Term
| If a rock melts, can it be considered a metamorphic rock? Explain. |
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Definition
| No, metaphoric changes do not involve melting. They undergo changes in chemical composition, mineral content, or physical texture |
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Term
| Contrast the temperature and pressures among the grades of metamorphism. |
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Definition
Low Grade: low pressure, 200-350C
Medium Grade: medium pressure 350-600C
High Grade: high pressure, 600- 1100C |
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Term
| What is the significance of the original rock in metamorphism? |
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Definition
| Parent rock/material determines which type of metaphoric rock forms |
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Term
| What are the variables that affect metamorphism? |
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Definition
| Parent material, temperature, pressure, depth, fluid availability |
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Term
| Which gas is most commonly released in metamorphic degassing reactions? |
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Definition
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Term
| List and describe the three common processes that cause rocks to experience increasing temperature after they form. |
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Definition
Sediment burial: temperature increases with depth
Tectonic Burial: one block of crust is forced over another block
Magma Intrusion: the injection of hot magma into rocks changes local geothermal gradient by increasing temperature |
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Term
| What causes an increase in pressure with increasing depth within the Earth? |
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Definition
| Forces are equal in all three dimensions. Increase force=increase pressure |
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Term
| What are the three ways foliation can form in a metamorphic rock? |
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Definition
a) preferred orientation of mineral
b) alternating bands of different minerals
c) flattening and stretching of minerals |
|
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Term
| Describe recrystallization |
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Definition
| Involves the transfer of atoms from one part of a crystal to another part of a crystal or to an adjacent crystal; changes the size and shape of existing minerals rather than making new minerals |
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Term
| Where do the fluids that drive metamorphism come from? |
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Definition
| They are either part of the original parent material or be introduced into the metamorphic environment |
|
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Term
| Why doesn't a diamond convert to graphite on Earth's surface? |
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Definition
| Because the transformation of diamond to graphite requires high temperatures to initiate the reactions |
|
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Term
| What does pressure affect? |
|
Definition
|
|
Term
| What causes minerals to become unstable? |
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Definition
| Increases in temperature and pressure |
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Term
| How does recrystallization differ from cementation of sedimentary particles? |
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Definition
| Recrystallization is a change in chemical composition while cementation is a physical change |
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Term
| Why is feldspar a poor index mineral for metamorphic grade purposes? |
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Definition
| Because it is found in all grades of metaphoric rocks |
|
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Term
| Summarize the relationship between the minerals present in a rock and metamorphic grade. |
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Definition
| Large mineral crystals indicates that it has a high metaphoric grade |
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Term
| What is an example of a low grade mineral? |
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Definition
|
|
Term
| What is the classification of metamorphic rocks based on? |
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Definition
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Term
| What factors can be inferred from a metamorphic rock's mineral context and texture? |
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Definition
| The depth at which it formed |
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Term
| Schist contains a lot of the mineral mica, which is what makes it shiny. Slate contains clay, but not much mica. Where do the mica minerals come from as slate metamorphoses into schist? |
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Definition
| Due to the increase of heat and pressure the mica recrystallizes into bigger more visible crystals |
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Term
Two students are thinking about how metamorphic minerals form. Student 1: In metamorphic rocks, the minerals melt a little bit due to the extremely high temperatures.
