Essentials of Geology Ch. 2 - Plate Tectonics, CH 1: Introducing Geology, the Essentials of Plate Tectonics, and Other Important Concepts, Chapter 3 - The Sea Floor, Geology 100 Chap 1 Intro to Geology, the Essentials of Plate Tectonics, and Other Im...

Period with the first early man (humans)

Pleistocene

Disconformity

an erosion surface in parallel sedimentary rocks

era of the phanerozoic eon, paleozoic

ancient life

Divisions of time on a geologic time chart are fundamentally based on

changes in fossil assemblages

Meteorites of a ________composition are used as a model for the non-volatile composition of the solar nebula from which the sun and planets formed. (Note: "non-volatile" means a composition that does not include gaseous elements like H and He).

chondrite

The bowl-shaped depression on the side of a mountain where a glacier originates is a (an)

cirque

Ocean Trenches

found in ocean basins along margins of some continents that are near the Pacific Ocean

Joints

fractures bedrock along which no movement has occurred

Rifts are

grabens associated with divergent plate boundaries

paleontology

study of fossils

Arrange in order of total water volume--- from least to greatest

streams, lakes, groundwater oceans

force per unit area

stress

N38E

strike

the compass direction of a line formed by the intersection of an inclined plane with a horizontal plane

strike

aseismic ridge

submarine ridge with which no earthquakes are associated

earthquake

sudden release of stored mechanical energy

Which of the following clearly does NOT meet the definition of a mineral

sugar

in an undisturbed sequence of sedimentary or volcanic rocks, layers get younger from bottom to top

superposition

Contacts

surfaces separating successive rock layers (beds)

when layers are folded downward; younger rocks are the inside

synclines

Numerical Age

the age of events or objects, expressed as a number or numbers

extinction

the death of every member of a species

Correlation

the determination of the time-equivalency of rock units

Dip:

the direction and angle from horizontal in which a plane is oriented

What is the Lithosphere?

- Composed of both the uppermost mantle & the crust - Rigid/brittle outer shell of Earth - Makes up Earth's tectonic plates

Controlling factors that make mountain belts (3)

- Intense deformation: compression (results in intense folding and faulting of sedimentary and volcanic rocks, and at depth results in foliation of metamorphic rocks) - Isostasy: vertical movement of mountain belts - Weathering and erosion: rate of weathering dependent on climate, type of rock, and height

change in earth's orbit

-dinosaurs would not have been able to adapt to cold temps -furry animals could adapt to the change in temperature

index fossil

-fossil of an animal that only lived during a short period of time -used to identify the age of the rock layer that it is found in -it is in ONE layer

asphalt

-gravel, sand, and tar trap preserve animals

uniformitarianism (james hutton)

-idea that the geologic changes that are happening have been happening the same way forever -changes happen slowly

three basic changes that cause rocks to melt

-increasing temperature -decreasing pressure -chemical reactions

things fossils tell us

-interpret the past -give us history of environmental changes -history of changing organisms -fossil record/age -life span of fossil

overpopulation

-lead to decreased amounts of food for the herbivores -without herbivores to eat, the carnivores starved to death

asteroid impact

-leading extinction theory -chemicals released in atmosphere -dust blocked sun for months and even years - 4-9 miles in diameter

mammals eating eggs

-mammals robbing eggs from nests causing decrease of dinosaur population -doesn't explain why so many other animals went extinct at the same time

petrification

-minerals seep into bone or tissue then it hardens to solid (rock)

cast fossil

-sediment fills in a mold fossil and becomes rock creating a fossil of that living organism

mold fossil

-something dies -gets covered with dirt, sand, gravel, etc. -rots and decays leaving an empty cavity in the rock

catastrophism

-the belief that the surface of the earth changes suddenly due to sudden events (bad things)

eon

-the largest division of geologic time

paleontology

-the scientific study of fossils

geologic time scale

-the standard method used to divide the earth's long natural history into manageable parts

half-life

-the time needed for half of a sample of a radioactive substance to undergo radioactive decay

fossil

-the trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock

Divergent plate boundaries

A boundary in which two plates move apart, resulting in upwelling of material from the mantle to create to create a new seafloor.

Convergent plate boundaries

A boundary in which two plates move together, resulting in oceanic lithosphere being thrust beneath an overriding plate, eventually to be reabsorbed into the mantle. Can also involve the collision of two continental plates to create a mountain system.

Transform plate boundaries (Transform faults)

A boundary in which two plates slide past one another without creating or destroying the lithosphere

What is Isostatic Adjustment?

Concept of vertical movement of section of Earth's crust to achieve balance or equilibrium.

- Earth's core and lithosphere composition

Consists of the entire crust and uppermost mantle and forms a relatively cool rigid outer shell

Which is a correct comparison of oceanic and continental crust?

Continental crust is thicker, lower density, and higher in silica (i.e. "felsic") compared to oceanic crust

Results of Divergent Boundary

Creation of a new ocean floor w/submarine volcanoes; mid-oceanic ridge; small to moderate earthquakes

What is the etymology of Cretaceous?

Creta is chalk in Latin

Fault-block mountain range

Crust of mountain belts can break into fault-bounded blocks If the upthrown blocks are large enough, this can result in fault-block mountain ranges - bounded by normal faults on either side of the range or tilted fault blocks - volcanic eruptions may occur along faults extending deep into the crust/upper mantle

During the last couple of decades, geologist have used a _____ approach to gain insight into the growth and wearing away of mountains. A. tectonic B. erosional C. weathering D. system E. climatic

D

Migmatites must have been transported much higher in the crust during and after ____. A. normal faulting B. volcanism C. emplacement of plutons D. an orogeny E. subduction

D

Of the two major mountain belts in North America, the _______ are in the West. A. Urals B. Himalyan C. Appalachians D. North American Cordillera E. Andes

D

The _____ resulted from the collision of Asia and Europe. A. Alps B. Pyrenees C. Caledonide Mountains D. Ural Mountains E. Himalayan Mountains

D

The region of a continent that has been structurally stable for a long period of time is called the ______. A. dome B. basin C. Precambrian shield D. craton E. mountain range

D

Volcanic rocks, mostly _______, accumulate near a convergent plate boundary. A. shales B. sandstones C. granites D. andesites E. marbles

D

How do rocks behave when stressed?

Deform

What are Mid-Oceanic Ridges?

Divergent boundaries coinciding with the crests of submarine mountains

What are the three types of Plate Boundaries?

Divergent, Convergent, Transform

• Basin and Range Area Faulting

Downward structures weather circular or elongated structure

A _____ terrane has rock types and ages that do not seem to be related to the rest of the geology of a mountain belt. A. mixed B. coupled C. partial D. integrated E. suspect

E

According to the concept of ____, lighter less dense continental crust "floats" higher on the mantle than denser oceanic crust. A. delamination B. gravitational collapse C. geosynclines D. block faulting E. isostacy

E

At the close of the Paleozoic, eastern North America was attached to what is now _______. A. Europe and Asia B. China and South America C. India and Antarctica D. Africa and China E. Europe and Africa

E

Frequent earthquakes, offshore trenches, and active volcanoes perched on top of older rock are all indications of ____. A. old mountain belts B. stable craton C. platform D. Precambrian shield E. active mountain ranges

E

Geologists regard most bodies of ultramafic rock as being _______. A. intrusions formed during the accumulation stage B. due to gravitational collapse and spreading C. due to lithospheric delamination D. areas left by block faulting and uplift E. mantle material faulted into the crust during orogeny

E

Most of the world's mountains existing today are a result of ____. A. intense deformation B. isostasy C. weathering and erosion D. intense deformation and isostasy E. intense deformation, isostasy, and weathering and erosion

E

The Himalayan Mountains formed as the result of ______ convergence. A. ocean-continent B. arc-continent C. ocean-ocean D. arc-ocean E. continent-continent

E

The sedimentary sequences that form on passive margins are predominantly ____. A. shale B. limestone C. sandstones D. andesitic flows E. shale, limestone, and sandstones

E

_____ are chains thousands of kilometers long composed of numerous mountain ranges. A. Mid-oceanic ridge B. Volcanic arcs C. Back arcs D. Valley and Ridge Province E. Mountain belts

E

Period

Each era of the standard geologic time scale divided into this (Cretaceous, Jurassic, Triassic)

Epoch

Each period of the standard geologic time scale is divided into this (EX: Pleistocene, Quaternary Period)

P Wave

Earthquake wave that pushes and pulls rocks in the direction of the water; also known as a compression wave. These are the first (or primary) waves to be detected,

Name some Geological Hazards

Earthquakes, volcanoes, landslides, floods, & tsunamis

dissapears on the release of the stress

Elastic Strain

How do rocks behave when stressed?

