EPSC 201 W2020

paleozoic era

"ancient life" - the part of geologic time 570-245 million years ago; invertebrates, fishes, amphibians, reptiles, ferns, and cone-bearing trees were dominant. worldwide sea levels rose and fell several times. Taconic orogeny created pre-Appalachians

archean eon

"ancient or archaic" - (3.8 to 2.5 Ga). the beginning: first abundance of preserved crustal rocks formed, process of plate tectonics began during this eon or just before - protocontinents. the first life appeared during this period. first undisputed fossil dated at 3.2 Ga. strata from this eon contain stromatolites. 85% of current continental area formed.

proterozoic eon

"before life" - (2.5 to 0.542 Ga). there were several rounds of super-continent assembly and rifting during this eon, 90 % of continental crust formed by halfway point. growth of cratons. Rodinia and Pannotia - supercontinents. the great oxygenation event. banded iron formations. eukaryotes, ediacaran. first ice age 'snowball earth.'

hydraulic fracturing

"fracking"; the process of drilling and opening up the rocks containing natural gas, by drilling with water, sand, and proprietary chemicals, in order to release natural gas; often results in groundwater contamination and can cause significant structural damage to the ground

hadean eon

"hell" - (4.6 to 3.8 Ga). earth's surface remained a magma ocean >100 km deep until ~4.4 Ga. moon formed during this period and used to have an orbit much closer to earth. there was a very different atmosphere during this period. humans and other modern lifeforms could not have existed in these conditions.

mesozoic era

"middle life" - (245-144 million years ago); rise of mammals and *dinosaurs*; the rise of birds; extinction of dinosaurs, rise of flowering plants. pangaea breaks up.

Tiktaalik

"missing link" thought to be a transitional form between fish and tetrapods. life emerges from the sea around 420 million years ago.

cenozoic era

"recent life" - era that began about 66 million years ago, known as the "Age of Mammals" final breakup of pangaea as australia rifts from antartica and greenland rifted from north america. italy, turkey, iran, india, etc collide with eurasia. formation of the alpine-himalayan orogeny

precipitation from a solution

"seed crystals" form when a solution becomes saturated

principle of uniformitarianism

"the present is the key to the past," aka the processes seen today are the same as those of the past. geologic change is slow and large changes require a long time. many of the geologic structures we are familiar with formed long before humans walked the earth.

Homo erectus

"upright man" these hominids became skillful hunters and invented more sophisticated tools for digging, scraping and cutting. They became the first hominids to migrate from Africa. Also were the first to use fire. Earliest known use of tools 2.4 million years ago

phanerozoic eon

"visible life" - the most recent eon, 542 million years ago to present. eon defined by widespread, diverse lifeforms. carbonate shells, skeletal material enhanced fossil preservation. is divided into three eras: paleozoic, mesozoic, cenozoic.

James Hutton

(1726-97) A Scottish physician and farmer often called the "the father of modern geology." he identified features in rocks that resembled features forming in modern sedimentary environments. was the first to describe the "principle of uniformitarianism"

Von Humboldt

(1799) noted that the same symmetry existed between the coastline of S. America and that of S. Africa and that there were extensions of mountain ranges between the continents

bridgmanite

(Mg,Fe)SiO3 found in the lower part of Earth's mantle, between about 670 and 2,700 km depth. They are thought to form the main mineral phases

half-life

(t1/2) length of time required for half of the radioactive atoms in a sample to decay

five ways to form new crystals

1. solidification from a melt 2. precipitation from a solution 3. solid-state diffusion 4. biomineralization 5. precipitating directly from a gas

creation of an oil/gas reserve

1. source rock 2. migration pathway 3. reservoir rock 4. trap

Three Mile Island

1979 - A mechanical failure and a human error at this power plant in Pennsylvania combined to permit an escape of radiation over a 16 mile radius, focused US public concern

intraplate earthquakes

5% of earthquakes not near plate boundaries, remnant crustal weakness from ancient plate boundaries, stress transmitted to lithosphere from asthenosphere (ex. New Madrid, Missouri)

Kola Peninsula borehole

9 inches in diameter, but at 40,230 feet (12,262 meters) reigns as the deepest hole

Chernobyl

A city in Ukraine that was the site of a 1986 meltdown at a Soviet nuclear power plant.

biodiesel

A diesel-equivalent, processed fuel derived from biological sources (such as vegetable oils), that can be used in unmodified diesel-engine vehicles.

sierran arc

A large continental volcanic arc along western North America that was initiated at the end of the Jurassic Period and lasted until about 80 million years ago. plutons from this arc eroded and uplifted to form the sierra nevada

drawdown

A lowering of the groundwater level caused by pumping.

darcy's law

A mathematical equation stating that a volume of water, passing through a specified area of material at a given time, depends on the material's permeability and hydraulic gradient.

oxbow lake

A meander that has been cut off from the river

Appalachian Mountains

A mountain range in the eastern United States extending from Quebec to the Gulf of Mexico

meander neck

A narrow isthmus of land separating two adjacent meanders.

antecedent stream

A stream that cuts across an uplifted mountain range; the stream must have existed before the range uplifted and must then have been able to downcut as fast as the land was rising.

avalanche

A turbulent cloud of debris mixed with air that rushes down a steep hill slope at high velocity; the debris can be rock and/or snow. over-steepened snow that detaches with enough force to flatten forests and tend to reoccur in defined chutes. can be wet or dry

flood

A very heavy flow of water, which is greater than the normal flow of water and goes over the stream's normal channel when a stream exceeds channel capacity

artesian well

A well in which water rises because of pressure within the aquifer

garnet

A3B2(SiO4)3 fundamentally a mineral structure rather than a composition. A-site usually occupied by divalent cations, B-site occupied by trivalent cations.

anthracite coal

Anthracite coal is a form of coal that is almost made entirely of carbon. Anthracite coal is much harder than other forms of coal such as bituminous, and is usually found in areas surrounding mountains or deep valleys. about 90% carbon, forms along mountain belts when bituminous coal is heated further to 200-300 deg C. 8-10 km deep.

exotic terranes

Blocks of broken off land too buoyant to subduct that are sutured onto the upper plate, that collide, converge and attach to a continent

uvarovite

Ca3 Cr2 (SiO4)3. rare green garnet

apatite

Ca5(PO4)3(F,Cl,OH) a biogenic mineral that comprises vertebrate bones and our own tooth enamel

aragonite

CaCO3 a biogenic mineral created by oysters, mussels, and other marine life for shells

calcite

CaCO3, common in biogenic minerals. known for it's ability to effervesce when it comes in contact with HCl and it's double refraction property

CANDU reactor

Canadian made and invented nuclear power plants

middle paleozoic

Consists of Silurian and Devonian periods. Often called Age of Fishes. Some invertebrates lived on land (cockroaches and dragonflies) Continents colliding forming mountain ranges. crustaceans, spiders, scorpions, insects. land plants evolved and developed protective tissues, vascular systems, seeds, size

coal gasification

Conversion of solid coal to synthetic natural gas (syngas). Coal is extracted and pulverized, steam and oxygen are then passed through the coal at a high temperature. The resulting flammable gas is recovered for use as a fuel

basaltic

Describes dense, dark-colored igneous rock formed from magma rich in magnesium and iron and poor in silica.

late paleozoic

Devonian, Mississippian, Pennsylvanian, Permian periods. defined by global cooling and regressing seas. formation of thick coal beds in the subtropics. formation of pangaea, alleghanian orogeny

olivine

Fe(0.2)Mg(1.8)SiO4 a mineral that is representative of mantle composition. has a Mg # of 9. distinctive green color

hematite

Fe2O3 mineral with a characteristic brown streak

GPS

Global Positioning System, can be used to measure mountain growth

turbulent flow

Irregular stream flow with random variations in pressure caused by irregularities in the bank and bottom, objects in the water and steep gradients

jovian planets

Jupiter, Saturn, Uranus, Neptune

submarine fans

Large fan-shaped deposits of fine-grained sediments that accumulate on the continental rise

nevadan orogeny

Late Jurassic to Cretaceous phase of the Cordilleran orogeny; most strongly affected the western part of the Cordilleran mobile belt

passive continental margin

Margins that consist of a continental shelf, continental slope, and continental rise. no plate boundary; distant spreading center, typically broad continental shelf. commonly think sedimentary cover and basins. little or no seismicity. originates after rifting end, sea-floor spreading begins.

halite

NaCl, rock salt. parallelepiped faces.

r-waves

Rayleigh waves. p-waves that intersect the land surface. causes the ground to ripple up and down like water.

cratonic provinces

Shields: Precambrian metamorphic and igneous rocks Platforms: shields covered by layers of Phanerozoic strata

permanent streams

Streams that have water flowing all year, typically in places of high rainfall and low evaporation. exist at or below the water table

coriolis effect

The effect of Earth's rotation on the direction of winds and currents, forms nearly closed gyres

cambrian

The first period in the Paleozoic era, between the end of the archean eon and the beginning of the Ordovician period.

stream runoff

The precipitation that is not used by plants, and does not evaporate, and travels to streams

a'a'

a Hawaiian word describing basalt that solidifies with a jagged, sharp, angular texture forms when hot flowing basalt cools and thickens then with flow crumbles into shards and fragments

pahoehoe

a Hawaiian word describing basalt with a glassy, ropy texture forms when extremely hot basalt forms a skin

glaucophane

a blue amphibole mineral favored by the low geothermal conditions of subduction metamorphism, results in the blue color of blue schist

plutons

a body of intrusive igneous rock.

unconformity

a break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time. three types: angular, nonconformity, disconformity

stair step canyon

a canyon created when variations in resistance to erosion result in a stair-step profile along canyon walls

gyre

a circular motion of water in each of the major ocean basins that can trap biologic materials and debris

coal

a combustible black or dark brown rock consisting mainly of carbonized vegetation that accumulates in an anoxic setting, found mainly in underground deposits and widely used as fuel. often formed in marine deltas and tropical coastal wetlands as sea level rises and buries vegetation deposits under clastics

trilobites

a common animal that lived in Earth's oceans during the Paleozoic Era. They are most closely related to the modern Horseshoe Crab.

alluvium

a commonly used term for stream sediments

kerogen

a complex fossilized organic material that is solid and waxy, formed when shale is buried and heating breaks down organics, found in oil shale and other sedimentary rock, that is insoluble in common organic solvents and yields petroleum products on distillation.

laurentia

a continent in the early Paleozoic Era composed of today's North America and Greenland

Cascadia Subduction zone

a convergent plate boundary that stretches from northern Vancouver Island to northern California. site of the 1700 megathrust event

siberian craton

a craton that formed during the early paleozoic

seismic reflection profile

a cross-sectional view of the crust made by measuring the reflection of artificial seismic waves off boundaries between different layers of rock in the crust.

eddy

a current, as of water or air, moving contrary to the direction of the main current, esp. in a circular motion

mare

a dark, basaltic plains on the surface of the moon

basalt

a dark, dense, extrusive igneous rock with a fine texture, found in oceanic crust

magnetometer

a device that can detect small changes in magnetic fields

rock formation

a distinct set of rock layers (package) that can be identified throughout a region by its physical properties and possibly by the assemblage of fossils it contains; able to be mapped. named for the places they are best exposed

East African rift valley

a divergent tectonic boundary stretching from East Africa to the Middle East that is the richest context for the recovery of early hominin archaeological sites

trellis

a drainage pattern in which the stream trunk flows through resistant rocks and tributaries flow between ridges that is common where the surface alternates between erodible resistant materials

rectangular

a drainage pattern that follows faults and cracks in the ground. most of these faults are straight. channels are aligned primarily in two directions. common in gently sloped areas of orthogonally jointed rocks

parallel

a drainage pattern where several streams have parallel courses that is common in areas with a uniform slope

oblique slip fault

a fault in which sliding occurs diagonally along the fault plane, components of both dip slip and strike slip faulting

normal fault

a fault in which the hanging wall moves down relative to the footwall. accommodates crustal extension (pulling apart). can create fault-block mountains and basins

sheetwash

a film of water less than a few mm thick that covers the ground surface during heavy rains. erodes the substrate, forming channels.