The melting causes the atoms to flow around and grow bigger minerals. Student 2: I
thought that new minerals form and grow bigger because the rock is getting compressed and heated. The atoms that formed the minerals in the original rock rearrange to form bigger, new minerals. With which student do you agree? Why? |
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Definition
| Student 2 because the minerals don’t melt, their chemical composition changes |
|
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Term
| Explain how metamorphic rocks form. |
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Definition
| With high pressures and temperatures the crystals recrystallize and grow forming new and bigger minerals and changing the chemical makeup of the rock |
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Term
A metamorphic rock is a "changed rock". How is it possible to use metamorphic
rocks to figure out the geologic history of an area before the area was metamorphosed? |
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Definition
| The composition of the parent rock can be interpreted as long as fluid is present |
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Term
| A large area undergoes the same amount of metamorphism (all rocks reach the same metamorphic grade). However, after the metamorphism, some rocks are marble and some rocks are slate. Why? |
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Definition
| It formed on a convergent plate boundary |
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Term
|
Definition
| Disconformity: an unconformity defined by a sharp erosional boundary between intervals of sedimentary or volcanic rocks where layers above and below the boundary are parallel to one another |
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Term
|
Definition
| One of two or more atoms of the same element that have the same number of protons but different numbers of neutrons |
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Term
| The use of fossils to correlate sedimentary layers is an application of the Principle of: |
|
Definition
| Principle of Faunal Succession |
|
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Term
Name the sequence of events, from oldest to youngest, that must always happen in
order to have an angular unconformity. |
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Definition
| Deposition uplifting and tilting of sedimentary layers erosion of tilted layers deposition of flat-lying sedimentary layers over eroded surface |
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Term
| What percentage of parent isotopes are present in a mineral after two half-lives have passed? |
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Definition
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|
Term
| 7. When you determine that a dike must be younger than the country rock it intrudes you are using the Principle of: |
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Definition
|
|
Term
| What is the scientifically reasonable estimate of Earth's age? |
|
Definition
|
|
Term
| The half-life of the radioactive decay process is the time interval during which the number of _______ atoms decreases by half |
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Definition
|
|
Term
Evaluate the following sentence: A disconformity marks where the geologic record is
incomplete because no rock exists to show the time interval of deposition or non-deposition separating horizontal layers. Is the statement correct? |
|
Definition
|
|
Term
| What is the meaning of the half-life of a radioactive decay process? |
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Definition
| Half-life: time interval required for half of the radioactive parent isotope atoms to decay to form an equal number of daughter isotope atoms |
|
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Term
| What is radioactive decay? |
|
Definition
| The process by which unstable isotopes transform to new elements by a change in the number of protons and neutrons in the nucleus |
|
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Term
| What is the basis of the geologic time scale? |
|
Definition
|
|
Term
The determination that a sedimentary rock layer is older than all the sedimentary
layers above it is an application of the Principle of |
|
Definition
|
|
Term
| How can you be sure you are correlating the same layers? |
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Definition
| The Principle of Lateral Continuity: correlation of rock layers |
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Term
| What is the relationship between the angle of repose and slope? |
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Definition
| Angle of repose: the maximum angle of a stable slope determined by friction, cohesion, and the shapes of the particles in the mass of loose material that make up the slope |
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Term
| If the driving forces are greater than the resistive forces, what happens? |
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Definition
| Mass wasting occurs; things fall |
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Term
| A student was asked the following question: "What criteria are needed for a meaningful classification of the gravity-driven, downslope movement of rock and regolith?" This student wrote the following answer: "The criteria needed for a meaningful classification of the gravity-driven, downslope movement of rock and regolith fall into three categories. You need to describe the nature of the mixture of solids, the type of motion, and the velocity of the motion. A meaningful classification scheme can be developed from these three criteria." How would you evaluate this student's answer? |
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Definition
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|
Term
| The driving force for the downslope movement of rock, debris or earth is: |
|
Definition
|
|
Term
| What are the major triggering events for mass movement processes? |
|
Definition
| Mudslides, earthquakes, flash floods & volcano triggers |
|
|
Term
| What is the main force responsible for mass movement processes? How is this force affected by slope angle? |
