Geo test two

what is the temp range when it comes to gradient

20-60 C Km

what is formed as a result of cementation?

a sedimentary rock

what are the four eons in order

Hadean, Archean, Proterozoic, Phanerozoic

what is gneiss rock

a type of foliated rk, high grade=large grains

what is a schist rock

a type of foliated rk, intermediate grade=medium grains

what is slate rock

a type of foliated rk, low grade=tiny grains

what are the types of sediments

detrital(clastic), chemical, biogenic,

what is a disconformity

different types of sediment rock above and below

what is strata

distinctive layers

what is the problem with metamorphic grade

each met grade covers a wide range of t/p changes, so we need another, more specific measurements

what are the half lives of radioactive isotopes

each radioactive isotope has its own half-life.

What is a left-lateral strike-slip fault?

each side appears to move to the left relative to the opposite side(each side thinks it moved to the left)

what is stratigraphy

studying the layers of strata in a lot of detail for things like age and what fossils they include; one of the goals is to put fossils in relative order. goes back to 1600s

what is a limit of carbon 14 dating

some organisms don't get carbo from the atmosphere or food chain.

what are the traits of detrital material(aka clastic)

sorting, rounding, grain size

what are two layers when it comes to deposition

strata and beds

what is structural geology

studies what happens to rocks when they get deformed.

what is topographic feature

stuff like canyons and hills

what do changes within minerals record

It can record p/t changes; you can measure the concentration of elements within a single mineral crystal

What is the geothermal gradient?(GT)

temp change over distance below the Earth's surface

what are the tectonic forces

tensional, compressional, shearing,

what is Carbon 14 makeup(C14)(slide 69)

N14+particle+energy

are the terms focus and epicenter interchangeable?

NO

does sorting and round apply when it comes to chemical sediments

NO

do half life vary depending on the environment?

No! it is as constant as anything else. It is always the same, no matter what.

are all fossils good for correlation

No! more mundane fossils are best, like seashells

What is the Cenozoic Era? what is the time frame

the age of the mammals, with Dinos out of the picture they were able to diversify. Reached its peak with the most recent ice age. 65 Ma-now

what is elastic deformation

the amount of stress and friction at a fault is almost equal; the stress will continue to apply, so it will almost balance out. this is the second step

What is a half-life?

the amount of time it takes to break down half of the parents

what are the 2 non-radiometric dating methods(absolute ages)

Varves, dendrochrononlgy

what is magnetostraigraphy

a correlation tool looking at the magnetic signal. igneous rocks are good for this

What is lithostratigraphy?

a correlation tool, correlate based on rock type, good at giving you a first past.

what is sequence stratigraphy? where is this used the most

a correlation tool; looking for unconformities, correlating the unconformities together. need a lot to work with, most in coastal areas. coastal environments are where a lot of oil deposits are.

What is chemostratigraphy?

a correlation tool; some chemical marker in the rocks that you would look for

what are index fossils

a fossil that is useful for dating and correlating the strata in which it is found. helps you to find the short timelines

what are metamorphic facies

a group of minerals that indicate specific t/p conditions

what was found on Saunders island

a lava lake found inside a volcano; only 8th known on earth

what is metamorphic grade

a measure of how much the rock was altered. this is used to id met rks.

what is marble

a non foliated rock; calute present; the parent rock is limestone and biogenic sed rk

what is hornsfels

a non foliated rock; hornblende commonly present; high t/low p

what is quartzite

a non foliated rock; quartz commonly present; parent rock is sandstone

what is anticline when it comes to folds

has the oldest layer between the limbs

what is a rockslide

solid rock exposed at the surface, and it begins to slide down.

Why can we date fossils?

- C-14 is made in atmosphere - 14CO2 is incorporated in food chain ex: photosynthesis, bunny eats plant, fox eats bunny - dating gives time when animal passed away

What can we date with C-14?

