Tuesday, August 3, 2010

The Ice Age at the Florissant Fossil Beds: The Discovery of a Columbian Mammoth

The Florissant Fossil Beds National Monument is one of the most important plant and insect fossil sites in the world. The late Eocene age, 34 million-year-old fossils range from plant and insect impressions in paper-thin lake shale to massive petrified tree stumps. A more recent time period is represented at the fossil beds in gravels that accumulated during the last Ice Age at several sites at the fossil beds. At one of these locations gravels buried the remains of a mammoth, the first and only mammoth scientifically documented in Teller County, Colorado.

The Florissant mammoth was discovered in 1994 in a road cut near the visitor center when a student noticed small fragments of bone material scattered around the entrance of a rodent burrow. The student made a significant fossil discovery. While many fossil discoveries are the result of organized scientific work, this discovery was by sheer chance.

Paleontology does not move fast. Two years later (1996), the area surrounding the rodent burrow was systematically excavated and a mammoth jaw and molar tooth were found. The tooth was sent to a laboratory for radiocarbon dating. The laboratory dated the tooth at 50,000 years old—the limit of radiocarbon dating: This age would be the minimum age for the Florissant mammoth.
Florissant Fossil Beds Specimen No. 2392

In 2004, studies of the fossil material continued. Measurements were made on the tooth fragment, making it possible to identify the fossil material as a Columbian mammoth rather than a woolly mammoth. These findings were presented at a scientific conference in Denver the same year, making the Florissant mammoth part of the permanent scientific record.

The mammoth fossil material is important for several reasons. It documents the presence of mammoths at Florissant and shows these animals lived at an elevation of 8,400 feet--a relatively high elevation for mammoths.

The Florissant mammoth is still being studied. In 2010, sediments found with the mammoth were sent to a laboratory in Canada to see if there were any Ice Age pollen and spores. The lab returned microscope slides that, under a microscope, revealed an assemblage of pollen and spores--opening up yet another avenue for exploration, this time studying microfossils. The Florissant fossil beds continue to yield intriguing and exciting information about the distant past.

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