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76 Cards in this Set
- Front
- Back
Define "differential stress" |
Stress is not equal in all directions |
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What is "confining stress"? |
Also called "lithostatic stress", confining stress is uniform stress that operates equally in all directions. |
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What metamorphic facies occurs above subduction zones with temperatures 300-550°C, and 3-10 kb of pressure? |
Greenschist facies occur above subduction zones under relatively low temperatures and pressures. |
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What metamorphic facies occurs above subduction zones with temperatures 550-750°C and 4-11 kb of pressure? |
Amphibolite facies occur above subduction zones under intermediate pressures and temperatures. |
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What metamorphic facies occurs above subduction zones with temperatures >700°C and 4-11 kb of pressure? |
Granulite facies occur above subduction zones under very high pressures and temperatures. |
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What metamorphic facies occurs in subduction zones with temperatures 50-400°C and under 4-11 kb of pressure? |
Blueschist facies occur in subduction zones under low temperature, high pressure conditions. |
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Define "hornfels" |
Hornfels are fine-grained, non-folated rocks formed from intruding shale. |
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Define "protolith" |
A protolith refers to a "parent rock" |
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What is slate's protolith? |
Shale is slate's parent rock. |
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What is marble's protolith? |
Limestone is marble's parent rock. |
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What are two major sources of radon in central Wisconsin? |
Granite and glacial till are two major sources of radon in central Wisconsin. |
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What element and process produces radon? |
Radon is produced by the radioactive decay of radium-226. It is a product of the decay chain of the uranium series. |
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What are the health impacts of radon? |
Radon exposure has been linked to lung cancer. |
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What rock is the source of the high radon concentrations in north-central Wisconsin? |
Soil derived from granite and carbonate rock is the principal geological factor leading to elevated indoor radon in Wisconsin. |
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Why are glacial deposits also a source of radon? |
The sandy tills derived from granitic rock have moderate to high uranium content. |
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How can high radon concentrations be remediated in homes? |
Sealing and caulking openings in the concrete foundation can prevent radon from entering the home. |
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Name six stratigraphic laws: |
1. Original horizontality 2. Original lateral continuity 3. Superposition 4. Cross-cutting relationships 5. Inclusions 6. Faunal succession |
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Define "original horizontality" |
Original horizontality refers to the law that sediments are originally deposited in horizontal beds or layers. |
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Define "original lateral continuity" |
Original lateral continuity refers to the law that sedimentary beds are originally deposited over a large geographic area such that the sedimentary layers are laterally continuous in all directions. |
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Define "superposition" as it relates to stratigraphy. |
Superposition refers to the law that sedimentary beds are deposited sequentially such that the oldest layers are on the bottom and layers become progressively younger towards the top of a stratigraphic sequence. |
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Define "cross-cutting relationship" |
Cross-cutting relationship refers to the law that older rocks may be crosscut by younger rocks. Therefore, faults, dikes, or other cross-cutting features are younger than the layers that are truncated. |
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Define "inclusions" as it relates to stratigraphy |
Inclusions refers to the law that fragments of preexisting rocks (called inclusions) are older than the rocks which contain these fragments. |
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Define "faunal succession" |
Faunal succession refers to the law that distinctly different fossil groups succeed other fossil groups through time such that the fossil assemblages may demonstrate age changes in fossiliferous rocks. |
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Name an isotope used to identify Precambrian age rocks |
Uranium-238 (lead-206) |
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Name a specific rock enriched in uranium-238 |
Uranium-238 is found in granite, specifically the zircon mineral. |
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Define "strike" as it relates to faults |
Fault strike is the direction of a line created by the intersection of a fault plane and a horizontal surface. |
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Define "dip" as it relates to faults |
Fault dip is the angle between the fault and a horizontal plane. |
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What is a "strike-slip fault" |
In a strike-slip fault, rocks move horizontally with little or no vertical movement. |
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What is a "dip-slip fault"? |
Dip-slip faults are inclined fractures where the blocks have mostly shifted vertically. |
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Which direction does the hanging wall move on a normal fault? What force is responsible? |
On a normal fault, the hanging wall moves down as a result of tension. |
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Which way does a hanging wall move on a reverse fault? What force is responsible? |
On a reverse fault, a hanging wall moves up as a result of compression. |
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What does this symbol mean? |
Horizontal beds |
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What does this symbol mean? |
Overturned beds |
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What does this symbol mean? |
Vertical bed. |
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Syncline or anticline? |
Syncline |
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Syncline or anticline? |
