Geology Final Exam

T/F When geologists categorize natural resources, they refer to reserves as the known supplies of the natural resource that can be exploited economically under current conditions.

True

Which is NOT one of the primary components that comprise the Earth System?

Exosphere

More Difficult

Lakes overturn because of changes in density of the different layers of water. density can change because of temperature, but also because of composition of the water. if a lot of carbon dioxide is dissolved into the waters at the bottom of a lake, would it be easier or more difficult for the lake to overturn?

One way we know that the Earth's core is composed of iron and nickel is:

The composition of meteorites, which are made up of iron and nickel

T/F One reason we know the Earth is layered is because earthquake waves bend as they pass through Earth

True

Which of the following statements concerning the Earth's tectonic plates is NOT true?

There are seven plates, each concisiting of one of the seven continents.

Truths:

the plates consist of crust and the uppermost mantle

the continental plates are thicker than the oceanic plates

the continental plates are less dense than the oceanic plates

Which of the following statements regarding the lithosphere is NOT true?

The lithosphere is partially melted

Truths:

the lithosphere lies above the asthenosphere

the lithosphere is less dense than the core

the lithosphere consists of both the crust and the upper part of the mantle.

Oxygen and Silicon are two of the five most common elements in the Earth as a whole. Another element of the top five is

Iron

Oxygen and Silicon are two of the five most common elements in the Earth's crust. another element of the top five is

Aluminum

The motion of plates is determined from all the following EXCEPT:

ISOSTASY

Is determined by:

the age of ocean crust

global positioning systems

transform-fault boundaries

T/F The primary difference between the lithosphere and the asthenosphere is a difference in the composition of the rocks that make up the two layers.

False

T/F the fundamental mechanism that drives plate tectonics is earthquakes

False

T/F The one type of convergent boundary that lacks abundant volcanoes is the boundary where two oceanic plates converge

False

T/F Ocean crust and continental crust are different both in their composition and their average thickness.

True

T/F An element is defined by the number of neutrons it has.

False

One of the most important factors in limiting ionic substitution in a mineral is the size of the ion, the other most important factor is

The charge of the ion

Sulfur has 16 protons and 16 electrons. if the atomic mass of an isotope of Sulfur = 34, then:

It has 18 neutrons

The ion of Sulfur (above) would have:

18 electrons and be an anion

the two most common elements in the sun are:

hydrogen and helium

The two most commone elements in the Sun are much rare in Earth's crust because:

they were lost to space because they are light elements.

T/F The type of atomic bonding that involves the sharing of electrons among atoms is called ionic bonding.

False

T/F A hydrothermal mineral deposit forms when circulating groundwater or seawater reacts with magma leaches mineral that are then precipitated in cracks of solid rock.

True

T/F The primary means of mineral formation is crystallization from a fluid.

True

T/F Carbonate minerals are the most common minerals in igneous rocks

True

a naturally occurring solid, having a definite chemical composition and an ordered atomic arrangement resulting in a set of specific physical and chemical properties, is a

Mineral

A large number of silicate mineral exist because of ionic substitution and because:

The silica tetrhedral can link in different ways.

Mineral C

Given the rock depicted above is a granite, mineral A is LEAST likely to be:

Olivine

Dike

An ophiolite suite is:

A piece of ocean crust found on land

Point A will move up but Point B will move down over time.

Along divergent boundaries, there are commonly uplifted ridges, even though the crust is thinning because:

The increased heat decreases denstiy, and therefore allows the crust to rise.

Why does partial melting of the mantle occur at divergent plate boundaries?

Asthenosphere rises and melts as the pressure reduces

T/F During fractional crystallization the minerals with the highest melting temperatures will crystalize first.

True

Oceanic crust is geologically young because it is..

Continually created at mid-ocean ridges and destroyed at convergent margins

T/F Magma forms along convergent plate boundaries primarily because the descending plate is heated as it descends deeper into the mantle, and because water is introduced from the descending ocean crust to lower the melting point.

True

Imagine a rock with 50% mafic minerals and 50% felsic minerals. as this rock is heated until it just starts to melt (partial melting) the first magma (liquid) to form will be:

More felsic in composotion then the remaining rock.

