rocks, oceans, the atmosphere, etc. earth is an open system: energy and matter also are exchanged with outer space (powered by the sun and earth's interior)

halite

table salt

partial melting

temperatures between the melting point of quartz and the crystallization of olivine: - partial melting more felsic than the original rock melting order: - felsic, intermediate, mafic, ultramafic

glacial surge

temporary increase of a glacier speeding up - surfaces breaks into crevasses, - terminus (end point) pushes forward weak and thinning glacier

block faulting

tensional block faulting: large tension across a broad area horsts: the uplifted blocks (footwalls - plateau) grabens: the down-dropped hanging walls (broad, flat valley) half grabens: - valleys formed by rotation of blocks that are hanging blocks on one fault and foot blocks on the other - peak on one side and valley on the other side - parallel mountains in a small area

geotherm

the average temperature of the crust at any given depth (temperature increases with depth) temperature rises gradually enough that the rising pressure keeps rock solid (equal) melting: - geotherm must enter the melt portion of the diagram - increase temperature, reduce pressure, or change the composition

transportation

the movement of sediment once it has been picked up the bigger the sediment, the more energy is needed to erode and transport methods: - water (rivers and waves) - wind (aeolian) - ice (glaciers) - gravity (assists other transportation methods) effects: - sorting sediment by size and mineralogy - further weathering out unstable minerals - rounding sediment

law of superposition

the oldest layers will be on the bottom and the youngest layers at the top exceptions: - intrusive igneous units - metamorphic rocks (parent rocks will follow this rule)

principle of uniformitarianism

the present is the key to the past physical, chemical, and biological laws that operate today also operated in the geologic past

habit (physical property)

the shape a mineral grows into some minerals have diagnostic habits one mineral can have multiple habits massive: no clear habit (magnetite) common habits: dipyramidal prismatic rhombohedral cubic botryoidal fibrous bladed dodecahedral crystal form: - geometric habits - every mineral has 1+ crystal form at the microscopic size - expresses underlying molecular crystal structure - some minerals display their crystal form at larger sizes cube: pyrite, halite, fluorite dodecahedron: garnet pyritohedron: pyrite octahedron: sagnetite, magnetite, some fluorite (usually cleavage, not habit) prism/dipyramid: quartz many factors can cause minerals to take a different habit or fail to show one at all: - cramped conditions (calcite vein) - fast cooling/growth (bismuth) - growth within sediment (garnet)

water table

the surface that separates the zone of aeration from the underlying zone of saturation level depends on withdrawal vs. recharge rate zone of aeration - some water remains suspended in a zone where pore spaces contain mostly air zone of saturation - some water moves downward and fill all the available pore space elevation tends to follow land surface elevation - smoother, more gentle curves - less steep and gently sloping

earth's formation 2) expansion/ordering

the universe grew energy started to drop and convert to subatomic particles which became hydrogen atoms that collected into galaxies in which dense pockets of gas collected into stars through nuclear fusion, stars converted hydrogen to heavier elements (iron)

earth's formation 1) the big bang

the universe was in a hot dense state, and nearly 14 billion years ago, expansion started big bang: theory explaining the evolution of the universe tiny loss of energy caused expansion that propelled itself forward as energy cooled and converted to matter

backshore (beach)

the usually dry part of the beach that is covered only by storm waves or the peak of spring tides stays dry during high and low tides

geodynamo

the whole core is iron: magnetic the outer core is liquid: convection the earth is spinning: causes the iron to become magnetized, generating a long-lasting magnetic field around earth the magnetic field protects earth from harmful solar radiation that destroys the atmosphere

compressive mountain building (1)

thrust faults within the accretionary wedge: - an entire ocean's bottom of sediment getting piled up in a tight wedge ocean-continent subduction high pressure, low temperature metamorphic area

volcanic hazards: ash falls

tiny shattered fragments of rocks - volcanic glass and very small mineral crystals (fast cooling) common for andesitic/rhyolitic volcanoes (felsic - intermediate) volcanic winters (blocks sunlight) dangers: burning, asphyxiation, entrapment moves slow most far-reaching volcanic hazard dating: radiometric dating can be done on volcanic rocks more accurately than sedimentary (use ash to constrain sedimentary sequences)

science

tool used to learn about the world by developing hypotheses and then subjecting them to scrutiny through observation and experiment systematic study of the structure and behavior of the physical and natural world through observation and experiment

bathymetry

topography of the ocean floor (oceans) requires sonar or other remote sensing at deeper depths echo sounder (sonar) - large swaths of the seafloor seismic profiling - penetrating the marine sediment layer - each subsequent layer bounces back a bit more of the wave - big bounce when waves hit crystalline basement rock ocean drilling program - international scientific collaboration with ship-based deep ocean drills to receive samples of sediment and oceanic crust - climate change and evolution of animals research submersibles - manned or unmanned - used to see the ocean floor and collect samples from it

where do earthquakes happen?