Anticline |
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Name a Precambrian eon |
Proterozoic Archean Hadean |
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Name the present-day eon |
Phanerozoic |
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Describe the difference between weathering and erosion. |
Weathering is chemical or mechanical breakdown in situ, erosion is the movement of those particles. |
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Describe the economic significance of laterite soils. |
Laterite soils are rich in iron and aluminum. |
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Describe how a residual soil underlain by limestone differs from that of basalt. |
A soil underlain by limestone will be rich in calcite, while a soil underlain by basalt will be rich in iron. |
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What geologic feature does this represent? |
Dome |
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What geologic feature does this represent? |
Plunging syncline. |
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What geologic feature does this represent? |
Dextral strike-slip fault |
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What geologic feature does this represent? |
Sinistral strike-slip fault |
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What geologic feature does this represent? |
Asymmetric syncline |
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What geologic feature does this represent? |
Symmetric anticline |
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What geologic feature does this represent? |
Normal dip-slip fault |
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What geologic feature does this represent? |
Reverse dip-slip fault |
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What type of fault would tension stress usually result in? |
Tension stress would normally produce a normal dip-slip fault. |
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What type of fault would compression stress normally result in? |
Compression stress would normally produce a reverse dip-slip fault. |
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What type of fault would shearing stress normally result in? |
Shearing stress would normally produce a strike-slip fault. |
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What is the name of the chemical process by which feldspars decompose to clay? |
Feldspars decompose to clay via hydrolysis. |
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What is the chemical process by which anhydrite alters to gypsum? |
Anhydrite alters to gypsum via hydration. |
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What is the chemical process by which calcite weathers? |
Calcite weathers via dissolution. |
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What sedimentary rock underlies the Stevens Point area? |
Stevens Point and the surrounding area is underlain by quartz and sandstone. |
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Which two erosional agents produce well-sorted sediment? |
Wind and water produce well-sorted sediment. |
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Which two erosional agents produce poorly-sorted sediment? |
Gravity and glaciers produce poorly-sorted sediment. |
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What is the most likely possible environment in which hematitic stiltstone may be produced? |
Hematitic stiltstone is often produced in a flood plain environment. |
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What is the most likely possible environment for rock salt to be produced? |
Rock salt is likely to be produced in a desert environment. |
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What is the most likely possible environment for quartz sandstone to be produced? |
Quartz sandstone is likely to be produced in a beach environment. |
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What is the most likely possible environment for chalk to be produced? |
Chalk is most likely to be produced in a marine environment. |
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What is the most likely possible environment for breccia to be produced? |
Breccia is most likely to be produced in a talus slope environment. |
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What is the most likely possible environment for coal to be produced? |
Coal is most likely to be produced in a swamp environment. |
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What is the most likely possible environment for coquina to be produced? |
Coquina is most likely to be produced in a marine environment. |
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What is the most likely possible environment for conglomerate to be produced? |
Conglomerate is most likely to be produced in an alluvial fan environment. |
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What is the protolith of hornfels? |
Shale is hornfels' parent rock. |
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Name the four most common folated rocks from low grade to high grade. |
Slate Phylite Schist Gneiss |
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Name the three eras of the Phanerozoic Eon |
1. Paleozoic Era 2. Mesozoic Era 3. Cenozoic Era |
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Name three major resource aspects of sedimentary rocks. |
1. Ore deposits 2. Aquifers 3. Fossil fuels |
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Name sedimentary rocks that make good aquifers or reservoirs. |
Sandstone Conglomerate Carbonate |
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Name mechanical weathering processes. |
Frost action Abrasion Pressure reduction Organic activity Thermal expansion |
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Name three types of unconformities |
1. Disconformity 2. Angular unconformity 3. Nonconformity |
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Describe "disconformity" |
Disconformity describes when: 1. Sedimentary layers of similar orientation occur above and below a stratigraphic horizon; however, a significant time gap exists between them. 2. Older sedimentary rocks overlain by much younger sedimentary rocks of the same orientation. |
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Describe "angular unconformity" |
Angular unconformity describes when older inclined sedimentary rocks overlain by much younger sedimentary rocks with a significantly different dip angle. |
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Describe "nonconformity" |
Nonconformity describes when younger sedimentary rocks overlie older crystalline rocks consisting of either igneous or metamorphic rocks. |