Florissant Fossil Quarry Collecting Trip

On Sunday, April 26th we will get to collect at one of the most famous fossil plant and insect localities in North America, which is the Florissant Fossil Quarry, next to the Florissant Fossil Bed National Monument, Colorado. To get to the quarry, meet on campus at D-Lot, 7am, to carpool. It is a 2 hour drive and we will get back around 3pm, we can stop for breakfast along the way. We will collect the delicate fossil impressions at the quarry by gently prying apart the layers of shale with paint scrapers and chisels. The collecting tools will be provided for us at the site. The cost to dig per person is $15 (cash) for 2 hours, a discounted rate from what it usually is. Max attendance of 24 people, please sign up on oreconnect to be eligible. The fossils of this site are of significant palaeontologic value, so be careful not to break specimens and try to identify them.

Geology of formation:
"The fine shales of the Florissant Formation contain a large number of compression and impression fossils of insects, flowers, leaves, and other types of biological remains that are rarely preserved as fossils. More than 1,850 fossil species have been described from the formation, many from the monument, including many type specimens (holotypes) and some fossils that have not documented elsewhere.

The Florissant Formation was deposited in a lake that formed when a river drainage was dammed by a volcanic mudflow (lahar) after eruption of the nearby Guffey volcanic complex about 35 to 34 million years ago, during the Eocene.

The compression and impression fossils in the Florissant Formation are in thin “paper shale” layers a millimeter or less thick. These consist of a couplet of layers –a layer rich in diatoms (a type of microscopic algae with cell walls of silica) over a layer of volcanic ash/clay. Diatoms bloomed as a response to silica-rich ash being washed into the lake. After they died off, they fell to the bottom of the lake and protected organisms and organic material from decay, ultimately leading to fossilization" (National Park Service).

References:
National Park Service. “Impressions and Compressions (including Carbonization).” U.S. Department of the Interior, n.d., https://www.nps.gov/articles/000/impressions-and-compressions.htm.

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