Elastic,ductile or brittle

What is External Heat Engine?

Energy from the Sun - Primary driver of atmospheric (weather) & hydrospheric (ocean currents) circulation - Controls weathering of rocks at Earth's surface

subdivision of geologic time scale, greatest expanse of time

Eon

Arc-continent convergence and orogeny

Ex New Guinea and much of western North America - island arc collides with a continent during convergence (intervening ocean floor is destroyed by subduction) - arc and continent are both too buoyant to be subducted, so continued convergence causes the remaining sea floor to break away from the arc and a new site of subduction occurs where faulting happens - a new trench (seaward of the arc) is also created - direction of subduction changes (flipping subduction zone) but can still supply the arc with magma - arc becomes welded to the continent and the continent increases in size

Continent-continent convergence and orogeny

Ex the alps and Himalayas - mountain belts form when an ocean basin closes and continents collide along a suture zone - mountain belts will have cratons on either side (and are within continents) - thick sequences of sedimentary rocks that build up on both continental margins are intensely faulted and folded - thrust belts develop and are carved by erosion to make the mountain ranges - normal faulting due to gravitational collapse takes place

What are the Earth's engines?

External & Internal

What is tectonic forces?

Forces generated inside of Earth

What is the Core?

Outer Core - metallic liquid; mostly iron Inner Core - Metallic solid; mostly iron; 3400 km radius

The first seismic waves to arrive at a seismic station are

P waves

body waves

P waves and S waves are body waves. These travel through earth's interior.

Paleomagnetism (fossil magnetism)

The natural remnant magnetism in rock bodies. The permanent magnetization acquired by rock that can be used to determine the location of the magnetic poles and the latitude of the rock at the time it became magnetized.

Curie point

The temperature above which a material loses it's magnetation.

Transform Plate Boundries

When two plates shift in opposite directions. No volcanoes are formed but will generate earthquakes

Principle of Faunal Succession

William Smith (1793) discovered that fossils occur in a predictable order from oldest to youngest (because of evolution)

Geologic Time Scale

Worldwide relative time scale, subdivides geologic times based on fossil, divided into eons, eras, periods and epochs

Resources needed to make a pencil?

Zinc, copper, Iron, Paint pigment, Clay, & Graphite

What is a subduction zone?

Zone where an oceanic plate descends into the mantle below beneath an overriding plate

oceanic trench

a narrow, deep trough parallel to the edge of a continent on an island arc

super position

a principle that states that younger rocks lie above older rocks if the layers have not been disturbed

fringing reef

a reef attached directly shore

barrier reef

a reef seperated from the shoreline by the deeper water of a lagoon

The Canadian shield is

a region of exposed cratonic rocks.

The Big Thompson Flood of 1976 (Colorado) was the result of

a relatively small and localized area of high rainfall, thunderstorm produced.

reef

a resistant ridge or calcium carbonate formed on the sea floor by corals and coralline algae

continental slope

a steep slope extending from a depth of 100 to 200 meters at the edge of the continental shelf down to oceanic depths

continental shelf

a submarine platform at the edge of a continent, inclined very gently seaward generally at an angle of less than 1

Unconformity

a surface between two layers that represents missing time (it is the opposite of conformable)

Unconformity

a surface that represents a gap in the geologic record

rift valley

a tensional valley bounded by normal faults,

continental rise

a wedge of sediment that extends from the lower part of the continental slope to the deep-sea floor

mass damper

a weight in the roof of a building that can shift to counteract the buildings movement.

The lithosphere is all of the following except

a zone that includes deep parts of the mantle.

Mining of coal can release _________ into _______ ___________.

acids; water supplies

What is fault considered if movement has occurred along them within the last 11,000 years?

active

Downcutting continues until the stream reaches:

base level

compressive, tensional and shear

basic types of stress

structures in which the beds dip toward a central point

basins

An example of a "mineral physical property" would be:

density

The older ocean seafloor

descends into the mantle at ocean trenches

Numerical ages

determine the actual age in years, also known as isotopic age

Relative ages

determine the sequence of events or rocks, "this rock is older than that one"

The two main categories of sedimentary rocks are referred to as _____

detrital (sometimes called "clastic") and chemical

heat engines

devices that convert heat energy into mechanical energy

53SE

dip

the direction and angle from horizontal in which a plane is oriented

dip

What category do active fault movement fall into?

dip-slip, strike-slip, oblique-slip

Elastic strain

disappears on the release of stress (like a rubber band)

Faunal succession is most helpful in recognizing a kind of unconformity in which sedimentary layers are undistrubed (i.e. flat lying) like in a layer cake. In this kind of unconformity (with flat-lying layers) there is a large time gap between the layers. This kind of unconformity is called a(n) ________.

disconformities

type of unconformity, strata on either side are parallel-missing time/formation in the bedding

disconformity

3 types of plate boundaries

divergent convergent transform classified based on the type of motion occurring between adjacent plates

Axial plane

divides a fold into its two limbs

Which one of the following minerals is a carbonate?

dolomite

Structures in which the beds dip away from a central point

domes

structures in which the beds dip away from a central point

domes

another name for domes

doubly plunging anticlines

another name for basins

doubly plunging synclines

Faunal succession

is the recognition of that different kinds of life lived at different times in the past.

folds with parallel limbs

isoclinal

variant of the same parent atom, different number of neutrons and mass number

isotope

When lithosphere breaks apart...

it forms a wide, steep walked depression known as a rift valley

multiple parallel joints

joint sets

fractures bedrock along which no movement has occurred

joints

fractures with no displacement between the sides

joints

Faults are classified on the basis of the ..... that occurs on them

kind of motions

Which of the following does not contain information about paleocurrents?

laminar bedding

terrigenous sediment

land derived sediment that has found its way to the sea floor

Deep red soils that are rich in aluminum are called _________.

laterites

oldest rocks are on the bottom

law of superposition

aesthenosphere

layer beneath the lithosphere. Layer is about 100-200 kilometers thick. Almost made out of solid rock, it flows slowly because 1 percent of minerals are melting.

Stratification

layering in sedimentary rocks

Synclines

layers are folded downward. younger rocks on inside

Anticlines

layers are folded upwards in what looks like an arch. Younger rocks on the outside

when observed strike-slip fault would observe it to be offset to their left

left-lateral

The age of ocean floor rocks are generally

less than 200 million years

Caves typically form in areas with this type of bedrock:

limestone

fracture zone

major line of weakness in crust that crosses the mid oceanic ridge at approx right angles

Oceanic lithosphere is consumed and its descends into the

mantle adjacent to trenches at regions (subduction zones)

3 major concerti zones

mantle, crust, core

number of protons added to the number of neutrons in the atom's nucleus

mass number

Correlation of Rock Units

matching rocks between two or more locations using rock type and fossils and relative age

Metamorphic processes all occur WITHOUT

melting

era of the phanerozoic eon, mesozoic

middle life

type of fossil, shell or other structure is buried and then dissolved by underground water

mold

magma

molten rock

when rock layer has a gently dipping bend in the horizontal rock layer

monocline

What do metamorphic rocks tell us about Earth's history?

mountain building

What do igneous rocks tell us about Earth's history?

plate tectonics

folds in which the hinge line is not horizontal

plunging

type of fossil, hardened resin of ancient trees surrounds and organism

preservation in amber

younger feature cuts through an older feature

principle of cross cutting relationships

layers of sediment initially extend laterally in all directions

principle of lateral continuity

sediment is deposited in horizontal layers, rules of relative dating

principle of original horizontality

Stenos laws :

principle of superposition, original horizontality, original later continuity

Geologic structures

produced as rocks change shape, location, and orientation in response to applied stress

Wegner's Theory

proposed the continental drift theory: suggests that continents had come together to form a single supercontinent mass (Pangaea)

When igneous rocks solidify, cooling rate controls grain size in the solidified rock. Rapid cooling produces--

small crystals

earth system

small part of the larger solar system the components of earth can be though of as sub spheres, and represent earth systems (known as "spheres")

geosphere

solid earth system = rock and other inorganic earth material that make up the bulk of the planet

A place where water flows naturally from rock onto the land surface is a:

spring

a change in size or shape in response to stress

strain

movement that is predominantly horizontal and parallel to the strike of the fault plane

strike-slip faults

Basins

structures in which the beds dip toward a central point

Ocean floor is being created in oceanic ridges and destroyed in

subduction zones

divergent boundary

two plates moving APART from each other result: creation of new ocean floor with submarine volcanoes; mid-oceanic ridge; small to moderate earthquakes most divergent boundaries coincide with the crest of submarine mountain ranges, called mid-oceanic ridges most divergent boundaries located within ocean plates by typically initiate within a continent

Geologic structures are indicative of the _______ and its _______, as well as the _______ or sediments.

type of stress; rate of application; physical properties of the rocks

anticline, syncline, monocline

types of folds

an _____ is a break in the rock record, indicates that sediments from a period of time are missing

unconformity

"geological processes operating at present are the same processes that have operated in the past" is the principle of

uniformitarianism

asthenosphere

uppermost mantle underlying the lithosphere soft (flows more readily)

Fold Classification

upright, inclined, recumbent, horizontal, plunging, vertical, reclined

submarine canyon

v shaped valleys that run across the continental shelf down the continetal slope

Above the saturated zone is an unsaturated zone known as the

vadose zone

Abyssal Plain

very flat, sediment-covered region of the deep sea floor, usually at the base of the continental rise

A rock with high permeability is likely to be:

well sorted

elastic deformation

when rock deforms like rubber

Superposition

within an undisturbed sequence of sedimentary or volcanic rocks, layers get younger from bottom to top

Intrusions and Faults

younger than the rocks they cut through

What are the Earth's systems?

