GSC 111 Chapter Notes - Chapter 5: Alluvial Fan, Distributary, Gorham'S Cave
13 Jan 2017
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Document Summary
Rocks embedded at the base of a glacier leave deep scratches in the underlying rock. This depositional body of sand, silt, and clay that is formed is called a delta: as river water mixes with standing water and begins to slow down, it loses sand first. Silt spreads farther from the mouth of the river, and clay goes even farther. This results in a delta structure that includes: delta-plain: consist largely of sand and silt, are nearly horizontal except where they are locally cross-bedded, distributary channel: some delta-plain deposits accumulate within river channels. Atolls: circular or horseshoe-shaped structures that form on volcanic islands; formed when a cone-shaped volcanic island was colonized by a fringing reef. The island then began to sink, turning the reef into a barrier reef with a lagoon separating it from the remnant of the volcano. After forming a mat, they grow up to produce another one.
