Possible hydrate mounds within large seafloor craters in the Barents Sea.

Long, D., Lammers, Stephan and Linke, Peter (1998) Possible hydrate mounds within large seafloor craters in the Barents Sea. In: Gas Hydrates: Relevance to World Margin Stability and Climate Change. , ed. by Henriet, J.-P. and Mienert, J.. Geological Society Special Publications, 137 . Geological Society, London, pp. 223-237. DOI 10.1144/GSL.SP.1998.137.01.18.

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Abstract

Interpretation of several surveys across a ‘crater field’ in the Barents Sea provide further evidence that the craters (large depressions, 300–500 m diameter, 10–30 m deep) are related to gas escape after deglaciation some 15 000 years BP. The disposition of the craters suggests that the flow of gas was controlled by fractures within the Triassic siltstone bedrock. Topographic highs within several craters, comprising angular blocks of rock locally rising above the level of surrounding crater walls, are interpreted as hydrate mounds indicating that gas flow continued after the formation of the craters. This may be the first reported occurrence of hydrate mounds in lithified sediments. Assuming the gas was methane and seabed temperature was similar to that at present then the hydrate mounds were formed at a time when the sea-bed was between 280 and 340 metres below sea level (mbsl)(i.e. 10–80 m lower than at present). Geochemical studies provide evidence that gas hydrates in the sub-bottom adjacent to the crater field are presently decomposing in accordance with seasonal temperature variations.

Document Type: Book chapter
Keywords: Barents Sea, crater field, hydrate mounds, methane hydrate stability
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
Open Access Journal?: No
DOI etc.: 10.1144/GSL.SP.1998.137.01.18
Projects: SEEPS
Expeditions/Models/Experiments:
Date Deposited: 04 Jul 2008 18:35
Last Modified: 22 Aug 2019 12:47
URI: http://oceanrep.geomar.de/id/eprint/2957

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