GEOL101 FINAL EXAM
Scientific Method
#1: Recognize the problem/make an observation. #2: Collect data; make more observations. #3: Develop idea(s) to explain; hypothesis. #4: Test hypothesis (experiments). #5: Validate or refute hypothesis.
What is Earth's water distribution?
96.5% of water is ocean, 0.9% is saline water, 2.5% is freshwater. freshwater consists of 68.7% is glaciers and ice cap, 30.1% is groundwater, 1.2% surface water or other water.surface water consists of 3% atmosphere, 0.49% is rivers, 0.26% is living things, 2.6% swamps, 20.9% lakes, and 69% ground ice and permafrost.
What are unconformities (e.g., angular)?
Angular Unconformity: where two layers of rock meet that are inclined at different angles to one another. Disconformity a gap between two sedimentary layers that are parallel; erosion, but no titling. Nonconformity: where sedimentary or volcanic rocks lie directly on igneous or metamorphic rocks.
What are the dominant greenhouse gases?
CO2 is 1st, CH4 (methane) 2nd most prevalent, N2O is the 3rd most prevalent gas.
Examples of nonmetallic resource.
Dimension stone, crushed stone/concrete, gypsum for wallboard, phosphate fertilizer, sand for glass, and salt.
What are examples of chemical weathering (e.g., dissolution)?
Dissolution: minerals completely dissolve in water; primarily affects salts an carbonate but quartz can also partially dissolve. Acid formation: formation of natural acids in water at Earth's surface also causes chemical weathering to occur, breaking down minerals that are not ionically bonded. Hydrolysis: water chemically reacts with minerals and breaks them down (feldspars-clay); minerals react with water to form a new mineral; breaks apart silicate minerals to produce clay minerals and other compounds. Oxidation: reaction of oxygen with iron-beating minerals in rock; iron atom loses electrons and precipitates as another mineral; RUST. Hydration: mineral absorbs water into their structure absorption of water by anhydrite, results in the formation of gypsum.
What might cause a mass wasting to occur?
Earth materials: fragmentation and weathering. Angle of Repose: because of resistance forces, granular debris tends to pile up to produce the steepest slope it can without collapsing—angle of repose. Effect of water: moderate amounts of water create increased structural integrity and increases angle of repose; saturation of sediment by water eliminates any structural competence—slope instability. Slope stability: slope angle, smoothness of a surface, and water content all influence slope stability. Shocks, Vibration and Liquefaction: if dry, shaking regolith results in compaction and generally a more stable mass of particles. if saturated with water, when shaken, contact between particles is broken and the entire mass behaves as a fluid. the mass of material is now highly unstable and may move downslope. Natural Triggers: rainfall and snowmelt, earthquakes, volcanic eruptions. Change in Slope: as streams, or construction, cut into a bank, slope is increased, and the downslope force is increased; eventually the downslope force becomes too great and movement occurs. Geologic Weakness: joints, faults, and bedding planes; water preferentially travels down such features, weakening them by reducing cohesion, and by weathering of the minerals. Lack of Vegetation: roots penetrate soils and act to bind particles together; plants are thus a stabilizing force on slopes. loss of vegetation, perhaps due to fire, may promote mass movement on a previously stable slope. Fire-Flood Events: fire destroys vegetation and creates an impermeable upper layer of soil (hydrophobic). rainfall then streams over surfaces, gathering huge energy as it is not impeded by any natural defense. this sets up ideal conditions for huge debris flows.
Define malleable.
Hammered into shapes; stress is applied is compression.
What are the differences between hypothesis, theory, and law?
Hypothesis: testable prediction, often implied by a theory. Theory: hypothesis that has not yet been proven wrong; abundance of evidence. Law: a concise statement of what will happen, but does not explain how or why they work.
What are the inner and outer planets?
Inner: Mercury, Venus, Earth, Mars Outer: Jupiter, Saturn, Uranus, Neptune
What are examples of physical weathering (e.g., jointing, sandblasting)?
Jointing: natural cracks that form in rocks due to removal of overburden or cooling. Frost wedging: water gets in joints, freezes pressure expands gaps. Salt wedging: similar to ice wedging but salt growth is what causes the pressure. Root edging: growing roots force joints apart, like roots under a sidewalk. Thermal expansion: repeated heating and cooling (fires). Animal attack: burrows, human activities. Wind: sandblasting.
What are the types of folds (e.g., anticlines)?
Limbs the two dipping sides of a fold (ductile structures). Axial Plane plane separating two dipping sides (ductile structures). Hinge Line line where the dipping limbs join (ductile structures). Plunging Fold when hinge line plunges downward into the ground and is not horizontal (ductile structures). Anticline folded structure that arches upward in the center and where limbs dip away from axial plane (ductile structures).example: virgin anticline northeast trending in St. George, UT Syncline folded structure that arches downward in the center and limbs dip in toward axial plane (ductile structures). Monocline: fold-like carpet draped over a stair step; these faults do not cut through to the surface.
What are the Milankovitch cycles?
Milankovitch cycles include three types of variations in Earth's orbit around the Sun and tilt of its axis that results in slight changes in the intensity of solar radiation reaching Earth, accentuating seasonal variation and resulting in climatic change. Milankovitch cycles occur over periods of 100,000 (eccentricity), 41,000 (obliquity degree of tilt), and 26,000 (precession) years.
What are the different types of glaciers (e.g., mountain)? What are examples of each (e.g., cirque)?
Mountain Glaciers flow from high to low elevation; include a variety of types: cirque glaciers fill mountain-top bowls. valley glaciers flow like rivers down valleys. mountain ice caps cover peaks and ridges. piedmont glaciers spread out at the end of a valley. Continental Glaciers vast ice sheets covering large land areas.ice flows outward from thickest part of sheet. two major ice sheets remain on Earth:Greenland and Antarctica.
Are mineral resources renewable?
No
What are the types of faults (e.g., normal) and how do you describe their motion?
