 Graywacke sandstone
Lithogenous sedimentary rock
This medium-to-coarse grained sandstone consists of a mix of sand, silt, and mud and contains grains of quartz, feldspars, and other mineral grains and some shell fragments. Limonite cement gives the rock its brownish color. This sample is similar to sedimentary rocks found along much of the coast on California formed from sediments eroded from ancient coastal mountains and deposited in coastal, nearshore, and on deep-sea fan deposits along the coastal margin. This sample is from Late Miocene sedimentary rocks exposed in the Santa Monica Mountains, California. |
| https://gotbooks.miracosta.edu/rocks/sedimentary/48.html |
2/2/2021 |
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