Thermogenic methane release as a cause for the long duration of the PETM.

Autor: Frieling J; Marine Palynology and Paleoceanography, Laboratory of Palaeobotany and Palynology, Department of Earth Sciences, Faculty of Geosciences, Utrecht University, 3584CS Utrecht, The Netherlands; j.frieling1@uu.nl., Svensen HH; Centre for Earth Evolution and Dynamics, University of Oslo, N-0315 Oslo, Norway., Planke S; Centre for Earth Evolution and Dynamics, University of Oslo, N-0315 Oslo, Norway; Volcanic Basin Petroleum Research, Oslo Innovation Centre, N-0349 Oslo, Norway., Cramwinckel MJ; Marine Palynology and Paleoceanography, Laboratory of Palaeobotany and Palynology, Department of Earth Sciences, Faculty of Geosciences, Utrecht University, 3584CS Utrecht, The Netherlands., Selnes H; Applied Petroleum Technology, N-2027 Kjeller, Norway., Sluijs A; Marine Palynology and Paleoceanography, Laboratory of Palaeobotany and Palynology, Department of Earth Sciences, Faculty of Geosciences, Utrecht University, 3584CS Utrecht, The Netherlands.
Jazyk: angličtina
Zdroj: Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2016 Oct 25; Vol. 113 (43), pp. 12059-12064. Date of Electronic Publication: 2016 Oct 10.
DOI: 10.1073/pnas.1603348113
Abstrakt: The Paleocene-Eocene Thermal Maximum (PETM) (∼56 Ma) was a ∼170,000-y (∼170-kyr) period of global warming associated with rapid and massive injections of 13 C-depleted carbon into the ocean-atmosphere system, reflected in sedimentary components as a negative carbon isotope excursion (CIE). Carbon cycle modeling has indicated that the shape and magnitude of this CIE are generally explained by a large and rapid initial pulse, followed by ∼50 kyr of 13 C-depleted carbon injection. Suggested sources include submarine methane hydrates, terrigenous organic matter, and thermogenic methane and CO 2 from hydrothermal vent complexes. Here, we test for the contribution of carbon release associated with volcanic intrusions in the North Atlantic Igneous Province. We use dinoflagellate cyst and stable carbon isotope stratigraphy to date the active phase of a hydrothermal vent system and find it to postdate massive carbon release at the onset of the PETM. Crucially, however, it correlates to the period within the PETM of longer-term 13 C-depleted carbon release. This finding represents actual proof of PETM carbon release from a particular reservoir. Based on carbon cycle box model [i.e., Long-Term Ocean-Atmosphere-Sediment Carbon Cycle Reservoir (LOSCAR) model] experiments, we show that 4-12 pulses of carbon input from vent systems over 60 kyr with a total mass of 1,500 Pg of C, consistent with the vent literature, match the shape of the CIE and pattern of deep ocean carbonate dissolution as recorded in sediment records. We therefore conclude that CH 4 from the Norwegian Sea vent complexes was likely the main source of carbon during the PETM, following its dramatic onset.
Competing Interests: The authors declare no conflict of interest.
Databáze: MEDLINE
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