Home > Rocks > Sedimentary Rocks

Sedimentary rocks make up only a thin layer of the Earth's outermost crust, barely five percent of the Earth's outer fifteen kilometers, but they account for seventy-five percent of all rocks exposed at Earth's landsurface. They serve as our principal source of coal, oil, and natural gas, as well as much of our iron and aluminum ores. They store nearly all of our fresh underground water and are the source of our cement and other natural building materials. Sedimentary rocks tell the history of the land in their layers and also contain the fossil record. Sedimentary rocks are classified into two types by their source material (what they are formed from). These two types are detrital sedimentary rocks and chemical sedimentary rocks.

Click below to learn about them.
1. Detrital
2. Chemical

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This page was last updated on December 4, 2000
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