Convergent Boundaries

Igneous rocks that are felsic or intermediate in composition are more common.
Large mountains are most common along this margin
Presence of a trench at or near this type of margin

Divergent Boundaries

Earthquakes limited to shallow depths AND a narrow zone
Thinner crust is more common along this margin
Plates move away from each other in relative terms

Mafic

basalt is a mafic rock
Mafic magma contains more Fe, Mg
Mafic rock forms the ocean crust
Mafic magma is higher in temperature
Pyroxene is a mafic mineral

Felsic

Higher silica content in felsic magma

How does the principle of isostasy explain variations in Earth's elevation?

The principle of isostasy explains variations in Earth's elevation because density affects Earth's elevation. if one part of the crust is less dense than another part the the less dense part will have a higher elevation. also thickness

Compare and contrast how igneous rocks form at divergent boundaries versus convergent boundaries. then list hte common igneous rocks found at each boundary.

at divergent boundaries the plates move away from each other an new rock forms i nbetween those two plates. at a convergent boundary one plate slides under another and melts and then a volcano may erupt and spew out the molten rock and then it hardens and forms igneous rocks.

Pyroclastic flows are particularly dangerous because:

They move rapidly along the ground and can bury buildings.

T/F As magma cools, it will become more viscous.

True

Explosive eruptions are more likely associated with volcanoes along tectonic margins because they typically form from magmas.

convergent.....felsic

T/F The primary products of weathering of rock are dissolved ions, altered/new minerals and residual minerals.

true

Which of the following is NOT a form of physical weathering:

Feldspars altering to clay in a pedalfer soil. Chemical Weathering

Forms of physical weathering:

Roots that grow into a cliff and split apart rock layers.

Mountain glaciers grinding granite into sand.

Rapid uplift or rocks causing fractures to form.

Which is NOT a main control on soil formation?

Strain

Main Controls of Soil formation:

time

climate

rock type

What was teh most significant form of pollution in Lake Victoria according to the video "seas of Grass" that we saw in class

Soil washed in from eroded land.

T/F Imagine particles of a certai nsize and density in a stream. These particles start to move once the water flows at a certain speed. If these same particles were found on a sand dune, the wind would have to travel faster than the water just to make particles move.

True

T/F the primary control on the composition of chemical sedimentary rocks i whether transport was by ice, water or wind.

False

T/F Sediment transported by wind will usually be better sorted (grains all the same size) compared to sediment transported by a fast moving stream.

True

One control on teh composition of sand along a beach is the composition of the rock from which it was eroded, the second most important control is the...

Climate of the region

Clastic sedimentary rocks are lithified by compaction or by

cementation

If a very thick sequence of sedimentary layers accumulated on continental crust, then it implies...

The crust was thinned by extensional tectonic processes or the crust was bent down (flexed) by compressional tectonic processes.

To the right of C

T/F Most of the early scientific estimates of the age of the Earth suggested the earth was much younger than modern scientific principles have shown it to be.

True

T/F the most accurate expression of uniformitarianism is that natural laws varied during the early part of Earth's history, but these laws have been constant since humans have been recording and observing the natural world.

False

T/F in all types of radioactive decay a radioactive element changes into a new element.

True

the 4.6 billion year age of Earth was determined by radiometric dates of:

meteorites

The sedimentary rocks I and J can both be determined to be:

Mesozoic in age

Which of the following geologic era ENDED about 250 million years ago

Paleozoic

Which of the following is the most important process in metamorphism

Chemical action of fluids

Increases in pressure

Increases in temperature

Which best defines the term recurrence interval

The time period between earthquakes along a fault.

the concept that rocks subjected to slow stresses surpass a limit and the nsuddently fail, causing sudden movement and release of the stresses is called:

Elastic rebound theory

Which of the following types of seismic waves travel the fastest through rock?

P-Waves

Which of the following would make it more likely that a rock layer will deform in a brittle manner:

High rate of stress

which of the following is NOT caused by compressional stresses:

Normal faults

are caused by compressional stresses

anticlinal folds

synclinal folds

reverse faults

Outline the four (or five) main processes in teh formation of a sedimentary rock.

1. Weathering and Erosion

2. Transportation

3. Deposition

4. Lithification

Contrast the following sets of terms as we've used them in Geology in a sentecne or two. Stress vs. Strain; Extension vs. Compression; Chemical vs. Clastic

Stress is the pressure put upon a rock, while strain is the actual damage the stress causes upon the rock.

Extension is stretching a rock, while compression is shoving a rock together and compressing it.

Clastic rocks are formed of tiny pieces of sediment pressed together, while chemical is formed by changing the chemistry of a rock.