phyllite

a fine-grained mica-rich rock. low-intermediate grade metamorphism of slate. clay minerals neocrystallize into tiny micas. has a silky sheen called phyllitic luster. is between slate and

flash flood

a flood with great volume and of short duration that is usually caused by heavy rainfall or dam failures

nonplunging fold

a fold in which the hinge line (or axis) is NOT tilted

plunging fold

a fold in which the hinge line (or axis) is tilted. ex: Sheep Mountain, WY

basin (fold)

a fold shaped like an upright bowl. exposes younger rocks in the center

anticline

a fold that looks like an arch. limbs dip out and away from the hinge

dome (fold)

a fold that looks like an overturned bowl. exposes older rocks in the center

syncline

a fold that opens upward like a trough, limbs dip inward and toward the hinge

fullerine

a form of carbon that consists of atoms arrange in the shape of a hollow sphere

shock quartz

a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure (but limited temperature), the crystalline structure of quartz is deformed along planes inside the crystal. has been considered to be an unequivocal signature of the impact of an extraterrestrial object such as a meteorite. can also be produced by lightning

natural gas

a fossil fuel in the gaseous state, more abundant than oil and a cleaner fuel. short-chain hydrocarbons: methane, ethane, propane, butane, and others. form at temperatures just above the oil window.

index fossil

a fossil known to have lived in a particular geologic age that can be used to date the rock layer in which it is found

continental shelf

a gently sloping, shallow area of the ocean floor that extends outward from the edge of a continent formed from passive-margin continental crust that thins seaward

tsunami

a giant wave usually caused by an earthquake beneath the ocean floor, extremely destructive

scoria

a glassy, mafic, igneous rock containing abundant air-filled holes

silica tetrahedron

a grouping of one silica ion and four oxygen ions that forms the basic building block of a silicate

geode

a hollow stone found on the earth that is lined on the inside with crystals

thrust fault

a kind of reverse fault, low angle. is a common fault type in compressional mountain belts.

hydrocarbon reserve

a known supply of oil and gas held underground

strip mining

a large drag-line bucket removes overburden (spoil) and then exposed coal is removed. hazard: acid mine damage

Marcellus shale

a large shale in North America which provides a lot of natural gas

monocline

a large steplike fold in otherwise horizontal sedimentary strata, like a carpet draped over a stair step. does NOT cut through to the surface, displacement folds the overlying sedimentary cover

abyssal plain

a large, flat, almost level area of the deep-ocean basin

unsaturated zone

a layer of rocks and soil above the water table in which the pores contain air as well as water

orogen

a linear range of mountains

Alpine-Himalayan orogenic belt

a linear zone of orogenic deformation extending from the Atlantic eastward across southern Europe and North Africa, through the Middle East and into Southeast Asia. the longest one on earth. formed as a result of continental collision during the cenozoic era

serpentinization

a low temperature metamoprhic process that often occurs in the ultramafic rocks near MORs

gabbro

a mafic, coarse-grained igneous rock composed predominantly of ferromagnesian minerals and with lesser amounts of calcium-rich plagioclase feldspar. basalt with larger crystals

ring of fire

a major volcanic arc along pacific margins; volcanoes develop on the overriding plate; continental and oceanic island arcs are both common

mantle plume

a mass of hotter-than-normal mantle material that ascends toward the surface, where it may lead to volcanic activity

scree

a mass of loose stones that form or cover a slope on a mountain

silica

a material found in magma that is formed from the elements oxygen and silicon, SiO2

competence

a measure of a stream's ability to move clasts of varying size; changes with discharge

volatility

a measure of how readily a substance vaporizes

hardness

a measure of the ability of a mineral to resist scratching as compared to the Mohs hardness scale

slab-pull

a mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and "pulls" the trailing lithosphere along

sulfides

a mineral consisting of a metal element combined with sulfur (ex. galena, pyrite, sphalerite) where a metal cations is bonded to a sulfide anion

gemstones

a mineral with special value - rare and/or beautiful

cleavage

a mineral's tendency to split along regular, well-defined planes of weaker atomic bonds. produces flat, shiny surfaces. not the same as crystal habit because this is internal, crystal habit describes only the outer faces

sevier orogeny

a mountain-building event that affected western North America between about 150 Ma and 80 Ma, a result of convergent margin; a fold-thrust belt formed during this event forming the canadian rockies

mineral

a naturally occurring usually inorganic (usually) solid with a crystalline structure that is formed geologically

quartzite

a non-foliated metamorphic rock that is almost pure quartz in composition. forms by the alteration of quartz sandstone when sand grains in the protolith recrystallize and fuse. breaks by conchoidal fracture cutting through grains.

hornfels

a non-foliated metamorphic rock, fine-grained, variety of metamorphic clay minerals that sedimented as mudstone protolith. associated with plutonic intrusions.composition depends upon protolith, P & T

cygnognathus

a nonswimming, land-dwelling mammal-like reptile, evidence for continental drift

The Origins of the Continents and Oceans

a novel written by Alfred Wegener in 1915 in which he hypothesized a former supercontinent, Pangaea. suggested continental drift and offered evidence

rapids

a part of a stream characterized by a turbulent flow of water that reflects a steep gradient and/or high friction. ex: flow over bedrock step/large clasts, narrowing of a channel, increase in gradient

migmatite

a partially melted gneiss that has features of both igneous and metamorphic rocks, behavior is controlled by mineralogy. light-colored felsic minerals melt at a lower temp, dark-colored mafic minerals melt at a higher temp

marker bed

a particularly unique layer of rock that provides a definitive basis for correlation

permian

a period in the late paleozoic known for the first mammal-like reptiles (Dimetredon) as hard-shelled eggs allowed for reproduction on land. widespread gymnosperms, cycads. large mass extinction event at the end of this period in which > 95% of marine species disappeared. possibly related to intense volcanism that changed the atmosphere and oceans

xenolith

a piece of rock within an igneous rock that is not derived from the original magma but has been introduced from elsewhere, especially the surrounding country rock.

waterfall

a place where the gradient is so steep that water cascades or free falls. results in a deep plunge pool at the base of the gradient.

oceanic hot spot

a plume under an oceanic plate

whirlpool

a powerful circular current of water (usually the resulting of conflicting tides)

perched water table

a quantity of groundwater that lies above the regional water table because an underlying lens of impermeable rock or sediment prevents the water from sinking down to the regional water table

butte

a raised, flat area of land with steep cliffs, smaller than a mesa

tributary

a river or stream flowing into a larger river or lake.

source rock

a rock (organic-rich shale) containing the raw materials from which hydrocarbons eventually form is heated sufficiently. always sedimentary

Mohs Hardness scale

a scale ranking ten minerals from softest to hardest; used in testing the hardness of minerals

richter scale

a scale that rates an earthquake's magnitude based on the size of its seismic waves, useful near the epicenter

moment magnitude scale

a scale that rates earthquakes by estimating the total energy released by an earthquake, Mw current scientific measure

graded beds

a sediment layer characterized by a decrease in sediment size from bottom to top

redbeds

a sedimentary bed that has developed a reddish color. the red comes from a film of iron oxide (hematite) that forms on grain surfaces.

Nuvvuagittuq faux amphibolites

a sequence of metamorphosed mafic to ultramafic volcanic and associated sedimentary rocks (a greenstone belt) located on the eastern shore of Hudson Bay, 40 km southeast of Inukjuak, Quebec. 4.28 billion years old

decay chain

a series of decays that certain radioactive isotopes go through until reaching a stable isotope

oil shale

a shale containing 15-30% kerogen, source rock that has not yet reached the oil window.

graphite

a shiny, black substance that is used in pencils. comprised completely of carbon, atoms are arranged in sheets.

graphene

a single sheet of carbon atoms (like one layer of graphite)

crystal

a single, continuous piece of a crystalline solid. typically bounded by flat surfaces

sill

a slab of volcanic rock formed when magma squeezes between layers of rock

debris slide

a slide comprised mostly of regolith; movement down the failure surface is sudden and deadly. slide debris can move at 300 km per hour on a cushion of air

rock slide

a slide consisting of rock only

Wadati-Benioff zone

a sloping band of seismicity defined by intermediate- and deep-focus earthquakes that occur in the descending slab of a convergent plate boundary

laminar flow

a smooth pattern of stream flow

parallelepiped

a solid body of which each face is a parallelogram. Also known as "cubes" or "prisms". (ex. halite)

Homo sapiens

a species of the creatures Hominid who have larger brains and to which humans belong, dependent of language and usage of tools. diverged from Homo neanderthalensis about 500 thousand years ago. modern members of this species appeared about 200 thousands years ago

continental slope

a steep incline of the ocean floor leading down from the edge of the continental shelf; 500m to 4 km of depth

thermocline

a steep temperature gradient in a body of water such as a lake, marked by a layer above and below which the water is at different temperatures.

braided stream

a stream consisting of numerous intertwining channels as a result of abundant sediment that chokes the flow of water creating ephemeral and gravel bars

anticline trap

a structural arch that traps oil, an upward fold in rock formed by compression of Earth's crust within a permeable bed such as sandstone

glossopteris

a subpolar plant with heavy seeds that was found in matching fossil records across continents

Rodinia

a supercontinent older than Pangaea that formed about 1.1 billion years ago and began to break up about 750 million years ago (proterozoic eon). is concurrent with the Grenville orogeny. precursors of present-day continents could be identified.

X-ray crystallography

a technique that depends on the diffraction of an X-ray beam by the individual atoms of a crystallized molecule to study the three-dimensional structure of the molecule (XRD)

equant

a term for a grain that has the same dimensions in all directions

inequant

a term for a mineral grain whose length and width are not the same

foliation

a texture of metamorphic rocks defined by the alignment of platy minerals (like mica) and the creation of alternating bands

yazoo stream

a tributary unable to enter the main stream because of natural levees along the main stream

wet avalanche

a type of avalanche that behaves like viscous slurry. hugs the slopes, entraining little air. move relatively slowly at ~30 km/hour

dry avalanche

a type of avalanche that moves cold, powdery snow above the ground surface on a layer of pressurized air moving rapidly at ~250 km/hour

debris flow

a type of mudflow (mass movement) with many large rocks

composite stratigraphic column

a type of stratigraphic column assembled from incomplete sections across the globe. brackets almost all of earth history

lithographic correlation

a type of stratigraphic correlation based on rock type, is regional. sequence is the relative order in which the rocks occur. marker beds have unique characteristics to aid correlation.

disconformity

a type of unconformity in which the sedimentary layers above and below the unconformity are parallel (parallel strata bounding nondeposition). often hard to recognize. occurs when there is an interruption in deposition

magnitude

a uniform measurement of size. the maximum amplitude of ground motion. measured by a seismometer at a specific distance. scales are log32 in energy

Juan de Fuca plate

a very active fault off the coast of Northern California where subduction occurs as this plate slips underneath the north american plate, Cascadia subduction zone.

batholith

a very large igneous intrusion extending deep in the earth's crust. a mark of former subduction

pumice

a very light and porous volcanic rock formed when a gas-rich froth of glassy lava solidifies rapidly.

left lateral strike slip

a viewer looking across to the other side of a fault would observe it to be offset to their left

right lateral strike slip

a viewer looking across to the other side of a fault would observe it to be offset to their right

seamount

a volcanic mountain rising from the ocean floor that doesn't reach the surface

Tambora eruption

a volcano on Sumbawa, Indonesia that erupted 10 april 1815, killing 71000 people. the following year was the "year without a summer." a year-long climate depression caused a global crop failure and resulted in the worst famine of the 19th century

levee

a wall of earth that prevents a river from flooding its banks; natural or manmade

accretionary prism

a wedge-shaped mass of sediment and rock scraped off the top of a down going plate and accreted onto the overriding plate at a convergent plate margin. has a low geothermal gradient that favors the creation of blueschist

earliest mineral grain

a zircon crystal found in the Jack Hills region of Western Australia dated to 4.404 billion years

linear grooves

abrasions that form due to the movement of a fault. They show the movement of a fault in a shear zone, especially in hard brittle rock, type of slip lineation

air-fall tuff

accumulations of ash that fall like snow

loading

adding weight to the top of a slope; water, materials, structures

salt-dome trap

aka diaper. salt buoyancy and plastic flow disrupt nearby rocks, forming traps. this kind of trap produced the first large oil fields that were developed in Texas.

