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Detection of gas-charged sediments and gas hydrate horizons along the western continental margin of India

DRS at CSIR-National Institute of Oceanography

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Title Detection of gas-charged sediments and gas hydrate horizons along the western continental margin of India
 
Creator Veerayya, M.
Karisiddaiah, S.M.
Vora, K.H.
Wagle, B.G.
Almeida, F.
 
Subject seismic reflection
continental margin
acoustic maskings
sediments
bottom simulating reflectors
gas hydrates
blanking zones
gas-charged sediments
 
Description High-resolution seismic reflection and sub-bottom profiling on the continental margin off western India has revealed the presence of characteristic acoustic maskings in the form of wipe-outs, reflector terminations and seep-associated features in the inner shelf. These maskings suggest the presence of gas-charged sediments. Further seaward on the outer shelf-middle slope, pockmarks and prominent plumes in the overlying water column indicate a significant seepage of gas from the slope sediments, and it is the seepage which may demonstrate the existence of source rocks. Seismic profiles also revealed the presence of bottom simulating reflectors (BSRs) in the mid-lower slope-rise regions, presumably suggesting the presence of gas hydrates. The BSRs occur at roughly 300-600 ms (TWTT) beneath the sea floor at water depths between 525 and 2200 m; they occasionally show discontinuities. Distinct blanking zones as well as acoustic voids have also been observed above the BSR. In contrast, chaotic and/or scattered hyperbolic reflctors occur in places below the BSR, which may suggest the presence of gas-charged sediments. Folds, diapiric features and faults present in the slope-rise areas may probably werve as traps and conduits for upward migration of fluids and methane gas from the deep
 
Date 2008-02-22T05:31:29Z
2008-02-22T05:31:29Z
1998
 
Type Book Chapter
 
Identifier In "Gas hydrates: Relevance to world margin stability and climate change. eds. by: Henriet, J.-P.; Mienert", 239-253p.
http://drs.nio.org/drs/handle/2264/975
 
Language en
 
Rights Copyright [1998]. It is tried to respect the rights of the copyright holders to the best of the knowledge. If it is brought to our notice by copyright holder that the rights are voilated then the item would be withdrawn.
 
Publisher Geological Society