Rifting under steam – how rift magmatism triggers methane venting from sedimentary basins.

Berndt, Christian , Hensen, Christian, Mortera-Gutierrez, C., Sarkar, Sudipta , Geilert, Sonja , Schmidt, Mark , Liebetrau, Volker, Kipfer, R., Scholz, Florian, Doll, M., Muff, Sina, Karstens, Jens , Planke, S., Petersen, Sven , Böttner, Christoph , Chi, W.-C., Moser, Manuel, Behrendt, Ruth, Fiskal, A., Lever, M. A., Su, C.-C., Deng, L., Brennwald, M. S. and Lizarralde, D. (2016) Rifting under steam – how rift magmatism triggers methane venting from sedimentary basins. Open Access Geology, 44 (9). pp. 767-770. DOI 10.1130/G38049.1 .

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Abstract

During opening of a new ocean magma intrudes into the surrounding sedimentary basins. Heat provided by the intrusions matures the host rock creating metamorphic aureoles potentially releasing large amounts of hydrocarbons. These hydrocarbons may migrate to the seafloor in hydrothermal vent complexes in sufficient volumes to trigger global warming, e.g. during the Paleocene Eocene Thermal Maximum (PETM). Mound structures at the top of buried hydrothermal vent complexes observed in seismic data off Norway were previously interpreted as mud volcanoes and the amount of released hydrocarbon was estimated based on this interpretation. Here, we present new geophysical and geochemical data from the Gulf of California suggesting that such mound structures could in fact be edifices constructed by the growth of black-smoker type chimneys rather than mud volcanoes. We have evidence for two buried and one active hydrothermal vent system outside the rift axis. The vent releases several hundred degrees Celsius hot fluids containing abundant methane, mid-ocean-ridge-basalt (MORB)-type helium, and precipitating solids up to 300 m high into the water column. Our observations challenge the idea that methane is emitted slowly from rift-related vents. The association of large amounts of methane with hydrothermal fluids that enter the water column at high pressure and temperature provides an efficient mechanism to transport hydrocarbons into the water column and atmosphere, lending support to the hypothesis that rapid climate change such as during the PETM can be triggered by magmatic intrusions into organic-rich sedimentary basins.

Document Type: Article
Additional Information: WOS:000382522700020
Keywords: Black Smoker, Guaymas Basin, PETM, sill intrusions, carbon release, RV Sonne, SO241
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS > Marine Mineralische Rohstoffe
OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
OceanRep > The Future Ocean - Cluster of Excellence > FO-R09
OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Kiel University
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1130/G38049.1
ISSN: 0091-7613
Projects: MAKS, Future Ocean, FLOWS
Expeditions/Models/Experiments:
Date Deposited: 12 Jul 2016 09:07
Last Modified: 23 Sep 2019 18:06
URI: http://oceanrep.geomar.de/id/eprint/33333

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