Florissant's Ancient Climate?
I think the mean annual temperature was
That is the correct answer for this sample. While different methods have produced higher or lower estimates, most estimates are on the order of 12-13 °C.
Earth's Dynamic Climate
The Early and Middle Eocene were much warmer than today. By the time the Florissant Formation was deposited, the Earth's climate had cooled gradually. Ancient Lake Florissant existed in a warm-temperate climate. Some scientists also believe that the elevation was high, and this would also have affected MAT.
Shortly after the deposition of the Florissant Formation, the Earth's climate cooled rapidly at the Eocene-Oligocene boundary, impacting ecosystems worldwide. This cooling trend continued through the Oligocene and into the present (Fig. 1).
Last updated: February 24, 2015