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Definition
| Gravity is the force responsible. The steeper the slope the less friction there is. |
|
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Term
| Use the concepts of driving and resisting forces to define what is meant by a stable hillside in contrast to an unstable hillslope. |
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Definition
| An unstable hillside is often effected by water, high permeability, a steep slope, very little vegetation |
|
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Term
| What movement does the moving mass loses contact with the surface |
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Definition
|
|
Term
| Bent tree trunks are an indication of... |
|
Definition
|
|
Term
| Define, describe, and sketch the hydrologic cycle. |
|
Definition
| The movement of liquid water and water vapor through all Earth’s systems; Water evaporates and transpiration into clouds with condense in the Earth’s atmosphere then precipitation occurs and water runs off into streams and sewers or infiltrates the ground water |
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Term
| 3. The undulating boundary between water-saturated regolith, and rock with unsaturated regolith and rock, is called the ________. |
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Definition
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Term
| What is a drainage basin? Describe how water moves through the drainage basin. |
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Definition
| The area from which a stream gathers water. Water moves downhill; smaller tributaries run into larger streams and most rivers usually deposit into the ocean |
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Term
|
Definition
| The volume of fluid that passes a location within an interval of time |
|
|
Term
| How is discharge measured? |
|
Definition
|
|
Term
| How does sediment get into a stream? |
|
Definition
Surface runoff after rain or snow washes sediment into streams
Move movement delivers regolith and rock from hill slopes directly into streams
Streams pick up sediment where they erode horizontally into banks or erode vertically downward through their beds |
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Term
| How is erosion by water flowing in an alluvial stream different from that in a bedrock stream? |
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Definition
| Alluvial streams erode when shear stress of the flowing water is sufficient to cause erosion; Bedrock streams erode by abrading the bed with transported sediment |
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Term
| For small grains such as clay, their main resisting force to sediment transport is: |
|
Definition
|
|
Term
| The ability of a stream to do work is measured by multiplying the shear stress by the average flow velocity, and is called |
|
Definition
|
|
Term
| What is the difference between bedload and suspended load? What is dissolved load? |
|
Definition
Bedload: large grains that roll, slide, and bounce along the bottom of a stream
Suspended load: the fine-grained sediment intimately mixed with the water and flowing above the bottom of a stream
Dissolved load: the chemical ions dissolved in stream water |
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Term
| Define stream power. What is the link between stream power and sediment deposition? |
|
Definition
| A measure of the ability of a stream to do work measured by shear stress times average flow velocity; a larger volume of sediment the more stream power is required; there must be stream power for deposition to exist |
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|
Term
What would you suspect to happen to the load of a stream if its channel shape
changes from being narrow and deep of being wide and shallow (assume the area of the channel and average velocity remain constant)? |
|
Definition
| Deposition will occur and alluvial fans form |
|
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Term
|
Definition
| Floods occur when a drainage basin is incapable of soaking up all of the water from rainfall or snowmelt |
|
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Term
| Define base level. What processes cause base level to change? |
|
Definition
| The elevation down to which a river has the ability to erode its bed everywhere along its course; Changes in land-surface slope, water discharge, or sediment supply |
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Term
| How does an alluvial fan differ from a delta? |
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Definition
| Alluvial Fan is just a mass of sediment while a delta is the landform produced by the deposition of sediment |
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|
Term
| What are the units used to measure discharge and velocity? |
|
Definition
Discharge: cubic meters per second
Velocity: meters per second^2 |
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Term
| Where water in a stream channel goes around a curve, faster and deeper water causes erosion on the ____________ and formation of a ______ on the channel where the water is shallower and slower |
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Definition
| Outside of the bank....cutbank |
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Term
| Judge the following sentence according to the criteria given below: A sinuous stream tends to meander [assertion] BECAUSE of high bank erodibility [reason]. |
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Definition
| This statement is false, Meandering streams are difficult to erode; channels braid are easily eroded. Highly sinuous channels meander because of simultaneous erosion and deposition |
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|
Term
| When the elevation of a stream is at base level it: |
|
Definition
|
|
Term
| What stream properties tend to increase downstream? |
|
Definition
| Streams become wider, deeper and faster downstream |
|
|
Term
| What stream properties tend to decrease downstream? |
|
Definition
| The slope and sediment size decrease downstream |
|
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Term
