Multidisciplinary investigations exploring indicators of gas hydrate occurrence in the Krishna–Godavari Basin offshore, east coast of India

We report some main results of multidisciplinary investigations carried out within the framework of the Indian National Gas Hydrate Program in 2002–2003 in the Krishna–Godavari Basin offshore sector, east coast of India, to explore indicators of likely gas hydrate occurrence suggested by preliminary...

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Bibliographic Details
Published in:Geo-marine letters 2009-02, Vol.29 (1), p.25-38
Main Authors: Ramana, M. V., Ramprasad, T., Paropkari, A. L., Borole, D. V., Ramalingeswara Rao, B., Karisiddaiah, S. M., Desa, M., Kocherla, M., Joao, H. M., Lokabharati, P., Gonsalves, Maria-Judith, Pattan, J. N., Khadge, N. H., Prakash Babu, C., Sathe, A. V., Kumar, P., Sethi, A. K.
Format: Article
Language:English
Subjects:
Bathymetry
Carbonates
Cores
Earth and Environmental Science
Earth Sciences
Geology
Geophysics
Marine
Methane
Natural gas exploration
Oceanography
Organic carbon
Original
Pore water
Sediments
Seismology
Sonar
Sulfate reduction
Sulfates
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Summary:We report some main results of multidisciplinary investigations carried out within the framework of the Indian National Gas Hydrate Program in 2002–2003 in the Krishna–Godavari Basin offshore sector, east coast of India, to explore indicators of likely gas hydrate occurrence suggested by preliminary multi-channel seismic reflection data and estimates of gas hydrate stability zone thickness. Swath bathymetry data reveal new evidence of three distinct geomorphic units representing (1) a delta front incised by several narrow valleys and mass flows, (2) a deep fan in the east and (3) a WNW–ESE-trending sedimentary ridge in the south. Deep-tow digital side-scan sonar, multi-frequency chirp sonar, and sub-bottom profiler records indicate several surface and subsurface gas-escape features with a highly resolved stratification within the upper 50 m sedimentary strata. Multi-channel seismic reflection data show the presence of bottom simulating reflections of continuous to discrete character. Textural analyses of 76 gravity cores indicate that the sediments are mostly silty clay. Geochemical analyses reveal decreasing downcore pore water sulphate (SO 4 2− ) concentrations (28.7 to
ISSN:0276-0460
1432-1157
DOI:10.1007/s00367-008-0121-7