transform boundary: - strike-slip fault - side to side (no up or down) divergent boundary: - normal fault - one block slides down convergent boundary: - reverse fault - one block pushed up

love waves (surface wave)

travel along the surface horizontal shear (side to side) motion perpendicular to wave propagation ground shakes sideways (no vertical motion)

rayleigh waves (surface wave)

travel along the surface vertical motion elliptical orbits ("rolling") the ground surface moves in a rolling, elliptical motion that decreases with depth beneath the surface

P-waves (body wave)

travels through the body of the earth push/pressure/longitudinal waves like sound waves motion parallel to propagation primary arrivals (fastest) travel through solids & fluids travel as a series of contractions and expansions (pushing and pulling particles in the direction os their path of travel)

S-waves (body wave)

travels through the body of the earth shake/shear/transverse waves like light waves motion perpendicular to propagation secondary arrivals (slower) travel only through solids push material at right angles to their path of travel

dendrochronology

tree ring dating each year leaves a pair of rings, one dark and one light wide = wet | thin = dry combining tree ring sequences for a region allows any tree to be dated in that region

subduction zones (convergent boundaries)

trench: - the valley formed as the plate going down bends - oceanic lithosphere bends as it descends into the mantle accretionary prism/wedge: the wedge of sediments scraped off the subducting plate and onto the overriding plate volcanic arc: subducted water causes the overlying plate to melt (volcanic arc on the overriding plate)

hanging valley (valley glacier landform)

tributary glacial valleys with a floor above the floor of the main glacial valley feed into the u-shaped valley

soda straw (cave deposit)

tubular stalactites hollow mineral cylindrical tube

tides

twice daily fluctuation in sea level caused by the gravitational forces from the moon and sun - 2 high tides per day day - 2 low tides per day day - flood tide = rising sea level - ebb tide = falling sea level - high tide (1) - ebb tide - low tide (1) - flood tide - high tide (2) - ebb tide - low tide (2) - flood tide high tide happens when the moon is: - directly overhead (near tidal bulge) - directly on the opposite side of the Earth (far tidal bulge) high tide is higher in the near tidal bulge tides recorded in rock records: rocks from intertidal depositional environments may have regular variations in grain sizes (mud vs fine sand) or thickness of crossbeds

sea waves

types of waves caused where a turbulent storm center generates waves occur further off the coast

foliation grades & textures

under differential pressure, platy & elongate minerals get rearranged into layers regional metamorphism micas & amphiboles are easy to rearrange - not quartz & calcite original bedding may still be visible not all parent rocks go through all foliation grades: - granite → gneiss shale (parent rock) goes through all foliation grades: slate → phyllite → schist → gneiss bigger minerals = coarser/higher grade low grade (slate): - no visible crystals - fine layering high grade (gneiss) - visible crystals - coarse layering

groundwater

underground water stored in the pore spaces of soil, sediment and rock constitutes only 0.6% of the world water 20% - 30% of the world supply of freshwater source of freshwater for: - agriculture - industry - domestic users demand depends on: - depletion of the groundwater supplies - pollution rendering the ground water supply unsafe originates from precipitation (rain or snow melt) - infiltrates the ground and seeps down through the void of soil, sediment and sedimentary rock water in pore spaces in the ground - groundwater movement and recovery depends on porosity and permeability

marine deposition: continental slope

underwater alluvial fan environment: - downslope movement - underwater mountain cliff steep gradient processes of underwater debris flows characteristics: - carbonate conglomerate - graded bedding - disarticulated fossils & plankton

sedimentary structures: ripple marks

undulating structures in sandstone or siltstone symmetrical: - slope is the same in both directions - formed by waves moving back and forth - beaches - bidirectional waves (2 directions) asymmetrical: - one slope (downstream side) is steeper than the other - associated with small-scale cross-bedding - unidirectional currents (1 direction)