- cannot date everything (can only be so old) - does not work on rocks or minerals - fossils can be dated

what are the problems with unconformities

1. Identification(hard to ID) 2. Duration(trying to figure out how much time went by/got lost)

does the amount of carbon 14 in living tissue vary through time

1. carbon 14 production varies over time; variations are small and on short timescales. 2. fossil fuel burning has changed the relative amount of the carbon isotopes in the atmosphere; the method can be corrected

what are the four characteristics of index fossils

1.numerous(need a large population), 2.widespread(geographically, you would want them to have lived all over the planet)3. went extinct quickly(the goal is to define very short lengths of time) 4. easy to identify(very distinct, makes sure that there is no confusion)

what is the estimated return on landslide prevention

10-2000 dollars per $1 spent on prevention; the cost of prevention is cheaper than cost of repair.

what do most met rks form at

10-30 km depth(mid-lower crust)

what is the stable daughter of carbon 14

14N

what happened in Thistle, UT

1983 slide caused $200 million in damage, deemed preventable .5 million dollars had been spent on drainage systems.

how deep are most foci(focus) in the continental crust

2-20 km deep

what is the avg geothermal gradeint

30 degrees C per Km

what is the average angle of repose worldwide.

35, but it is not the case for every slope

how many ice ages has earth gone through

5 or 6

what is the half life of carbon 14. how many half lives can you track through

5730 years; can track through 10 half-lives(usually only 5 with other elements)

What is deposition?

Deposition is the process by which sediments settle out of the water or wind carrying it.

what are the three eras of the Phanerozoic eon in order

Paleozoic, mesozoic, Cenozoic

what are the three types of seismic waves?

Primary waves (p-waves), secondary waves/shear (s-waves), long/surface waves(l-waves)

What is radioactive decay?

The process in which unstable isotopes decay into other elements and emit radiation as they attempt to become more stable

What is radiation?

The transfer of energy by electromagnetic waves

how many half lives can you go back in parent isotopes

about 5 half lives until it runs out.

how do we use age when classifying folds

age of the layer relative to each other(which layer is the oldest)

What is a decay series?

aka chain; shows you the list of daughters that you have to go through to get a stable atom.

what is fluid interactions when it comes to forming met rks

aka metasomatism; hot fluids move through the rocks below the surface

How are metamorphic rocks formed?

altering rocks via heat, pressure, or fluid interaction.

what are the three types of unconformities and how are they classified

angular unconformity, disconformity, nonconformity. classified by comparing strata above and below the gap

what is a basin

any location that you can deposit sediment, a low spot or hole that can be filled with dirt(pot holes, ocean floors)

what is saprolite formation

any rock that has undergone a lot of chemical weathering

how are met rocks formed from an increase in temp

as temp rises, some materials in the parent rock will become unstable; temp increases the deep below the surface you go.

where do deeper earthquake occur

at subduction zones. when the oceanic crust gets subducted it is very cold, so until it warms up again and gets more ductile, earthquakes will continue to occur

what are isotopes?

atoms of the exact same element but they have different numbers of neutrons. Some are stable on their own, and others are not(unstable isotopes)

what are index minerals

bc every mineral is stable at certain t/p conditions, you often see certain minerals in each grade. these index minerals define categories called metamorphic facies

what is odd about Pilot mountain in north Carolina

because its not part of a continuous mountain belt. analyzing the met res that make up part of pilot mt help us determine how it formed.

why are chemical sediments economically viable

because most of these rocks are over 90 percent one mineral.

why are S waves slower than p waves

because the movement is vertical

why do we care about mass wasting(landslides)

because they are dangerous to people around the world.

Why are ores economical?

because they can be mined.

what are geological stuctures

bodies of rock that have been deformed

what are the two responses to tectonic and what do they mean

brittle- with enough force, it will crack and split apart. ductile-with enough force it will bed, warp or twist.

