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Morphology of pockmarks along the western continental margin of India: Employing multibeam bathymetry and backscatter data

DRS at CSIR-National Institute of Oceanography

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Title Morphology of pockmarks along the western continental margin of India: Employing multibeam bathymetry and backscatter data
 
Creator Dandapath, S.
Chakraborty, B.
Karisiddaiah, S.M.
Menezes, A.A.A.
Ranade, G.
Fernandes, W.A.
Naik, D.K.
PrudhviRaju, K.N.
 
Subject pock marks
continental margins
backscatter
seepages
 
Description This study addresses the morphology of pockmarks along the western continental margin of India using multibeam bathymetry and backscatter data. Here, for the first time we have utilized the application of ArcGIS (Geographical Information System) for understanding the morphology of pockmarks from the western continental margin of India. The pockmarks observed in water depths of 145-330 m are circular, elliptical or elongated in plan-view, with an average length and width of 157 (+ or - 72) m and 83 (+ or - 19) m respectively. The average pockmark relief and perimeter are 1.9 (+ or – 0.9) m and 412 (+ or - 181) m, respectively. The pockmarks have average areas and volumes of 10 759 m sup(2) and 15 315 m sup(3) respectively. Spatial separation that coincides with 210 m isobath divides the pockmarks into two groups with differing distributions and morphologies. These pockmarks originated from seepages of biogenic or thermogenic gas or from pore fluids from deeper sources, migrated vertically along the faults. Besides a possible structural control, the pockmark morphologies are also affected by bottom currents and/or by submarine slumping. The average acoustic backscatter strength from pockmark centre is higher (+ or -35 dB) than the average backscatter of the total area (- 40 dB), which suggests their possible linkage to the precipitation of diagenitic minerals from biodegradation of seepage material.
 
Date 2010-11-29T07:39:59Z
2010-11-29T07:39:59Z
2010
 
Type Journal Article
 
Identifier Marine and Petroleum Geology, vol.27(10); 2107-2117
no
http://drs.nio.org/drs/handle/2264/3746
 
Language en
 
Relation Mar_Pet_Geol_27_2107.jpg
 
Rights An edited version of this paper was published by Elsevier. Copyright [2010] Elsevier
 
Publisher Elsevier