Atmosphere, hydrosphere, biosphere, & geosphere

"visible life"-most recent, youngest eon

phanerozoic

Devonian

10th Period

graben

Down drop blocks

Stress

Force per unit area

A lithospheric plate includes

a and b

James Hutton

"Father of Geology"

What is a Theory?

- A concept that has been highly tested and in all likelihood is true. - Used for what scientists call a hypothesis

Mountain range

- A group of closely spaced mountains or parallel ridges - composed of tectonically deformed sedimentary, volcanic, or metamorphic rocks - may show a history of intrusive igneous activity

What is a Divergent Boundary?

- Involves two plates moving away from each other - Magma rises, cools & forms new lithosphere - Typically express as mid-oceanic ridges

What is the superficial process of Deposition?

- Loose sediment is deposited when transport agent loses its carrying power - Earlier sediments get buried & harden into sedimentary rock

Age of mountain belts

- Major mountain belts with higher mountain ranges tend to be younger than those where mountains are lower - individual ranges within a mountain belt may vary considerably in height even though they are the same age

Mountains vs cratons

- Mountains are overlain by thick (more than 10km) layers of sedimentary rock, mostly marine-deposited (originally deposited on a continental margin (slope and shelf)), either at a passive continental region (shale, sandstone and limestone) or a active continental region (sediment has a significant component of volcanic material). Lots of folds and faults that indicate intense orogenic deformation - crust is thicker under mountain ranges - Cratons - overlain by a thin cover of sedimentary rocks, overlies the basement in the craton (basement is exposed because the rest of the mountain range has been eroded). Sedimentary rock in cratons may show no deformation, or may have been gently warped into basins and domes above the basement - crust is thinner under the craton

What are the physical aspects of Geology?

- Natural Resources - Geological Hazards - Environmental Protection

What are the four steps of the Scientific Method?

- Observe - Gather Facts - Hypothesize & est - Theory

What is Continental Drift Hypothesis?

- Originally proposed in early 20th century by Alfred Wegener to explain the "fit of continents", matching rock types & fossils across ocean basins, etc. - Insufficient evidence found for driving mechanism

What is Plate Tectonics Theory?

- Originally proposed in the late 1960's 9based on earlier work hypothesis of Continental Drift) - Included new understanding of the sea floor & explanation of driving force - Describes lithosphere as being broken into plates that are in motion - Explains origin & distribution of volcanoes, fault zones & mountain belts

What is Convergent Boundary?

- Plates move toward each other - Mountain belts & volcanoes common - Oceanic plates may sink into mantle along a subduction zone, typically marked by a deep ocean trench

What is the superficial process of Weathering & Erosion?

- Rainfall & glaciers flow down slopes - Moving water, ice & wind loosen & erode geologic materials, creating sediment

What is the Asthenosphere?

- Soft,flows more readily than the underlying mantle - zone on which the lithosphere floats

What is the superficial process of Uplift?

- Volcanic and/or tectonic forces build crust above the sea level - Removal of material by erosion allows isostatic uplift

Accreted Terrane (and where they come from)

- a terrane for which evidence (fossil assemblages or paleomagnetic poles) indicates it did not form at its present site on a continent - could have been an island arc, a microcontinent, or fragments of distant continents that split off and moved a long distance because of transform faulting

Suspect Terrane

- a terrane that may not have formed at its present site - has rock types and ages that do not seem related to the rest of the geology of the mountain belt

Natural Resources Key Facts

- all manufactured objects depend on Earth's resources - localized concentration of useful geological resources are mined or extracted - if it can't be grown, it must be mined - most resources are limited in quantity and non-renewable

Exotic Terrane

- an accreted terrane that evidence shows has traveled great distances - its fossil assemblages will indicate a very different climate or environmental setting compared to that of the adjoining terrane - its magnetic minerals will plot at some part of the world very distant from poles of adjoining terranes that formed in place

The Wilson Cycle

- cycle of splitting of a supercontinent - opening of an ocean basin - closing of the basin - collision of continents - has happened before Pangaea and many times throughout history

Delamination

- detachment of part of the mantle portion of the lithosphere beneath a mountain belt - the lithospheric mantle underlying the thicker continental crust (of a mountain range) is thicker and gets softened from the underlying asthenosphere - the softened lithosphere detaches/breaks off, and sinks through the asthenosphere, and underlying hot asthenosphere flows upwards to fill the void - hot asthenosphere causes the crust to heat up and allowing the lower crust to flow, which makes it thin out, and extension results in block-faulting in the upper part of the crust (mountain range)

Orogeny and plate convergence

- different types of plates converging creates different mountains and different conditions for orogeny to occur - three types: ocean-continent, arc-continent and continent-continent

Iceberg analysis

- even the highest and best exposed mountains show less than 1/8th of the bedrock a mountain is composed of - much of the mountain has been eroded away (usually thousands of meters) - and most of the mountain is underground, the roots of a mountain (ex the Himalayas rise 8000 meters above sea level, and extends 65,000 meters below)

Ocean-continent convergence and orogeny

- ex the Andes - accretionary wedge develops where newly formed layers of sediment are folded and faulted as they are snowplowed off the subducting oceanic plate - rock caught in and pulled down the subduction zone is intensely sheared, and if carried farther down becomes metamorphosed - fold and thrust belts can develop on the craton (the backarc of the mountain belt) because the magmatic arc is high and crust is thicker and composed of hot igneous and metamorphic rocks, so large thrust sheets move towards and overtop the craton while crust is shortening b/c of convergence - gravitational collapse and spreading takes place

Active mountain ranges have

- frequent earthquakes - deep-ocean trenches parallel to mountain belts (young ones) - trenches lie off the coasts of island acres (which are very young mountain ranges) - isolated active volcanoes (melting is still taking place at depth)

How continents grow

- grow larger when new mountain belts evolve along continental margins - addition of terranes that may have traveled great distances before colliding with the continent

System approach to mountains

- looks at the interrelation of tectonics (plate tectonics and isostacy), climate, and erosion on mountain forming - changes in one affect others Ex - climate affects erosion - wet climate, primary erosion running water, or heavy glaciation, dry climate, slower rate of erosion - tectonics affects climate - height = increase in cold and glaciation - erosion effects tectonics - a region that experiences lots of erosion into deep valleys and mountain tops will lose more weight and rise upwards because of isostacy - climate and tectonics (height) affect erosion - decide what kind of erosion will take place

Gravitational collapse and spreading

- mountain belt gets thicker and higher during convergence b/c of compression and volcanic eruptions and emplacement of plutons - the welt in the mountain belt becomes too high to be supported and collapses - collapse forces rocks outward and downward - movement of deep rocks in the mountain is ductile, but near the surface rock fractures and moves through faulting - rock is pushed outward and helps create the fold and thrust belt while in the high parts outward flowing rock results in extension and normal faulting - once deep-seated metamorphic rocks are squeezed, forcing them to flow upward and outward bringing them closer to the surface of the mountain belt

Normal faulting

- occurs after the orogeny that results in tight folding, thrust faults and metamorphism, and after most batholiths have formed - is a result of vertical uplift or horizontal extension - can also occur in the high, central part of a mountain belt while folding and thrust faulting are taking place at the outer parts of the belt, mountain belt is being compressed so the central portion is pushed upwards - takes place as rock at high levels flows outward over the rock being compressed at lower level

Process of a mountain belt

- rise high above sea level during an orogeny - erode to hills or low plains - experience later episodes of isostatic uplift and rise again - this process can repeat numerous times over the millions of years a mountain belt gets formed - eventually mountain ranges stabilize and are eroded to plains

