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Seismic and sequence stratigraphy of the central western continental margin of India: late-Quaternary evolution

DRS at CSIR-National Institute of Oceanography

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Title Seismic and sequence stratigraphy of the central western continental margin of India: late-Quaternary evolution
 
Creator Karisiddaiah, S.M.
Veerayya, M.
Vora, K.H.
 
Subject continental margins
sea level changes
seismic data
stratigraphy
quaternary
sedimentary environments
 
Description Seismic and sequence stratigraphic architecture of the central western continental margin of India (between Coondapur and south of Mangalore) has been investigated with shallow seismic data. Seismic stratigraphic analysis defined nine seismic units, that are configured in a major type-1 depositional sequence possibly related to fourth-order eustatic sea-level changes, comprising regressive, lowstand, transgressive and highstand systems tracts. The late-Quaternary evolution of the continental margin took place under the influence of an asymmetric relative fourth-order sea-level cycle punctuated by higher frequency cycles. These cycles of minor order were characterized by rapid sea-level rises and gradual sea-level falls that generated depositional sequences spanning different time scales. During the regressive periods, dipping strata were developed, while erosional surfaces and incised valleys were formed during the lowstands of sea level. Terraces, v-shaped depressions, lagoon-like structures observed on the outer continental shelf are the result of the transgressive period. In the study area we have recognized a complex erosional surface that records a long time span during the relative sea-level fall (regressive period) and the following sea-level lowstand and has been reworked during the last transgression. We also infer that sedimentation processes changed from siliciclastic sedimentation to carbonate sedimentation and again to siliciclastic sedimentation, marking an important phase in the late-Quaternary evolution of the western continental shelf of India. An abrupt climate change at the end of the oxygen isotope stage 2 is attributed between the Last Glacial Maximum and the Boelling-Allerod event (14000 yr BP). This sensitive climate change (warming) favoured the formation of reefs at various depths on the shelf, besides the development of Fifty Fathom Flat, a carbonate platform on the outer shelf off Bombay developed prior to 8300 yr BP. The highstand systems tracts were deposited after the sea level reached its present position.
 
Date 2008-08-05T11:40:20Z
2008-08-05T11:40:20Z
2002
 
Type Journal Article
 
Identifier Marine Geology, Vol. 192(4); 335-353p.
http://drs.nio.org/drs/handle/2264/1369
 
Language en
 
Rights Elsevier
 
Publisher Elsevier