Normal Dip-slip Fault tensional forces (pulling apart), hanging wall moves down relative to footwall. example: Death Valley, CA fault. Strike-slip Fault (Left or Right Lateral) a type of fault in which rocks on either side move past each other sideways with little up or down motion. think San Andreas Fault, LV Valley shear zone, Rainbow Garden in LV. Reverse Dip-slip Fault hanging wall moves up compared to the foot wall. Oblique-slip Fault a fault in which sliding occurs diagonally along the fault plane; reverse plus left-lateral displacement or normal plus right-lateral displacement. Thrust Dip-slip Fault hanging wall moves up relative to footwall, dip angle <30 degrees (compressional forces). example: Red Rock, NV
What are relative age dating principles (e.g., superposition)? How do we apply them?
Principle of Superposition: sedimentary/some volcanic rocks are created in succession, with the oldest rocks at the bottom and progressively younger rocks above.sandstone on top, then limestone, then shale on bottom. Principle of Original Horizontality: sedimentary rock layers are deposited horizontally; if flat rocks are no longer horizontal, some tectonic event titled layers to the angle they are now. Principle of Cross-Cutting Relationships: geologic features such as dikes and faults cut across rock must be younger than the rock they cut. Principle of Inclusions: objects enclosed in rock are older than rock itself; inclusions of granite in overlying sedimentary rock—the granite is older; inclusions of sedimentary rock in underlying granite—the granite is younger. Principle of Lateral Continuity: rock layers are continuous until encountering an obstruction. Principle of Faunal Succession: fossils of different organisms first appear at different times in the rock record; fossils of related organisms exhibit regular changes in progressively younger rocks everywhere they are found. when they become extinct, fossil organisms disappear from the rock record everywhere at the same time and do not reappear in younger rocks.
Nuclear Pros and Cons:
Pros: no CO2, SO2, particulates, reliable and long lifetime, provide large quantities of electricity., and low fuel costs which reduces mining and transportation effects. Cons: costly to build and decommission, radioactive waste, and NIMBY.
Geothermal Pros and Cons
Pros: renewable and sustainable, reduce carbon footprint, reliable sources, small land footprint, large and small scale install, and heat pumps and are viable almost anywhere. Cons: geographically dependent, high initial cost, and water waste and subsidence.
Solar Pros and Cons
Pros: renewable, abundant, sustainable, reduce carbon footprint, reduce electricity costs, and cheaper than ever right now. Cons: high upfront costs (investment), intermittent, energy storage expensive, associated with some pollution, requires space, and waste is becoming an issue.
Hydroelectric Pros and Cons
Pros: renewable, no CO2 production, minimal pollution, can provide recreation, operations and maintenance costs are relatively low, and manipulate release of water. Cons: high investment costs, block fish migration, ecosystem manipulation and other environmental impacts, site specific/location, dependent on water source, political obstacles, and evaporation loss.
Wind Pros and Cons
Pros: renewable, reduce carbon footprint, low operating costs, and efficient use of land space. Cons: high upfront costs, intermittent, noise and visual pollution, and ecological issues (birds, bats).
How do we calculate earthquake magnitudes?
Richter magnitude from the logarithm of the amplitude of waves recorded by seismographs.
Volcano examples (e.g., Mount St. Helens, Hawaiian Islands).
Shield Volcano: Mauna Loa Hawaii). Composite Volcanoes/Stratovolcanoes: Mt. Fuji, Mt. Rainer and Mt. St. Helens, Mt. Vesuvius, and Mt. Pinatubo. Mt. St. Helens: Explosions occurred when a landslide suddenly released pressure on the magma chamber. Eruption of Mt. St. Helens in 1980. The blast devastated 600km^2 and killed 61 people.
Define ductile.
Stretched into thin wires; stress applied is tension.
Who was Alfred Wegener? What was his evidence for the continental drift hypothesis?
THEORY OF PLATE TECTONICS! evidence he had includes Pangaea, which means "all earth," glacial striations and deposits, paleo-climate, fossil evidence, and rock and mountain correlation.
Are rocks recycled? If so, how?
YES sedimentary rocks come from weathered pieces of other preexisting rocks. metamorphic rocks are preexisting rocks that have changed through T and P increases. igneous rocks are made from any rocks that have melted and crystallized. all three rock types are connected!!! the rock cycle shows that the genetic classification of rocks connects the three classes of the processes responsible for each different rock type; any of the rock types can thus can be recycled into any of the others. this in part explains the relative scarcity of very old rocks on the Earth, most rocks have been recycled
Explain the Nebular Theory.
a model for the origin of the solar system that supposes a rotating nebula of dust and gases that contracted to form the Sun and planets.
What are seismic shadow zones? What is the difference between S & P shadow zones)?
a shadow zone implies that there is a sharp density change at depth. P-Wave Shadow Zones in 1914, seismic stations between 103-143 degrees away from an epicenter did not record P-waves. S-Wave Shadow Zones it was discovered that S-waves also have a shadow; s-waves cannot pass through a liquid, therefore, at least the outer portion of the core was liquid. the shadow zone of S-wave is much larger than that of the P-waves.
What is absolute age dating and how is it applied (e.g., decay, isotopes, ½-life)?
absolute dating is based on determining how ratio between parents and daughter isotopes change with time. clock starts when mineral crystallizes from magma. absolute dating works best for igneous and metamorphic rocks—crystal need to be cool enough for both parents and daughter isotopes to be locked into crystal lattice. a radioactive parent isotope decays to a stable daughter isotope. if we know decay rate, we can use ratio of both isotopes to calculate age of rock or mineral.half-life—amount of time it takes for ½ of parent isotopes to decay to daughter.
How do glaciers form? What are the three conditions for formation?
accumulation of snow and ice, that lasts year round, and thick enough to flow downhill under its own weight. snow transformed into ice; snow is buried by later falls; compression reduces volume; burial pressure causes melting/recrystallization; snow turns into granular firn; firn becomes interlocking crystals of ice; amount of time is variable. three conditions: old local climate (polar latitudes or high elevation), abundant snow; more snow must fall than melts, and snow must not be removed by avalanches or wind.
What are metamorphic rocks? How do they form? How are they classified?
alteration of pre-existing rock to form another rock; the pre-existing rock is known as protolith or parent rock.