How are faults classified?

by slip direction; in a vertical or horizontal direction

What is contact metamorphism?

changed by heat only (touching magma)

what does metamorphism do

changes mineralogy and or texture in the parent rock

what is gradient

changes over distance

what is correlation

comparing areas and trying to relate them to one another

what are the two kinds of pressure that can be applied to rks

confining pressure and directed pressure

what is confining pressure? what is directed pressure

confining pressure is when you squeeze evenly from all sides. directed pressure is when you squeeze mainly from one direction

what are the uses of dendrochronology?

correlation allows you to extend the record farther and farther back.

what is road cut view

cross sectional view

what are the dark layers of varves made up of

dark layers were the organic layers that was decaying under the ice

how can we think of facies like superhero teams?

each super hero is an index material, and when you find certain superheroes together, you know they represent a specific team. (teams=facies) Iron man and hulk and hawk-eye= avengers, even if the other Avengers are not present in every scene.

what does data suggest about earthquakes

earthquakes occur in streaks(a lot of earthquakes at once along a fault) and slumps(not many earthquakes happening along the fault). Nothing is easily spaced out.

what does it mean when we say that faults occur in sets? what do they outline

earthquakes tend to occur in clusters. where you have one fault, you have a bunch of them. they outline all of the plates(pacific, nzca, etc). motions between boundaries of rock will create earthquakes.

what does erosion require

energy

what are eons? how many are recognized

eons are big chunks of time, there are only 4 recognized.

how do met rks get back to the surface

erosion overlying rocks, plus uplift via faults and plate tectonics movements

why do we care about geologic time

figuring out the age of things revolves around the key issues of geology

what is a good rule to follow about problems in methods

finding a problem with a method does not instantly invalid the method

what are the types of structures

folds, joints, faults

what are the types of metamorphic rks

foliated met rocks and non foliated rocks

What are foliated metamorphic rocks?

form when differential pressure is applied to the parent rock; causes the minerals to realign themselves into layers/sheets(Foalation)

what is detrital (clastic) sediment

formed by physical weathering, transported and dumped, and the put back together.

what is a fault (when it comes to geo structures)

formed from a brittle response; the rock on either side of the crack will shift around and move. it can be inches to 100s of miles. like to come in groups

how are non foliated rocks formed?

formed when confining pressure is applied to the parent rock

what are chemical sediments

forms via chemical reactions like saltwater evaporation or dissolution and re-precipitaiton.

how do most pot holes form

frost wedging.

what are the uses of varves

give you info about the lake, tells you what the climate history is like.

Earth is older than 57,000 years, so why haven't we run out of C-14?

global distribution; steady state: the amount that you're loosing is the same as the amount that you're gaining.

what is the most common trait of detrital (clastic) sedimentary rocks

grain size is key, sand=sandstone, silt=siltstone

what is a normal dip slip fault

hanging wall down, footwall up

what is a reverse dip sip fault

hanging wall shifted up, foot wall down; reverse of what usually occurs naturally.

what is the principle of faunal succession

has to do with fossils; the following sequence is always the same starting from the bottom (dimetrodon, archeaepterx, t.rex, woolly mammoths)

what factors play into mass wasting (landslides)

heavy rains, ice/slow melting all at once, earthquakes, human landscaping(making a slope steeper than it was), humans clearcutting(removing tress that may have been preventing the landslides.

What is a strike-slip fault?

horizontal movement(parallel to the fault plane)

what are some common nonfoliated rocks

hornsfels, quartzite, marble

what is liquefaction

houses are built on sediment and water comes into the picture. it turns to mud, and the buildings will sink into the mud.

what is an accommodation space

how much sediment will a basin hold, in terms of volume.

describe rounding (detrital material)

how rounded are the rocks, if it is not very rounded that means it did not travel far when it came to erosion.

describe sorting (detrital material)

how uniform the grain sizes are. if they are jumbled up the it means it did not go far with erosion.

what is cementation when it comes to lithification?

how we will make the particles stick together. the water is flowing out, but leaving the minerals behind, binding the particles together.

how does lack of vegetation make a slope unstable

if there are not plant roots present to keep sediment steady.

