Editing Florissant Formation (section)

==Paleoclimate==
Fossil plants, and in particular their leaves, have been the most useful sources of information of paleoclimate during the time of deposition of the Florissant Formation. Plants have a smaller tolerance on average to climatic changes, whereas many animals can be mobile and respond to rapid seasonal or daily changes.<ref>Larsen, D. (2000) Upper Eocene and Oligocene Lacustrine Deposits of the Southwestern United States, with Emphasis on the Creede and Florissant Formations. AAPG Studies in Geology, v. 46, p. 425-438</ref>

Comparing fossil plants and leaves to modern analogs enables inferences about the climate to be made based on physiological and morphological similarities. One of the best ways to do this is by studying the characteristics of the leaves that have been found. By looking at the physiognomy, or analysis of gross appearance based on climatic factors, the mean average temperature (or MAT) has been estimated to be around 13&nbsp;°C, much warmer than the modern MAT at Florissant of 4&nbsp;°C. There have also been estimates that the MAT was between 16 and 18&nbsp;°C, based on comparisons to the closest living relatives of the plants. There are also indications that the seasonal changes in the area were not as great as what is seen in modern times. Estimates of MAT, based on pollen, have put the temperature as high as 17.5&nbsp;°C, but pollen is arguably less diagnostic than leaves. .<ref name = "Gregory, 1992" />

Based on the small size and the features of the teeth, the precipitation during the late Eocene to early Oligocene has been estimated to be around 50-80 centimeters per year, with a distinct dry season. This is much wetter than the average 38&nbsp;cm that falls in the area during modern times. Most of the precipitation would have come in the late spring to early summer, with the rare snowfall in the winter.<ref name="book"/>

Tree-ring analysis indicates that the environment that the redwoods grew in during the time of sediment deposition would have been even more favorable than the current climate that the redwoods in California grow in. The average ring width, one year of growth, is larger than the width of redwoods in central California.<ref name="book"/>
Towards the end of the Eocene, the global temperature began to decrease. However, this episode of global cooling is not indicated in the fossil record at Florissant.<ref name = "Gregory, 1992" />

===Paleohabitats===
The fossilized algae and aquatic angiosperms indicate that the lake was freshwater and shallow. Near the streams and shore, moisture was plentiful, allowing lush vegetation to grow. However, further up the hillsides was more dry-adapted vegetation. At the base of the valley, trees (such as sequoias) dominated the landscape. The understory of this forest would have been composed of smaller trees and shrubs. There would have been a gradual transition between the different habitats from the base of the valley up the hillsides, with some overlap between the two.<ref name="book"/>

Insects from the area indicate different habitats as well. There are exclusively aquatic insects, such as dragonflies, that would have lived their entire lives on or near the lake. Meanwhile, the bees and butterflies would have preferred more open spaces in the surrounding hillsides and meadows.<ref name = "Thoene, 2012"/>

===Paleoaltitude===
Early estimates of the elevation of the Florissant beds was determined to be between 300 and 900 meters, much lower than the modern elevation of 2,500-2,600 meters. However, more recent estimates that are based on paleoflora have put the elevation in the Eocene much higher. Ranges from 1,900 to 4,100 meters have been proposed. This would indicate that global climate change, rather than tectonic uplift, would be the main cause of changing environments in the area.<ref name="book"/>
The actual elevation of the Florissant area during the Eocene is still being determined. While most of the analysis using paleoflora has the area at a higher elevation than modern times, there is evidence that the elevation was as low as the earlier estimates.<ref>Meyer, H. W. (2007). A Review of Paleotemperature-Lapse rate Methods for Estimating Paleoelevation from Fossil Floras. Reviews in Mineralogy and Geochemistry, v. 66, p. 155-177</ref>