Sticking with the sedimentary theme, today’s deskcrop is another biochemical limestone – this time, an algal stromatolite from the Eocene Green River Formation at Douglas Pass, in western Colorado. Algal stromatolites are some of the oldest fossil life forms preserved in the rock record, but they’re not limited to the Precambrian. This sample is one of a couple of very nice textural samples of carbonate rocks I’ve collected from the lacustrine deposits on the southern approach to Douglas Pass. Look for another one from this locality with a very different texture next week!
Explore this and all of my 2010 Deskcrops and Outcrops in Google Earth!