Buried channels provide keys to infer Quaternary stratigraphic and paleo-environmental changes: A case study from the west coast of India
High resolution shallow seismic data was acquired from inner continental shelf of Goa, west coast of India to map underlying stratigraphic and buried geomorphic features of shelf strata. Seismic data revealed characteristic channel incisions beneath 4–15 m thick sediment layer and corresponds to mul...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2019-07-01
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| Series: | Geoscience Frontiers |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674987118302330 |
| _version_ | 1797713168371286016 |
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| author | K.M. Dubey A.K. Chaubey V.P. Mahale S.M. Karisiddaiah |
| author_facet | K.M. Dubey A.K. Chaubey V.P. Mahale S.M. Karisiddaiah |
| author_sort | K.M. Dubey |
| collection | DOAJ |
| description | High resolution shallow seismic data was acquired from inner continental shelf of Goa, west coast of India to map underlying stratigraphic and buried geomorphic features of shelf strata. Seismic data revealed characteristic channel incisions beneath 4–15 m thick sediment layer and corresponds to multi cycle incisions. Stratigraphic analysis of these incision signatures reveals three prominent subaerial unconformities S6, S7 and S9. These unconformities were exposed during the last glacial, penultimate glacial (MIS-6) and prior to penultimate glacial (MIS-8) periods. On the basis of interpreted age of subaerial unconformities and differences in their morphological features, observed channel incisions have been divided grossly into three phases of incision. Phase-1 incisions are older than ∼330 kyr BP, whereas, incisions of Phase-2 and Phase-3 correspond to ∼320–125 kyr BP and ∼115–10 kyr BP respectively. Plan form of these incisions varied from a straight channel type to ingrown meander and then to anastomosing channel types. These channels meet at the confluence of present-day Mandovi and Zuari rivers. The confluence point has varied in due course of time because of cyclic incision and burial with repeated sea level fluctuations. The preserved main channel width varies from ∼100 m to 1000 m, and maximum channel depth reaches up to ∼35 m. Comparison of quantitative and qualitative morphologic results of different phases of incisions suggest that Phase-2 channels had ∼33% more mean bank full discharge than that of the Phase-3 channels. Phase-2 incisions had been carved in higher hydraulic energy condition as compared to Phase-3 incisions implying that the Indian summer monsoon was better during formative stages of Phase-2 incisions. Keywords: Buried channels, Glacial period, Indian summer monsoon, Quaternary sea-level, Subaerial unconformity, West coast of India |
| first_indexed | 2024-03-12T07:32:11Z |
| format | Article |
| id | doaj.art-bb17f3e291c648118a31d6c402b5ad78 |
| institution | Directory Open Access Journal |
| issn | 1674-9871 |
| language | English |
| last_indexed | 2024-03-12T07:32:11Z |
| publishDate | 2019-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Geoscience Frontiers |
| spelling | doaj.art-bb17f3e291c648118a31d6c402b5ad782023-09-02T21:44:44ZengElsevierGeoscience Frontiers1674-98712019-07-0110415771595Buried channels provide keys to infer Quaternary stratigraphic and paleo-environmental changes: A case study from the west coast of IndiaK.M. Dubey0A.K. Chaubey1V.P. Mahale2S.M. Karisiddaiah3CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, India; Department of Marine Sciences, Goa University, Taleigao Plateau, Goa, 403206, IndiaCSIR-National Institute of Oceanography, Regional Centre, Lokhandwala Road, Andheri (West), Mumbai, Maharashtra, 400053, India; Corresponding author.CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, IndiaCSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, IndiaHigh resolution shallow seismic data was acquired from inner continental shelf of Goa, west coast of India to map underlying stratigraphic and buried geomorphic features of shelf strata. Seismic data revealed characteristic channel incisions beneath 4–15 m thick sediment layer and corresponds to multi cycle incisions. Stratigraphic analysis of these incision signatures reveals three prominent subaerial unconformities S6, S7 and S9. These unconformities were exposed during the last glacial, penultimate glacial (MIS-6) and prior to penultimate glacial (MIS-8) periods. On the basis of interpreted age of subaerial unconformities and differences in their morphological features, observed channel incisions have been divided grossly into three phases of incision. Phase-1 incisions are older than ∼330 kyr BP, whereas, incisions of Phase-2 and Phase-3 correspond to ∼320–125 kyr BP and ∼115–10 kyr BP respectively. Plan form of these incisions varied from a straight channel type to ingrown meander and then to anastomosing channel types. These channels meet at the confluence of present-day Mandovi and Zuari rivers. The confluence point has varied in due course of time because of cyclic incision and burial with repeated sea level fluctuations. The preserved main channel width varies from ∼100 m to 1000 m, and maximum channel depth reaches up to ∼35 m. Comparison of quantitative and qualitative morphologic results of different phases of incisions suggest that Phase-2 channels had ∼33% more mean bank full discharge than that of the Phase-3 channels. Phase-2 incisions had been carved in higher hydraulic energy condition as compared to Phase-3 incisions implying that the Indian summer monsoon was better during formative stages of Phase-2 incisions. Keywords: Buried channels, Glacial period, Indian summer monsoon, Quaternary sea-level, Subaerial unconformity, West coast of Indiahttp://www.sciencedirect.com/science/article/pii/S1674987118302330 |
| spellingShingle | K.M. Dubey A.K. Chaubey V.P. Mahale S.M. Karisiddaiah Buried channels provide keys to infer Quaternary stratigraphic and paleo-environmental changes: A case study from the west coast of India Geoscience Frontiers |
| title | Buried channels provide keys to infer Quaternary stratigraphic and paleo-environmental changes: A case study from the west coast of India |
| title_full | Buried channels provide keys to infer Quaternary stratigraphic and paleo-environmental changes: A case study from the west coast of India |
| title_fullStr | Buried channels provide keys to infer Quaternary stratigraphic and paleo-environmental changes: A case study from the west coast of India |
| title_full_unstemmed | Buried channels provide keys to infer Quaternary stratigraphic and paleo-environmental changes: A case study from the west coast of India |
| title_short | Buried channels provide keys to infer Quaternary stratigraphic and paleo-environmental changes: A case study from the west coast of India |
| title_sort | buried channels provide keys to infer quaternary stratigraphic and paleo environmental changes a case study from the west coast of india |
| url | http://www.sciencedirect.com/science/article/pii/S1674987118302330 |
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