Define unconformity and in one or two sentences explain its significance in understanding why we don't see rock layers that represent all of geologic time

An unconformity is a place where the sedimentary layers of rock have been deformed or disturbed. when a rock is deformed or disturbed it disrupts the representaiton of all of geologic time because some of the rock might be missing because of weathering or erosion or the layers are just so deformed that it is not easy to tell the relative ages.

it is hypothesized that the extinction of the dinosaurs was caused by a large meteorite impacting the earth. explaine WHY this does not directly contradict uniformitarianism even though humans have never seen such a large meteorite impact he eaerth.

even though uniformitarianism means that the geological processes of the earth have always and will always be the same there are sometimes occurrences that do not repeat or have not repeated yet.

how do volatiles in magma affect the explosiveness of a volcano?

if there are a lot of volatiles and dissolved gasses in magma it causes pressure to build until there is an explosive eruption. but if the volatiles and dissolved gasses are allowed to escape there will not be an explosive eruption.

explaine froma a scientific viewpoin, why the following statement is not necessarily true: "Seashells and other marine fossils have been found on mountaintops, even very tall ones, these indicate that the sea once covered the mountains, which is evidence for a global flood."

Because the seashells and other marine fossils may have gotten on the top of the mountain some other way. in the past that mountain may have been the seafloor that was pushed up by another plate crashing into it forming a mountain.

T/F Given equal volumes, water is able to hold more heat without changin temperature compared to sand.

true

T/F The sun's energy radiates at a shorter wavelength compared to the wavelenght of the Earth's radiant energy

true

Nitrogen and are the two most abundant gasses in Earth's modern atmosphere

Oxygen

Carbon Dioxide and are considered the two most imporant greenhouse gasses

Water vapor

When air in the atmosphere rises it...

cools

t/f the energy absorbed by Earth is equal to the incoming energy from the sun minus the energy reflected by clouds, dust, etc.

true

Location B

Where would surface winds be coming FROM the northeast?

Location Z

High pressure belts form at latitudes that are dominated by air that is moving

, which leads to conditions

downward, dry

why are certain areas of teh ocean's surface considered deserts? that is why so little life?

Lack of nutrients

Why is there more dissolved oxygen at the surface of the oceans near the pole compared to the surface of the oceans near the equator?

The polar oceans are colder, and can "hold" more dissolved oxygen.

t/f thermohaline circulation occurs because warm water from teh Mediterranean Sea spills into the Atlantic Ocean and displaces the cold water near the pole.

false

False

t/f There is almost no difference in water temperature between teh poles and equator in water depths > 1000 m

True

what is a drainage basin

it represents the area drained by a river and all its tributaries

urbanization increases the level of looding because:

Less of teh rainfall soaks into the ground allowing for more run off.

which of the following is NOT a significant benefit of rivers seasonally flooding their channels.?

The permeability of the soil decreases.

Benefits:

nutrients are supplied to the floodplain

natural levees are built up

sediment is deposited that enriches the soil

t/f meandering streams are those with one major channel, whereas braided streams commonly ahve numerous channels.

true

t/f if a dam is emplaced across a river valley, the river will respond by eroding more deeply farther upstream and depositing that sediment near the dam.

true

t/f the mississippi river flood of 1993 was a bigger flood, in terms of discharge, than the Missoula Flood.

False

t/f if the discharge of a river increases the velocity of the river will increase and/or the area of the stream channel must increase.

true

the percent of a rock that is made up of empty space is called

porosity

Which of the following is NOT a major control on teh level of the water table of a particular area:

How old the rock is

Major controls

climate

porosity and permeability of the rocks

how much groundwater pumping is taking place

in the map to the right, the ground water would most likely travel

toward teh west

groundwater always flows toward lower elevation!

groundwater discharge occurs at

wells

streams

lakes

t/f the high levels of arsenic found in some wells around Norman, Ok are caused by fertilizers used on poultry farms in western OK

False

t/f if precipitation increases in a region, the amount of infiltration must decrease

false

the primary health concerns related to groundwater movement through the mines in NE OK is...

The groundwater absorbs heavy metals as it flows through the underground mines.

the process by which a stream channel abruptly changes to a new location is called

Avulsion

Portions of deltas become submerged by seawater when:

sediment is delivered to another part of the delta

subsidence of teh land occurs

sea level rises

Longshore drift is due to

waves striking the shore at an angle.

which of the following is NOT a cause of hypoxia in the Gulf of Mexico

the ocean water become so cold with river water that oxygen cannot be held in teh water

do cause hypoxia in Gulf

MS River water caries huge quantities of fertilizers into the Gulf

MS River water causes a fresh-water cap such that oxygen cannot enter the underlying ocean water

the algae in teh Gulf of Mexico die and decay, using oxygen in the water.