strike-slip fault

aka transcurrent or transform fault, one block slides laterally past the other block. little or no vertical motion. fault plane is essentially vertical

framework silicates

all four oxygens in each silica tetrahedra are shared (ex. feldspars, silica-quartz group)

gneissic banding

alternating layers or lenses of light and dark medium to coarse grained minerals; develops via: original layers in protolith, extensive high temperature shearing, and metamorphic differentiation

stick-slip behavior

alternation between stress buildup and slip events

taconic orogeny

an Ordovician episode of mountain building resulting in deformation of the Appalachian mobile belt

confined aquifer

an aquifer beneath an aquitard, isolated from the surface, less susceptible to pollution

unconfined aquifer

an aquifer that intersects the surface and is in contact with the atmosphere, easily contaminated

floodplain

an area along a river that forms from sediments deposited when the river overflows its banks

hot spot

an area where magma from deep within the mantle melts through the crust above it

drainage network

an array of interconnecting streams that together drain an area

fold-thrust belt

an assemblage of folds and related thrust faults that develop above a detachment fault. center of belt consists of high-grade metamorphic rock

Cascadia megathrust event

an earthquake in 1700 that occurred as the Juan de Fuca plate slipped beneath the N. American plate resulting in a 8.7-9.2 moment magnitude earthquake, extremely deadly. caused a huge tsunami that reached Japan.

fuel cells

an electrochemical cell that uses renewable substances such as hydrogen or oxygen or water to convert energy to electricity. efficient and clean

uranium

an element that occurs naturally in many rocks in varying amounts. is often leached from plutons and transported by water. may precipitate in fractures and veins as pitchblende (UO2). has two major isotopes: 238U (99.3%, not fissionable) and 235U (0.7%, fissionable).

cordilleran orogeny

an episode of deformation affecting the western margin of North America from Jurassic to Early Cenozoic time; divided into three separate phases called the Nevadan, Sevier, and Laramide orogenies

pleistocene epoch

an epoch of the Quaternary period beginning about 1.8 million years ago and ending about 10,000 years ago. Best known as a time of extensive continental glaciation beginning ~ 2.5 million years ago. ice advanced and retreated ~20 times.

graptolites

an extinct marine invertebrate animal of the Paleozoic era, forming mainly planktonic colonies and believed to be related to the pterobranchs.

trap

an impermeable capping seal rock that acts as a structure to localize hydrocarbons

mesa

an isolated flat-topped hill with steep sides, found in landscapes with horizontal strata

stable isotope

an isotope that does not break down and does not emit particles or rays, are the eventual breakdown products of radioisotopes

radioactive isotope

an isotope whose nucleus decays spontaneously, giving off particles and energy.

coal swamp

an oxygen-poor environment where, over a period of time, decaying plant material changes into coal

mid-ocean ridge

an undersea mountain chain where new ocean floor is produced; a divergent plate boundary. lots of heat flow

inclination

angle between magnetic field line and the surface of the Earth. depends on latitude

pumice lapilli

angular pumice fragments formed from frothy lava

growth rings

annual layers from trees or shells

rhythmic layerings

annual layers in sediments or ice

talus

another word for scree

feldspar

any of a group of hard crystalline minerals that consist of aluminum silicates of potassium or sodium or calcium or barium

biochemical sedimentary rock

any sedimentary rock produced by the chemical activities of organisms, have a crystalline (interlocking) texture.

gem minerals

attract human passions

pyroclastic flow

avalanches of hot ash that race downslope (200 to 450C), can move up to 300 kmh, incinerates everything in its path ex: mount vesuvius, mount pelee, mount augustine

eukaryotes

bacteria with nuclei that evolved during the proterozoic eon ~2.7-2.1 Ga.

fault type

based on relative block motion

intercontinental basins

basins that form in interiors far from margins, may b e linked to failed crustal rifts. continue to subside for millions of years after formation

foreland basins

basins that form on the continent side of a mountain belt because the forces produced during convergence or collision push large slices of rock up faults and onto the surface of the continent.

rift basins

basins that occur at divergent boundaries, crust thins by stretching and rotational normal faulting then thinned crust subsides, sediment fills the down dropped troughs

passive margin basin

basins that occur over thinned crust at the edge of an ocean basin

early paleozoic

beginning of an era, characterized by vast, shallow epicontinental seas and platform deposits. he rifting of Pannotia created new ocean basins, the Siberian craton, Baltica, Laurentia, Gondwana

chert

biochemical sedimentary rock, made from cryptocrystalline quartz (opal). from silica (SiO2) skeletons of some marine plankton. silica in pore fluids solidifies into a gel which precipitates as nodules or beds. also found in fossilized wood

strike slip fault

blocks move parallel to fault plane strike

dip slip fault

blocks move parallel to the dip of the fault. move up or down the slop of the fault. types: reverse fault (& thrust fault, special type of reverse fault), normal fault

Principles of Geology

book written by Sir Charles Lyell in 1830-33. laid out a set of principles for deciphering earth history. used to establish relative ages of earth materials, the principle of uniformitariansism

bedding plane

boundary between two sedimentary rock layers

epicontinental seas

broad shallow seas connected to the ocean that covered continental interiors during the early paleozoic

shield volcano

broad, slightly dome-shaped; effusive constructed by lateral flow of low-viscosity basaltic magma) low slope and cover large geographic areas ex. mauna loa, hawaii

submarine debris flows

broken material moves as a slurry of mud with larger clasts, material moves as a slurry

fission waste

by-products of the nuclear reaction include highly radioactive wastes and toxins that remains hazardous for many half-lives—that is, hundreds of thousands of years or longer. storage/disposal is a multifaceted and complex societal issue

phlegraean fields

campi flegrei; the site of the city of naples, sits within the caldera of a supervolcano had major eruptions 39000 and 15000 years ago mt. vesuvius

fault motion

cannot occur indefinitely, arrested by friction. occurs in jumps

organic sedimentary rock

carbon-rich remains of once living organisms (ex. coal)

characteristic symmetry

caused by ordered atomic patterns in minerals. results in mirror images or the ability to rotate about an axis/axes. can be used to identify a mineral

magnetic reversals

changes in Earth's magnetic field over geologic time, recorded in ocean-floor rocks and continental basalt flows. no one knows why these flips occur. occur in a geologically rapid timespan. occur at uneven intervals

river environments

channelized sediment transport, sand and gravel fill up concave-up channels. fine sand, silt, and clay are deposited on nearby flood plains

travertine

chemical sedimentary rock formed when CaCO3 precipitates from groundwater where it reaches the surface. often occurs at thermal springs and caves (speleothems). the Colosseum is made of this

dolostone

chemical sedimentary rock, limestone altered by Mg-rich fluids.

replacement chert

chemical sedimentary rock, nonbiogenic. cryptocrystalline silica gradually replaced by calcite ling after limestone has been deposited. comes in many colors/varieties (ex. flint, agate, petrified wood)

independent tetrahedra

class of silicate mineral. shares no oxygens, linked by cations. (ex. olivine, garnet)

single chain silicates

class of silicate that shares two oxygens. (ex. pyroxenes)

rank

classification of coal based on carbon content

mineral classes

classified by their dominant anion

near base level

close to the lowest point to which a stream can erode its channel; gradient is nearly flat, discharge is high, competence is low (sediments are fine), channels meander

accretion lapilli

clumps formed by falling through moist air

phaneritic

coarse grained

mineral properties

color, crystal shape, hardness, magnetization, specific gravity, streak, luster, crystal habit, fracture or cleavage

bolide impact

comet or asteroid hits the Earth, iridium rich clay layer mark these events around the world

bearing

compass direction along a line from one point to another

hydrocarbons

complex organic molecules consisting of only carbon and hydrogen, usually in rings or chains. size of this molecule determines viscosity and volatility. short chains are gases, medium are liquid (gasoline, petroleum), long are solid (tar)

stream flow

concentrated flows of water in channels; is crucial for humans: drinking, irrigation, industrial use, transportation, recreation, aesthetics, energy

obsidian

conchoidal fracture pattern. volcanic glass, produces extremely sharp edges. was used in native cultures to make tools and weapons

scoria cones (cinder cones)

conical piles of tephra; smallest type of volcano built of ejected lapilli and blocks up at a vent often symmetrical, with a deep summit crater typically from a single eruption event small pyroclastic eruptions

two types of lithosphere

continental and oceanic

volcanic rock

cooled fragments of pyroclastic debris broken up by eruption

chicxulub crater

crater that formed when a meteorite collided with earth approximately 66 Ma ago. the impact would have created a 2 km high tsunami. crater is 100 km wide and 16 km deep. sediments from around the world at this time show a layer of clay containing iridium between layers of plankton skeletons (disruption of plankton ecosystem), shock quartz, ash, glass spherules.

cross beds

created by ripple and dune migration

craton

crust that hasn't been deformed since 1 Ga. has a low geothermal gradient (cool, strong, stable). consist of distinct orogens, blocks, and terrains.

faults

crustal breaks where movement occurs. abundant in the crust, occur at all scales. sudden movements along these breaks cause earthquakes. can be active or inactive

glassy

crystal unable to form; rapid rate of cooling prevents crystals from forming

interfacial angles

crystals demonstrate constancy in these angles, same faces. reflects internal crystalline structure

solidification from a melt

crystals grow when melt cools, liquid freezes to form solid

gems

cut and polished stone created for jewelry, usually rare and expensive. do not have natural crystal faces

seismogram

data recording earthquake wave behavior. earthquake waves arrive at a station in a specific order. p-waves, s-waves, then l-waves

numerical ages

dating geologic materials based upon the actual number of years since an event. a quantitative method that was developed recently

relative ages

dating geological materials based upon order of formation. a qualitative method that was developed hundreds of years ago.

submarine canyons

deep, steep-sided valleys that cut into the continental slope and are associated with large (current or former) rivers. canyons eroded through shelves during sea-level lows. deeper parts of canyons eroded by turbidity currents.

brittle deformation

deformation caused when rocks break by fracturing. occurs in the shallow crust

ductile deformation

deformation caused when rocks deform by flowing and folding. occurs at a high temperature and pressure within the deeper crust. starts occurring at approximately 10-15 km depth (continental crust)

sphericity

degree to which a clast nears a sphere; increases with transport distance

turbidity currents

dense current that carries large amounts of sediment down the continental crust

coal extraction

depends on depth, strip mining if < 100 km deep. mountain top removal in hilly areas like West Virginia, underground mining for deep seams

earthquake damage

depends on magnitude, distance from hypocenter, and the nature of the subsurface material. liquefaction, fires, tsunamis, disease

viscosity

depends on silica content of the lava; increases with increased silica content, as well as increased temperature, gas content, and crystal content

point bar

deposit of sediment build up by a river on the inside bend of a meander

terrestrial environment

deposited above sea level

marine delta environments

deposited at sea level, sediment carried by the river is dumped when velocity drops. they grow over time, building out the basin. many sub-environments present

stratigraphic trap

depositional features (such as sand "pinch-out" between shales) create traps

bathymetry

depth variations and bottom topography of the sea floor

stratigraphic column

describes the sequence of strata. formations can be traced over long distances. contacts define boundaries between formations or beds. several formations may be combined as a group

porphyritic

describing an igneous rock composed of both large and small crystals, indicates a two stage cooling history

Sir Charles Lyell

developed the study of geology, believed the earth took millions of years to form. wrote the "Principle of Geology" (1830-33)

preferred orientation

development occurs when compression and shear combine with elevated temperature and pressure. minerals rotate and grow the way they want

hardest mineral

diamond

transportation

dispersal of sediment and detritus by gravity, wind, water, and ice

matching geologic units

distinctive rock assemblages and mountain belts match across the Atlantic

Mid-Atlantic Ridge

divergent boundary in the middle of the Atlantic Ocean. 1500 km wide and 2km above abyssal plains. symmetrical. new sea floor created along axis

nonmetallic luster

does not reflect light like a metal; silky, glassy, satiny, resinous, pearly, earthy

amphiboles

double chain silicate minerals, dark long crystals, two cleavages at 60 and 120

dendritic

drainage pattern resembling the branches of a tree that is common in regions with uniform material

radial

drainage pattern that is characterized by draining in all directions away from a point, usually found at the perimeter of a high/elevated region or feature

glacial environments

due to movement of ice. creates glacial till, poorly sorted gravel, sand, silt, and clay. ice carries and dumps every grain size.