Folding and faulting

- sedimentary and volcanic layers that originally made up a large section of an ocean floor can be folded and faulted during mountain building into a much smaller area - open folds indicate not very intense deformation - tight folds indicate greater deformation - overturned and recumbent folds were intensely deformed - reverse faults are common in intensely folded regions - fold and thrust belts are also common (characterized by large thrust faults stacked one upon another - intervening rock was folded while it was being transported during faulting

Normal faulting - settings where it develops after orogeny - things it can cause - what its caused from

- when a continent splits and a divergent boundary forms - when part of the crust moves upward isostatically more than the adjoining crust does - can cause fault-block mountain ranges - normal faulting implies horizontal extension strain when the crust pulls apart regionally

epoch

-4th biggest geologic time

dipslip faults reverse

-Hanging wall block moves up relative to the footwall block - accommodate horizontal shortening of the crust

dipslip faults thrust

-Hanging wall block moves up relative to the footwall block - reverse faults having dips less than 45 degrees so the overlying block moves nearly horizontal over the underlying block

Four oceanic ridge regions

-Mid-Atlantic Ridge -East Pacific Rise -Indian Ridge -Antarctic Ridge

- Primary waves

-P waves are push and pull -they momentarily push (compress) and pull (stretch) rocks in the direction the wave is traveling

secondary waves

-S waves are identified through their mode of travel through intervening materials

- Surface vs. body waves and their destruction - material that they travel through

-Surface waves also retain their maximum amplitude longer -Surface waves tend to cause longer ground shaking and greater property damage

unconformity

-a break in the geologic record when rock layers are eroded or when sediment is not deposited for a long period of time

era

-a unit of geologic time that includes two or more periods -2nd largest

relative dating

-any method of determining whether an event or object is older or younger than other events or objects -age compared to something else

absolute dating

-any method of measuring the age of an event or object in years by experimenting it -actual age of something

tar pit

-asphalt at the earth's surface traps animals and preserves their bones and other hard parts

divergent boundary formation

-begins with a rift (split) in the continent caused by either, existential (stretching) forces within continent, or by the upwelling of hot asthenosphere from mantle below. (continental plate pulls apart) -narrow valley is formed -fissures extend into magma chamber -magma flows into fissures -separation continues, valley deepens, crust beneath the valley sinks and a narrow sea floor is formed -underlying the new sea floor is rock that has been newly created by under water eruptions and solidification of magma in fissures (igneous rock) = oceanic crust as ocean basin widens, the central zone where new crust if created remains relatively high. this is the mid oceanic ridge that will remain as the divergent boundary as the continents continue to move apart and the ocean basin widens mid oceanic ridge is higher than the ocean floor because the rocks are hotter and less dense a rift valley runs along the crest of the ridge process of filling and cracking continues indefinitely new oceanic crust is continuously developed, created at a divergent boundary

frozen fossil

-block of ice covers an entire animal or plant and it is preserved for a long time -EXAMPLE- woolly mammoth -lived up to 10,000 yrs. -died because it was stuck in mud and buried by an avalanche

volcanic activity

-cause acid rain which killed vegetation -global climate change

trace fossil

-these show evidence of an animal or plant leaving -fossils that are not bones, teeth, and claws but they DO turn into rock from the sediment

sickness and disease

-through overpopulation, disease quickly swept through the dinosaur population leaving very few healthy animals to reproduce

amber

-tree sap that traps insects and animals

What four factors determine the effects of earthquakes

1. Distance from the epicenter 2. Strength of the earthquake 3. local geology (what is the ground made of) 4. type of construction (what are the buildings made of)

What are the 8 major plates

1. North American 2. South American 3. Pacific 4.Nazca 5.Eurasian 6.African 7. Antarctic 8.Indian-Austrialian

What percent of the Earth time is represented by the Cretaceous?

1.7%

Silurian

11th Period

Ordovician

12th Period

Cambrian

13th Period

The last ice age began to wane around

15000 years ago

Phanerozoic

1st Eon

Holocene

1st Epoch

Cenozoic

1st Era

Quaternary

1st Period

how long do reversal last?

250,000 years to 37 million years

Proterozoic

2nd Eon

Pleistocene

2nd Epoch

Mesozoic

2nd Era

Neogene

2nd Period

Archean

3rd Eon

Pliocene

3rd Epoch

Paleozoic

3rd Era

Paleogene

3rd Period

period

3rd largest time that is divided

The earth, other planets, and the sun all formed at about the same time. Evidence (primarily from meteorites and lunar samples) suggests that this was ________ years ago

4,500 million

How old is the Earth?

4,600 million years old

Current best estimate of Earth's age

4.56 b.y.o.

The Earth is ____ Years Old

4.6 Billion

How long did the Laramide orogeny last?

40 million years

Hadean

4th Eon

Miocene

4th Epoch

Precambrian

4th Era

Cretaceous

4th Period

How many major glaciations did the Earth experience?

5

Oligocene

5th Epoch

Jurassic

5th Period

Eocene

6th Epoch

Triassic

6th period

How long did the Cretaceous Period last?

79 million years

Paleocene

7th Epoch

Permian

7th Period

What percent of the Earth time is represented by the Precambrian?

88%

Pennslyvanian

8th Period

Mississippian

9th Period

A(n) _________ mountain range, such as the Basin and Range and Tetons, implies a horizontal extension strain. A. fault block B. erosional C. volcanic D. fold E. strike-slip.

A

If the San Andreas Fault remains active, Los Angeles will continue northward and crash into ___. A. Alaska B. Japan C. the Imperial Valley D. British Columbia E. Hawaii

A

In many mountainous regions are found ____, which are characterized by large thrust faults stacked one upon another. A. fold and thrust belts B. numerous rock types C. evidence of intrusions D. patterns of deformation E. volcanic landforms

A

In some mountain belts the crust breaks into fault-bounded blocks resulting in _____ mountain ranges. A. fault-block B. extremely high C. extensional D. isostatically adjusted E. metamorphic

A

Most of the _____ of the United States has/have a very thin blanket - only 1000 to 2000 meters - of sedimentary rock layers. A. craton B. Gulf Coast C. Rocky Mountain region D. Oregon-Washington coast E. Blue Ridge Mountains

A

The present ________ represent rejuvenation following uplift in Late Tertiary time. A. Appalachian Mountains B. Alps C. Himalayan Mountains D. Ural Mountains E. Sierra Nevada Mountains

A

_____ faults in the Tibetan plateau indicate that gravitational collapse is taking place. A. Normal B. Reverse C. Thrust D. Strike-slip E. High-angle thrust

A

_____ is the detachment of part of the mantle portion of the lithosphere beneath a mountain belt. A. Delamination B. Mantle convection C. Terrane shift D. Isostatic adjustment E. Craton formation

A

strikeslip faults (transform)

A Fault in which the dominant displacement is horizontal and parallel to the strike of the fault surface

Volcanic island arc

A chain of volcanic islands generally located a few hundred kilometers from a trench where there is active subduction of one oceanic plate beneath another

Hot spot track

A chain of volcanic structures produced as a lithospheric plate moves over a mantle plume.

Magnetic reversal

A change in Earth's magnetic field from normal to reverse or vice versa

Precambrian Shield

A complex of precambrian metamorphic and plutonic rocks exposed over a large area - these kinds of shields and basement complexes of cratons are the roots of mountain ranges that completed the deformation process more than a billion years ago

Hot spot

A concentration of heat in the mantel, capable of producing magma that, in turn, extrudes onto Earth's surface.

Fault

A fracture in Earth along which movement has occured

Tsunami

A huge destructive wave (especially one caused by an earthquake)

Continental Drift

A hypothesis, credited largely to Alfred Wagner, which suggested that all present continents once existed as a single supercontinent. The supercontinent began breaking about 200 million years ago, and the smaller continents began drifting to their current positions.

Supercontinent

A large landmass that contains all, or nearly all, of the existing continents.

Continental rift

A linear zone along which continental lithosphere stretches and pulls apart. It's creation may mark the beginning of the creation of a new ocean basin.

Fracture zone

A linear zone of irregular topography on the deep ocean floor that follows transform faults and their inactive extensions

Rift valley

A long, narrow trough bounded by normal faults. It represents a region where divergence is taking place.

Reverse polarity

A magnetic field opposite that which presently exists

Normal polarity

A magnetic field the same as that which presently exists

Mantle plume

A mass of hotter-than-typical mantle material that ascends towards the surface, where it may lead to igneous activity. May originate as deep as core-mantle boundary

What is intensity?

A measurement of the effects of an earthquake at Earth's surface.

What is an earthquake-hazard level?

A measurement of the likelihood that an area will have a damaging earthquake.