|
Definition
| A ridge of sediment alongside a stream channel produced by deposition of sediment adjacent to the channel during floods |
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Term
| Describe the processes that naturally form lakes. |
|
Definition
| A lake accumulates water in a low part of the landscape; surface runoff runs into the bowl, ground water seeps in through the bottom |
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Term
| Judge the following sentence according to the criteria given below: It takes less shear stress to erode clay and silt size grains than sand size grains [assertion] BECAUSE clay and silt grains are smaller than sand grains [reason]. |
|
Definition
| Clay minerals are very cohesive and require higher shear stress to erode |
|
|
Term
| What percentage of the Earth is covered in glaciers? |
|
Definition
|
|
Term
| How does snow transform into glacial ice? |
|
Definition
| Fresh snow falls and thickens then forms into rounded snow grains, the snow grains freeze becoming ice grains and as time goes by the ice grains recrystallize and interlock with other ice grains to form a glacier |
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|
Term
| What is the difference between valley glaciers and ice sheets? |
|
Definition
| Valley Glaciers are long and narrow glaciers confined within bedrock valleys and move downslope where Ice Sheets are glaciers not confined by valleys and can be subdivided based on size |
|
|
Term
| Name two examples of ice sheets. |
|
Definition
|
|
Term
| What are the two zones of a glacier? |
|
Definition
Zone of Accumulation: high elevation zone where the winter snow accumulates is greater than the amount of snow that melts during the summer
Zone of Wastage: low elevation zone (also called zone of ablation) where the summer melting exceeds the winter snow accumulation |
|
|
Term
| What part of the glacier flows the fastest? |
|
Definition
| At the surface in the center of the glacier |
|
|
Term
| What agent polishes rocks smooth as a glacier passes? |
|
Definition
| Erosion by abrasion: glacial flour – very fine grained rock dust |
|
|
Term
| What is a lateral moraine? |
|
Definition
| Boulder-rich sediment that forms a ridge along the margin of a valley glacier |
|
|
Term
| What is the difference between till and outwash? |
|
Definition
Till: sediment deposited directly by the glacier; poorly sorted
Outwash: sediment mostly eroded by glaciers and then carried away by melt-water streams; better sorted |
|
|
Term
|
Definition
| Rock transported by a glacier and deposited where similar rocks are not present |
|
|
Term
| How do end moraines form? |
|
Definition
| They form at the leading snout of the glacier; till that is deposited at the front end of a glacier |
|
|
Term
| What is frozen seawater called? |
|
Definition
|
|
Term
| What are blocks of ice that detach from a glacier and float off into the ocean called? |
|
Definition
|
|
Term
|
Definition
| The floating part of a glacier that moved from land into deep water |
|
|
Term
Judge the following sentence according to the criteria given: It is important to
understand landscape modification by moving glaciers [assertion] BECAUSE while they
are not as common as streams, glaciers do more erosive work [reason]. |
|
Definition
| This statement is correct |
|
|
Term
| A U-shaped valley was most likely formed by: |
|
Definition
| The retreat of a valley glacier; erosion of both the bottom and the sides of a valley |
|
|
Term
| How did the Great Lakes form? |
|
Definition
| During the last 2 million years glaciers scooped out easier eroded rocks carving out the lakes and a bowl of water was left in its place; carved out of relatively soft rock by ice-age glaciers |
|
|
Term
| What has been attributed to cause ice ages? Why? |
|
Definition
| The tilt of the Earth’s axis, the eccentricity of Earth’s orbit, and the wobble of the Earth all effect the solar heating of the Earth’s surface |
|
|
Term
| What are four lines of evidence for global warming? |
|
Definition
| Local temperature records; global temperature records; retreating glaciers; rising sea levels |
|
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Term
| One misconception concerning global warming is that temperatures uniformly increase at the same times at every location. What data do climate scientists collect and analyze in order to get an accurate picture of climate change? |
|
Definition
| Scientists take an average of temperatures around the world |
|
|
Term
| Describe the Earth's energy budget. |
|
Definition
| The energy budget is the balance of incoming and outgoing energy |
|
|
Term
|
Definition
| A data record that substitutes for direct instrumental measurements; usually refers to estimates of climatic conditions prior to collection of temperature and precipitation measurements |
|
|
Term
| What role does albedo play in Earth's climate? |
|
Definition
| How reflective something is. Albedo controls how much heat is trapped in the Earth’s atmosphere; clouds have high albedo and water and vegetation have low albedo; helps regulate Earth’s temperature |
|
|
Term
| What role does the greenhouse effect play in Earth's climate? |
|
Definition
| Greenhouse effect: the warming of Earth’s surface that results from gases in the atmosphere that permits solar energy to reach Earth’s surface but stop radiated heat from going back into space |
|
|
Term
6. What was the average carbon dioxide concentration in the atmosphere in the one
hundred years prior to the Industrial Revolution (when fossil fuel use rose significantly)? |
|
Definition
|
|
Term
| What atmospheric gas limits or restricts incoming solar radiation? |
|
Definition
| CO2, water vapor, methane, ozone, & nitrous oxide |
|
|
Term
| What atmospheric gas does not significantly limit or restrict the amount of outgoing Earth radiation |
|
Definition
|
|
Term
| How can different geographic locations at the same latitude have different average temperatures? |
|
Definition
| Due to the tilt of the Earth's axis and because of the ocean currents |
|
|
Term
| What is the difference between weather and climate? |
|
Definition
| Weather is local; Climate is global; climate is driven by the sun |
|
|
Term
| What is the carbon cycle? |
|