why do we need measurable amounts of parent and daughter isotopes to use radioactive dating

if there is no parent, essentially the clock stopped running; you can't use it to date. if there is no daughter, essentially the clock hasn't started yet bc nothing has happened yet.

what is the problem with a closed system in radiometric dating

if you add a parent or loose a daughter it looks like time has passed

what is compaction when it comes to lithification?

if you get the particles under more pressure, it will make it easier for them to stick together. Adding pressure will squeeze water out of them.

how does increased pressure make met rks

increase the pressure on the parent rock. remember, minerals are also sensitive to pressure changes.

why don't scientists use the Richter scale anymore

it could only get data while the ground was in motion, it depended on proximity of where you are in relation to the earthquake.

what causes angular unconformity

it happens over a long period of time. after the bottom half was tilted, erosion occurred. it represent a large gap in time.

how can we use the principle of faunal succession to correlate.

it is a very powerful tool; this is the only principle that will allow us to practice correlation in geology.

How can we predict earthquakes?

it is difficult because every fault is different. it makes it hard to come up with a universal tool/equation.

what does one bar equal

it is the atmospheric pressure at earths surface

what is a P-T graph?

it shows how log the rock was exposed to higher pressure and temp.

What is the geologic time scale? how was it originally built; how do fossils and numbers play into it?

it was orginally built via stratigraphy. Fossils were key for defining boundaries. numbers were added long after the chart was made.

how long does it take to form a metamorphic rock

its a slow process, million year timescales to create them

how do we use fossils in relative dating

its any evidence we find of past life; footprints, shells; people have been finding fossils for a long time, way before geology was established as a science

what does feldspar + H2O + H2CO3 make

kaolinite + dissolved ions

what is a foreshock

small movements that happen before the main earthquake. a lot of potential energy build up. the area is trying to adjust

what is the mesozoic era. what is the time frame

known as the age of the dinosaurs; mammals coexisted with Dinos but were still pretty small like rodents. 200 Ma-65 Ma(135 million years)

what are ways that a slope can be destabilized

lack of moisture, too much moisture, lack of vegetation, and too much vegetation.

what are retaining walls

large materials at the base of the slope; works well for low level slopes

What was the Proterozoic Eon? what were some key events and what were the years

lasted about 2 billion years. Key events; oxygen starts to build on at earths surface (Great oxidation event), lifeforms continue to evolve. 2.5 Ga-550 Ma.

What was the Archean eon? what were some key events and what were the years

lasted one and a half billion years. Key events; oldest known record of life(simple microscopic life), when plate tectonics starts, first pieces of continental crust forms. 4 Ga-2.5 Ga

what is synform when it comes to folds

layers are bent downward, bowl shape

what is antiform when it comes to folds

layers are bent upward, looks like a rainbow or frowny face

what are rock bolts

like a giant staple gun so the rock at the surface is pinned to a rock deeper within; works well for steeper, higher levels.

what is relative dating

list thing in order; come up with a sequence of events, qualitative. its easier, cheaper, and quicker.

what is a horizontal fold

looking from above or second side, everything looks horizontal

What is an angular unconformity?

looks at how the strata relate. layers below a given point are at an angle, above that point it is normal

what is low grade and high grade

low grade= little t/p change, so met was minor high grade=big t/p change, so met was major

What is subsidence? What causes it to occur?

lowering of ground surface; it will happen if a lot of sediment is dumped in a basin. if you have a cheap book shelf and put a bunch of textbooks there, the slabs of wood will start to warp down.

what does it mean to decrease slope grades

make the slopes less dangerous.

what are the types of mass wasting based on

material, type of movement, speed

how is pressure measured

measured in bars and pascals

moment magnitude scale

measures how much the rock slipped. the bigger the number, the bigger the magnitude. its logramithic. you can go back and measure it long after the earthquake stopped.

what are some other things to know about non foliated rocks

minerals are not realigned into layers, we id these by mineral content instead of by met grade

what is chemical weathering

more common in many environments, and involves a chemical reaction. quartz is hard to be broken down by chemicals, but as you go down the bones reaction series list, it get easier.

