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Survey of Earth Science exam 2 (Ch. 6)

Terms in this set (30)

What are four classes of sedimentary rock?
-Clastic
-Biochemical
-Organic
-Chemical
Biochemical
cemented shells of organisms.
Chemical
minerals that precipitate from water or gas.
Where are sedimentary rocks found in the Earth's crust?
What "history" do these rocks preserve?
-Only in the upper part of the crust.
-The layers record a history of ancient environments.
What are the five processes that lead to clastic
sedimentary rock formation?
Weathering, Erosion, Transportation, Deposition, and Lithification.
Weathering
generation of detritus via rock disintegration.
Erosion
removal of sediment grains from parent rock.
transportation
dispersal by gravity, wind, water, and ice.
Deposition
settling out of the transporting fluid.
Lithification
transformation into solid rock.
What three clast sizes are considered to be "gravel"?
boulder, cobble, and pebble
What two clast sizes are considered to be "fines"?
silt and clay
Angularity, sphericity, and sorting of clasts are useful in
determining the relative distance to the source.
True/False
False. Composition yields clues about the original source rock.
What is the common depositional environment for
conglomerates?
River channel
What mineral is most common in sandstones?
Quartz
What settings are fine clastics found in?
quiet water settings (Floodplains, lagoons, mudflats, deltas, deep-water basins.)
What two polymorphs make up the shells of deceased
organisms that are preserved as limestones?
Fossiliferous limestone—contains visible fossil shells.

Chalk—made up of plankton shells.
Coal primarily consists of the fossilized remains of
animals. True/False
True
Evaporites, such as Halite and Gypsum, are examples of
which type of mineral formation (from Chapter 3)?
Precipitation from a solution
A change in water velocity will have no influence on
bedding. True/False
False
Geologic maps are used to depict the distribution of
formations. True/False
True
Which type of deposit features fining upwards (i.e.
coarsest at bottom to finest at top) graded beds?
turbidite deposits
___________ are polygonal desiccation features.
Mudcracks
In what "environments" does deposition occur?
Terrestrial, Coastal, and Marine.
Which terrestrial environment features all grain sizes in
poorly sorted deposits named "tills"?
Glacial environments—due to movement of ice.
What grain-sizes are deposited on floodplains?
Fine sand, silt, and clay
Which terrestrial environment features uniform
sandstones with gigantic cross-beds?
Sand-dune environments
What is the grain-size and sorting of beach sands?
-Sediments are constantly being processed by wave action.

-A common result? Well-sorted, well-rounded medium sand.
Which (sub-)environment is the source of limestones?
Shallow water carbonate environments.
Coastal flooding events due to sea-level rise are termed
___________. Coastal exposure events due to sea-level
fall are termed ___________.
Transgression; Regression
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