What causes the greenhouse effect? Why is it a "good thing"?

the greenhouse effect is when certain gasses allow the sun's radiation to pass through them and then those gasses either reflect the radiation back to earth or the rays pass through the gases back into space. it is a good thing because the gasses trap in heat and keep our planet warm.

Define aquifer

An aquifer is like an underground well that holds water that can be naturally discharged or artificially discharged by pumping the water out.

List at least two positive and two negative effects of the construction of dams along a river. Be specific!

Positive: protects people and cities from being flooded and destroyed and the water rushing through the dam can be used for power.

Negative: the area upstream of the dam will displace people and animals because the river will spread out naturally and the area downstream of the land will no longer receive new nutrienta nd sediments from teh river.

Explain why deltas build out and add new land over time. Then explain why levees along deltas can lead to loss of wetlands along parts of the delta as in the MS River

Rivers deposit sediment as they run into the ocean and all of this deposited sediment forms deltas. building levess along dealtas keeps the river from changing its course and moving to old deltas. since the river can no longer deposit sediment there, teh ocean will begi nto flow back into those areas and destroy the wetlands.

Why do we have seasons? and why those villagers only experience two seasons (wet and dry)

We have seasons because of the tilt of earth's axis the tilt causes the sun's rays to hit different hemispheres more directly the n the other hemispheres at certain times of the year.

What are the different forms of carbon? Organic vs inorganic, gas, liquid, solid

Organic carbon is a solid

Inorganic can be dissolved in liquid or a solid in a rock

Know the main reservoirs of carbon in the Earth System and their relative sizes

Biomass 610

Atmosphere 750

Soils 1500

Fossil Fuels 4200

Oceans 39,000

Limestones and Shales 50,000,000

Know main fluxes of carbon—know whether the process takes carbon dioxide from the atmosphere or adds it back into the atmosphere.

Photosynthesis = uses CO2

Respiration = releases CO2

Weathering of silicate minerals = uses CO2

Volcanism = releases CO2

Burning fossil fuels = releases CO2

Decomposition = release CO2

Be able to outline or identify the reservoirs and fluxes for:

Terrestrial organic carbon cycle

Oceanic carbon cycle

Long-term carbon cycle

Terestrial: reservoirs = Biomass, Atmosphere, Soils fluxes = respiration, decomposition, photosynthesis,

Oceanic: Atmosphere, Aquatic Biomass, Oceans fluxes = respiration, decomposition, photosynthesis.

Long-term: Limestones and Shales, Fossil Fuels,

Has carbon dioxide in the atmosphere changed in the past? By approximately how much?

350 million years ago: Decreasing CO2 and increasing 0xygen

300 million years ago: Decreasing CO2

150 million years ago: Increasing C02

Be able to explain the main hypotheses of how the carbon cycle changed 350, 300 and 150 million years ago as described in class. Be able to explain the natural processes that led to the large scale increases or decreases of carbon dioxide in the atmosphere during those times.

350 Million years ago: Large areas of land within tropical belt Growth of vast swamps Much of the dead organics buried Ultimately formed into coal

Increase in burial of organic carbon leads to decrease in carbon dioxide AND increase in oxygen of atmosphere…

What is a proxy indicator of climate—know at least 2 or 3 mentioned in class.

Pollen:

infer temperature/rainfall

Tree Rings

Temp/rainfall of growing season

Ice Cores

Dust and Bubbles = atmosphere
chemistry of ice

Ocean and Lake Sediments:

Look at fossils, chemistry, sediments

Know the general concept of how we can use oxygen isotopes to determine the temperature of the ocean millions of years ago

Calcite uses ocean water. and when ocean water is colder and there is more ice on land that ocean water has more O 18 in it because all of the O 16 is up in the ice. and therefore the calcite will have more O18 in it when the earth was colder.

Know (IN GENERAL) the timing and range of temperature change over the last 2000 years. Approximately when was the Little Ice Age? When was the Medieval Warm Period? How much temperature change was there over these periods? Where they global warming or cooling?