Define the different types of texture (e.g., aphanitic).
aphanitic texture: small crystals, usually extrusive, but not always (very shallows intrusions); rhyolite and basalt typically have this texture. phaneritic texture: large crystals, generally intrusive rocks; granite, diorite, and gabbro typically have this texture. porphyritic texture: large crystals are set in a finer-grained or glassy groundmass. pyroclastic: explosive volcanic debris that has compacted and cemented. glassy: fracture conchoidally, rapid cooling of lava, i.e. obsidian frothy: more bubbles than rock, can actually float on water, and i.e. pumice and scoria. pegmatitic: rock contains exceptionally large crystals, sometimes contain minerals rarely found, often occurs in small pockets of superheated water rich in dissolved ions; along margins of batholiths.
What are confined and unconfined aquifers (also aquitard and artesian)?
aquifer: permeable rock layer or sediment that holds and transmits groundwater freely. confined aquifer: two impermeable units, one above and one below. unconfined aquifer: one impermeable unit below. aquitard: sediment/rock that doesn't transmit water easily; low permeability. artesian: well from which water flows under natural pressure without pumping.
How do we locate an earthquake?
arrival times/epicenter can be found by determining the elapsed time between the arrival of the first P-wave and first S-wave and through triangulation.
Atomic structure and bonding.
atom -> molecule ionic bond: formed when one or more electrons are transferred from one atom to another. covalent bond: created by sharing electrons with other atoms. metallic bond: formed by the attraction between positively charged metal ions and the electrons around them. van der waals bond: sheet of covalently bonded atoms held together by weak electrostatic forces and are very weak bonds. polymorphs: a mineral in which has the same composition as another mineral but their atoms are arranged differently.
How do we reduce the impact of a mass wasting event (protection)?
barriers and retaining walls, drainage pipes, terracing the slope to reduce the steepness of the cuts, and immediate revegetation.
How and why do glaciers move?
basal sliding: basal →forming or belonging to a bottom layer. significant quantities of meltwater forms at glacier base. water decreases friction, ice slides along substrate. plastic deformation: grains of ice change shape.new grains form while old grains disappear. crevasses form at surface—upper zone is brittle (formed due to stretching as glacier passes over convex slopes).
What is bathymetry? What is paleomagnetism? What do they tell us about tectonics?
bathymetry: the topography of the ocean floor and the measurement of ocean depths. reflects plate tectonics processes associated with global-scale mantle convection. paleomagnetism: fossil magnetism →created by Earth's magnetic field when rocks formed.iron (Fe) minerals in rock preserve information.in hot magma, thermal energy of atoms is very high (no magnetism. as magma cools, iron atoms align themselves with the field and eventually become 'locked' into place, preserving the direction of the earth's magnetic field. supports the theory of plate tectonics because of magnetic signatures of the rocks on the ocean floor
What is the angle of repose?
because of resistance forces, granular debris tends to pile up to produce the steepest slope it can without collapsing—angle of repose. dry sand cannot support an angle of >35 degrees from horizontal. coarser grains and more angular materials support steeper angles of repose.
What is ductile deformation? What are its factors?
bending/flowing of a material without cracking and breaking, subjected to stress.atoms within grains rearrange, and the grains change shape without permanent cracks forming, like chewing gum or soft dough. hotter: more ductile pressure is high deeper within Earth: rocks are more ductile. slow rate: ductile (plate tectonics). low strength: ductile
What are the characteristics of both body and surface seismic waves?
body waves: move through Earth's interior; considered fast; two types include P-waves and S-waves; friction absorbs energy as waves pass through material (farther traveled, less energy). p-waves: aka compressional waves; waves travel by compressing and expanding material; material moves back and forth parallel to wave direction; the fastest waves; they travel through solids, liquids, and gases. s-waves: aka secondary/shear waves; waves travel by moving material back and forth perpendicular to wave direction; slower than P-waves; only travel through solids. surface waves move along Earth's surface; considered slow; two types include L-waves and R-waves; friction absorbs energy as waves pass through material (farther traveled, less energy); don't travel very far. l-waves: move the ground back and forth like a writhing snake. r-waves: cause the ground to ripple up and down like water.
How do different earthquake waves move through the Earth?
both P-waves and S-waves can travel through solid materials but only P-waves can travel through a liquid. waves travel more slowly in liquids than solids, so travel time of a wave through a magma or the liquid outer core will be slower than through solid rock or the solid inner core.
Can we predict volcanic activity/hazards?
can be predicted through increased earthquake activity, changes in heat flow, changes in shape, and increase in gas emission and steam.
What are the cycles that affect our planet (e.g. rock)?
carbon cycle: biochemical cycle that regulates climate; weathering. Milankovitch cycles: major glacial (cold) and interglacial (warm) periods are initiated by changes in the Earth's orbit around the Sun. rock cycle: shows that the genetic classification of rocks connects the three classes of the processes responsible for each different rock type.
What is desertification?
causes dust storms, aridification of non-desert areas, human activity expands deserts, overpopulation, overgrazing, careless agriculture, diversion of water supplies, and leads to famine.
What are caves and karst?
caves: cave formation involves both erosion and deposition of soluble minerals. karsts: the dissolution of limestone and other soluble rock types lead to the formation of cave systems, sinkholes (collapsed cave roofs), and pillars of rock isolated by dissolution of surrounding materials.
How do we classify igneous rocks?
chemical composition; felsic, intermediate, mafic, ultramafic.
What are examples of the different plate boundaries?
convergent: mountains divergent: rift valleys, mid-ocean ridges transform: faults
What is brittle deformation? What are its factors?
cracking and fracturing of a material subjected to stress.bonds break and stay broken, like a plate or a window. cooler: more brittle pressure is low near surface: rocks are more brittle fast rate: brittle (earthquakes). high strength: brittle
What are the types and characteristics of each (e.g. creep, slump)?
creep: slow, gradual down slope movement of regolith on a slope due to expanding and contracting. solifluction: similar to creep, but in the arctic tundra/high elevations; melted permafrost slowly flows over deeper-frozen soil. slumping: a mass of regolith detaches from its substrate along a curved sliding surface and slips downhill semi-coherently. mudflow: slurry of rock/regolith moving as a non-cohesive mass, similar to a liquid. debris flow: mud mixed with larger fragments. lahar: mudflow with ash. landslides: sudden movement of rock and debris down a non-vertical slope. avalanches: turbulent clouds of debris mixed with air that rush down steep hill slops at high velocity. rockfalls/debris falls: a mass of rock or debris free-falls from a steep/vertical cliff. underwater mass movement: can trigger tsunamis.
