We present trace metal geochemistry and stable isotope records for the middle Eocene Alano di Piave section, NE Italy, deposited during magnetochron C18n in the marginal Tethys Ocean. We identify a ∼500 kyr long carbon isotope perturbation event we infer to be the middle Eocene climatic optimum (MECO) confirming the Northern Hemisphere expression and global occurrence of MECO. Interpreted peak climatic conditions are followed by the rapid deposition of two organic rich intervals (≤3% TOC) and contemporaneous positive d13C excursions. These two intervals are associated with increases in the concentration of sulphur and redox- sensitive trace metals and low concentrations of Mn, as well as coupled with the occurrence of pyrite. Together these changes imply low, possibly dysoxic, bottom water O2 conditions promoting increased organic carbon burial. We hypothesize that this rapid burial of organic carbon lowered global pCO2 following the peak warming and returned the climate system to the general Eocene cooling trend.

Organic Carbon Burial following the Middle Eocene Climatic Optimum (MECO) in the central - western Tethys Paleoceanography

LANCI, LUCA;
2010-01-01

Abstract

We present trace metal geochemistry and stable isotope records for the middle Eocene Alano di Piave section, NE Italy, deposited during magnetochron C18n in the marginal Tethys Ocean. We identify a ∼500 kyr long carbon isotope perturbation event we infer to be the middle Eocene climatic optimum (MECO) confirming the Northern Hemisphere expression and global occurrence of MECO. Interpreted peak climatic conditions are followed by the rapid deposition of two organic rich intervals (≤3% TOC) and contemporaneous positive d13C excursions. These two intervals are associated with increases in the concentration of sulphur and redox- sensitive trace metals and low concentrations of Mn, as well as coupled with the occurrence of pyrite. Together these changes imply low, possibly dysoxic, bottom water O2 conditions promoting increased organic carbon burial. We hypothesize that this rapid burial of organic carbon lowered global pCO2 following the peak warming and returned the climate system to the general Eocene cooling trend.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11576/2502684
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