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

Ridge push

A mechanism that may contribute to plate motion. It involves the oceanic lithosphere sliding down the oceanic ridge under the pull of gravity.

Moment Magnitude

A more precise measure of earthquake magnitude than the Richter scale, which is derived from the amount of displacement that occurs along a fault zone and estimates the energy released by an earthquake

What is an Oceanic Trench?

A narrow, deep trough parallel to the edge of the continent or an island arc.

Deep ocean trenches

A narrow, elongated depression in the sea floor.

Liquefaction

A phenomenon, sometimes associated with earthquakes, in which soils and other unconsolidated materials saturated with water are turned into a liquid that is not able to support buildings

Fold and Thrust belt

A portion of a major mountain belt characterized by large thrust faults (reverse faults at a low angle to horizontal) stacked one upon another - layered rock between the faults was folded while it was being transported during faulting

Terrane

A region within which there is geologic continuity - mountain belts are divided into terranes - boundaries between terranes are usually faults - named after major geographic features

Richter Scale

A scale that rates an earthquake's magnitude based on the size of its seismic waves.

Mercalli Scale

A scale that rates earthquakes according to their intensity and how much damage they cause at a particular place

S Wave

A seismic wave that shakes particles perpendicular to the direction the wave is traveling. These waves cannot travel through liquid.

Surface wave

A seismic wave that travels along the surface Earth. These are the most destructive.

Magnetometers

A sensitive instrument used to measure the intensity of Earth's magnetic field at various points

What is a Mudflow?

A slurry of water & rock debris that flows down a stream channel.

Aftershock

A small earthquake that follows the main earthquake

base isolator

A structure that acts like a shock absorber

What is Biosphere?

All living or once living materials.

Folds syncline (circular: basin)

Almost always found in association with antique lines are downloads or troughs

Altitude crustal thickness relationship

Altitude above sea level is related to local crustal thickness The higher a mountain range is the thicker the crust beneath it is

What is a System?

An arbitrarily isolated portion of the universe that can be analyzed to see how its components interrelate.

Seismic Gap

An area along a fault where there has not been any earthquake activity for a long period of time

Orogeny

An episode of intense deformation of the rocks in a region (usually lasts millions of years) usually accompanied by metamorphism and igneous activity - involves folding and faulting of sedimentary and volcanic rock, regional metamorphism, and igneous activity - associated with plate convergence - occurs during mountain building - layered rocks are compressed into folds - reverse faulting is widespread - normal faulting may occur, but is not as common - more deeply buried rocks are converted to schists and gneisses - magma generated in the deep crust or upper mantle works its way upward to erupt in volcanoes or form batholiths - continental crust comes thicker (because of intense compression that results in tight folds and reverse faults, and addition of batholiths in the crust) and will isostatically 'float' higher, becoming taller

seismograph

An instrument that records seismic waves

- Elastic rebound and energy release

An object's ability to return to its original shape after being broken apart

What are some examples of convergent boundaries?

Andes mountain range, where the Nazca plate is subducting beneath the N. American plate.

Where would we go to find a continental ice sheet?

Antartica

Negative Effects of Volcanoes

Ash flows & mud flows can overwhelm populated areas

Isotopes

Atoms of the same element that have different number of neutrons but the same number of protons

A _____ is a group of closely spaced mountains or parallel ridges that may show a history of intrusive tectonic activity. A. volcano B. mountain range C. back-arc basin D. spreading center E. any uplifted region

B

A ______ is the source of sedimentary and volcanic material accumulating along a convergent boundary. A. subduction zone B. magmatic arc C. suspect terrane D. mid-oceanic ridge E. folded mountain range

B

Extension and normal faulting take place in a mountain range ____. A. during their early stage of formation B. when rock at high level flows outward C. before folding and metamorphism D. randomly throughout the range's history E. and is always related to late stage intrusions

B

Geologists believe that when the thick and high part of a mountain belt becomes too high and gravitationally unstable _____ occurs. A. massive landslides B. gravitational collapse and spreading C. volcanic eruptions D. rapid downcutting E. basalt flows

B

Major mountain belts with higher mountain ranges tend to be geologically ___________ relative to those where the mountains are lower. A. the same age B. younger than C. random in age D. older than

B

Terranes that can be shown to have traveled great distances are known as _____ terranes. A. accreted B. exotic C. suspect D. cratonic E. shield

B

The continental crust is _______ beneath mountain belts than under the craton. A. thinner B. thicker C. the same thickness D. more felsic E. more dense

B

The cycle of splitting of a supercontinent, opening of an ocean basin, followed by closing of the basin and collision of the continents, is known as a ________. A. Wegener plan B. Wilson Cycle C. delamination plan D. Hess Process E. Vine-Mathews system

B

The once deep-seated roots of former Precambrian mountain belts are the _____ rock for the now stable, central part of the continent. A. cratonic B. basement C. core D. platform E. isostatic

B

The system approach regards mountains as the products of three closely interdependent components. Which of the following is not one of those components? A. plate tectonics B. meteor impacts C. climate D. erosion

B

________ beneath the Basin and Range helps to explain the extensive rhyolitic and basaltic eruptions that occurred tens of millions of years after the last orogeny. A. Obduction B. Delamination C. Wilson Cycles D. Subduction E. Thickening of the continental crust by "rooting"

B

Why do cratons consist of plutonic and metamorphic rock?

Because these were the rocks that formed the deep roots of the former mountain belt before it eroded down

What general relationship exists between rising sea levels and the amount of volcanism?

Both increase and decrease together

A(n) __________ is an episode of intense deformation of the rocks of a region. A. isostatic adjustment B. geosyncline C. orogeny D. buoyancy event E. basin to dome event

C

Continents grow bigger as _______. A. accretionary wedges form at the margins B. gravitational collapse and spreading widens the craton C. mountain belts evolve along their margins D. uplift and block-faulting takes place E. isostacy lifts them up

C

Late stage normal faulting in a mountain range is a result of _______. A. volcanism B. igneous intrusions C. vertical uplift or extension D. sea-floor spreading E. geosyncline formation

C

The Grand Canyon, Ozark dome, Black Hills, and Adirondacks expose ________. A. a fold and thrust belt B. ophiolites C. a Precambrian basement D. an ancient magmatic arc E. the result of delamination

C

The _____ is(are) the product of oceanic-continental convergence and Earth's second highest mountain belt. A. Appalachians B. Himalayas C. Andes D. Basin and Range E. Sierra Nevada

C

____, intermixed granitic and metamorphic rock, may represent those parts of mountain belts that were once at even deeper levels of the crust. A. Pegmatites B. Sutures C. Migmatites D. Extensional fabric E. Subduction patterns

C

Which is older, Cambrian or Permian?

Cambrian

amount and rate of stress application, type of rock, temperature & pressure

Causes for elastic, ductile or brittle behavior of rocks

What is Sedimentary Rock?

Cementation of the loose particles, the sediment becomes lithified (cemented or consolidated)

Which is younger, Cenozoic or Paleozoic?

Cenozoic

Mountain belt

Chains of mountian ranges that are thousands of kms long

What is Magma?

Composed of molten rock & volatiles (gas), created by melting rock above a subduction zone

produced as rocks change shape, location and orientation in response to applied stress

Geologic Structures

Abyssal Fan

Great fan shaped deposit of sediment on the deep sea floor at the base of many submarine canyons

Earthquakes definitions and features

Ground shaking caused by the sudden and rapid movement of one block of rock slipping past another along fractures in Earth's crust called faults

What should you do before an earthquake?

Have an evacuation plan. Have a location where you will meet others. Safeguard you home. Store food, water, and safety supplies.

What is Internal Heat Engine?

Heat moving from hot interior to cooler exterior - Primary driver of most geospheric phenomenon (volcanism, magmatism, tectonism)

Earth's highest mountain belt

Himalayas

What is a Pryoclastic flow?

Hot, turbulent mixture of expanding gases & volcanic ash that flows rapidly down the side of a volcano;can reach speeds over 100 kilometers an hour

Tsunamis

Huge ocean waves usually caused by displacement of the sea floor (deep oceans have small wave height)

Relative dating was used by _______________ (1795) and others.

James Hutton

father of modern geology, proposed rock cycle, wrote Theory of the Earth with Proofs and Illustrations

James Hutton

Period with the first birds

Jurassic

Mountain

Large terrain feature that rises abruptly from surrouding levels Volcanoes and erosional remnants like plateaus are mountains

Isostacy

Lighter, less dense continental crust "floats" higher on the mantle than the denser oceanic crust - cratons have achieved equilibrium and are floating at the proper level for their thickness - mountains are thicker continental crust due to the compressive stresses that result in folding/faulting during an orogeny, so mountains float higher - as material is eroded off mountain ranges they undergo uplift as the range regains is isostatic balance, but adjustment doesn't take place right away, there can be a considerable time lag between erosion and adjustment

What are the 2 mechanical layers?