What are the different layers of Earth (e.g., crust, mantle; lithosphere, asthenosphere)?
crust: layer that overlaps the biosphere and is the source of all of humanity's resources. mantle: layer that ranges in thickness from 2,820 to 2,890km, lies beneath the crust and the core. consists entirely of ultramafic rock called peridotite. the flow occurs very slowly here at a rate of about 15km per year. lithosphere: the strong, cold, and rigid outer layer (100km to 150km) that acts as a shell and consists of the crust plus the cool uppermost part of the upper mantle. asthenosphere: hot, ductile, and weak and is the portion of the mantle in which rock behaves like soft plastic and can flow and lies below the depth of 100-150km.
What are the causes of melt (e.g., decompression)?
decompression: pressure prevents melting; decrease in pressure can trigger melting; as mantle rock slowly rises, pressure reduces while temperature remains nearly unchanged. addition of volatiles: volatiles enter hot mantle; this lowers melting temperature of rock at convergent plate boundaries. heat transfer: rising magma carries mantle heat up with it; this raises temperature in nearby rock, which melt (e.g. injecting hot fudge into ice cream).
What are the properties of lava (e.g., viscosity, silica content)? How does it affect flow?
density: magma is less dense than surrounding rock and can be squeezed up by wight of overlying rock. rate of magma rise is a reflection of the viscosity, resistance to flow; depends on temperature, volatile content, and silica content. viscosity: temperature: cold temperature increases the viscosity. volatiles: more volatiles means lower viscosity and less volatiles means higher viscosity. silicia content: less silica (mafic) means lower viscosity and more silica (felsic) means higher viscosity. density increases as we go down, temperature increases as we go down, viscosity decreases as we go up. flow: felsic magmas (rhyolitic) are cooler, very viscous (thick, sticky), and large amount of gases can build up in it. mafic magmas (basaltic) are hotter, less viscous, and have significantly less gas. the result is that felsic magmas produce short, thick lava flows and explosive pyroclastic rocks. mafic magma produces long, thin lava flows, and eruptions are generally not as explosive (effusive).
What is the hydrologic cycle and its components?
describes the movement of Earth's water from one reservoir to another. water cycle consists of three major processes: evaporation--the process of turning from liquid into vapor. condensation--the conversion of a vapor or gas to a liquid. precipitation--rain, snow, sleet, or hail that falls to the ground.
How are sedimentary rocks classified (e.g., clastic)? What are examples of each (e.g., sandstone)?
detrital (clastic): composed of mineral grains weathered from pre-existing rock and cemented together by precipitated minerals, i.e. sandstone and mudstone. chemical: composed of minerals precipitated directly from water, i.e. gypsum and rock salt. biochemical: consists of fossil and or consists of carbon-rich relicts, i.e. chalk and coal.
What are intrusive igneous settings and what are examples (e.g., dike, pluton)?
dikes are tabular intrusions that cut across preexisting layering (bedding or foliation). sills are tabular intrusions that inject parallel to layering. laccoliths are intrusions between layers that dome upward, creating blister-shaped intrusions. plutons are irregular (blob-shaped) intrusions that range in size from 10s of meters across to 10s of kilometers. batholiths form by the intrusions of numerous plutons in a region creating a vast composite bod that may be several hundred kilometers long and over 100 kilometers wide.
What is the terminology associated with stream flow and stream dynamics (e.g., discharge, velocity, load, erosion)?
discharge: volume of water flowing past a given point in a river.discharge will vary with time and weather conditions.units of ft^3/s or m^3/s gradient slope of stream channel; change in elevation divided by distance. longitudinal profile is a concave upward; steep at headwater and nearly flat at discharge area. velocity length divided by time; varies within the channel; highest velocity in center of channel. load material carried along by the stream; dissolved load: ions from chemical weathering; suspended load: fine particles (silt and clay); bed load: coarse particles that roll, slide, and bounce along the bottom (saltation).
What is weathering?
disintegration of rock into particles.
Name the 3 types of plate boundaries.
divergent, convergent, transform.
What are the processes that occur along plate boundaries?
divergent: where two plates are moving apart, magma comes up to create new crust; think mid-ocean ridges and the creation of new ocean floor after it spreads. convergent: tectonic plate boundary where two plates collide, come together, or crash into each other; think mountains, tsunamis, volcanoes. transform: boundary between two plates that are sliding past each other; think displacement and faults.
What is mass wasting and what does it include?
down slope transport of rock, regolith, snow, ice. examples include creep, solifluction, slumping, mudflows, debris flows, lahars, landslides, avalanches, rockfals, debis falls, tsunamis.
What are drainage basins?
drainage networks collects water from a broad region and drains into a specific trunk stream. a drainage divide separates adjacent drainage basins.
How do we know Earth's interior?
drilling and mining only go so far. because of occasional pieces of the deeper earth brought to the surface. because of earthquakes and the resulting seismic waves.
How do mineral crystals form?
each crystal starts small and grows as more atoms are added. many grow from water rich in dissolved minerals, but they also grow from melted rock and even vapor. under the influence of different temperatures and pressures, atoms combine in an amazing array of crystal shapes.
What are some of the environmental and sustainability concerns?
environmental concerns: mineral extraction and processing leaves a big footprint, open-pit mines are large scars on the landscape, mining creates huge volumes of waste tailings, tailings piles are often acidic and laden with toxic metals, and unvegetated tailing may be sources of dust and runoff, and ore processing and smelting releases toxic chemicals. sustainability concerns: world demand for mineral resources is enormous, but mineral resources are nonrenewable, like coal and oil, they form as the result of geologic processes and these processes are too slow to generate new deposits, and mineral resources are unevenly distributed.
