Mud volcano gas hydrates in the Gulf of Cadiz |
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| Authors: | L L Mazurenko V A Soloviev I Belenkaya M K Ivanov L M Pinheiro |
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| Institution: | All-Russia Research Institute for Geology and Mineral Resources of the Ocean, St. Petersburg,;UNESCO Centre on Marine Geology and Geophysics, Moscow State University, Geology Faculty, Vorobjovy Gory, 119899, Russia;;Departamento de Geologia Marinha, Instituto Geológico e Mineiro, Estrada da Portela, Apartado 7586, 2720 Alfragide,;Departamento de Geociências, Universidade de Aveiro, 3800 Aveiro, Portugal |
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| Abstract: | ABSTRACT This paper presents new geochemical data on gas-hydrate-bearing mud volcanoes discovered for the first time in the Gulf of Cadiz during cruises TTR9 and TTR10 of the R/V Professor Logachev in 1999–2000. The estimated gas hydrate content is 3–16% of sediment volume and 5–31% of pore space volume. Estimated values of the water isotopic composition for the Ginsburg mud volcano are very heavy for δ18O (up to +53‰) and light for δD (up to ? 210‰). Gas released from the hydrates contains 81% of C1 and 19% of C2+. The inferred source of the gas in the hydrates is enriched in C2–C6 (≤ 5%), indicating that the gas has a thermogenic origin. Gas hydrate of cubic structure II should be formed from a gas of such composition. It is interpreted that the composition of the mud volcano fluid corresponds to deep oil basins below the Gulf of Cadiz. |
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