Lithosphere & Asthenosphere

What is Sediment?

Loose material resulting from a break down of rock.

Size and alignment of mountains

Major mountain belts are very long compared to their width and are often aligned parallel to a coast (Some aren't parallel to a coast, like the Himalaya)

Earth's Three Major Concentric Zones

Mantle, crust, & core

The largest volcano in the solar system is Olympus Mons, a Martian shield volcano. Why does Mars have such giant shield volcanoes compared to those on Earth?

Mars has no tectonic activity so hot spot volcanoes remain over the hot spot for hundreds of millions of years

Origins of metamorphic and plutonic rock in mountain ranges

Metamorphic rock: - originally sedimentary and volcanic rocks that were deeply buried, they were subjected to intense stress and high temperature during an orogeny and became metamorphic rock. Some that were even deeper and experienced partial melting become migmatites then were transported to higher levels of the crust Plutonic rock: - magma generated from partial melting collects in large blobs (diapirs) that work their way upward into an upper level of earth's crust and form batholiths

Mesozoic

Middle Life, dinosaurs abundant, era ended by mass extinction

Ice ages can be "forced" by changes in the amount of incoming solar radiation, ultimately caused by variations in earth's orbital parameters. These fluctuations are called

Milankovitch Cycles

- Types of destruction - Tsunamis, landslides and mudflows

Most tsunamis are generated by displacement along a Megathrust fault that suddenly lifts a large slab of seafloor

Continental volcanic arcs

Mountains formed in part by igneous activity associated with the subduction of oceanic lithosphere beneath a continent

- Horst

Movement along a fault produce alternating uplifted for blocks

Cenozoic

New Life, mammals and birds abundant, most recent ice ages occurred during the Pleistoncene Epoch of the Quarternary Period

What is Equilibrium?

New material adjusted to the physical & chemical conditions of its environment so that it does not change or alter with time.

What are the three types of pla tes for convergent boundaries?

Ocean-Continent, Ocean-Ocean, Continent-Continent

What are the 2 major types of crusts?

Oceanic crust & Continental crust

Paleozoic

Old Life, appearance of complex life

Period with the first fishes

Ordovician

permanent on release of stress

Plastic Strain

epicenter

Point on Earth's surface directly above the hypocenter

Era with the oldest dated algae

Precambrian

Which is older, Precambrian or Triassic?

Precambrian

sediments are deposited in flat, horizontal layers

Principle of Original Horizontality

the sediment will not only be deposited in a flat layer, it will be a layer that extends for a considerable distance in all directions; the layer is laterally continuous

Principle of Original Lateral Continuity

the older the beds are on the bottom and the younger the beds are on the top

Principle of Superposition

Sediments are deposited in flat, horizontal layers. which law is this?

Principle of original horizontality

the sediment will not only be deposited in a flat layer, it will be a layer that extends for a considerable distance in all directions. (layer is continuos)

Principle of original later continuity

The older beds are on the bottom, and the younger beds are on the top. Which steno law is this?

Principle of superposition

Age of Earth

Prior to the 19th century, accepted age of Earth was based on religious beliefs. Biblical-6,000 years for western culture Chinese/Hindu-old beyond comprehension 4.56 billion years old

The 2 Most Deadliest Volcanic Hazards

Pyroclastic flow & Mudflow

What is Plate Tectonics?

Regards the lithosphere as being broken into plates that are in motion

Two ways to measure geologic time:

Relative Ages & Numerical Ages

Dip-slip faults has

Reverse faults( block has moved up)(thrust fault) and normal faults(block has moved down)

What is Igneous Rock?

Rock that forms when magma solidifies.

California's Greatest Fault were located in...

San Andreas

Nicolaus Steno (1667) developed

Stratification, The principle of Original Horizontality, and The principle of Superposition

To deform

Stress

All applied ..... cause rock to deform.

Stresses

Tilted beds, joints, and faults are described by their _____ and _____.

Strike and dip

the study of the shapes, arrangement, and interrelationships of rock units and the forces that cause them

Structural Geology

Elastic rebound

Tendency for deformed rock along a fault to spring back to its original shape after an earthquake

Destruction of the old sea floor at convergent boundaries ensures what?

That the Earth does not grow in size.

What is the etymology of Jurassic?

The Jura mountains

What is the etymology of Cambrian?

The Roman name for Wales

What is the Solar system?

The Sun, planets, the moons orbiting planets, and asteroids.

The deepest portions of earth's oceans are found

The deepest portions of earth's oceans are found

What is Atmosphere?

The gases that envelope the Earth.

Eon

The largest unit of Geologic time

Epicenter

The location on Earth's surface directly above the focus, or origin, of an earthquake

- Focus (hypocenter)

The location where slippage begins

Paleomagnetism

The magnetic field has negative and positivve poles that are located near the geographic North and South poles (11.5 degree difference)

What is Erosion?

The physical removal of rock by an agent such as running water, glacial ice, or wind.

Focus

The point within Earth where an earthquake originates

Actualism

The principle that the same processes and natural laws that operated in the past are those we can actually observe or infer from observations as operating at present.

Partial melting

The process by which most igneous rocks melt. Since individual minerals have different melting points, most igneous rocks melt over a temperature range of a few hundred degrees. If the liquid is squeezed out after some melting has occurred, a melt with a higher silica content results

Pangaea

The proposed supercontinent that 200 million years ago began to break apart and form the present landmasses

seismogram

The record made by a seismograph. Some describe this as a tracing of earthquake motion.

Cratons

The region of a continent that has been structurally stable for a prolonged period of time (ex Canadian Shield) - most continents have a craton at their core - some cratons are covered by thin blankets (1000-2000meters) of sedimentary rock layers, but the Canadian Shield has no sedimentary rocks over it - the Canadian Shield is a Precambrian shield (it is the roots of a mountain range that completed the deformation process more than a billion years ago)

What is Geology?

The scientific study of Earth

What is Geosphere?

The solid rocky Earth; solid Earth system

What is magnitude?

The strength of an earthquake

What is Physical Geology?

The study of Earth's materials, changes of the Earth's surface and interior of the Earth, and the forces that cause those changes.

Convection

The transfer of heat by the mass movement or circulation of a substance.

Earthquake

The vibration of Earth produced by the rapid release of energy when blocks of rock move

What is the Mantle?

Thick shell of rock that separates Earth's crust above from the core below; hot solid that flows slowly overtime; 2900 km thick

Types of destruction - liquefaction

Transforming a somewhat stable soil into Mobile material capable of rising toward Earth's surface

Period with the first dinosaurs

Triassic

Every manufactured object relies on Earth's resources. True or False

True

Jurassic rocks would most likely me found above Mississippian rocks, true or false?

True

What is a Transform Boundary?

Two plates slide horizontally towards each other.

Moraines are composed of

Unsorted and poorly consolidated till

Uplift

Uplift occurs to mountain belts after orogeny is finished and is accompanied by erosion - isostatic adjustment was part of the orogeny process, but once orogeny is done and compressive horizontal forces relax and isostatic adjustment takes over as the main process - takes many millions of years, isostatic adjustment lifts up the land while erosive process wear down the mountain belt - if erosion keeps pace with uplift, the area remains low, but if uplift outpaces erosion, plateaus and mountains ranges occur - eventually entire mountain belts are eroded to a plain and become part of the craton

What are the 3 types of Surficial Processes?

Uplift, Weathering & Erosion, Deposition

Folds anticline (circular: dome)

Usually arise by up folding or arching of sedimentary layers and are sometimes spectacularly displayed along highways that have been cut through deformed strata

Geologic Time

Vast, a long human lifetime represents only about 0.000002% of this

What is the Crust?

Very thin outer rocky shell of Earth; 3 - 70 km thick

Seismic waves

Vibrations that travel through Earth carrying the energy released during an earthquake

What is Hydrosphere?

