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Geology Midterm1 (Sedimentary)

Terms in this set (8)

What is the definition of a clastic sedimentary rock?
Clastic sedimentary rocks are composed of fragments or clasts of preexisting minerals and rock.
Examples:Conglomerate, breccia, shale or mudstone, sandstone
What is a chemical/biological sedimentary rock?
Chemical sedimentary rocks are the rocks that are deposited from aqueous solutions and precipitation which may be caused by chemical or biological processes.
Be able to describe the difference between the rocks you learned in section and lab such as shale/mudstone, sandstone, conglomerate, breccia, limestone, evaporite and a chert.
Conglomerate is a clastic sedimentary rock composed of a gravel sediment and it contains large rounded fragments.

Breccia is a clastic sedimentary rock that is composed of a gravel sediment with small angular fragments.

Sandstone is a clastic sedimentary rock composed of sand sediment with very small fine grains

shale/mudstone is a clastic sedimentary rock composed of silt and clay sediments with small fine grains.

Limestone is a biological clastic sedimentary rock composed of calcite

chert is a bilogical clastic and crystalline sedimentary rock composed of microcrystallized quartz and diatoms.
Describe the environment in which sandstone, shale/mudstone, conglomerate, breccia, limestone, and chert are formed.
conglomerate and sandstone are formed in marine and costal environments
Why are sedimentary rcoks important?
Sedimentary rocks are important recorders of the earthssurface conditions of the past. Sedimentary rocks also contain fossils so they show what kind of animals had lived in the past. Sedimentary rocks are also the kind of rocksthat contain oil, gas. coal itself is a sedimentary rock. These are also the rocks that contain the earths ground water.
What is the principle of uniformitarianism?
Uniformitarianism- present is key to past. Geological processes operate now as much as they did in the past producing the same types of products. Modern deposits can be used to interpret processes in aincient rocks.
The earth is dominated by muddy sedimentary rocks like shales and mudstones. California has a higher proportion of coarse grained sedimentary rocks like conglomerate and sandstone why might this be?
This is most likely because california has a very long coast. Coastal and marine areas are where rocks like conglomerate and sandstone are formed. Most parts of the geologic world do not have coastal regions. So they would have shale and mudstone.
Where are the major occurences of sedimentary rocks in california?
Coast ranges, Great Central Valley, Eastern CA, and great basin
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