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Evidence of slumping/sliding in Krishna-Godavari offshore basin due to gas/fluid movements

DRS at CSIR-National Institute of Oceanography

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Title Evidence of slumping/sliding in Krishna-Godavari offshore basin due to gas/fluid movements
 
Creator Ramprasad, T.
Dewangan, P.
Ramana, M.V.
Mazumdar, A.
Karisiddaiah, S.M.
Ramya, E.R.
Sriram, G.
 
Subject gas hydrates
lithology
stratigraphy
petroliferous basins
 
Description The Krishna-Godavari (KG) offshore basin is one of the promising petroliferous basins of the eastern continental margin of India. Drilling in this basin proved the presence of gas hydrate deposits in the shallow marine sediments beyond 750 m water depths, and provided lithologic and stratigraphic information. We obtained multibeam swath bathymetry covering an area of about 4500 sq. km in water depths of 280-1800 m and about 1260 line km of high resolution seismic (HRS) records. The general lithology of mid-slope deposits is comprised of nannofossil-rich clay, nannofossil-bearing clay and foraminifera bearing clay. The HRS records and bathymetry reveal evidence of slumping and sliding of the upper and mid-slope sediments, which result in mass transport deposits (MTD) in the northwestern part of the study area. These deposits exhibit 3-9.5 km widths and extend 10-13 km offshore. The boundaries of the MTDs are often demarcated by sharp truncation of finely layered sediments (FLS) and the MTDs are characterized by acoustically transparent zones in the HRS data. Average thickness of recent MTDs varies with depth, i.e., in the upper slope, the thickness is about 45 m, while in the lower slope it is about 60 m, and in deeper offshore locations they attain a maximum thickness of about 90 m. A direct indication for slumping and mass transportation of deposits is provided by the age reversal in sup(14)C AMS dates observed in a sediment core located in the mid-slope region. Seismic profiling signatures provide indications of fluid/gas movement. We propose that the presence of steep topographic gradients, high sedimentation rates, a regional fault system, diapirism, fluid/gas movement, and neotectonic activity may have facilitated the slumping/sliding of the upper slope sediments in the KG offshore basin.
 
Date 2011-11-09T12:10:42Z
2011-11-09T12:10:42Z
2011
 
Type Journal Article
 
Identifier Marine and Petroleum Geology, vol.28; 2011; 1806-1816
no
http://drs.nio.org/drs/handle/2264/3947
 
Language en
 
Relation Mar_Pet_Geol_28_1806.jpg
 
Rights An edited version of this paper was published by Elsevier. Copyright [2011] Elsevier
 
Publisher Elsevier