Water on or near the Earth's surface; oceans, rivers, lakes; Earth's surface covered by 2/3 with oceans

dipslip faults normal

When the hanging wall block moves down relative to the footwall block

Which of the following is a correct match of fault type and stress?

a and b

contour current

a bottom current that flows parallel to the slopes of the continental margin

Strain

a change in size or shape in response to stress

atoll

a circular reef surrounding a deeper lagoon

theory

a concept that has been highly tested and in all likelihood is true

Red Sea and Gulf of Aden is the outcome of

a convergent plate movement

One of the following is NOT a typical feature of a passive continental margin-which is it?

a deep trench

Cross cutting relationships

a disrupted pattern is older than the cause of the disruption.

ophiolite

a distinctive rock sequence found in many mountain ranges on continents

turbidity current

a flowing mass sediment lade water that is heavier than clear water and therefore flows downslope along the bottom of the sea or lake

a convenient tool that geologists use for recording such information and the location of outcrops, the nature of their rocks, and the dips and strikes on inclined layers

a geological map

active continental margin

a margin consisting of a continetal shelf, a slope, and an oceanic trench

passive continental margin

a margin that includes a conintental shelf, slope, and rise that generally extend down to an abyssal plain at a depth at about 5 kilometers

The western margin of north america is a(n) _____________plate margin, whereas the eastern margin of the African continent is a(n)______________plate margin.

active, passive

Which of the following is/are correct pair/s of sedimentary structure and depositional environment.

all are correct

Evidence for "turbidity currents" has included

all but d

Fold and thrust belts are characterized by

all of the above

Melting in the earth (producing "magma") can occur via

all of the above

biosphere

all of the living, or once living, material on earth

Early evidence for continental drift (e.g. Alfred Wegener's work) included

all the above

A scientific theory is

among other things, well substantiated and has been thoroughly tested.

Rocks behave as elastic, ductile or brittle materials depending on ???

amount and rate of stress application, type of rock, temperature and pressure

The Appalachians are a good example of

an old mountain range

Nonconfomity

an unconformity in which an erosional surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rock. Typically represents a large gap in the geologic record. Exposed by large amounts of erosion

Disconformity

an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other

Angular unconformity

an unconformity in which the contact separates overlying younger layers from eroded tilted or folded layers

crust

analogous to the skin on apples; the thickness of the crust is insignificant compared to the whole earth

Oceanic lithosphere is composed of the following rocks except

andesite

type of unconformity, tilted rocks are overlain by flat-lying rocks

angular

when layers are folded upwards in an arch shape; younger rocks are the outside

anticlines

Principle of Cross Cutting Relations

any body of rock that cuts across the boundaries of other units of rock must be younger than those it cuts (ex. Dikes)

Transform boundaries occur where--

any of the above scenarios could be termed a "transform boundary"

Polar wandering refers to the ________ movement of the ancient magnetic poles, at the time a particular rock forms and retains the prevailing magnetic field.

apparent (but not actual)

system

arbitrarily isolated portion of the universe that can be analyzed to see how its components interrelate

fractures, faults and joints

are brittle

Tilting, Folding and cleavage

are ductile

Obtaining Radiometric Dates

as minerals crystallize they incorporate atoms of some radioactive isotopes.

spheres

atmosphere hydrosphere atmosphere

number of protons in the atoms nucleus

atomic number

divides a fold into its two limbs

axial plane

asymmetrical

axial plane is on an angle

symmetrical

axial plane is upright

Original Horizontality

beds of sediment deposited in water are initially formed as horizontal or nearly horizontal layers

The Sierra Nevada in California, the Tetons in Wyoming and the Basin and Range Province in Nevada are all examples of a(n)

block-fault mountain area

Formations

bodies of rock of considerable thickness with recognizable characteristics allowing them to be distinguished from adjacent rock layers

Partial Melting

breaking down some of the bonds that hold atoms or molecules which can produce magma

If it fractures, it is called _____.

brittle

if a material fractures, it is said to be ...

brittle

Oceanic Ridge

broad areas of shallow seafloor that are like a giant zipper that holds the outer layer of Earth in place. These are all sources for volcanic activitiy

How are rock structures determined on the ground by geologists?

by observing rock outcrops

Mechanical weathering

can occur when water freezes in a crack and forces rock apart.

S-waves

cannot pass through liquids

used to date very recent events, as far back as 50,000 years, half life of only 5730 years

carbon 14 dating

type of fossil, organic matter becomes a thin residue of carbon, life-form completely buried and compressed, removing fluids and gases, commonly found in black shales

carbonization

type of fossil, hollow space of a mold is filled with mineral matter

cast

Lithification of a sedimentary rock occurs via compaction and ______

cementation

Earthquakes only happen in

cold, brittle lithosphere

Strike:

compass direction of a line formed by the intersection of an inclined plane with a horizontal place

Faults and the forces that cause them

compression, tension, or sheer

Basic types of stress are

compressive(flattening), tensional(stretching), and shear(side to side)

seamount

conical mountain rising 1000 meters or more above the sea floor

surfaces separating successive rock layers (beds), geologic age determination

contacts

Baked Contacts

contacts between igneous intrusions and surrounding rocks have expierenced contact metamorphism

A tectonic boundary where one tectonic plate is subducted beneath another is a

convergent boundary

Faults or joints are breaks that tend to _______

create planar failure

lithosphere

crust and uppermost part of mantle relatively rigid

isotopes formed from the decay of a parent

daughter products

Along a river, as one moves from headwaters to downstream, gradient generally

decreases

All applied stresses cause rocks to ___

deform(strain)

The feature that forms where a stream flows into a standing body of water is a:

delta

earths internal heat engine

driven by heat moving from the hot interior of the earth toward the cooler exterior products of internal heat engine = moving plates and earthquakes

earths external heat engine

driven by solar power

If a material undergoes continuous plastic deformation it is called _____.

ductile

when a material undergoes continuous plastic deformation, it is....

ductile

What do sedimentary rocks tell us about Earth's history?

earth surface processes and evolution of life on earth

most dangerous geologic hazards

earthquakes volcanic eruptions landslides floods tsunamis

Strain can be...

elastic or plastic

An object that returns to its original shape after the force is released is ______ and an object that continuously deforms under force is ______.

elastic, plastic

Chemical bonds involve either sharing or loss/gain of

electrons

subdivision of an eon

era

True or False: Anticlines always form topographic ridge-like features.

false

True or False: Aquifers are always "perched".

false

True or false: A magnitude 6 earthquake is twice as powerful as a magnitude 3 earthquake.

false

Horsts

fault blocks bounded by normal faults that are uplifted

Grabens

fault blocks, bounded by normal faults, that drop down

fractures in bedrock along which movement has occurred

faults

fractures with a distinct offset along the plane of breakage

faults

dipslip faults

faults in which movement is primarily parallel to the dip (or inclination) of the fault surface

Breaks that tend to create planar failure surfaces are called

faults or joints

all of the animal life of any particular region or time

fauna

radioactive isotopes decay at a ______ ______

fixed rate

guyout

flat topped seamount

plants of any particular region or time

flora

_____ are wavelike bends or curves in a layered rock. They also represent rock strained in a ductile manner, usually under compression

folds

______ occur when strain accumulates slowly.

folds

occur when strain accumulates slowly

folds

wavelike bends or curve in layered rock; represent rock strained in a ductile manner, usually under compression

folds

Plunging fold

folds in which the hinge is not horizontal

Isoclinal folds

folds with parallel limbs

tectonic forces

forces generated inside the earth cause deformation of rock as well as vertical and horizontal movement of portions of the earths crust stronger than gravitational force (as indicated by the existence of mountains) mechanical force

bodies of rock of considerable thickness with recognizable characteristics allowing them to be distinguished from adjacent rock layers

formations

reverse fault

forms at convergent boundries

normal fault

forms at divergent boundreis

strike-slip fault

forms at transform boundaries

based on the observation that sedimentary rock strata have fossilized flora and fauna and these fossils succeed each other in a specific order

fossil succession

matching rocks of similar age in different regions often relies upon____

fossils

Earth materials (blocks or layers) tend to fail within the crust, when subjected to forces, by ... or by plastic flow

fracture

When earth materials such as blocks or layers within the crust are subjected to forces, they tend to fail either by ______ or by ______.

fracture; plastic flow

Faults

fractures in bedrock along which movement has occurred-----offset

Faults are _____

fractures with a distinct offset along the place of breakage.

Joints are ____

fractures with no displacement b/w the sides

Inclusions

fragments embedded in host rock are older than the host rock

Earth's core is primarily made of

iron and nickel

Monocline

gently dipping bend in the horizontal rock layer

divides geologic history into units, originally created using relative dates

geologic time scale

type of stress, rate of application and physical properties of the rocks/sediments

geological structures are indicative by this

faults blocks, bounded by normal faults, that drop down

grabens

the oldest eon, represents time when the earth solidified

hadean

the time for one-half of the radioactive nuclei to decay; distinctive for different isotopes, requires a closed system

half life

Which of the following is not used to determine relative time.

half-life

The many waterfalls that pour into the main valley of Yosemite Valley occupy

hanging valleys

A plunging fold (syncline or anticline) is one that

has a dipping (i.e. non-horizontal) "fold axis"

Where does the energy for plate movements occur?

heat flow from Earth's interior and gradual cooling

As a tsunami wave approaches shore-like all waves-its _________.

height (i.e. "wave amplitude") increases

Contact metamorphism is generally produced in ___________settings.

high temperature (and low pressure)

surface trace of an axial plane

hinge linge

Probably the biggest problem with Wegener's theory of continental drift was that

his mechanism was not consistent with what geologists understood about the strength of rocks.