Vine and Matthews

duo who used magnetic striping on the seafloor to help prove sea-floor spreading. noted that the pattern of positive and negative stripes of polarity is symmetric on either side of the MOR

correlating formations

earth history is recorded in sedimentary strata. formations can be correlated over long distances. ex: layers of the Grand Canyon

seismicity

earthquake activity

permeability

ease of fluid movement through pore space. low results in small well yields, vice versa.

special physical properties

effervescence, magnetism, taste

bombs

ejected as hot lava, roundish streamlined shape

hydroelectric power

electricity produced by flowing water when dams halt the flow of water, converting kinetic energy to potential energy by storing water at higher elevation

isotopes

elements that have the same number of protons but different number of neutrons. have similar but different mass numbers. can be stable or radioactive

ridge-push

elevated MOR pushes lithosphere away

renewable energy

energy from a source that is not depleted when used, such as wind or solar power.

solar energy

energy from the sun that is converted into thermal or electrical energy via photovoltaic panels, the most abundant energy source at earth's surface

7 sources of energy

energy from the sun, from gravity (hydroelectric), photosynthetic energy, from chemical reactions, nuclear fission, and earth's internal heat

nuclear power

enormous amounts of energy harnessed from fission reactions among radioactive isotopes is a nuclear reactor

miocene epoch

epoch of the cenozoic era 23 million - 5.3 million years ago. human genus of primates (Homo) appeared 2.4 Ma.

blocky or equant crystal habit

equal growth rate in three dimensions

Mt. St. Helens eruption

erupted 18 may 1980 the volcano bulged as the magma chamber filled, it exploded vertically initially followed by a much larger lateral blast that moved 440 m of debris also triggered a landslide that released a lot of pressure lahars plugged the toutle river and closed the columbia, highways and railways stopped destroyed timber was valued at several million dollars killed 61 people

active

erupting, recently erupted or likely to erupt

parts of the hydrologic cycle

evaporation, transpiration, precipitation, sublimation, infiltration, melting, runoff

alternating magnetism on the sea floor

evidence for sea floor spreading, recorded in sea floor basalts.

regression

exposure due to sea level fall, depositional belts shift seaward, strata shallow upward. tied to erosion, less likely to be preserved.

archaeopteryx

extinct primitive toothed bird of the Jurassic period having a long feathered tail and hollow bones. first feathered birds, shows reptilian and bird-like characterisitics.

mountain stream environments

fast-flowing water carries large clasts during floods. during low flow, these large boulders and cobbles are immobile. course conglomerate is common

fault geometry

fault orientation that varies with the relative motion of the offset block

brittle faulting

faulting that results in shattered and crushed rock

blind faults

faults that don't reach the surface

deep marine environments

fine sediments settle out far from land. skeletons of planktonic organisms make chalk or chert. fine silt and clay lithifies into shale

schist

fine to coarse metamorphic rock with abundant larger micas like biotite and muscovite. forms at higher temperatures than phyllite. distinct foliation derived from large micas called schistosity.

oil shales

fine-grained sedimentary rock rich in solid organic material called kerogen

mud

fine-grained sediments; silt, clay

shallow-marine clastic deposits

finer sands, silts, muds. finer sediments deposited offshore where energy is low. turn into siltstones and mudstones. usually supports an active biotic community

coal bed fires

fires that occur naturally, are hard to extinguish, and render areas uninhabitable

Chalk River incidents

first ever nuclear reactor accidents, occurred in the 1950s in Ontario, Canada.

Shaw Gusher

first gusher, drilled in Oil Springs, Ontario in 1861

evidence of continental drift

fit of continents, glacial deposits far from polar regions, paleoclimatic belts, distribution of fossils, matching geologic units

natural gas

flammable gas, consisting largely of methane and other hydrocarbons, occurring naturally underground (often in association with petroleum) and used as fuel.

transgression

flooding due to sea level rise. sediment belts shift landward, strata deepen upward.

flexural slip

fold develops when layers slide past one another. imagine the movement of a folding deck of cards

passive flow

folds form in hot, soft, ductile rock at high temperatures

types of metamorphic rocks

foliated and non-foliated

slate

foliated, fine-grained, low-grade metamorphic shale. has a distinct foliation called slaty cleavage. develops by parallel alignment of platy clay minerals.

tectonic foliation

foliation develops via compressional deformation, flattening develops perpendicular to shortening strain. sand grains flatten and elongate, clays reorient. foliation is parallel to the axial planes of folds indicates metamorphic strain. relict bedding may be visible.

sheet silicates

form when each tetrahedron shares three of its oxygen atoms with other tetrahedra (ex. micas, clays), characterized by one direction of perfect cleavage

double chain silicates

form when two single chains of tetrahedra link to each other by sharing oxygen atoms (ex. amphiboles)

Great Meteor hot spot

formed the New England hot spot track, of which Mont Royal is a part of.

peat

forms from the compaction and decay of partially decayed plant matter found in bogs that is ~50% carbon. is easily cut, dried, and burned.

detachment

forms when thrust faults merge at depth

ediacaran fauna

fossils of multicellular, varied organisms lacking a mouth, anus, and gut that were widely distributed in the shallow oceans of the late Proterozoic and flourished between 570 and 670 million years ago. complex, soft-bodied form that resembled jellyfish & worms

hot spot reference frame

frame of reference for tectonic motion

mesosaurus

freshwater reptile whose fossil provided evidence for Pangaea and continental drift

pumice

frothy volcanic glass

vesicles

gas bubbles in rocks

weathering

generation of detritus via rock disintegration

caldera

gigantic volcanic depression, can be tens of km across usually have steep sidewalls and flat floors magma chamber empties; Lake Toba, Yellowstone

crystalline structure

gives minerals a shape they can maintain indefinitely. minerals are always solid, but can be melted or vaporized (but then no longer minerals)

epeirogeny

gradual downward and upward movements of broad regions of crust without significant folding or faulting

downslope force

gravitational pull

hot springs

groundwater discharges of hot water with temperatures that range from 30 C to 104 C and are usually high in dissolved minerals. they develop in two settings: where deep groundwater surfaces along faults and in geothermal regions

nautiloids

group of molluscs, related to octopus and squid, parrot-like beak and tentacles, reached 30 feet in length, only one species left today. appeared in the paleozoic era.

euhedral

grown in an open cavity, good crystal faces. geodes

anhedral

grown in tight space, no crystal faces. prevalent

bladed crystal habit

growth results in shape like a knife blade

Spindletop gusher

gusher that marked the beginning of the oil boom in Texas; discovered Jan. 10, 1901.

Vaiont Dam Disaster

happened because a properly engineered dam was built in a geologically unstable location. 600 million tons of limestone slid into the reservoir, inciting a flood wave that destroyed villages and killed 2600 people.

volcanic neck

hardened magma in a volcano's pipe

physical properties of minerals

hardness, cleavage, fracture, luster, color, streak, density, crystal habit. depends on the identity, arrangement of, and nature of atoms and atomic bonds

valley

has gently sloping sidewalls and wider bottom

composition of magma

has three components: liquid, solid, gas. different mixtures yield different magmas

tar sands

heavy residual petroleum (bitumen) found in sand. residue from a former oil field, are too viscous to be pumped therefore are mined and processed -> difficult, expensive, inefficient: 2 tons == 1 barrel of oil. extensive deposits in Alberta, CA and Venezuela

stegosaurus

herbivorous ornithischian dinosaur with a row of bony plates along its back and a spiked tail probably used as a weapon

rhyolitic

high silica composition, high viscosity, high gas content

strike

horizontal intersection with a tilted surface, describes the 3D orientation of a plane

geysers

hot springs that shoot jets of steam and heated water into the air

hydrothermal fluid metamorphism

hot water with dissolved ions and volatiles facilitate metamorphism by acceleration chemical reactions and/or altering rocks by adding or subtracting elements (metasomatism)

plate velocity

how fast plate are moving relative to one another

synthetic minerals

humans can recreate natural processes to make minerals (ex. can make diamonds, quartz)

pleistocene ice ages

ice ages at the end of the cenozoic era in which sea levels dropped, exposing the sea floor and particularly the bering straight. the last ice age ended rapidly at 11 ka beginning the present interglacial holocene epoch

laccolith

igneous intrusion that has been injected between two layers of sedimentary rock.

aquitard

impermeable or low permeability sediment or rock that hinders water flow

extinct

incapable of erupting

assimilation

inclusion of xenoliths into magma which alters its composition as magma melts the walls it passes through

platy grain

inequant; one dimension is shorter (like mica)

elongate

inequant; one dimension is shorter (like staurolite)

seismometer

instrument that records ground motion. a weighted pen on a string traces movement of the frame. modern ones use a magnet and electric coil. can detect ground motion that people cannot sense.

tabular intrusion

intrusion that is planar with uniform thickness, can be traced laterally. sills and dikes

blister-shaped intrusion

intrusion with a sill that domes upward

balloon-shaped intrusions

intrusions that are blobs of melted rock

echinoderms

invertebrates with an internal skeleton and a system of fluid-filled tubes called a water vascular system. appeared in the paleozoic era

axial plane (of a fold)

is an imaginary plane that divides a fold as symmetrically as possible and connects hinges of successive layers

refining oil

is an industrial process plant where crude oil is processed and refined into more useful products such as petroleum naphtha, gasoline, diesel fuel, asphalt base, heating oil, kerosene and liquefied petroleum gas distilled into separate mixtures by weight. lighter molecules rise to the top of distillation columns, vice versa. heaviest at the bottom are made in to plastics.

oceanic crust

is covered by sediment, thickest near the continents, thinnest at the MOR. primarily composed of basalt. lacks variety of continental rock types. NO metamorphic rocks.

alleghanian orogeny

is one of the geological mountain-forming events that formed the Appalachian Mountains and Allegheny Mountains during the late paleozoic era

veins

joints filled with minerals from groundwater deposition within the fractures

systemic joints

joints that occur in parallel sets

epicenter

land surface right above the hypocenter

phenocrysts

large crystals in porphyritic rocks

fault zones

large expanses of rock where movement has occurred; if breccia and gouge are present preferential erosion occurs, may be mineralized by fluid flow

siberian traps

large igneous province formed about 250 million years ago from the same volcanism that caused the Permian Extinction.

lake environments

large ponded bodies of water, gravels and sand trapped near shore. well-sorted muds deposited in deeper water

metamorphic shield

large regions of ancient high-grade metamorphic rocks, the eroded remnants of orogenic belts. basement of sedimentary cover

lopolith

large, tabular, concordant, spoon shaped, convex up and down

deccan traps

largest basalt flows on earth (2,000 m thick beds) in India, possibly contributed to the mass extinction at the end of the cretaceous, 68-80 mya, just before to the end of the extinction. CO2 emitted during eruptions caused climate to warm.

permian extinction

largest mass extinction in history, wiped out about 90% of all marine animal species at the end of the Paleozoic Period

laurasia

late Paleozoic, Northern Hemisphere continent composed of the present-day continents of North America, Greenland, Europe, and Asia

sea-floor bathymetry

learning about the sea floor using sonar (echo sounding), a lot of unexpected findings.