Definition
| The ways carbon is transmitted from organisms to the environment and back; photosynthesis, respiration, industrial emissions, carbonic rocks, and carbon in he atmosphere all play a role |
|
|
Term
| Describe and explain the difference between El Nino and La Nina |
|
Definition
El Nino: relatively weak trade winds, suppressed upwelling of cold water along the west coast of South America, unusually warm ocean temperatures in the Equatorial Pacific
La Nina: strong trade winds, increased upwelling of cold water along South America; unusually cool waters in Equatorial Pacific |
|
|
Term
| There are many atmospheric gases that contribute to greenhouse warming, so why do climate scientists focus on carbon dioxide and methane and not on more abundant water vapor? |
|
Definition
| CO2 and Methane account for 90% of the changes in the greenhouse effect. The carbon immediately bonds to the oxygen in the atmosphere making it abundant and dangerous while the methane is released directly into the environment from coal mining and agricultural processes |
|
|
Term
| What quantities are greenhouse gases measured (in other words, what are the units used to report these gases)? |
|
Definition
|
|
Term
| Describe thermohaline circulation. |
|
Definition
| The thermonhaline system is affected by salinity and temperature. Dense cold water sinks and as it moves in the ocean current it warms near the equator and rises as it keeps travelling in the current it cools and sinks and so on. |
|
|
Term
| What role does oceanic circulation play in Earth's climate? |
|
Definition
| If the conveyer belt stops, the climate temperatures will cool and a domino effect will form |
|
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Term
| Which changes in the energy budget over the last 150 years are natural and which are caused by human activities? Be sure to note whether each change would cause cooling or warming of the atmosphere near Earth's surface. |
|
Definition
Natural: solar radiation, albedo, greenhouse effect, ocean circulation, volcanic eruptions
Human Induced: deforestation, Excessive release of CO2 and methane |
|
|
Term
| What role does solar energy play in Earth's climate? |
|
Definition
| Solar energy warms the Earth |
|
|
Term
| Does mass movement require a specific trigger? |
|
Definition
|
|
Term
| How does vegetation affect slope stability? |
|
Definition
| Vegetation makes a slope more stable b/c it hold the sediment down |
|
|
Term
A student was asked the following question: "How can adding water to sand both
increase and decrease cohesion?" This student wrote the following answer: "Adding
water to sand can increase or decrease cohesion depending on the composition of the
water. Adding fresh water to sand will decrease cohesion and adding saltwater to sand
will increase cohesion. The salt in the water helps to hold the sand together when the
water evaporates." How would you evaluate this student' s answer? |
|
Definition
| The student’s answer is incorrect; adding small amounts of water makes it more stable; large amounts of water increase instability |
|
|
Term
| How are volcanic eruptions and mass movements connected? |
|
Definition
| Volcanos cause debris flow called lahars; deposition of loose ash and pumice settle on the steep slope; eruptions destroy large areas of vegetation; snowmelt generated by lava flows or heavy rainfall following the eruption cause rapid erosion and sliding |
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|
Term
| Seismic shaking in loose, water-saturated sediments causes: |
|
Definition
| The compacting grains displace the water and the water acts like a fluid creating a flow |
|
|
Term
|
Definition
| The pressure of water within sediment |
|
|
Term
| What happens if a slope is steeper than the angle of repose? |
|
Definition
| A mass movement will occur |
|
|
Term
| What are the two components gravity is resolved to? |
|
Definition
|
|
Term
| Which minerals have high cohesive properties? |
|
Definition
|
|
Term
| What factors effect slope stability? |
|
Definition
| Water, geologic material, geologic structure, steepness, weathering, vegetation |
|
|
Term
| What three factors are used to describe and classify the variety of mass-movement processes? |
|
Definition
Nature of the rocks/regolith
Types of Motion:
Falls: material detaches from a steep slope and free falls
Slides: moving material separates from a stationary object and slides down
Flows: continuous movement of rock and regolith that behave like liquids
& Velocity |
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|
Term
| Evaluate the following sentence: Measuring the abundances of parent and daughter isotope in a mineral is sufficient for determining the mineral's age [assertion] BECAUSE the decay rate doesn't need to be known, only the ratio of parent to daughter isotope[reason]. |
|
Definition
| The decay rate depends on the amount of parent/daughter isotopes; both the abundance and half life must be known |
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|
Term
| What do you conclude if you were examining an exposure of rocks along a canyon wall, and Pennsylvanian Period age rocks appeared higher on the canyon wall than Permian Period age rocks? |
|
Definition
| The Permian Period occurred first |
|
|
Term
| Evaluate the following sentence: Radioactive decay rates are considered reliable by rational individuals [assertion] BECAUSE laboratory experiments indicate that decay rates are unaffected by changes in temperature, pressure, variations in gravitational field or different magnetic fields [reason]. |
|
Definition
|
|
Term
| How do we know the age of the Earth? |
|
Definition
| From rocks we found from the moon |
|
|
Term
| What evidence provides support for the assumption that Earth formed at about the same time as other objects in the solar system? |
|
Definition
| The rocks found from different planets from meteors are the same age |
|
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Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| Start of Mesozoic; Age of the Dinosaurs |
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Term
|
Definition
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Term
|
Definition
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