What are depositional environments (e.g., terrestrial, marine)?
environments include terrestrial, intermediate/coastal, and marine. glacial environments: removes rock from underside and sides of glacie; a pile of debris is left called a moraine, composed of glacial till; glaciers produced rigged fragments while rivers produce rounded fragments. mountain stream environments: fast-flowing water carries large clasts during floods; during low flow, these cobbles and boulders are immobile; coarse conglomerate is characteristic of this setting. alluvial fan environments: alluvial fan: sediments that pile up at a mountain front; rapid drop in stream velocity creates a cone-shaped wedge; resulting rocks could be breccia, conglomerates, arkose, shale. sand dune environments: occur in dry climate, anything medium sand size and smaller can be easily moved by wind; well sorted sand; resulting rocks are usually sandstones. river environments: depending on energy and type, rivers can carry everything from clay to boulders; sand and gravel fill concave-up channels; fine sand, silt, and clay are deposited on flood plains; resulting rocks: sandstones, mudrock, conglomerates. lake environments: accumulate fine grained sediment and algae; resulting rocks: mudrocks, shale; where rivers enter lakes you can also get deltas. delta environments (intermediate): sediment accumulates where river enters sea; sediment carried by the river is dumped when velocity drops; deltas grow over time, building out into the basin. beach Environments: due to ocean currents and surface, sediments are transported along the coast; well-sorted, medium-grained sandstone; ripples often preserved. shallow-marine clastic environments: deeper offshore (limited to no wave energy); fine-grained, well-sorted, silt and mud; inhabited by mollusks and worms; siltstone, mudstone with marine fossils. shallow-marine carbonate environments: most sediments are carbonates—shells of organisms; warm, clear, marine water, relatively free of clastic sediments; limestone is the dominant rock type; if shallow, shell fragments and reef debris. deep marine carbonate environments: fines settle out from land; skeletons of planktonic organisms make chalk or chert. sedimentary basins: basins from where tectonic activity creates space; weight of the mountain belt pushes down the crusts' surface;downward slip on faults produces narrow troughs; the basin forms in the interior of a continent, perhaps over an old rift; subsidence occurs over thinned crust at the edge of an ocean basin.
What are erosive (e.g., ventifacts) and depositional (e.g., dunes) features in arid landscapes?
erosive: deflation - lowering of elevation in an area due to removal of material by winds. produces pans. abrasion - driven by wind-blown particles such as sand and produces ventifacts and yardangs. depositional: dunes - particles roll up windward slope and fall down leeward; dunes migrate in direction of prevailing winds over time and cross-bedded sandstones yield ancient wind patterns.
What are erosive (e.g., striations) and depositional (e.g., moraines) features in glacial landscapes?
erosive: glaciers carve deep valleys (e.g., Yosemite Valley); polished granite domes & vertical cliffs →result of glacial erosion. glacial abrasion—a "sandpaper" effect on substrate; substrate is pulverized to fine "rock flour"; sand in moving ice abrades and polishes bedrock. cirques, tarns, aretes, horns, U-shaped valleys, hanging valleys, fjords depositional: moraines, glacial till, erratics, loess, glacial lake-bed sediment.
What are the drainage networks (e.g., dendritic, radial)?
eventually, an array of linked streams evolves, with smaller tributaries flowing into a trunk stream. configuration of tributaries and trunk defines drainage networks. dendritic: pattern: branching tree. radial: forming on the surface of a cone-shaped mountain; water flows outward from peak. rectangular: rectangular grid of fractures (joints); stream joints at right angles. trellis: occurs in landscapes of parallel valleys and ridges; tributaries flow down valleys and join a trunk stream cutting across ridges. parallel: streams are swift and straight, with very few tributaries, and all flow in the same direction
What is some of the evidence and causes for present climate change?
evidence: increasing temperatures over land and ocean surfaces and in the troposphere, increasing sea-surface temperatures and ocean heat content, melting glacial ice and sea ice, rising sea level, and increasing humidity. causes: contributions of greenhouse gases including carbon dioxide, methane, nitrous oxide, and more.
Extrusive vs intrusive?
extrusive: forms at or near the surface. intrusive: forms below the surface.
How do different particles move during the blowing of winds?
fast winds needed to move small to large particle. typically <0.5 mm can be moved, sometimes larger. small (clay, silt) have electrostatic forces so require proportionally stronger wind. when particles bounce, they kick up other particles; smaller ones may remain suspended in the air and larger ones fall back and dislodge more particles.
Define the different types of composition (e.g., felsic)?
felsic: very low density, very low temperatures, very high viscosity and silica content (ex: Granite). intermediate: low density, low temperatures, and high viscosity and silica content (ex: Diorite). mafic: high density, high temperatures, low viscosity and silica content (ex: Basalt). ultramafic: very high density, very high temperatures, and very low viscosity and silica content (ex: Peridotite).
What are the metamorphic rock types (e.g., foliated) and examples (e.g., gneiss)?
foliated rocks—have aligned minerals, or layered minerals, or otherwise linearly arranged minerals. progressive changes in rock texture and mineral content take place as the metamorphic grade increases; high grade is closer to the surface! degree of foliation is the primary characteristic for classification. start with a sedimentary rock like shale, goes to slate (low grade, fine-grained minerals like clays, mica, chlorite, and quartz) turns into phyllite (medium grade, white mica, some chlorite; feldspars may begin to form), turns to schist: (medium grade, but higher grade than phyllite, chlorite is now gone), and turns into gneiss (high grade, altering bands of felsic and mafic minerals). non-foliated rocks are further identified by their component minerals. composition is the primary characteristic for naming the rock. state crystal size, determine protolith, determine dominate minerals. examples: quartzite, marble, stretched pebble conglomerate, greenstone, serpentinite, and anthracite coal.
What is stress? What are the different types?
force applied to a give area; stress is force adjusted for the area over which it is distributed. compression, tension, and shear stress. shear stress: a stress that occurs when two tectonic plates move side-by-side past one another, causing material to twist and become distorted.
What are the different types of energy resources? How do they form? How do they work?
fossil fuels: combustible (capable of burning) hydrocarbon compound; include oil, natural gas, tar sands, oil shale, coal, etc. nuclear: energy produced through fission (the breaking of nuclear bonds that hold protons and neutrons together in the nucleus); controlled chain reaction splitting of Uranium-235; stored in fuel rods. solar: need sun, amount of solar energy varies by location, season, and time of day, near the equator = more sun, devices have to follow the sun; two types of solar energy systems are collectors and photovoltaic; passive collectors: direct heating by the sun versus active collectors: move energy from on location to another (i.e. solar water heater). wind: kinetic energy, the turning of a rotor to produce electricity, blades average 100-200' in height and towers up to 460'; the ideal for this to succeed would be where it is strong and steady. hydroelectric: potential energy (example: Hoover Dam), about 17% of total electricity production, and China is the largest producer. geothermal: thermal energy in the Earth's crust which originates from the formation of the planet and from radioactive decay of materials in currently uncertain but possibly roughly equal proportions (examples: Iceland and heat pumps).