paleozoic lifeforms

lifeforms during this period included: conodonts, trilobites, brachiopods, nautiloids, gastropods, graptolites, crinoids, echinoderms, and jawless fishes

micrite

limestone formed from a fine carbonate mud

chalk

limestone formed from plankton shells

hinge (of a fold)

line along a fold where curvature is the greatest

isograds

lines between different zones of an index mineral map

petroleum

liquid fossil fuel; oil

mudstone/shale

lithified mud

suspended load

load comprised of fine particles (silt and clay) floating in the water

dissolved load

load comprised of ions from chemical weathering

bed load

load comprised of larger particles that roll, slide, and bounce along the bottom moving via saltation

springs

locations of natural groundwater discharge that yield fresh, clear, clean water with no need for drilling. the flow is often steady

depositional environments

locations where sediment accumulates differ in chemical, physical, and biological characteristics; sediment delivery/transport and depositional conditions; energy regime. include: terrestrial, coastal, marine

chrons

long intervals between magnetic reversals, named for scientists

snake river plain

low area across southern Idaho marking the passage of North America over the stationary Yellowstone hot spot

crustal root

low-density crustal rock that protrudes downward beneath a mountain range

fault gouge

made of pulverized, powdered rock from brittle fault movement

lava

magma once is reaches the surface

mafic magma

magma that is silica poor, low viscosity, releases volatiles, high density, high temperature. rich in Mg and Fe

felsic magma

magma with a high silica content and large volume of gas (explosive eruptions) 66-76% silica, feldspar

intermediate magma

magma with a silica content between 52% and 66% and an overall composition between mafic and felsic magma

ultramafic magma

magma with less than 45% silica, low viscosity

dry magma

magma with scarce volatiles

wet magma

magma with up to 15% volatiles

san andreas fault

major transform fault in California formed by a sliding transform boundary. the Pacific plate shears north while the N. American plate shears south

active continental margin

margin that is adjacent to an active plate boundary, typically a narrow continental shelf, sediment usually sparse and thin, seismically active

submarine mass movements

mass movements/wasting that occur underwater. can be much larger than continental movements. can be tied to catastrophic tsunamis

resisting force

material properties that resist motion

incised meanders

meanders initially develop on a gentle gradient, uplift then raises the landscape therefore resetting the base level, and the meanders erode into the uplifted landscape

decompression melting

melting due to a drop in confining pressure that occurs as rock rises; occurs in mantle plumes, beneath rifts, beneath mid ocean ridges

flux melting

melting that occurs due to the addition of volatiles which lower the melting temperature of the rock. common volatiles are H2O and CO2. common at subduction zones where water is carried into the mantle

mineral destruction

melting, dissolving, chemical reaction

native metals

metals that are not combined with other elements (Cu, Au, Ag, Pt, Au/Ag)

gneiss

metamorphic rock with distinct compositional banding, often contorted. has light bands of felsic minerals (quartz, feldspars) and dark bands of mafic minerals (biotite, amphibole)

regional metamorphism

metamorphism associated with large-scale mountain-building processes, pressure and temperature alteration due to orogenesis, aka dynamothermal metamorphism. results in deformation of huge mobile belts, rocks are heated by geothermal gradient and plutonic intrusions, squeezed and heated by deep burial, smashed and deformed by compression and shearing

hydrothermal metamorphism

metamorphism by alteration by hot, chemically aggressive water leaching (mid-ocean ridge). cold ocean water seeps into fractured crust and is heated by magma, then reacts with mafic rock. how water rises and is ejected by black smokers

shock metamorphism

metamorphism by extremely high pressure and heat upon bolide impact (comet/asteroid). vaporizes or melts large masses of rock, generates high pressure minerals

thermal/contact metamorphism

metamorphism by heating by a plutonic intrusion, creates zoned bands of alteration in host rock called a metamorphic aureole, which surrounds the intrusion. high grade near the pluton, low grade far from the pluton

subduction metamorphism

metamorphism by high pressure, low temperature alteration, trenches and accretionary prisms (blue schist facies). low geothermal gradient (high pressure, low temperature) that favors glaucophane

burial metamorphism

metamorphism by increases in pressure and temperature by deep burial in a basin, metamorphism begins around 8-15 km depth

dynamic metamorphism

metamorphism by shearing in fault zone, causes breakage of rock. fault location determines type of alteration. in the shallow crust (10-15 km) rocks are brittle, mineral grains are crushed and form fault breccia. in the deeper crust (below 15 km) rocks are ductile, minerals smear like taffy to form mylonite

pressure metamorphism

metamorphism occurs in the 2-12 kbar range (5-40 km depth). denser minerals created, phase changes and neocrystallization. formation and stability depends on P and T

heat metamorphism

metamorphism that occurs between 250C and 850C (between diagenesis and melting at 1200C). energy breaks and reforms atomic bonds. new minerals form, solid-state diffusion allows for the migration of atoms between grains

coal bed methane

methane associated with, and extracted from, coal deposits

underground mining

method by which tunnels and shafts are used to access and remove coal. hazards include tunnel collapse, methane gas (asphyxiation, explosions), black lung disease, coal bed fires

bathymetric features

mid-ocean ridges, abyssal plains, trenches, sea mounts, submarine volcanoes, huge fracture zone segment the mid-ocean ridge

channel bars

midstream accumulations of sand and gravel

metamorphic facies

mineral assemblages from a specific protolith at specific P and T conditions, creates rocks that are predictably similar. named for dominant mineral

diamond

mineral comprised completely of carbon. atoms arranged in a tetrahedra structure, valuable. hardest mineral. originate under extremely high pressure, ~150 km deep.

precipitation from a gas

mineral formation from a gas, ex. sulfur

pressure solution

mineral grains partially dissolve. dissolution requires small amounts of water, minerals dissolve where their surfaces press together. ions from the dissolution migrate in the water film

plastic deformation

mineral grains soften and deform. requires elevated temp. and pressure. rock is squeezed or sheared. minerals change shape but do not break (like plastic)

oxides

minerals containing oxygen and a metal, metal cations are bonded to oxygen. (ex. magnetite, hematite, rutile)

biogenic minerals

minerals created by living organisms (ex. apatite, aragonite)

halides

minerals that contain a halogen ion plus one or more other elements (ex. halite, fluorite)

silicates

minerals that contain silicon and oxygen and usually one or more other elements, is the most abundant mineral class (SiO2 4-) constitute almost the entire crust and mantle of earth (ex. quartz)

sulfates

minerals that contain sulfur and oxygen where a metal cation is bonded to a sulfate anion. many result from the evaporation of seawater (ex. gypsum, anhydrite)

carbonates

minerals that contain the elements carbon, oxygen, and one or more other metallic elements (CO3 2-) (ex. calcite, dolomite)

index minerals

minerals used to estimate the temperature, depth, and pressure at which a rock undergoes metamorphism. help define metamorphic zones.

magma

molten rock beneath the earth's surface

lava flows

molten rock that moves over the ground

ethanol

most common biofuel, made when alcohol is derived from corn, sugarcane, etc. added to gasoline as a motor vehicle fuel.

black shale

most common sedimentary rock being formed on the deep ocean floor. lithified black, organic-rich mud that is a petroleum source rock

inactive faults

motion occurred in the geologic past

orogeny

mountain building, leads to the formation of all three rock types: igneous activity beneath collisions and rift zones, erosion of uplifted rocks and sedimentation in basins, metamorphism resulting from continental collisions

ouachita mountains

mountains in eastern Oklahoma and western Arkansas (south of the Ozarks) that formed during the late paleozoic era as eastern north america collided with northwest africa. large scale folding and thrust faulting occurred, thrust-faults emplaced Precambrian basement basement atop paleozoic sedimentary rocks

old-age mountains

mountains that are deeply eroded and often buried

young mountains

mountains that are presently rising because they are at the location of converging plates or at the site of a hot spot. tall and steep

middle-age mountains

mountains that have been partially lowered by erosion

solid-state diffusion

movement of atoms or ions through a solid to arrange into a new crystal structure

shear metamorphism

moves one part of a material sideways, causes material to be smeared out like sliding out a deck of cards

bed surface markings

mudcracks, scour marks, fossils

H2O rich movement

mudflows, debris flows, lahars. types of mass wasting that move at various speeds, driven by water. faster when there is more water and/or a steeper slope angle. tend to follow river channels down valley, able to carry huge boulders, houses, and cars

control rods

neutron-absorbing rods that help control the reaction by limiting the number of free neutrons

neocrystallization

new minerals form from old. original protolith minerals are digested in reactions, elements restructure to form a new mineral assemblage (ex. shale to garnet mica schist)

phase change

new minerals form with same chemical formula and different crystal structure (ex. andalusite to kyanite)

non-foliated

no planar fabric is evident. minerals have recrystallized without compression or shear. comprised of equant minerals only. classified by mineral composition

marble

non-foliated metamorphic rock that is comprised of coarsely crystalline calcite or dolomite. forms from a limestone protolith. extensive recrystallization completely changes the rock. good for stone sculptures. variety of colors, may have color banding

lystrosaurus

non-swimming, land-dwelling reptile, evidence for continental drift

Fukishima

nuclear disaster caused by a tsunami in 2011, where the storage pools containing radioactive material leaked when backup electricity failed, meltdown.

human-induced earthquakes

occur as a result of the injection of fluids under very high pressure into the crust, mobilizing existing faults or even creating new ones. hence why fracking is problematic

intermediate and deep earthquakes

occur at convergent boundaries

shallow earthquakes

occur at divergent and transform boundaries

kimberlite pipes

occurs in the Earth's crust in vertical structures, pipes. They are formed deep within the mantle, at between 150 and 450 kilometers depth, from anomalously enriched exotic mantle compositions, and are erupted rapidly and violently, often with considerable carbon dioxide and other volatile components. They deliver rocks from throughout the crust to the surface where they can be studied. explodes diamonds to the surface

conventional hydrocarbons

oil and gas that form a normal accumulation, and include a source, migration, trap, and reservoir. Typically sandstone.

first commercial oil well (in North America)

oil well dug in August 1858 at Oil Springs, Ontario by James Wilson

Acasta Gneiss

oldest rock on earth, dates to 4.03 billion years ago

baltica

one of six major Paleozoic continents; composed of Russia west of the Ural Mountains, Scandinavia, Poland, and northern Germany.

facet

one of the cut surfaces of a gem, unnatural. ground by a lapidary machine

yellowstone caldera

one of the largest calderas in the world. the most recent one formed about 640,000 years BP. The Lava Creek Caldera is the youngest large caldera formed by the Yellowstone hot spot. The hot spot is responsible for about one dozen super-eruptions in the last 15 million years.

stream piracy

one stream captures the flow of another when a stream with vigorous headward erosion and steeper gradient intercepts a stream with a gentler gradient so the captured stream flows into the new stream

active faults

ongoing stresses produce motion

porosity

open space in a source rock that stores fluid

collision zones

orogenic crustal compression occurs as continental lithosphere compresses along thrust faults. earthquakes can be very large. orogenic uplift creates landslide hazards

accretionary orogens

orogens that grew laterally by the attachment of exotic terranes

spoil

overburden removed in strip mining, stockpiled nearby for sale or reuse in restoration

finding the epicenter

p-waves arrive first, then s-waves ; separation between two waves grows with distance from epicenter; time delay between p and s waves establishes distance

foliated

parallel surfaces or layers in metamorphic rocks, alignment of inequant grains or compositional banding. classified by composition, grain size, and foliation type

jawless fish

parasitic fish that have skeletons made of cartilage but lack a proper skull, ex: hagfish and lampreys. appeared in the paleozoic

great pacific garbage patch

patch of solid waste the size of Texas floating in the currents of the North Pacific gyre, mostly consisting of plastics.

lapilli

pea-sized fragments of glassy lava and scoria that cool in the air

cretaceous

period at the end of the mesozoic era. breakup of pangaea continued, the south atlantic (between south ameriaa and africa) opened. south america, africa, antartica, and australia separated. india broke from gondwana. sea levels rose dramatically as vast seaways transgressed continental interiors. formation of the canadian rockies, sierra nevada, american rockies. increased sea-floor spreading (3x as fast). atmospheric CO2 increased

ordovician

period during Paleozoic. Before Silurian, after Cambrian. Graptolites, 1st fish and fungi, shallow seas. a mass extinction event occurred at the end of this period

silurian

period during middle Paleozoic. After Ordovician, before Devonian. Eurypterids/sea scorpions, invertebrates, 1st land plants and insects, all landmasses, generally flat. 'greenhouse' period. sea levels rose (transgression) climate warmed, continents flooded. vast reef complexes in shallow epicontinental seas. new amrine species evolved. Acadian orogeny uplifts the early Appalachians

devonian

period during the Paleozoic era, the 'age of fish'

mississippian

period during the late paleozoic characterized by the appearance of the first coal swamps, first winged insects.

pennsylvanian

period during the late paleozoic, first reptiles

triassic

period in mesozoic era after Permian, before Jurassic. Age of Ammonites, rapid evolution of species after the permian extinction. swimming reptiles, new corals, first turtles and flying reptiles, first dinosaurs and earliest ancestors of mammals. Pangaea breaks apart and forms deep basins. vast salt deposits formed from the evaporation of inland seas. thick sediments in basins.

jurassic

period of the Mesozoic Era in which the first birds appeared, from 190 million to 135 million years ago, many seagoing reptiles, early large dinosaurs, later, flying reptiles and earliest known birds. after triassic and before the cretaceous. continued rifting opens the proto-atlantic ocean. west cost of north america becomes a convergent margin

