Ancient Climate (Unit 5) - Quiz - Answer C

Florissant's Ancient Climate?

I think the mean annual temperature was

  1. 7-9 °C
  2. 10-11 °C
  3. 12-13 °C
  4. 14-16 °C
  5. 16+ °C

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).

Mean annual temperatures derived from leaf-margin analysis
Figure 1. Figure of inferred mean annual temperatures derived from leaf-margin analysis of four North American locations near sea level (Florissant is not on this graph). Dotted lines mean data is lacking or not considered reliable. Based on Wolfe (1978).

Last updated: February 24, 2015

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