What are the different types of fossils (e.g., frozen, amber)?
frozen or dried body fossils, body fossils preserved in amber or tar, preserved or replaced bones, teeth, and shells, molds or casts of bodies, carbonized impressions, permineralized organisms, and trace.
What are some types of change (e.g. gradual)? What are examples of each?
gradual—geologic time. catastrophic—fast (hazards). unidirectional—transformations that never repeat (evolution). cyclic—repeats itself (rock cycle).
What are the hazards associated with earthquakes?
ground shaking, tsunamis, landslides, disease and starvation, liquefaction, fire.
What are the agents of metamorphism (e.g., heat, pressure)?
heat: heat causes atoms to vibrate rapidly, stretching and bending chemical bonds that lock atoms to their neighbors. if bonds stretch too far and break, atoms detach from their original neighbors, move slightly, and from new bonds with other atoms. repetition of this process leads to rearrangement of atoms within grains, or to migration of atoms into and out of grains. stress: force applied to a given area; affects mineral stability and influences crystal size and orientation (rock texture). compression and shear stress, think of offset deck of cards when you move them. pressure and temperature: from sediment burial and mountain building along faults. deeper we go, the more pressure and the hotter it gets. chemical activity (hot fluids): includes fluids reacting with protolith minerals to form new minerals; mostly water that carries ions in solution.; hot water is more reactive than cold; typically low grade metamorphism. not all are required; often do co-occur.
Rock types, formation (basics), and type of geologic settings we find them?
igneous: intrusive forms from magma that cools below the surface with large crystals while extrusive forms from flowing lava at or near surface or from ejected magma fragments that form glossy deposits with small crystals. sedimentary: form from fragments of pre-exisitng rocks that cement together or from precipitated minerals from water solutions at or near the surface. metamorphic: forms when pre-existing rock undergoes changes in response to changes in temperature and pressure.
What are examples of climate reconstruction and how do we use them?
isotopic analysis—investigate changes in the concentrations of certain atomic isotopes.: isotopes—variation of a particular atomic nuclei. stable oxygen isotopes: oxygen has 8 protons, electrons, and neutrons, but it can vary. 16O or light -> most common ~99.7%. 18O or heavy.
How do humans impact change?
landscape modifications, ecosystem modifications, and pollution.
What are some of the volcanic hazards?
lava flows and fires, pyroclastic flow, ash, lahar, CO2 outgassing.
What are some volcanic features (e.g., pahoehoe, a'a', calderas)?
lava tubes: conduit created after cooled crust forms on top. pahoehoe: forms when extremely hot basalt forms a skin. a'a': forms when hot flowing basalt cools and thickens and with flow, lava crumbles into shards and fragments; jagged, sharp and angular in texture. columnar jointing: contraction, loss of heat, and tensile failure (fracturing) lead to polygonal columns. pillow lava: lava erupting underwater cools rapidly and is common along fissures at mid-ocean ridges. volcaniclastic deposits: ash and lapilli. pyroclastic flows: turbulent cloud of hot ash/glowing avalanche. tephra: unconsolidated pyroclastic deposits. tuff: ash and/or lapilli form a coherent rock. lahar: very fast, wet, ash-rich debris flow (slurry).
What are contour lines?
let's say there are three peaks on a mountain. you can measure the height above sea level of each peak and then climb to a certain height above sea level and walk around all three peaks while staying at the same height. these lines are called contour lines where are the lines of equal elevation above sea level. these measurements can be used to construct a two-dimensional map on a sheep of a map; this is a contour map.
Major mineral classes (e.g., silicates, carbonates).
main classes include silicate, oxide, sulfide, sulfate, halides/carbonates, native element class. silicates: most abundant and common in the Earth's crust. non-silicates Less than 5% of Earth's crust; oxides, carbonates, etc.
Describe two categories/types of mineral resources and provide examples.
metallic: Gold (Au), silver (Ag), copper (Cu), lead (Pb), zinc (Zn), iron (Fe), aluminum (Al) nonmetallic: Sand, gravel, gypsum, phosphate rock, dimension stone
What are the rock-forming environments?
metamorphic rock: deep within the Earth or where tectonic plates meet. igneous rock: erupting volcanoes and oozing fissures. sedimentary rock: on or near the Earth's surface
How do humans impact groundwater?
most wells are not artesian (they are dug into an unconfined aquifer) and most water must be pumped or lifted to the surface; this leads to cone of depression and over-pumping.also humans can cause land subsidence, reverse flow direction, salt water intrusions, and contamination.
What is orogenesis and where does this occur?
mountain building on convergent boundaries.
What is wind?
moving air driven by convection.
What are sedimentary structures and what are examples (e.g., cross beds)?
mud cracks (wet, then dry climate), ripple marks, cross bedding (think sand dunes), formation (beddings that come together), graded bed (large sediments on bottom, smaller ones on top).
What are braided rivers? What are their characteristics?
multiple channel system. interlaced channels with islands.high sediment load. common in arid/semi-arid regions; seasonal high flows. common in front of glaciers; large sediment load, fluctuating water flow.
What is the difference between native metals and mineral ore?
native metals occur naturally in a pure form. mineral ore is a rock with metal-rich minerals.
What are springs?
natural occurring outflow of water. occurs where water table intersects surface of the earth: high water table, fault and fracture controlled, perched water table, and impermeable layer.
What are nonrenewable resources? Provide examples.
non-renewable—cannot be replenished, or too slow with respect to human life span (hundreds to millions of years). examples: Uranium, natural gas, coal, soil; most of what we use.
What are examples of industrial and building minerals?
nonmetallic resources are called industrial minerals, like dimension stone, crushed stone/concrete, gypsum for wallboard, phosphate fertilizer, sand for glass, salt. crushed stone (aggregate) is used for many purposes: forms the foundation for all roads and railways, raw material for cement, concrete, and asphalt, used extensively in the construction industry. calcite—base material of cement and concrete. clay—bricks, pottery, porcelain, and other ceramics. gypsum—wallboard and plaster. quartz—used to make window glass. rare earth elements (REEs)—high-tech applications.