Ted Irving

person credited with the discovery that the location of the magnetic poles are fixed and the continents themselves have moved

crude oil

petroleum that has not been processed

diagenesis

physical, chemical, and biological changes to sediment (ex. lithification) as sediments are buried, temperatures and pressures rise.

fragmental

pieces of preexisting rocks, often shattered

joints

planar rock fractures without any offset. develop from tensile tectonic stress in brittle rock. often control weathering of the rock they occur in. groundwater often flows through these fractures, depositing minerals

leachate

polluted liquid produced by water passing through mining wastes

mudcracks

polygonal desiccation features in wet mud, indicates alternating wet and dry terrestrial conditions

secondary porosity

pores developed after rock formation; fracturing, faulting, dissolution

primary porosity

pores originally formed with the material, voids in sediment, vesicles in basalt, open-reef framework

wind power

power obtained by harnessing the energy of the wind.

shields

precambrian metamorphic and igneous rocks crop out at the ground surface, cratonic

dikes

preserved magma conduits

causes of melting

pressure release, volatile addition, heat transfer

Earth's magnetic field

prevents charged particles in the solar wind from reaching the surface, caused by flow in the liquid outer core. the magnetic pole is tilted ~11.5 degrees from the axis of rotation and is rapidly moving across the Arctic Ocean towards Siberia

p-waves

primary or compressional waves. travel by compressing and expanding material. material moves back and forth parallel to wave direction. the fastest wave. can travel through solids, liquids, and gases.

principle of fossil succession

principle: a principle by which fossil organisms succeed one another in a definite and determinable order, and any time period can be recognized by its fossil content. fossils are often preserved in sedimentary rocks, are useful time markers for relative dating. fossil range, first appearance, and extinction.

principle of inclusions

principle: a rock fragment within another. inclusions are always older than the enclosing material. weathering rubble must have come from older rock. fragments (xenoliths) are older than igneous intrusion

principle of baked contacts

principle: an igneous intrusion cooks the invaded country rock. the baked rock must have been there first (and is therefore older)

principle of superposition

principle: in an undeformed sequence of layered rocks, younger strata are on top, older strata are on the bottom

principle of original horizontality

principle: sediments settle out of a fluid by gravity causing sediments to accumulate horizontally. sediment accumulation is not favored on a slope therefore tilted sediments rocks must be deformed.

principle of lateral continuity

principle: strata often form laterally extensive horizontal sheets. subsequent erosion dissects once-continuous layers. flat-lying rock layers are unlikely to have been disturbed

principle of cross-cutting relations

principle: younger features cut across older features. faults, dikes, erosion, etc must be younger than the material that is faulted, intruded, or eroded

subduction

process by which one oceanic lithospheric plate slips beneath a continental plate. continental plate is too buoyant (Himalayas). recycles oceanic lithosphere, occurs in ~400 million year old cycles.

fractional crystallization

process in which different minerals crystallize from magma at different temperatures, removing elements from magma

partial melting

process in which different minerals melt into magma at different temperatures, changing its composition. Si-rich minerals melt first

ore genesis

process of ore formation

exhumation

process that occurs due to uplift, collapse, and erosion; reveals deep crustal metamorphic rocks.

Harry Hess

proposed the sea-floor spreading model in 1960, which ignited a scientific revolution. a complete model was developed by 1968

acid rain

rain containing high amounts of chemical pollutants such as SO2

cambrian explosion

rapid diversification of most major animal groups marking the start of the Paleozoic era

needle-like crystal habit

rapid growth in one direction, slow in others

specific gravity

ratio of a mineral's weight compared with the weight of an equal volume of water

industrial minerals

raw materials for manufacturing

bedding

reflects changing conditions during deposition, such as transporting medium and sediment source. they have a defining thickness that can change

capillary fringe

region above the water table with water drawn up by capillary action

sedimentary basins

regions of variable size where the combination of sedimentation and subsidence has formed thick accumulations of sediments and sedimentary rocks, form where tectonic activity creates space

basaltic eruptions

released gases eject clots and drops of molten magma

erosion

removal of sediment grains from the parent rock

displacement (orogenesis)

result of deformation, a change in location (by faulting)

rotation

result of deformation, a change in orientation

distortion

result of deformation, a change in shape

baked zone

rim of heat-altered wall rock

chill margin

rim of quenched magma at contact

heat transfer melting

rising magma carries mantle heat with it, raising the temperature in nearby crustal rock which then melts

igenous rock

rock formed from hardened molten materials, freezes at extremely high temperatures (1100 C to 650 C)

intrusive igneous rock

rock formed from the cooling and solidification of magma beneath Earth's surface

extrusive igneous rock

rock that forms from the cooling and solidification of lava at Earth's surface. lava flows, pyroclastic debris

reasons for no foliation

rock was not subjected to differential stress, dominance of equant minerals, absence of platy minerals (clays, micas)

elastic rebound theory

rocks bend elastically due to accumulated stresses; rock snaps back after slip along fault releases stress

fault creation

rocks break or a preexisting one is created, becomes a permanent zone of weakness in the crust regardless of level of activation

reservoir rocks

rocks that have the ability to store and transmit oil (or other fluids) that can be pumped out. ability depends upon porosity and permeability

mercalli intensity scale

roman numerals assigned to different levels of damage. damage occurs in zones and diminishes with distance

dissolution

running water dissolves soluble minerals

coastal beach sands

sand is moved along the coastline. common result is well-sorted and well-rounded medium sand. beach ripples often preserved in sedimentary rocks

geologic time

scale used by paleontologists to represent evolutionary time; provides a frame of reference for understanding rocks, fossils, geologic structures, landscapes, tectonic events, change

Max van Laue

scientist who proposed using X-rays to study minerals 1912

positive anomaly

sea floor rock normal polarity

crinoids

sea lilies and feather stars, appeared in the paleozoic era

negative anomaly

sea-floor rock reversed polarity

s-waves

secondary or shear waves. travel by moving material back and forth. material moves perpendicular to wave motion. slower than p-waves. only travel through solids.

delta

sediment deposited where a river flows into an ocean or lake builds up a landform; topset, foreset, bottomset geometry

aquifer

sediment or rock that transmits water easily

percolating

seeping; filtering

liquefaction

seismic waves liquefy H2O filled sediments. groundwater forces grains apart, reducing friction. liquefied sediments flow as a slurry. sand becomes quicksand and clay becomes quickclay. sand blows and sand volcanoes disrupt the ground surface. causes soil to lose strength

biofuels

semi-renewable fuels, such as ethanol or methanol, that are created from the fermentation of plants or plant products.

Morley and Larochelle

set the precedent discovery of sea floor magnetic stripes before Vine and Matthews

strata

several beds of rock together

fault breccia

shattered rock created by crushing fault movements. rock fragments along a fault

platforms

shields covered by layers of Phanerozoic strata, cratonic. sedimentary rocks covering Precambrian basement. series of domes and basins, results in epeirogeny

subchrons

short intervals between magnetic reversals

phyllitic luster

silky sheen caused by the mica particles within the rock, common in phyllite

dunes

similar to ripples except much larger, forms when water or wind deposits sand. occur in streams, desert or beach regions. range in size from tens of cm to hundreds of m. often preserve large internal cross beds.

pyroxenes

single-chain silicate minerals, dark long crystals. two cleavages near 90 deg.

subsidence

sinking of the land during sedimentation

conodonts

slender, soft bodied vertebrates from the paleozoic era with prominent eyes that were controlled by numerous muscles and armored; extinct

slumping

sliding of regolith as coherent blocks; a type of mass wasting. slippage occurs along the spoon-shaped failure surface. distinctive features include head scarp, toe, and discrete faulted slices. are common along seacoasts and cut river banks. can move slowly

pele's tears

small pieces of lava that were thrown into the air and cooled quickly; frozen droplets

foreshocks

small tremors that indicate crack development. may warn of impending larger earthquakes

aftershocks

smaller quakes produced after a major quake caused by rocks shifting to new positions, may occur for weeks or years afterward

slickensides

smooth faced fault surfaces that are normally striated in the direction of movement, type of slip lineation

crystal faces

smooth, flat surfaces with regular geometric outlines

gastropods

snails and slugs, appeared in the paleozoic era

terra firma

solid ground

metamorphic rock

solid-state alteration of a protolith

compositional banding

solid-state differentiation, chemical reactions segregate light and dark layers

crustal source magmas

source of mafic, intermediate, and felsic magmas

mantle source magma

source of ultramafic and mafic magmas

unconventional hydrocarbons

sources of oil and gas which require additional or "unconventional" extraction methods which are not normally necessary in traditional oil and gas extraction

ore minerals

sources of valuable metals

fold geometry

special terminology is used to describe folds; hinge, limbs, axial plane. are described by the geometry of the hinge

mineral formation

starts with a seed crystal. growth continues outward as atoms attach to the outer faces, reflects internal atomic order

canyon

steep sidewalls and narrower bottom

stretching strain

strain caused by rock pulling apart (elongation)

shortening strain

strain caused by rock squeezing together (contraction)

deformed rocks

strained rocks; tilted beds, metamorphic alteration, folding and faulting

fossil correlation

stratigraphic correlation based on fossils within the rocks, applicable to much broader areas

meandering stream

stream with sinuous, looping curves that form where the stream gradient is low, the substrate is soft and easily eroded, and the stream exists within a broad floodplain. these curves evolve during times of flood.

vanishing rivers

streams that disappear due to humans overusing/abusing rivers via pollution, dam construction, overuse of water, and urbanization & agriculture

ephemeral streams

streams that have flowing water either episodically or during a portion of the year. exist above the water table. occur in dry climates with low rainfall and high evaporation

compression metamorphism

stress is greater in one orientation. different from pressure which is equal in all directions; result of tectonic forces

compression

stress that squeezes rock until it folds or breaks. results in shortened, thickened material

causes of deformation

stress/strain/fracture

geochronology

study of the numerical ages of geologic events, not very useful for sedimentary materials

epochs

subdivisions of a period (0.011 to 22 Ma)

eras

subdivisions of an eon (65 to hundreds Ma). cenozoic, mesozoic, paleozoic

causes of seismicity

sudden motion along a newly formed crustal fault, sudden slip along an existing fault, a sudden change in mineral structure, movement of magma in a volcano, volcanic eruption, giant landslides, meteorite impacts, nuclear detonations

-zoic

suffix that means 'life,' used in naming time-scale subdivisions

gondwana

supercontinent that existed before Pangea, more than 500 million years ago during the early paleozoic era (proterozoic eon) consisted of modern S. America, Africa, India, and Australia

Pannotia

supercontinent the formed 600 Ga after the rifting of Rodinia. precursors of present-day continents could be identified.

brachiopods

superficially resemble clams and other hinge-shelled molluscs, but the two halves of the shell are dorsal and ventral rather than lateral as in clams. appeared in the paleozoic era.

l-waves

surface waves or love waves. slowest kind of wave, the most destructive. intersect the land surface. moves the ground back and like a writhing snake.

syngas

synthetic gas, a mixture of carbon monoxide and hydrogen, obtained by coal gasification

softest mineral

talc, graphite

radioactive dating

technique in which scientists calculate the age of a sample based on the amount of remaining radioactive isotopes it contains

generating earthquake energy

tectonic forces add stress (push, pull, shear) to the rock. bends. continued stress causes cracks to develop and grow, progresses to the point of failure. stored elastic energy is released at once, creating a fault

active continental margins

tectonically active zones between where land meets ocean

passive continental margins

tectonically inactive zones between where land meets ocean

agents of metamorphism

temperature, pressure, tectonic stresses, amount of reactive water, compression and shear, hot fluids

continental rift

tensional faults created by normal stretching that generate shallow earthquakes similar to that of the MOR

abrasion

the 'sandblasting'mof rock by particles in fast-moving water

meltdown

the accidental melting of the uranium fuel rods inside the core of a nuclear reactor, causing the release of radiation by explosion

salinity

the amount of dissolved salt in water

pressure

the amount of force exerted per unit area of a surface, occurs when an object feels the same stress on all sides

sediment load

the amount of material moved by running water load; three types: dissolved, suspended, bed

displacement (faults)

the amount of movement or slip across a fault plane, cumulative over time. aka offset, shown by markers

fossil range

the amount of time a species exists (from evolution to extinction)

discharge

the amount of water flowing in a channel; volume of water passing a point per unit of time. can be found by multiplying cross-sectional area by average water velocity

plunge

the angle from horizontal that the hinge is inclined at

dip

the angle of the surface down from the horizontal, describes the 3D orientation of a plane. perpendicular to strike & measured downward

coriolis deflection

the apparent deflection of objects moving across Earth's surface to the right of direction of travel in the Northern Hemisphere and to the left of direction of travel in the Southern Hemisphere

drainage basin

the area from which a single stream or river and its tributaries drains all of the water

watershed

the area of land that drains into a stream

saturated zone

the area of permeable rock or soil that is totally filled or saturated with water

topography

the arrangement of the natural and artificial physical features of an area.

isostasy

the balancing of the downward force of the crust and the upward force of the mantle. results as gravitational attraction pulls plates into the mantle while buoyancy floats the lithosphere (counteracting forces). adding or removing weight (changing lithospheric thickness/density) resets/alters the equilibrium

deformation

the bending, tilting, and breaking of Earth's crust (often during orogenesis); the change in the shape of rock in response to stress. changes the character of the rocks results in displacement, rotation, distortion. easily visible types: brittle, ductile. depends on temp, pressure, rate, composition

folded rock

the bends in layered rock due to movement in the lithosphere; a type of deformed rock. occur in a variety of shapes, sizes, and geometries. produced in large volumes by orogenic processes. may record multiple events of deformation.

footwall

the block of rock that forms the lower half of a fault

hanging wall

the block of rock that forms the upper half of a fault

drainage divide

the boundary between adjacent drainage basins.

