Ocean-continent interactions in the mid Cretaceous Equatorial Atlantic realm
Final Report Abstract
During the mid-Cretaceous greenhouse world, high atmospheric pCO2 levels, a global increase of air and water temperatures, and smoother latitudinal temperature gradients occurred than today. As a consequence, the development of worldwide occurring Oceanic Anoxic Events (OAEs) triggered the massive and widespread deposition of organic carbon in marine sediments. The OAEs are associated with prominent carbon isotope shifts and are thus representing major perturbances in the ocean system and the global carbon cycle. While past research on the dynamics of the mid-Cretaceous world was so far almost exclusively based on marine proxy data, only limited information is yet available on environmental dynamics and atmosphere/biosphere interactions in terrestrial settings. This project anticipates deciphering paleoceanographic changes and terrestrial environmental dynamics during the formation of various paleoceanographic events. The project was designed to identify runoff variations and thus terrestrial climate change, to provide an estimate of terrestrial input into Demerara Rise and to estimate the changes in large-scale hydrology and its consequence for the accumulation of organic-rich sediments. A multiple proxy analysis of organic matter including coal petrography, bulk geochemistry, organic geochemistry (lipid biomarkers) and compound-specific stable carbon and hydrogen isotope analyses of those was carried out on samples from Demerara Rise (ODP Leg 207, sites 1258 and 1260). The samples were taken from the upper Albian to lower Turonian interval, including the Mid Cenomanian Event (MCE) and the late Cenomanian OAE 2. Terrestrial proxy records reveal a variable and sporadically significant influx of terrigenous organic matter into the marine realm of Demerara Rise, recording changing hydrologic conditions on the continent.
Publications
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(2008). Ocean-continent interactions in the mid-Cretaceous Equatorial Atlantic realm – first results from a multi-parameter study at Demerara Rise (ODP Leg 207). IAS Regional Meeting 2008, 01. – 03. September, Bochum
Beckmann, B., Birgel, D., Erbacher, J., Lückge, A.
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(2009). Investigation of D/H and 13C isotopes on long-chain n-alkanes – Implications for the upper Cretaceous paleoenvironment in the western mid-Atlantic. IMOG 2009, 6. – 11. September, Bremen
Beckmann, B., Birgel, D., Erbacher, J., Lückge, A.
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(2009). Ocean-continent interactions during mid Cretaceous Oceanic Anoxic Events in the western tropical Atlantic. IODP-ICDP Kolloquium 2009, 16. – 18. March, Potsdam
Beckmann, B., Birgel, D., Erbacher, J., Lückge, A.
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(2009). Reconstruction of paleoenvironmental variations during the Cenomanian-Turonian greenhouse – results from the western mid-Atlantic at ODP Site 1258. 98th Assembly of the Geologische Vereinigung, 5. – 7. October, Göttingen
Beckmann, B., Birgel, D., Erbacher, J., Lückge, A., Scheeder, G.
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(2009). Terrestrial input into the upper Cretaceous western tropical Atlantic as traced by biomarker and maceral analyses. EGU General Assembly 2009, 20. – 24. April, Vienna, Austria
Beckmann, B., Birgel, D., Erbacher, J., Lückge, A.
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(2010). Evaluating terrestrial input into the upper Cretaceous western tropical Atlantic by biomarker and compound specific isotope analyses. EGU General Assembly 2010, 2. – 7. May, Vienna, Austria
Beckmann, B., Birgel, D., Erbacher, J., Lückge, A., Scheeder, G., Schefuß, E.