waves

undulations on the surface of the water crest: highest part of the wave trough: lowest point between the crests wavelength: distance from crest to crest height: distance from crest to trough individual water molecules (and suspended sediment) moves in an orbital pattern waves cause: - erosion - sediment transport - deposition

continental deposition: rivers & streams

unidirectional flow (follows a certain path, channelized) stretch from mountains to oceans mountains: - fast moving - high energy - moves large particles oceans: - energy drops - takes quartz into the ocean different subdivisions: - braided stream (upper) - meandering river (lower) deposition: - conglomerate (mountains) - arkose sandstone (close to mountains) - quartz sandstone & mud (end of river) rivers: - accumulate terrestrial fossils - bones and shells get caught and buried on point bars (inside bends of rivers) characteristics: - better sorting downstream - arkose, sandstone, conglomerate - cross-bedding

plate tectonics: a paradigm shift

unifying theory of geology: theory of plate tectonics connects every observation, law, and principle of geology, physical/bio geography, climatology, and oceanography the lithosphere is divided into plates that move across earth's surface as new oceanic crust is created at mid-ocean ridges and old oceanic crust is destroyed in subducting trenches rules: - plates are rigid (they break, not bend) - tectonic activity only occurs at plate edges - plate motions include rotation (earth is a sphere) - earth stays the same size (equal amounts of material are created and destroyed) - don't say plate tectonic acceptance: widespread accpetance had been reached by the late 1960s (1968)

color (physical property)

unreliable plagioclase feldspar (creme) vs. potassium feldspar (pink) fluorite & quartz: occur in a wide range of colors variations: caused by ion substitutions - change whole element - olivine: iron (green) or magnesium (black) caused by trace elements - add a little of an element - quartz: titanium (pink quartz)

radioactive decay

unstable isotope: an isotope that undergoes radioactive decay and changes to a new isotope beta decay - neutron ➤ proton - neutron kicks out an electron + neutrino and forms a proton (+1 proton results in Carbon14 to Nitrogen14) parent isotope: the starting, radioactively unstable isotope (Carbon14) daughter isotope: the radiogenic isotope produced by decay (Nitrogen14) half-life: the amount of time it takes for 1⁄2 the parent isotopes in a sample to decay into daughter we can not predict which isotopes in a sample will decay, just that, statistically, half will each half life - 50% chance to decay it doesn't matter how many isotopes are in the material at any given time, after the next half-life, half will have changed - 50 ➤ 25 (will change)

anticline (fold)

upward bend - oldest rock (center) - youngest rock (outside) young ➤ old ➤ young

stalagmite (cave deposit)

upward-growing projection built from dripping water from stalactites that builds up on the cave floor

classifying glaciers

valley glaciers: - form in mountains - follow stream channels - constrained to a narrow body of ice - mountain/alpine glaciers (flow through valleys in mountains) - tidewater glaciers (form where tides meet them into the ocean) continental glaciers: - spread wide over an area on land - ice sheets

differential weathering

variation in the rate and degree of weathering caused by factors such as mineral makeup, degree of jointing, and climate caprock: less weatherable rock protecting softer underlying layers canyons

pegmatites

very coarse-grained igneous rock (granite) commonly found as a dike associated with a large mass of plutonic rock that has smaller crystals crystallization in a water-rich environment results in the large crystals known for its unusually large crystals

marine deposition: deep ocean

very low energy (not affected by waves) washed out clays settle shallow deep ocean: chalk characteristics: - shales, cherts (silica rich) - planar bedding - open ocean fossils

volcanos & volcanism

volcano: a landform formed around a vent from which magma reaches the surface of the earth to become lava - or other materials are ejected due to volcanic activity (underwater or on land) significance: - emitted the earliest surface and atmospheric gasses - produces oceanic crust at spreading ridges - produces new land (oceanic islands) - produces highly fertile soil through weathering in tropical areas - water in the atmosphere (water vapor, gas, and steam) volcanism: process by which magma and associated gases are extruded onto Earth's surface or atmosphere products: - lava - gasses - pyroclastic material (bombs, blocks, ash, and lapilli) warning signs: - seismic activity (earthquakes) - inflation or swelling - increased heat and gas emissions 2 primary factors that determine how magma erupts: - viscosity - gas content