Where do we find earthquakes and at what depth might they occur (e.g. shallow)?
occur in the crust or upper mantle, which ranges from the earth's surface to about 800 kilometers deep (about 500 miles).
How is the understanding of mass wasting important for geology and humanity?
one of the most widespread natural hazards on Earth. U.S.: ~$1.4 billion and kill 20-50 people each year. catastrophic events are infrequent, but they do occur which leads to a false sense of security, so it is important to have a real understanding of these processes. plays a critical role in the rock cycle (transportation of sediment and landscape evolution).
Describe igneous rock formation and how it is important to us.
ore deposits are associated with igneous intrusions, ore is rock containing native metals or concentrated accumulation of ore minerals can be economically beneficial. insight into Earth's dynamic internal processes allows us to study hazards.
How do ore deposits form?
ores form via geological processes: magmatic activity, hydrothermal alteration, sedimentary deposits, residual mineral deposits, and placer deposits.
What are mass extinctions and what are some examples?
periods of time when many unrelated groups of organisms go extinct; these events correspond to major geologic time boundaries and these boundaries were originally defined by the fossils in them. example: Cretaceous-Paleogene extinction
Volcanic vs plutonic?
plutonic rocks are formed when magma cools and solidifies underground (intrusive). volcanic rocks are formed from lava that flows on the surface of the Earth then cools and solidifies (extrusive).
What is porosity and permeability? What causes these to change?
porosity: the amount of pore space in a rock, sediment, or soil.the total volume of open space; typically expressed as a percentage. two categories of porosity: primary and secondary. permeability: ability of a porous material to allow a fluid to pass through it.i what causes these to change? it depends on shape, packing, sorting, cementation, particle size, and interconnectedness of pore spaces.
What are the long term causes of glaciation?
positioning of continents near poles by plate tectonics and the Wilson Cycle and changes in ocean circulation due to re-positioning of the continents such as the closing of the Panama Strait.
What is the Principle of Uniformitarianism?
principle that geologic processes that occurred in the past can be explained by current geologic processes. (the present is the key to the past!!!) THINK HUTTON & LYELL
Explain the 3 processes associated with magmatic differentiation (e.g., assimilation).
process by which different rocks can form from a single magma. partial melting: refers to the process by which only part of an original rock melts to produce magma. assimilation: magma may incorporate chemicals dissolve from the wall rocks or from blocks that detached from the wall and sank into the magma. fractional crystallization: a process by which a chemical compound is separated into components by crystallization.
What does metamorphic grade tell us about the rocks?
progressive changes in rock texture and mineral content take place as the metamorphic grade increases. high grade is closer to the surface! degree of foliation is the primary characteristic for classification. start with a sedimentary rock like shale.
What is wave reflection?
ray bounces off of surface or material.
What is wave refraction?
ray is bent by surface or material.
What are the categories of metamorphic processes (e.g., regional, contact)?
regional metamorphism: burial places pressure on large regions and temperature is elevated. contact metamorphism: magma bakes (metamorphic rocks) or boils the surrounding rocks and this surrounds batholiths, dikes, sills. fault metamorphism (dynamic metamorphism): blocks of solid rock slid past each other; highly deformed or pulverized zone; relatively rare occurrence; creates stretched pebble conglomerate.
What are the consequences of continental glaciation?
reorganized river systems, flattened topography, and buried topography producing areas of erosion, old drift, and young drift.
What are renewable sources? Provide examples.
replenished in a reasonable amount of time (months to decades). examples: solar, wind, biomass, hydropower, geothermal.
What is viscosity and what causes it to change?
resistance to flow that depends on temperature, volatile content, and silica content. increase in temp, decrease in viscosity. increase in volatiles, decrease in viscosity increase in silica content, higher viscosity; more silica is felsic and less silica is mafic.
What is the difference between resources and reserves?
resource—total amount of existing material (estimate). reserves—what we obtain economically; change with price, technology, and legal climate. amount of reserves will be less than amount of resources.
What are meandering streams? What are their characterisitcs?
rivers that flow in a sinuous pattern. turbulent flow and velocity changes cause both erosion on one side and deposition on the other.erosion changes course of river.
What are sedimentary rocks? How do they form?
rock that forms at or near the Earth's surface such as: cementing together of loose clasts produced by physical and or chemical weathering of pre-existing rocks, or precipitation of minerals from water solution, or growth of shell masses or the cementation of shells and shell fragments, or accumulation and alteration of organic material.
What are fossils, what type of rock(s) do we find fossils in, and how are they preserved?
sedimentary and sediments; exceptions include volcanic ash and low grade metamorphic rocks. fossils are preserved when sedimentary rock forms around the remains of living things; tar is oil that seeped to the surface, volatiles evaporate and bacteria degrades; animals get stuck and can be as old as 40,000 or through amber/tree sap or sediments compact and conform to the shape of the shell of body; weathering and dissolution will break this down, but the cavity or mold will remain; more sediment will fill in the mold, preserving organism's shape; a cast is formed
What are the types of volcanoes (e.g., shield)?
shield volcano: broad, gentle domes (shape resembles a soldier's shield), form from low viscosity lava accreting over time, effusive (e.g. Mauna Loa Hawaii). lava/volcanic domes: high-viscosity magma, cools quickly into hardened plug, relatively small, bulbous masses, can be found in large caldera floors due to movement in the magma chamber beneath it. cinder cone: smallest type of volcano; short eruptions, conical piles of basaltic (and some andesitic) ejected ash and fragments around a vent and often symmetrical, with a deep crater. composite volcanoes/stratovolcanoes: large (up to 4km, 25km across) and cone-shaped, made up alternating layers of lava, tephra, and debris, i.e. xamples include Mt. Fuji and Mt. St. Helens.
What is the fundamental building block of Earth?
silica tetrahedron.