At what depth do most earthquakes occur?

most earthquakes are shallow.

What is a dip-slip fault?

motion is predominately vertical(one side goes up, the other goes down)

What is a thrust fault?

move exactly the same as a reverse fault. the fault is laying down at a very low angle. found at a lot of subduction zones, hard to id in the real world.

how frequent are earthquakes?

small ones are quite common, small earthquakes are one of the most mundane processes on earth.

What is an aftershock?

movement after the main earthquake, can still be dangerous. that same section of the fault has energy left and is trying to get rid of it. can also occur in nearby areas. when the main earthquake happened, that introduces a lot of pressure on the surrounding rocks.

What on richter scale? what does it measure? do scientists use it?

named after Charles Richter. goes from 1-10, uses regular numbers, goes along a logarithmic scale, an increase of a decimal actually matter. it measures how much the ground shook. scientists don't use it anymore

can you carbon date Dino bones

no

what does it mean to have a closed system

no interaction between the object and its surroundings.

do unstable slopes automatically have a landslide occur?

no, other factors come into play

what are the two approaches for absolute ages

non-radiometric(no radioactive techniques) radiometric(involve radioactive techniques)

what are the restrictions of dendrochrononolgy

not every type of tree grows a growth ring each year

go back to lecture 6 pt 2 and practice identifying the faults and slips

ok

go look at slide 22 on lecture 6 notes

okay

go look at slide 28

okay

look at slide 26

okay

what is syncline when it comes to folds

oldest layer going outside of the limbs

what are beds

one layer of that sediment

What is a nonconformity?

only have sedimentary rock on one side, the other rock will be igneous or metamorphic

what does fluid interactions aka metasomatim often form

ore deposits since the water can deposit high concentrations of a certain material.

what is physical weathering

physical breaking up of rocks and soil; plant roots moving and burrowing.

What is regional metamorphism?

pressure is the main factor(t occurs too); these are the large scale events, like a convergent plate boundary, lots of pressure is generated when the plates collide.

how do building codes help with earthquake damage control

prevents people from building on a fault line (1972 California Law)

what is a p wave

primary wave; the fastest seismic wave. no matter where the location, it will be the first to reach.

what are the requirements for radiometric dating (4)

radioactive isotopes must be present in your specimen, need measurable amounts of the parent and daughter in your specimen, it can only go so far back in time, you have to have a closed system.

what is a parent isotope

radioactive unstable atom

what are the two approaches to geologic dating

relative and absolute; both are useful

what are ways to prevent mass wasting

risk assessment maps, drainage control, decrease slope grades, building codes, retaining walls, rock bolts,

what do the responses to tectonic forces depend on

rock type, t/p conditions, speed of deformation(the faster you apply the force, the more likely it will react as brittle. with a slower force, it will react as ductile. remember the glass example

what is an ore

rock with a higher than usual concentration some mineral/element

what is a right-lateral strike slip fault?

rocks across fault appear to have moved to right

what happens when stress<friction along a faultline

rocks move on the fault line; its hard to move these rocks because there is a lot of Friction, this is the first step

what is a myth about building on solid rock

rocks will crack and swallow your entire house. its actually the opposite; solid rock is the best thing you can build.

what are the types of mass wasting

rockslides, creep

what does saprolite mean

rotton rock

what are the three reasons that unconformities occur

run out of sediment, run out of accommodation space, start eroding sediment(you have a net loss of material)

What are S waves?

secondary/shear waves; they move a lot slower than P waves, about half the speed but still fast by human standards

What is the S-wave shadow zone?

section of the earth where the s-waves never show up

what is the most common rock type at earths surface

sedimentary

what are biogenic sediments

sediments that form from the remains of living animals.