Mohorovicic discontinuity

the boundary between the earth's crust and the upper part of the asthenosphere; seismic waves change speed at this boundary

strain

the change in shape caused by deformation. types: stretching, shortening, shear

streak

the color of a mineral's powder when dragged across an unglazed porcelain plate. is less variable than color

holocene

the current interglacial period, extending from 10,000 years ago to the present on the geologic time scale.

metamorphic grade

the degree to which the parent rock changes during metamorphism, determines new mineral assemblages. is a measure of intensity.

declination

the difference between geographic N and magnetic N, depends on the absolute position of the two poles

slope failure

the downslope movement of material on an unstable slope

mass wasting

the downslope movement of rock, regolith, and soil under the direct influence of gravity, characterized by a wide range of rates; is a costly type of natural hazard. is aided by human activity.

geothermal energy

the energy produced by heat within the earth. hot groundwater pumped to heat buildings, pools, spas. steam from very hot groundwater can be used for electricity generation.

William "Strata" Smith

the first person to note that strata could be matched across distances. similar rock types in a similar order. rock layers contain the same distinctive fossils. after years fo work, he made the first geologic map

mudflow

the flow of a mass of mud or rock and soil mixed with a large amount of water. an h2o rich mass movement in a slurry of water and fine sediment. is common in tropical settings with abundant rainfall

hypocenter

the focus, the place where fault slip first occurs. usually occurs on a fault surface, earthquake waves expand outward from this point

crystal habit

the general shape of a crystal or cluster of crystals that grew unimpeded

continental rise

the gently sloping transitional surface at the base of the continental slope; 4-4.5 km in depth

geothermal gradient

the gradual increase in temperature with depth in the crust

fault trace

the ground surface expression of a fault, shows the fault intersecting the ground

reverse fault

the hanging wall moves up relative to the footwall. results from compression (squeezing or shortening), dip is steep

northern hemisphere

the hemisphere north of the equator where south-moving winds and currents are deflected to the west, north-moving winds and currents are deflected to the east

southern hemisphere

the hemisphere south of the equator; north-moving winds and currents are deflected to the west, south-moving winds and currents are deflected to the east

continental drift

the hypothesis that the continents slowly move across Earth's surface.

peak oil

the hypothetical point in time when the global production of oil reaches its maximum rate, after which production will gradually decline. we are close to this peak, though fracking has extended the timeline

parent isotope

the isotope that undergoes radioactive decay

amount of fault slip

the larger the earthquake, the larger the fault slip. displacement is greatest near the hypocenter and decreases with distance

eons

the largest subdivision of geologic time; hundreds to thousands of Ma. phanerozoic, proterozoic, archean, hadean

regolith

the layer of unconsolidated rocky material covering bedrock

lignite

the least pure coal, soft, dirty and dark-brown. ~50% carbon. formed from the burial of peat

limb(s) (of a fold)

the less curved sides of a fold

water table

the level below which the ground is saturated with water.

delamination

the loss and sinking (foundering) of the portion of the lowermost lithosphere from the tectonic plate to which it was attached. ex: Tibet Plateau

base level

the lowest point to which a stream can erode, velocity drops to zero, ultimate is sea level. a lake or a ledge of resistant rock can exist as a local/temporary.

K-T boundary event

the mass extinction that happened at the end of the cretaceous period, 65 million years ago, possibly due to the collision of an asteroid with the Earth. all dinosaurs (except avian), 75% of plants, and 90% of plankton species disappeared. chicxulub crater formed

clast composition

the mineral makeup of sediments, may be individual minerals or rock fragments. tells the story about the original source rock

bituminous coal

the most common form of coal; produces a high amount of heat and is used extensively by electric power plants. forms from lignite at around 100-200 deg C. about ~70% carbon.

laramide orogeny

the mountain-building event that lasted from about 80 Ma to 40 Ma (cretaceous period), in western North America; in the United States, it formed the Rocky Mountains as a result of basement uplift and the warping of the younger overlying strata into large monoclines.

pangaea

the name of the single landmass that broke apart 175 million years ago and gave rise to today's continents

oil window

the narrow range of temperatures under which oil can form in a source rock.

protolith

the original rock from which a metamorphic rock formed, undergo solid-state changes in texture and mineralogy

color

the part of visible light that is not absorbed by a mineral. can be diagnostic for some minerals, while others come in a broad spectrum of colors (usually suggests the presence of trace impurities)

slope stability

the potential of soil covered slopes to withstand and undergo movement

biomineralization

the precipitation of minerals by organisms, as in the formation of skeletons or tooth enamel (ex. CaCO3)

metasomatism

the process by which a rock's overall chemical composition changes during metamorphism because of reactions with hot water that bring in or remove elements, often associated with mineralization of ore deposits

headward erosion

the process by which a stream channel lengthens up its slope as the flow of water increases

recrystallization

the process by which bonds between atoms in minerals break and re-form in new ways during metamorphism. mineral identity need not change (ex. limestone -> marble)

dolomitization

the process by which limestone is converted to dolomite by the replacement of calcium carbonate by magnesium carbonate

sea-floor spreading

the process by which new oceanic lithosphere forms as magma rises toward the surface and solidifies

radioactive decay

the process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element

orogenic collapse

the process in which mountains begin to collapse under their own weight and spread out laterally as deep, hot rocks are forced outward.

stratification

the process in which sedimentary rocks are arranged in layers

downcutting

the process in which water flowing through a channel cuts into the substrate and deepens the channel relative to its surroundings

directional drilling

the process of controlling the trajectory of a drill bit to make sure that the drill hole goes exactly where desired.

orogenesis

the process of mountain building

outgassing

the process of releasing gases from a planetary interior, usually through volcanic eruptions, helped form the denser atmospheric conditions of the hadean eon (H2O, N2, CH4, NH3, H2, CO2, SO2)

uplift

the process that moves large bodies of Earth materials to higher elevations

crystal lattice

the regular pattern in which a crystal is arranged by atom

mylonite

the resulting rock from dynamic metamorphism; has a foliation that parallels the fault

lithosphere

the rigid outer part of the earth, consisting of the crust and upper mantle. is in motion over the upper mantle. bends elastically when loaded

bedform

the ripples formed from streams and rivers flowing over mud. character is dependent on flow velocity and grain size. development is perpendicular to flow, ripple marks are frequently preserved in sediments.

earthquake

the shaking that results from the movement of rock beneath Earth's surface, large ones can be extremely destructive

Bowen's reaction series

the simplified pattern that illustrates the order in which minerals crystallize from cooling magma according to their chemical composition and melting point

polar wandering

the slow and erratic, real or apparent, movement of the earth's rotational or magnetic poles relative to the continents throughout geological time, due largely to continental drift. preserved by iron minerals in layered basalts. inclination and declination indicate change in position

creep

the slow downhill movement of regolith, a type of mass wasting due to seasonal soil expansion and contraction from the wetting/drying, freezing/thawing, warming/cooling of regolith. grains move perpendicular to slope upon expansion, vertically downward by gravity upon contraction.

solifluction

the slow downhill movement of tundra; a type of mass wasting. melted permafrost slowly flows over deeper-frozen soil. this process generates hillsides with solifluction lobes

nuvvuagittuq faux amphiboles

the source magma that formed this metamorphic rock has been age-dated to 4.28 billion years

headwaters

the source of a stream or river; gradient is usually steep & discharge is low, competence is high, sediments are coarse. channels are straight

Homo neanderthalensis

the species before us homo sapiens; lived form 30,000 to 300,000 years ago; they were stronger and had bigger brains

daughter isotope

the stable isotope produced by the radioactive decay of the parent isotope

angle of repose

the steepest angle at which loose material remains stationary without sliding downslope

mesophere

the strong, lower part of the mantle between the asthenosphere and the outer core

paleomagnetism

the study of changes in Earth's magnetic field, as shown by patterns of magnetism in rocks that have formed over time, preserved by iron minerals. this info is used to trace continental drift

periods

the subdivision of eras based on life existing at the time and on geologic events (2 to 70 Ma)

late-heavy bombardment

the surge in cratering impacts in the solar system that occurred about 3.8 billion years ago. destroyed nearly all of earth's earliest surface.

closure temperature

the temperature of rock below which isotopes are no longer free to move. isotopic date measured from this

plate tectonics

the theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle

great oxygenation event

the time in Earth's history, about 2.5 Ga, when the concentration of oxygen in the atmosphere increased dramatically.

capacity

the total quantity of sediment a stream can carry; changes with discharge

slaty cleavage

the type of foliation characteristic of slates in which there is a parallel arrangement of fine-grained metamorphic minerals and cleavage develops perpendicular to compression

submarine slump

the underwater downslope movement of a semi coherent block of sediment along a weak mud detachment, blocks break and slip

asthenosphere

the upper layer of the earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur. mainly comprised of bridgmanite. flows plastically when loaded

isotopic dating

the use of naturally occurring radioactive elements to determine the ages of rocks, can give the timing of polarity reversals

fracture

the way a mineral looks when it breaks apart in an irregular way (ex. quartz is conchoidal). implies equal bond strength in all directions

luster

the way a mineral surface scatters light; metallic or nonmetallic

Himalayas

the world's highest mountain range, forming the northern border of the Indian subcontinent. uplifted through the collision of the Indian plate with the Eurasian plate. India is still pushing northward at ~4cm/yr relative to the Eurasian plate

The Geysers, CA

the world's largest geothermal field, containing a complex of 18 geothermal power plants, drawing steam from more than 350 wells, located in the Mayacamas Mountains approximately 72 miles (116 km) north of San Francisco, California. Geysers produced about 20% of California's renewable energy in 2019

Mount Everest

the world's tallest mountain, located in the Himalayas. 8.85 km above sea level. made of sediments deposited in oceans

sauropods

these are huge, 4 legged, long necked/ long tailed, herbivores that thrived in the Jurassic. weighed up to 100 tons

rockfalls

these happen when large blocks of rock break loose from a steep slope and start tumbling in a vertical freefall of mass. bedrock or regolith falls rapidly downward. when blocks impact, they fragment and continue moving. talus/skree blocks pile up at the base of the slope

formation of hydrocarbons

these molecules oroginate from lipids (fatty molecules) as plankton die and sink to the bottom. this organic material accumulates. under anoxic conditions, organic materials are preserved and further lithification forms black shale

