Chert |
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ChertBiogenous sedimentary rock.This rock is a sample layered chert. It possibly formed from siliceous diatoms or microbial forms in a freshwater or brackish-water lake basin between volcanic ranges of Late Tertiary to early Quaternary age. The surface of this sample preserves small fossil root traces. Sample from alluvial fan deposits along the Colorado River near Lake Havasu City, Arizona. |
| https://gotbooks.miracosta.edu/rocks/sedimentary/43.html | 2/2/2021 |