how are folds classified

shape, age of the layers, geometry

what is anti formed when it comes to folds

shaped like a c or backwards C. know overturned antiform, and overturned synform as well slide 15 on lecture 6 pt 2

what are some common foliated rocks

slate, schist, gneiss

how to we use geometry to classify folds

the cross sectional view won't help with some folds, so we need t see from above or at a second cross section

what does the temp of the geothermal gradient depend on

the crusts thickness; thicker=lower gradient.

what is the key to finding the focus of a earthquake

the different waves travel at different speeds; you have to know when each wave showed up.

what do we need to know about an earthquake that would help us know where to send emergency help

the epicenter

what is a creep (mass wasting)

the fence example. the fence was probably built straight, but it gradually crept its way forward/down the hill. as the sediment moved so did the fence.

What was the Hadean Eon? what were some key events and what were the years.

the first half billion years of plants history. Key events were the theia impact(formation of earths oceans and atmosphere) 4.5 Ga-4.0 Ga

what are the parts of a fold

the limbs(the part that looks like arms). the hinge(the part where all the motion seemed to occur)

which earthquake wave causes the most damage

the long waves cause a lot of the motion and damage we experience.

What is the angle of repose?

the maximum angle that the slope (landslide slope) is still stable at

what is a plunging fold

the most common fold; from above, you can see the fold, and from the second view, the layers/folds are plunging, not horizontal.

how does too much moisture make a slope unstable

the mud can become sloshy and watery

what is a tensional force

the object is being pulled apart, the middle section is being ripped apart; lines up with divergent plate boundaries

how do you know what met rk will form

the parent rocks composition helps determine which specific met rks form.

what is retrograde

the portion of the rks history when p and t were both decreasing.

what is prograde

the portion of the rock's history when p and or t was increasing

What is a daughter isotope?

the product of radioactive decay; break down of the parent; can either be stable or unstable.

what is the rate of radioactive decay

the rate of radioactive decay is constant. (remember popcorn example in lecture)

what is compressional force

the rock is getting squeezed; pressing in from opposite directions; lines up with convergent plate boundaries

what is a parent rock

the rocks you start out with in the rock cycle.

how does lack of moisture make a slope unstable

the sediments are looser

What is the epicenter of an earthquake?

the spot directly above the focus on the surface of the earth

what is the focus of a earthquake

the spot directly on the fault where the rock slipped or moved

what happens when stress>friction at a fault

the stress will eventually overcome friction and the rocks will move. The energy is rebased and the process starts over. this is the third step.

what is shearing force

the two halves are shearing past each other, moving in opposite directions of each other; lines up with transform boundaries

what are three myths to debunk about seismometers/seismographs?

there are more than one machines, they are old fashioned machines, they use swinging needles

what kind of wave is a primary wave

they are compressional waves; there is no vertical or lateral movement, it just causes it to expand and contract.

how do we know radiometric techniques work

they are developed by first dating things that we already know the age of; like Egyptian mummies.

why do we care about metamorphic rocks

they document changes in the earth's crust throughout time(ex mountain formation, uplifts, collision zones. T/P @ depth

what are some restrictions of varves

they don't form everywhere, you have to make sure that the sediment is undisturbed(the bands would mix together). if you have a lot of biological material, this will mix the sediments and the varves will get disturbed.

why are long waves the slowest of the waves

they have a more complicated motion; they go up and down, left to right.

how do we used metamorphic facies

they provide more detail about t/p conditions that met grade. this helps id the tectonic setting/ metamorphic environment in which the met rk formed. you won't always find every mineral in the facies bc the parent rk composition may not be suitable for creating same minerals. Ex; some rks may contain 2 of the 3 main index minerals

What can primary waves travel through?

they will move through any material. the speed will change based on density but they are hard to stop.

does the system remain closed after death (carbon 14)

this is a bad assumption; they can be objective. you're assuming its a closed system.

how does too much vegetation make a slope unstable

too many plants equal a lot of mass sitting on an inclined plane, which makes it unstable. the plants are also soaking up a lot of water from the sediments, which makes it unstable

what is erosion

transportation of sediments

What is dendrochronology?

tree ring dating; each ring represents the end of a year.

what recently happened in clemson

two earthquakes affected the Clemson area in late august. both around magnitude 2.0

how can you tell the difference between quartzite and marble(they look the same and come in the same colors)

two ways to tell: hardness and effervescence.