Persian Gulf

this body of water separates the Arabian peninsula from the more mountainous land of Persia. countries bordering this region contain the world's largest conventional petroleum reserves

oldest sedimentary rock

this rock is estimated to be 3.85 Ga. most other rocks were destroyed by the late-heavy bombardment

oldest crustal rock

this rock is estimated to be 4.03 - 4.28 Ga. most other rocks were destroyed by the late-heavy bombardment

maximum mountain height

this upper height limit occurs because the weight of mountains overwhelms rock strength, resulting in orogenic collapse

oldest geologic material

this zircon mineral from Australia is thought to be 4.4 Ga

volcanic ash

tiny particles of pulverized volcanic rock and glass

migration pathway

to fill the pores of a reservoir rock, oil and gas must first migrate (move) from the source rock into a reservoir rock, which they will do over millions of years of geologic time. Hydrocarbons migrate because oil and gas are less dense than water, so they try to rise toward the Earth's surface to get above groundwater. Natural gas, being less dense, ends up floating above oil, thus buoyancy drives oil and gas upward. Typically, a hydrocarbon system must have a good ___ ___, such as a set of permeable fractures, in order for large volumes of hydrocarbons to move.

finding coal

to find it, geologists look for specific sedimentary sequences deposited in shallow, marine, coastal, fluvial, and deltaic environments in warm paleoclimates. never found in large beds.

fault scarp

topographic expression of faulting attributed to the displacement of the land surface by movement along faults

saltation

transportation of sediment through a series of leaps or bounces

fault trap

trap in which displacement juxtaposes rocks with varying permeability

scour marks

troughs eroded in soft mud by current flow

ignimbrite

tuff deposited while hot that welds together

polymorph

two minerals that have the same chemical composition but a different crystal lattice structure (ex. graphite and diamond)

horizontal tension

type of deformation stress that drive crustal rifting. stretches and thins material

horizontal compression

type of deformation stress that drives collision. shortens and thickens material

shear stress/strain

type of deformation stress that occurs when surfaces slide past one another. does not result in a change in thickness

metaconglomerate

type of rock, a metamorphosed conglomerate. pebbles and cobbles are flattened by pressure solution and plastic deformation. foliation is defined by the flattened clasts

mountaintop removal mining

type of surface mining that uses explosives, massive power shovels, and large machines called draglines to remove the top of a mountain and expose seams of coal underneath a mountain. the environment is permanently altered. this method is destructive and controversial

nonconformity

type of unconformity in which igneous/metamorphic rocks capped by sedimentary rocks. igneous and metamorphic rocks exposed by erosion, sediments are then deposited on the eroded surface

angular unconformity

type of unconformity that lies at an angle relative to the strata of rocks above it. represents a huge gulf of time. ex: horizontal marine sediments deformed by orogenesis, mountains completely eroded away, renewed marine invasion, new sediments deposited

Hutton's unconformity

unconformity in Siccar Point, Scotland. a common destination for geologists. has vertical beds of ordovician sandstone, overlain by gently dipping devonian redbeds. missing time ~50 million years

banded iron formations

unique, shallow marine deposits made up of alternating bands of chert and iron oxides that formed due to locally high oxygen levels produced by stromatolites from 2.4-1.8 Ga

undeformed rocks

unstrained rocks; horizontal beds, spherical sand grains, no faults or folds present

volcanic gas

up to 9% of magma may be comprised of gases; water is most abundant, followed by CO2 and SO2/H2S

mountain building processes

uplift deformation jointing faulting folding foliation metamorphism igneous activity erosion sedimentation

piezometer

used to measure hydraulic head

black smokers

vents on the sea floor where water that has entered fractured rock and been heated and dissolves minerals cycles back out. minerals are quickly deposited. deep sea organisms derive energy and nutrients from these

Mt. Mazama

volcanic eruption 7800 years ago that was 40x greater than the Mt. St. Helen's eruption. left a massive caldera that now holds Crater Lake in Oregon

phreatomagmatic

volcanic eruptions resulting from interaction between magma and water

Nevado del Ruiz

volcano that generated deadly lahars nov. 13th 1985 that attained speeds of 60 miles per hour and claimed 20,000 lives when the mountain's snowcap meltwater mixed with ash and raced down river valleys, burying the town of Armero.

mount vesuvius

volcano that violently erupted in 79 CE. pyroclastic debris destroyed Pompeii and killed 20000 people. the city and their way of life was preserved under the ensuing ash fallout

flood basalts

voluminous lava eruption above a plume; when a mantle plume intersects the base of rifting lithosphere great thicknesses stack up creating large igneous provinces (LIPs)

shallow water carbonate environments

warm, clear, marine water, relatively free of clastic sediments.

mount toba

was an active volcano which exploded 75000 years ago causing a volcanic winter period of several years, and as much as a thousand year cooling of the planet, as volcanic ash clouded the light from the sun. the eruption formed a caldera that formed a lake

groundwater

water held underground in the soil or in pores and crevices in rock that is a major component of the hydrological cycle, is a major source of water for a thirsty world. a precious resource that is susceptible to contamination and provides ~2/3 of freshwater resources

scouring

water picks up and moves sediment

common volatiles

water vapor (H2O) carbon dioxide (CO2) sulfur dioxide (SO2) nitrogen (N2) hydrogen (H2)

lahar

water-rich debris flow of ash and blocks

abrade

wear away by friction; scrape; erode

creation of clastic rock

weathering, erosion, transportation, deposition, and lithification

avulsion

when a flood in the river breaks through a levee

metallic luster

when a mineral reflects light as polished metal does

stream terrace

when a stream downcuts through the alluvium of a floodplain so that a new, lower floodplain develops and the original floodplain becomes a step-like platform

depostition

when detritus and sedimentary grains settle out of the transportation medium

cementation

when minerals grow in pore spaces, often quartz or calcite. said minerals precipitate from ground water and help glue sediments together

continental collision

when two continental plates collide as an ocean basin closes, pushing the continental crust up to form mountains. subduction ceases. rock may be up to twice its normal thickness in this zone. metamorphic rock is brought to shallow depths

divergent boundary

where tectonic plates move apart. lithosphere thickens away from the ridge axis. new lithosphere created at the divergent boundary. aka mid-ocean ridge. ocean depth increases with depth from the ridge

convergent boundary

where tectonic plates move together. the process of plate consumption is called subduction. trench

transform boundary

where tectonic plates slide sideways. plate material is neither created nor destroyed.

triple junctions

where three plate boundaries intersect at a point

width of magnetic stripes

wider stripes = faster spreading and vice versa. isotopic dating is then used to find the duration of chrons/subchrons

sand-dune environments

wind-blown, well-sorted sand - aeolian deposition. dunes move according to the prevailing winds, results in uniform sandstones with gigantic cross beds

anoxic

without oxygen

oceanic lithosphere

~100 km thick. basalt and gabbro. heavier, more dense. less buoyant, sinks lower

continental lithosphere

~150 km thick. felsic to intermediate crustal rocks. less dense, more buoyant

volcanic crater

a bowl-shaped depression atop a volcano; up to 500m across and 200m deep form as erupted lava piles up around the vent

arkose

a clastic sedimentary rock containing both quartz and feldspar grains, sands and gravels. commonly deposited in alluvial fans. feldspar indicates short transport

sedimentary rock

a rock that forms from compressed or cemented layers of sediment, only occurs in upper part of the crust. usually forms in water

volcano

an erupting vent through which molten rock surfaces; a mountain built from magmatic eruptions

classifying clastic sedimentary rocks

clast (grain) size, clast composition, angularity and sphericity, sorting, character of cement -> results in a diverse range of clastic rock

sandstone

clastic rock made of sand-sized particles, common in beach and dune settings. quartz is very common mineral in this sedimentary rock

breccia

coarse sedimentary rock consisting of angular fragments; or rock broken into angular fragments by faulting. found close to clast source

gravel

coarse-grained sediments; boulders, cobbles, pebbles

calcite/aragonite

CaCO3, limestone. a biochemical sedimentary rock

andesitic or rhylolitic eruptions

more viscous magmas, more volcanic gases therefore volcanoes with these materials are more prone to explosions; generates huge volumes of debris debris: tephra, tuff (may or may not contain lapilli)

columnar jointing

occurs when solidified flows contract with vertical fractures to create polygonal columns (think basalt columns)

effusive eruption

eruption that produces a vast outpouring of lava lava flows stream away from vents lava lakes can form near or inside the vent can produce huge lava fountains -common with mafic/ultramafic magma (basalt) (very hot, low viscosity)

volcanic gases

expelled vapor and aerosols from a volcano

alluvial fans

fan-shaped deposits of sediments dropped by streams flowing out of mountains. the rapid drop in velocity creates the fan shape. sediments become conglomerate and arkose

pyroclastic debris

fragments blown out of a volcano

ash

fragments less than 2mm in diameter

dormant

hasn't erupted in hundreds or thousands of years

eruption pressure

if magma is low viscosity (basalt), gas can escape easily and therefore the eruption is mellow if magma is high viscosity (rhyolite), gas cannot escape easily and therefore the eruption is violent

stratovolcano (composite)

large, cone-shaped volcanoes with steeper slopes made of alternating layers of lava, tephra, and debris from alternating effusive and pyroclastic eruptions ex. includes Mount Fuji, Mount Rainier, Mount Vesuvius, Mt. Etna

andesitic lava flows

lava flow with a higher SiO2 content, higher viscosity does NOT flow rapidly forms a mound around the vent and flows slowly, therefore is always mound in close vicinity to the vent

rhyolitic lava flows

lava flow with the highest SiO2 content and the most viscous lava rarely flows, instead the lava plugs the vent as a lava dome sometimes the lava domes are blown to smithereens

fossiliferous limestone

limestone that contains visible fossil shells

siltstone

lithified silt

tuff

lithified volcanic ash

flank eruption

located along the side of a volcano

summit eruptions

located within the summit crater

detritus

loose clasts -> mineral grains, rock fragments

clastic rock

loose rock fragments cemented together; consists of detritus and cementing material

characteristic features of a volcano

magma chamber fissures and vents craters calderas distinctive profile

character of cement

minerals that fill sediment pores, quartz and calcite are the most common

tephra

rock fragments and particles ejected by a volcanic eruption

evaporites

rock from evaporated sea or lake water. evaporation triggers the deposition of chemical precipitates (ex. halite, gypsum)

pillow basalt

round blobs of basalt cooled in water the surface is cracked, quenched glass pressure erupts a blob to form the next blob process repeats to form a mound common on the mid-ocean ridge

conglomerate

sedimentary rock borne from clasts with a high sphericity, deposited far from source.

chemical sedimentary rock

sedimentary rock that forms when minerals crystallize directly from a solution

limestone

sedimentary rocks made of CaCO3, include calcite and aragonite.

recurrence interval

the average time between successive geologic events

angularity

the degree of edge or corner smoothness, fresh detritus is usually angular and non spherical

clast size

the diameter of fragments or grains, ranges from very coarse to very fine. boulder, cobble, pebble, sand, silt, clay.

fissure eruptions

the eruption of lava from a crack in the lithosphere rather than from a central vent; may display a "curtain of fire"; eventually evolve in into discrete vents and craters

lithification

the physical and chemical processes that transform sediments into sedimentary rocks

magma chamber

the pocket beneath a volcano where magma collects; usually located in the upper crust sometimes cools to form intrusive igneous rock sometimes may rise to surface and become a volcano

compaction

the process by which sediments are pressed together under their own weight, pressure increases with burial depth. squeezes out air and water, compresses sediment grains

clastic sorting

the uniformity of grain size, occurs along stream flow

volcaniclastic deposits

these deposits include: pyroclastic debris preexisting rock landslide debris lahars

continental hot spot

thin crust, shallow magma ex: Yellowstone, 72 km caldera; magma beneath still fuels modern-day geysers

pele's hair

thin glass strands

speleothems

various intricately shaped formations that grow in caves by the accumulation of dripstone

eruptive style

very explosive, catastrophic release of pressure high gas pressure caused by high viscosity magma (rhyolitic and andesitic compositions), SiO2 rich creates pyroclastic flows and covers land with tephra can eject many cubic km of debris skywards

mafic lava flows

very hot, low silica, low viscosity; basaltic lava flow flow up to 30 kmh, can flow for long distances (long distance flow is facilitated by lava tubes)

Krakatau eruption

volcano located between Java and Sumatra, initially exploded 20 may 1883. continued erupting through june and july. on 27 august 1883, the island was obliterated, tsunami waves killed 36000 people. the magma chamber was breached by the ocean