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Sedimentary Rocks

Overview of how plate tectonics affects sedimentation. Answer the following questions:

o Where do sedimentary rocks originate?
o How are they formed?
o What are the three categories of sedimentary rocks?
o What are the distinguishing characteristics between the three categories of rocks?

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RESPONSE:

1. Where do sedimentary rocks originate?

Sedimentary rocks originate and form on (or very near) the Earth's surface where rocks particles transported by wind, water and ice are deposited on dry land, on the beds of rivers and lakes and in marine environments: beaches, deltas and the sea. The origins of the particles that make up sedimentary rocks determine their appearance and give clues to their identity. Also, the type of fossil found in a sedimentary rock suggests the rock's origin: a marine fossil, for instance, suggests that the rock formed from sediments deposited in the sea. Rocks especially rich in fossils include limestone (Sedimentary Rocks, 2009).

After their formation, sedimentary (and igneous) rocks may remain undisturbed or are deformed to different degrees through plate tectonics. According to the plate tectonic model, the surface of the earth consists of a series of relatively thin, but rigid, plates which are in constant motion. The surface layer of each plate is composed of oceanic crust, continental crust or a combination of both. Theoretically, this constant motion of the plates deforms rocks (Seismology, 2001). For example, a volume of rock may change shape, rotate bodily, fracture or be displaced from one place to another. Such changes may be visible to the eye, such as, by the tilting of horizontal strata, by development of folds in originally planar beds, ...

Solution Summary

By answering the questions, this solution provides an overview of how plate tectonics affects sedimentation e.g. where sedimentary rocks originate, how they are formed, the three categories of sedimentary rocks and the distinguishing characteristics between the three categories of rocks.

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