Beyond the PETM:
Are hyperthermals common features of a high CO2 world?
Sandra Kirtland
Ph.D. Candidate
Scripps Institution of Oceanography
University of California, San Diego
Wednesday, April 6th, 2011
--------------------------------------------------------------------------------
Abstract: The early Eocene was a time of extreme global warmth, high atmospheric greenhouse gas concentrations, and no permanent polar ice caps. During this epoch, Earth reached the highest temperatures of the Cenozoic, with the global deep sea around 10-15 deg C warmer than today. Abrupt warming events, commonly referred to as hyperthermals, punctuated the already warm background climate. The discovery of the Paleocene-Eocene Thermal Maximum (PETM) raised the possibility of finding analogs to modern global warming in the geologic past. More recently, deep-sea records from the Paleogene indicate that other hyperthermal events, though tyically smaller in magnitude and duration than the PETM, are fairly common. The dominant identifying feature of all hyperthermal events is a pronounced negative excursion in the carbon isotopic composition of both organic and inorganic sources. These excursions indicate the massive release of isotopically light carbon into the atmosphere and oceans over a geologically short interval of time.
In this seminar, I will discuss new high resolution records for the early-middle Eocene demonstrating that hyperthermal events occur regularly and may be orbitally paced. The development of high-resolution, multi-proxy records of these events is helping to refine proposed mechanisms of carbon release responsible for generating these events through model-data comparison, and is providing a more complete picture of the environmental changes associated with these extreme climatic transitions.
Biography: Sandra Kirtland is a 5th year doctoral candidate at Scripps Institution of Oceanography and a National Science Foundation Graduate Research Fellow. She completed her undergraduate at Georgetown University in Washington, DC in 2006. Sandra's research interests include paleoceanography and paleoclimatology of warm climates and carbon cycle modeling.
« Hide