What is radiometric dating?

use of radioactive materials for dating specimens(using small amounts of the material)

What are varves? explain how they form and how they are used for dating

used as non-radiometric dating(absolute); they are very thin layers of sediments that build up in lakes if the lake freezes over. the lighter layer forms in the summer and the dark layers forms in the winter. each pair of dark and light represents a year of time

what is the mercalli index

used for earthquakes; scale that goes from 1-12 represented with Roman numerals. you are measuring the amount of property damage. used for emergency and recovery efforts. not used by scientists.

What is a seismometer/seismograph?

used to measure the seismic waves in earth quake

what are chemical sediments made up of

usually comprised of 1 major mineral type

What is frost wedging?

water builds up in the cracks or wedges of the rock. when water freezes and turns into ice, it expands and applies pressure, which will eventually break the rock

explain fluid interactions aka metasomasim when it comes to met rks

water is squeezed out the rocks/minerals at depth. the water can dissolve some minerals and deposit materials that form new minerals. this changes the chemistry of the rock.

what are the four main agents of erosion

water, wind, ice, gravity

what are long/surface waves

waves that stay closer to the surface of the earth. these are the slowest

Why do we care about sedimentary rocks

we deal with them alot

what are we looking for in fossils that we want to use for correlation

we want them to be mundane and be able to id short spans of time. this means that we will get a more precise match up

what are the steps in forming sedimentary rock

weathering, erosion, deposition, lithification

what is the Paleozoic era? what is the time frame and key events

when biology goes nuts. up to this point life is simple. 550 Ma-200 Ma. Key events; Cambrian explosion: when an explosion of life occurred.

What is shock metamorphism?

when pressure increases extremely rapidly; when asteroids hit earth, tremendous pressure and temp is generated at the impact site; near-melting conditions can occur, creates metamorphic features.

what are the three causes of earthquakes

when stress<friction along the fault line, when stress~friction, and when stress>friction

how do S waves move

when they move through material, there is a vertical shift. this generates the ground motions we associated with earthquakes

what is absolute dating

when you assign an actual number to the dates; quantitative; very time consuming, expensive

what is the principle of original horizontality

when you first form strata, they are horizontal (flat). when they are not flat, you know something must have happened.

What is the principle of superposition?

when you have Strata stacked, the oldest is on the bottom, and they get progressively younger as you get closer to the top. helps to tell the difference between anticlines and sinclines. (look back to make sure you know these)

what is a fold

when you have a ductile response to a compressional force

what is drainage control

when you pump water out of the slopes to prevent landslides.

What are unconformities?

when you're looking at a strata, there will be a missing chunk of time. long periods of time where you don't have new layer development. time went by, but we don't have a record to represent it.

What is the Phanerozoic Eon? how many eras is it divided into?

where we are now, its divided into 3 eras

what is a joint

will form when you have a brittle response to the force. the most common type of geological structure. they can come in any size and they tend to occur in groups.

what kind of material do S waves move through

will not move through all material; won't move through the more ductile materials. if you push on a liquid, it just pushes away.

are strata and beds interchangable

yes

do different fault types form depending on the type of force applied

yes!

does subsidence create more space?

yes, it means you have more space above, which means the hole will go deeper.

how long does it take to form a given met rk.

you can chart the rks history on a P-T path

what is a risk assessment map

you can look at them and act accordingly to prevent landslides; they need to be updated regularly based on moisture change and other changes.

why do metamorphic rocks take so long to form

you have to bury the rocks very deep before the process even begins

what is the principle of cross cutting

you have to things that intersect. ex: faults; you need to figure out the age of the fault. whatever feature does the cutting Is the youngest. everything that got cut through are the older features.