Florissant Fossil Beds National Monument

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Florissant, Colorado: Paleoelevation Estimates
Thomas Viney along Boulder Creek Trail at Florissant Fossil Beds National Monument Summer 2012
Today, Florissant is at an elevation of between 2,500 and 2,600 meters (Meyer, 2003, p. 62). Multiple methods have been used to estimate the paleoelevation of the fossil ecosystems of Florissant. MacGinite was the first person to estimate the paleoelevation of Florissant using the composition of fossil vegetation. MacGinite estimated the paleoevlevation of Florissant to be no more than 3000 ft. or around 900 meters (MacGinite, 1953, p. 57). During the 1990s paleotemperatures and lapse rate were used to estimate paleoelevation. The paleotemperature of Florissant can be compared to the paleotemperature of a similar aged fossil flora at the same latitude, but at sea level. Taking into account the lapse rate or how temperature changes with altitude, a paleoelevation can be estimated. Depending upon the lapse rate and paleotemperature used elevations ranging from around 900 meters to 4133 meters can be calculated. A third method of estimating paleoelevation uses fossil plant characteristics to infer paleoenthalpy or heat content of the atmosphere. The paleoaltitude calculated for the Florissant basin using this method is 2,700 meters (Leopold & Clay-Poole, 2001, p. 50). Recent paleoelevation estimates are much higher than MacGinite’s original estimate. The paleoelevation may have been closer to present day Florissant.
Thomas Viney on Pikes Peak Granite Florissant Fossil Beds National Monument Boulder Creek Trail	Mike Viney on Pikes Peak Granite Florissant Fossil Beds National Monument Boulder Creek Trail
Bibliography
Leopold, E.B. and Clay-Poole, S.T. (2001). Fossil leaf and pollen floras of Colorado compared: climatic implications. In Evanoff, E., Gregory-Wodzicki K.M. and Johnson, K.R. [Eds.] Fossil Flora and Stratigraphy of the Florissant Formation, Colorado. (pp. 17-55). Proceedings of the Denver Museum of Nature and Science, series 4, number 1. MacGinitie, H.D. (1953). Fossil Plants of the Florissant Beds, Colorado. Washington, D.C.: Carnegie Institution of Washington Publication 599. Meyer, H.W. (2003). The Fossils of Florissant. Washington: Smithsonian Books.