Earth was cold until roughly 1000 then it began to warm. From 1000 to roughly 1350 was the Medieval Warm Period. Then from 1350 to 1850 was the Little Ice Age. and then the earth began to warm again. Temperature would change to roughly +-0.5 degrees

When was the last “Ice Age”? (when did it start? when did it end?) What were the major changes associated with it? That is, know (again, in general) where was the ice? How did climate change? Vegetation? Animals? Sea Level?

began 18,000 years ago ended roughly 10-15,000 years ago. On land Canada and such. there was much less vegetation and animals were very different. sea level was lower.

What was the trend in temperature over the last 60 million years?

Temperature has actually decreased over the last 60 million years

What were the general conditions like at the time of the dinosaurs in terms of temperature at both the poles and the equator? How much more atmospheric CO2 was likely present?

The earth was warmer then so there was more CO2 present in the atmosphere.

What is meant by a “Snowball” earth?

a "Snowball" earth is when the earth is mostly covered with ice

What are main controls on climate? Both at one place, and over time.

At one place:

Latitude

Solar radiation

Shoreline position

“continentality”

Geography

Presence of mountains, large lakes, etc

Atmospheric Carbon Dioxide

Long-term control of global temperature
Carbon Cycle

Long-term carbon cycle--plate tectonics
Ocean/Terrestrial carbon cycle--productivity

What is the trend of global temperatures over the last 130 years? How much change?

the temperatures have risen about 0.75 degrees

How certain are scientists that the temperatures have increased over the last 100 years?

very likely > 90%

What was the warmest decade in the last 130 years

2000s

What is the IPCC

The Intergovernmental Panel on Climate Change

What is the range of projections by the IPCC for global temperature over the 21st Century?

2 to 5 degrees warmer

What are the regional projections for temperature? Where will warming be most severe over the next century?

Projected warming in 21st century expected to be greatest over land and at most high northern latitudes and least over the Southern Ocean and parts of the North Atlantic Ocean

Temperatures have been warmer in the past. Why are scientists concerned about the present warming trend

• Rate of change is biggest concern...

• Slow change allows biosphere to adapt, even to mitigate to some extent.

• Rapid change leads to extinctions and fundamental changes in populations.

What will likely happen with respect to precipitation patterns with global warming?

Rising water vapor content

higher nighttime temperatures
more evaporation

Higher intensity rainfalls

less inﬁltration: groundwater recharge reduced
more run-off: larger magnitude ﬂoods
soil erosion
nutrient ﬂux to ocean/lakes

Hurricanes/Tropical Storms?

What will likely happen to sea level over the next century

It will rise

What are some other impacts mentioned in class that are related to global warming?

Fastest extinction rate in 65 million years (1000x normal rate)
Increased poverty and hunger
Increased disease

Air-borne (e.g. asthma)
Insect-borne (e.g. malaria)

More extreme weather

Droughts/Floods
Heat-wave

What are the main forms of mitigation? How does mitigation differ from adaptation?

Reduction of energy use (conservation)
Shifting from carbon-based fossil fuels to alternative energy sources
Carbon capture and storage

capturing carbon dioxide from power plants and subsequently storing it away safely instead of releasing it into the atmosphere

Carbon sequestration

a variety of means of artiﬁcially capturing and storing carbon already in the atmosphere, as well as of enhancing natural sequestration

What is a resource

Minerals

Water

Fossil Fuels

What are the different processes that can concentrate mineral resources?

Igneous/Metamorphic

Fluids--carry metals

Sedimentary

Weathering
Placer

What is the Hubbert Curve? What is the significance of Hubbert’s Curve?

A graph with a curve that predicts that oil production will peak and then drop. The significance is that we know we will run out of oil at some point.

What are some ways of “extending the curve”?

More efﬁcient extraction

Large-scale co-generation

More efﬁcient combustion, better engines

New energy-efﬁcient technologies

Unconventional Reservoirs (shale-gas

What is shale gas? What is fracking?

Shale gas is natural gas that is trapped in shale rock. Fracking is fracturing that rock in order to extract the gas to be used.

What are four direct drivers of ecosystem change?

Habitat Change

Climate Change

Invasive Species

Overpopulation

Pollution

How are the ecosystems of Lake Tanganyika impacted by warming of the waters and by increased sediment input?

With warmer temperatures there are less winds and upwelling is less intense and so nutrients cannot make it down into the bottom of the lake and that is destroying the ecosystems.

Geology Final Exam

Geology 1104 with Soreghan at University of Oklahoma

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