Long-term (105) or short-term (103) δ13C excursion near the Palaeocene-Eocene transition: evidence from the Tethys |
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| Authors: | Gangyi Lu Gerta Keller Thierry Adatte Nieves Ortiz Eustoquio Molina |
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| Institution: | Department of Geological &Geophysical Sciences, Princeton University, Princeton, NJ 08544, USA;1nstitut de Géologie, 11 rue Emile Argand, 2007 Neuchdel, Switzerland;Departamento de Geología (Palaeontología, Universidad de Zaragoza, E-50009 Zaragoza, Spain |
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| Abstract: | Expanded sedimentary records from the Tethys reveal unique faunal and isotopic changes across the Palaeocene-Eocene (P-E) transition. Unlike in the open oceans, the Tethys exhibits a gradual decrease of 1.5% in δ13C values prior to the rapid δ13C excursion. Associated with the 613C excursion is a decrease in calcite burial, increase in detrital content and appearance of a unique opportunistic planktic foraminifera1 assemblage (e.g. compressed acarininids). The existence of a prelude decrease in δ13C values in the Tethys suggests that the P-E δ13C excursion may have occurred in two steps and over a few hundred thousand years, rather than as one step over a few thousand years as previously suggested. This slower excursion rate is readily explained by changing organic carbon weathering or burial rates and avoids the need of invoking ad hoc scenarios. |
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