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What is limestone
made of calicium carbonate found in marine environment. it makes fossils. The most abundant chemical rock.
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What is Chert?
made of silica it is very smooth fine grained
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What is gypsum?
Calcium sulfate evaporite found in arid environments. The most abundant evaporite.
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what is rock salt?
Halite it forms in arid environments
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What is Coal?
made of organic parts found in swamps
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What are the 5 sedimentary structures that determine environment of deposition?
- Stratification
- Crossbedding
- Graded Bedding
- Ripple Marks
- Mud cracks
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Define Stratification
the deposition of sediment under wind or water. stratified rocks are layered. This is the Most important feature of sedimentary rocks.
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Define Crossbedding
beds deposited at an angle by wind or water. Eolian(wind) environment is where we find large-scale crossbedding. it indicates direction of wind or water
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Define Graded bedding
the decreases of size of sediment upward through a bed. indicates sediments being deposited by turbidity currents in a deep marine environment
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Define ripple marks and mudcracks
found in a tidal flat environment. after its all dried out.
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What are the 6 environments of deposition
- River(fluvial)-small scale crossbedding
- wind(eolian)-large scale crossbedding
- Glacial(tillite)-angular, unsorted and unstratisfied
- Tidal Flat-ripple marks and mudcracksÂ
- Lagoon/swamp-coal between layers of sanstone and shale
- Shallow Marine-limestone and fossils(deep marine shows graded beds)
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What is a metamophic rock?
rock that has been changed due to Heat,Pressure, and Chemically active fluids.
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What is Contact metamorphism?
High temperatures bake igneous rocks in a zone called an aureole.
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what is regional metamorphism?
Both High temperatures and pressure deform rock. Generally at convergent plate boundaries
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What are the 2 types of metamorphic rocks?
- Foliated(regional)-has layers
- Non-foliated(contact)-no layers
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What is foliation?
having a definite Planar texture(layered)
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where do most metamorphic rocks form?
In the roots of ancient mountin systems at convergent plate boundaries/subduction zones. (regional metamorphism)
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What is spheroidal weathering
the rounding of rocks over long periods of time.
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what is the most important factor influencing the rate of weathering?
climate, temperature and humidity
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What is Talus?
the small rock debris that accumulates at base of cliff
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Describe the 4 types of foliated rocks
- Slate-lowest grade,very fine grains, parent rock shale
- Phyllite-fine grains, kind of glossy, parent rock slate
- Schist-medium to coarse grain, scaly, parent rock Phyllite
- Gneiss-medium to coarse grain, compositional banding, parent rock Schist, Granite or volcanic rocks
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Describe the 2 types of nonfoliated rocks
- Quartzite-came from sandstone(quartz)
- Marble-came from limestone(calcite)
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