how soil forms: parent rock*

weaker rocks develop soil faster (thicker soil develops over a weaker parent rock) parent rock chemistry controls soil chemistry weathering happens at different rates - soft = fast regolith production (shale) = hard = slow regolith production (granite) hot spot volcanoes (hawaii): - iron-rich minerals = iron-rich soils - mafic minerals weather quickly (good soil)

deposition

when sediment is released from transportation and finds its final resting point

discharge (channel flow)

volume of water in a stream or river moving past a specific point in a given interval of time

rip currents (rip tides)

water flowing out of the breaker/surf zone in narrow, concentrated, strong channels reasons: - circulating longshore currents coming from opposite directions - shoreline is u-shaped

groundwater movement

water moves through the zone of aeration to the zone of saturation water moves from area where the water table is high toward area where it is lower - flows toward valleys (pools in streams, lakes, and swamps) water in zone of saturation - reservoir whose surface rises or falls depending on the amount of addition (recharge) versus the amount of withdrawal recharge: - adding water to groundwater system - rainfall, melting of snow or waste-water treatment plants, recharge pond withdrawal: - removal of water from the groundwater system - flow of water into streams, lakes, swamp, spring or water wells

convergent boundary (ocean-ocean)

water released from the subducting slab of oceanic lithosphere triggers melting in the hot wedge of mantle rock above volcanoes grow up from the ocean floor rather than upon a continental platform 1. older plate subducts - older plates are more dense then younger plates 2. deep ocean trench - produced where oceanic lithosphere bends as it descends into the mantle along subduction zones 3. oceanic island arc - volcanic island arc (chain of volcanic islands located a few kilometers from a trench where there is active subduction of one oceanic plate beneath another) - most are in the western Pacific

chemical weathering: dissolution

water totally dissolves rock into ion components halite: salt water

reefs

wave-resistant, mounded structure of coral or other invertebrate skeletons coral (most common) form barrier islands around islands/volcanoes (protection) grow in shallow water and keep-pace with changing water depth - shallow water = good for carbonates - water deepens = reefs grow faster to catch up - water gets shallow = tops will die off flourish in warm, clear tropical seas away from sediment-choked deltas

breakers (type of wave)

waves in shallow water that steepen and topple over as the wave base drags against the seafloor waves break (push forward and move sediment to land) when water depth is less 1/2 the wavelength, the lower orbiting molecules encounter drag along the ocean floor - makes the water unable to complete its orbit and causes the upper orbitals to become off-balanced

wave depth & movement

waves only affect the top layer of water - nothing below the wave base moves wave base: - the maximum depth affected by the wave - 1/2 the wavelength

swells (type of wave)

waves with broad, rounded crests in deep water where the wave base does not drag up & down (gentle and repetitive)

shoreline weathering & erosion

weathering: breaks up rock and creates loose sediment physical weathering: - abrasion (sand and gravel in the waves) - salt wedging erosion: removes the sediment from the location where it formed erosional force: water (in the form of waves) shorelines that erode more than they deposit generate sea cliffs

weathering

weathering: the process that breaks rocks into smaller particles or chemical components physical/mechanical weathering: - mechanical breakdown of rocks into smaller pieces (clasts) - not changing chemically chemical weathering: chemical alteration of rock to release chemical components and produce new minerals biological weathering: chemical and physical weathering caused by life forms (plants, animals, etc.) uplift: - all weathering happens at the surface, so deeply buried rocks must come up - rise to the surface via tectonics and erosion

evidence for plate movement *

wegener's evidence: 1. jigsaw fit of continents 2. distribution of fossils across oceans - distribution of fossils matches the jigsaw-fit of the continents 3. distribution of equivalent rock units across oceans - line up across continents 4. paleoclimate (ancient climate) records - remains of glaciers at the equator plus: 1. earthquake distribution - earthquakes perfectly follow ridges 2. gps plate movement - different plates move at different rates and plates can move differently relevant to each other - pacific plate: fast - north american plate: slow 3. discrepancies in polar wander - declination: difference between true North and magnetic North - declination changes over time (within a single polarity stripe) called polar wander 4. mid-ocean ridges & trenches - deep quakes happen at trenches 5. magnetic reversals - zebra stripe pattern of magnetic reversals on the sea floor (symmetrical across mid- ocean ridges) 6. age of oceanic crust - combines paleomagnetic and radiometric dating - young: center of ridges - old: up against trenches (further away) - elevation of the sea floor is controlled by ocean crust cooling with age (causes it to contract, becoming denser and more deeply settled in the mantle) all illustrate the mechanism for pushing plates around: sea floor spreading (convection and upwelling mantle pushes the plates)