Angular Unconformity

horizontal sedimentary rocks with angled rocks below

fault blocks bounded by normal faults that are uplifted

horsts

pyroclastic flow

hot, turbulent mixture of expanding gases and volcanic ash that flows rapidly down the side of a volcano

Radiometric Dating

how much radioactive decay of a specific element has occurred since a rock formed or an event occurred. Gives numerical time brackets for events with known relative ages

Elastic rebound theory can be described as a model for

how rocks eventually break (rupture) when sufficient stress is applied

tsunamis

huge ocean waves, usually caused by displacement of the sea floor in deep ocean, a tsunami has a small wave height and it travels rapidly so it goes unnoticed by people on boats in the ocean drop in sea level often precedes the arrival of first giant wave

If a proton is removed from a helium atom it becomes a

hydrogen atom

Isotopic (sometimes called "radiometric") dates are best determined using

igneous rocks

type of fossil, replica of the fossil's surface preserved in fine grained sediment

impression

one rock contained within another rock (rock containing the_______ is younger)

inclusions

At an ocean-continent Benioff Zone (where subduction occurs), the earthquake depth ______ as one moves further from the trench, and towards the continent interior.

increases

a fossil that is useful for dating and correlating the strata in which it is found

index fossil

The theory of plate tectonics

interactions of the plates along these boundaries form new lithosphere, mountains, earthquakes, and volcanoes in order for movement of contienets

Erosion

involves movement of rock material by air, wind, water, and ice.

The tremendous thermal energy generated inside the earth through the decay of radioactive elements eventually finds its way to the surface (conduction and convection). This energy is the main driving force behind all the following phenomena except

movement of water in the hydrologic cycle (rivers, glaciers, etc.)

Strike-slip faults

movement that is predominantly horizontal and parallel to the strike of the fault plane. Right lateral and left lateral

The seafloor spreading formed along the ridge system of magma rising from below theory

new oceanic lithosphere is continuously formed along the ridge system by magma pushing upward and older seafloor moves away from the ridge

If a stream undergoes a 100yr flood, would we nessarily expect a much lower chance (than 1 in 100) of a 100 yr flood the very next year?

no

Resources are _______________.

non-renewable

metamorphic or igneous rocks were exposed to erosion and younger sedimentary rocks were subsequently deposited above the erosion surface, younger sedimentary rocks above

nonconformity

hanging wall block has moved down relative to the footwall block

normal faults

the age of events or objects expressed as a number or numbers

numerical age

Magnetic reversals

occur irregularly, but on average, about every 500,000yrs

Divergent Plate

occur where hot, rising mantle, rock causes plates to move apart.

2 major types of crust

oceanic crust and continental crust crust under oceans is much thinner and made up of rock that is much denser then the rock underlying continents

Age of Ocean Floor

oceanic crust is pretty young compared to the age of the continents

Ophiolites provide a means to examine ancient

oceanic lithosphere

convergent plate boundries

oceanic lithosphere is consumed at subduction zones where it descends into the mantle beneath trenches

fossils found in lower strata are ____ than those found in higher strata

older

surfacial

on the earths surface

folds in which the limbs dip gently

open

Lateral Continuity

original horizontal layer extends laterally until it tapers or thins at its edges

Rock structures are determined on the ground by geologists observing ______, places where bedrock is exposed at the surface

outcrops

places where bedrock is exposed at the surface

outcrops

have limbs that dip in the same directions

overturned

an unstable isotope

parent

solar system

part of the much larger universe includes the sun, planets, the moods orbiting planets, and asteroids

Decomposition Melting

partial melting below oceanic ridges and decreasing in pressure

Plastic strain

permanent on release of stress (like clay)

type of fossil, cavities and pores are filled with precipitated mineral matter- parts are filled in, formed by replacement

petrified

Numerical Dating

puts absolute value (millions of years) on the ages of rocks and geologic time periods uses radioactive decay of unstable isotopes only possible since radioactivity was discovered in 1896

biggest danger of volcanoes

pyroclastic flow

Volcanic rock fragments are called

pyroclasts

Which of the of the following minerals is LEAST affected by chemical weathering-

quartz

A ______ shows more evidence of weathering and transportation than a ______

quartz sandstone, arkose

spontaneous breaking apart (decay) of atomic nuclei

radioactivity

determines an actual or approximate age of an object by studying the rate of decay of radioactive isotopes within that object

radiometric dating

igneous formations are _____ dated

radiometrically

era of the phanerozoic eon, cenozoic

recent life

overturned to the point of being horizontal

recumbent

The moon does not have soil, but it does have_____

regolith

the order of events or objects from oldest to youngest

relative age

placing rocks and events in sequence

relative dating

Precambrian

represents 87% of geologic time

types of dip slip faults

reverse and normal

hanging wall block has moved up relative to the footwall block

reverse faults

Which of the following magmas is likely to be the most viscous, and therefore the most explosive?

rhyolitic (felsic)

grabens associated with divergent plane boundaries

rifts

You are standing in the middle of a road on the west side of a strike slip fault looking eastward across the fault. The road has been displaced southward on the opposite side of the fault. You are looking at a ______ fault that is ______ the San Andreas fault.

right lateral, like

when observed strike-slip fault would observe it to be offset to their right

right-lateral

types of strike slip faults

right-lateral; left-lateral

lithosphere

rigid outer layer which is made out of the crust and uppermost mantle

footwall location

rock surface below the fault

hanging wall location

rock surface immediately above the fault

igneous rock

rock that forms when magma solidifies

Regional metamorphism tends to produce

rocks with foliation

pelagic sediment

sediment made up of fine grained clay and the skeletons or microscopic organisms that settle slowly down in ocean water

When are geologic structures are most obvious in deformed ...

sedimentary rocks

Nonconformity

sedimentary rocks overlying igneous and metamorphic rocks

The principle of Original Horizontality

sediments are deposited in horizontal layers, if they are tilted then tectonics changed them

Paleomagnetism supports seafloor spreading by

seeing the change of the ocean floor overtime

Negative Effects of Earthquakes

shaking can damage buildings and break utility lines; large undersea quakes may generate tsunamis

a geologist could use the principle of inclusion to determine the relative age of

shale layers

Which of the following is a general order for "progressive" metamorphism, from least to greatest degree of metamorphism? (In other words, increasing metamorphic grade.

slate, phyllite, schist, gneiss, migmatite

mudflow

slurry of water and rock debris that flows down a stream channel

physical geology

the division of geology concerned with art materials, changed in the surface and the interior of the earth, and the dynamic forces that cause those changes

At oceanic ridges the ridges are younger (1 million years) than....

the edges of the oceans (180 million years old)

atmosphere

the gases that envelop earth

An anticline is a fold in which the

the limbs dip away from the axis and it is a upward arching fold.

mantle

the most voluminous of earths 3 major concerti zones solid rock parts of it flow slowly (generally upward or downward) depending on whether is hotter or colder than adjacent mantle

Abyssal Plains

the ocean level flattens out to form level areas

When two oceanic plates collide...

the older of the two plates will descend into the mantle because it is colder and denser

The principle of Superposition

the oldest strata is on the bottom

Relative Age

the order of events or objects, from oldest to youngest

The hottest part on Earth is located in...

the ridge system where melted rock, magma is forced upwards

geology

the scientific study of earth

Structural geology

the study of shapes, arrangement, and interrelationships of rock unites and the forces that cause them (joints, folds, faults)

lag time

the time between the arrival of P waves and the arrival of S waves

Half Life

the time it takes for 1/2 of the unstable parent atoms to decay to the stable daughter form.

hydrosphere

the water on, or near, the earths surface 2/3 of the earths surface is covered by oceans

plate tectonics

theory that regards the lithosphere as broken into plates that are in motion plates move relative to one another along plate boundaries, sliding upon the underlying atmosphere

A craton is

those portions of a continent composed of ancient Precambrian bedrock.

reverse faults with dip angles less than 30 degrees from horizontal

thrust fault

are planar features whose orientation is described by their strike and dip

tilted beds, joints, and faults

Geologic maps use standardized symbols and patterns to represent rock types and geologic structures such as ______, _____, ____, and ____.

tilted beds, joints, faults and folds

Half Life

time it takes for a given amount of radioactive isotope to be reduced in half

What is the data from seismograms used for?

to find an earthquakes epicenter and its magnatude