What are the metamorphic effects on texture and mineralogy?
stable minerals—ranges of temperature (T) and pressure (P). changes in T and P, mineral may transform into a new mineral which is stable in the new conditions. if you exceed the stable range, you will change a new mineral. some minerals form only over a limited range of pressure and temperature—these are good index minerals. Chlorite: low grade and far from the source. Staurolite: medium grade. Sillimanite: high grade.texture: texture is altered by changes in size, shape, and orientation of the minerals (old and/or new). directed pressure leads to alignment of minerals grains—differential stress. shear stress: stress that acts parallel to the surface in opposite directions. foliation: layering formed as a consequence of the alignment of mineral grains, or of compositional banding in a metamorphic rock. recrystallization: increased temperature and pressure can cause recrystallization of minerals into new shapes and sizes. mineralogy: regional, contact, fault metamorphism
Stalactites versus stalagmites?
stalactites grow down from the cave ceiling, while stalagmites grow up from the cave floor.
Define physical properties (e.g., streak, luster, cleavage)
streak: color in powdered form and can be found using a streak plate (same color as mineral = congruent or different color than mineral = incongruent). luster: the way a mineral surface scatters light; metallic and nonmetallic. hardness: scratching resistance of a mineral. crystal habit/shape: external expression of a mineral's internal arrangement of atoms. cleavage: the way a mineral breaks into smaller pieces of characteristic shape. fracture: some minerals do not exhibit cleavage and break into irregular surfaces. striation: very thin, parallel grooves caused by two or more inter-grown crystals formed in a symmetrical fashion.
What is the elastic rebound theory and what does it have to do with earthquakes?
stress builds and accumulates energy, deformation occurs, exceeds rock strength, there is release of stress, "snaps" and releases stored energy, waves travel outward form release points, but not all faults exhibit a surface rupture. in relation to earthquakes, elastic rebound is what happens to the crustal material on either side of a fault during an earthquake; a fault is stuck until the strain accumulated in the rock on either side of the fault has overcome the friction making it stick.
What are the different types of deserts (e.g., subtropical, rain-shadow)?
subtropical deserts: occur in high-pressure zones between 20 degrees & 30 degrees latitude; warm, dry air descends constantly. example: Sahara rain-shadow deserts: moist air rides up along mountains, rain forms due to cooling, and descends as dry air down leeward side. example: Great Basin and Mojave coastal deserts: deserts that form in warm coastal areas near cold ocean currents when the cool,.capacity to hold moisture. example: Atacama Desert, S. America (cold Humboldt Current) polar deserts: result from descending cold dry air, what little moisture exists stays frozen; air temperatures rarely exceed freezing.
What factors affect wind (e.g., density, Coriolis effect, landscapes)?
temperature - heating causes air to expand (thus becoming less dense) and rise; water molecules have lower mass than nitrogen and oxygen molecules, so...warm moist air is buoyant and rises, cool dry air is dense and sinks. humidity - moist air is less dense than dry air at any given Coriolis effect - the Earth rotates and this makes things traveling long distances around Earth appear to move at a curve as opposed to a straight line. landscapes - winds are present everywhere, but impact on landscapes is more apparent where: strong winds exist, little vegetation, fine grained soils with loose, dry particles.
What is strike and dip and what do they look like on a geologic map?
the "T" shapes are used to record the strike and dip of rock units that we can measure on the surface. the long line of the "T" tells us the N-S-E-W strike direction. the small line of the "T" indicates the N-S-E-W direction and angle that the rock layer makes with the surface.
What is strain? What are the different types?
the change in shape that happens when rocks are deformed by stress. shortening, stretching, shear.
Generally, how much energy is expended to allow certain grains to deposit (e.g., high energy large grains)?
the higher the energy (that is, the faster the wind or water is moving) the larger the grains that can be kept in suspension.
What is residence time?
the length of time water spends in the groundwater portion of the hydrologic cycle may be as little as days, or as much as 10,000 years or more.
Lithosphere-Asthenosphere Boundary
the lithosphere lies on top of the asthenosphere and the boundary between these two has high temperatures that allows for the mantle to soften for plates to move. 100-150km down and the Moho is above this boundary.
What is differential weathering?
the process by which softer, less weather resistant rocks wear away and leave harder, more weather resistant rocks behind.
What is flooding?
the stream leaving its channel and filling part or all of the floodplain, blanketing it with fresh sediment after the flood subsides. occurs when heavy rains dump large volumes of water quickly, long continuous rains have saturated soil pores, warm weather rapidly melts snow, or dam breaks.
What are the standard map requirements?
title, date, legend, scale, and direction. strike (T) & dip, anticlines & synclines, faults, and rock formations.
How does water move?
two forces influence groundwater movement: 1) gravity: all else equal, water will flow downhill. 2) water pressure: water will flow in direction of lower pressure. the velocity of groundwater flow is: proportional to the hydraulic gradient (rise/run) and proportional to permeability.
***What is the classification criteria (e.g. material type, velocity) and what do these criteria tell you about the type of mass wasting?
type of material (rock, regolith, mud) velocity (slow, intermediate, fast) character of moving mass (coherent, chaotic, slurry) environment (subaerial, submarine) speeds depend on slope angle and water content.
What are unsaturated zones, water tables, and saturated zones?
unsaturated zones: immediately below the land surface, contains water and air in the open spaces, or pores. saturated zones: a zone in which all the pores and rock fractures are filled with water, underlies the unsaturated zone. water tables: upper limit of the zone of saturation; depth is highly variable; shape is usually a subdued replica of the surface topography.
What are index minerals and how do they help in identification?
used in geology to determine the degree of metamorphism a rock has experienced. examples: chlorite, staurolite, sillimanite.
What is science?
using observations, experiments, and calculations to explain how something works and involves critical thinking which is a sequence of steps for systemically analyzing scientific problems in a way that leads to verifiable results.
What are proxy methods?
using pieces of information found in the natural environment to reconstruct historic climates through: trapped gas bubbles in glacial ice, fossil plankton in ocean sediments, tree growth rings, speleothems.
What is hydrophobic soil and how does this affect mass wasting?
when a waxy residue builds up on the soil particles resulting in it repelling water rather than absorbing it. can cause debris flow.
What is the difference between Richter and Mercali Scales?
while the Mercalli scale describes the intensity of an earthquake based on its observed effects, i.e. damages, the Richter scale describes the earthquake's magnitude by measuring the seismic waves that cause the earthquake.
What is glacier advancement and glacier retreat?
zone of accumulation—area of net snow addition; colder temperatures prevent melting; snow remains across the summer months. zone of ablation—area of net ice loss.zones meet at the equilibrium line.toe - the leading edge of a glacier; ice always flows downhill, even during toe retreat.