scientific theory

well-tested and widely accepted view that explains certain observable facts consistently describes objective facts reliably predicts outcomes of experiments and other tests closely scrutinized and tested repeatedly very high probability of being correct always remains open to tests and revision ex. theory of plate tectonics (provides a framework for understanding the origins of mountains, earthquakes, and volcanic activity and explains the evolution of the continents and the ocean basins through time)

sedimentary structures: mud cracks

wet clay-rich sediment dries and shrinks (cracks) preserved when other sediment fills them in before they get wet again periodically wet but dry for an extended time (deserts) cycles of wet/dry: - wet = swells - dry = dries & cracks

resetting radio-isotopic dates

when minerals melt or alter, the radiogenic daughter isotopes have a chance to escape and reset the clock - igneous events - metamorphic events

law of lateral continuity

when sedimentary or extrusive igneous layers are deposited, they are laid down in a broad expanse, stretching until they either reach an edge of a basin or pinch out (layers are continuous laterally) 1. if two outcrops of strata on opposite sides of a canyon/valley have the same sequence, they were connected across that canyon at some point in the past 2. a canyon or other feature separating outcrops of a bed must have formed after the bed was deposited

neap tides

when the sun and moon are at right angles to the earth cancel each other out and reduce the tidal range (weak high tides) - 1st quarter moon - 3rd quarter moon

spring tides

when the sun, earth, and moon are in alignment exaggerates the tidal range (higher high tides) - new moon (most extreme) - full moon (less extreme)

mid-ocean ridges & rifts (divergent boundaries)

where new oceanic crust is formed (constructive) youngest & thinnest part of the lithosphere ridge is pushed up by elevated mantle and is not actually that thick longest mountain chain with the longest valleys on earth (interconnected ridges) fast spreading rate: - east pacific rise - no/very narrow axial rift - few sea mounts - broad ridge - empty of features slow spreading rate: - north atlantic ridge - well-defined axial rift - numerous seamounts - narrow ridge - full of features life on mid-ocean ridges: - greatest heat flow on the surface of earth - supports rich biological communities rift: linear zone along which continental lithosphere stretches and pulls apart rifting: - begins when plate motions produce tensional forces that pull and stretch the lithosphere - marks the beginning of a new ocean basin

continental margins

where oceanic and continental crust meet passive: - continent crust transitions into ocean crust without a distinct plate boundary - continent and attached oceanic crust form a single, stable plate - have lots of sediments active: - continent and oceanic crust are on different plates (plate boundary) - differential movement and seismic activity between the two - earthquakes, volcanoes, trenches continental shelf (p/a): the gently sloping submerged portion of the continental margin that extends form the shoreline to the continental slope continental slope (p/a): the steep gradient that leads to the deep-ocean floor and marks the seaward edge of the continental shelf continental rise (p): the gently sloping surface at the base of the continental slope

what generates waves

wind blowing over the water pulls the water along with it - friction between air and water fetch: continuous distance wind can blow over a water surface bigger waves are caused by the wind blowing harder over a longer fetch

physical weathering: abrasion (wind)

wind blown sand particles grind away at exposed rock weathers them flat or grinding holes in them

wwii + the cold war & geophysics

wwii: - ocean surveys - magnetic fields (to detect submarines) - submarine tracking (detect bombs and enemies) - bathymetry (elevation/typography on the seafloor) - navigation (know what areas to avoid) cold war: - world-wide standardized seismographic network (monitors seismic activity searching for hints of nuclear bomb testing) - satellites & gps - promoted a big push in making sea floor maps submarines could use to navigate wwssn findings: - highly ordered pattern of earthquake distributions, including depth harry hess: - dragged sonar to map bathymetry (sea floor elevation) - mapped north pacific sea floor and found trenches (via patterns reflected by sonar waves) marie tharp: - noticed patterns when making seafloor maps (found a ridge in the atlantic)