Abstract
From a transact along 15‡N latitude in the middle Bengal Fan, temporal and spatial variations in the granulometric parameters and clay minerals in14C dated box cores from the eastern, the central and the western regions were studied to determine climate induced changes in the hydrography. Clay assemblages have spatial and temporal changes and are markedly different in the eastern and the western bay. From a high abundance of the clay smectite, which has its major source in the Deccan Basalt in peninsular India, it is inferred that the western bay is predominantly a depocenter of ‘peninsular sources”. The eastern and the central regions of the bay, however, mostly receive sediments of the ‘Himalayan source’. Related to unstable climate, the reported dominant illite-chlorite (I + C) assemblage in the eastern region of the bay (I + C > 60% smectite <15%), between 18 and 12.6 ka BP, points to a predominant supply from the Himalayan sources through equatorwards dispersal by the winter hydrography. Higher smectite, and reduced clays of the Himalayan sources (smectite > 25%; I + C > 45%) are reported also after 12.5 ka BP from the eastern bay. These are interpreted as evidences of an intensified SW monsoon and associated change in the dispersal pattern by stronger summer monsoon hydrography which supports across bay dispersal by anticyclonic gyre. The influence of climate on hydrographic changes is consistent during the short events of arid climate (weak NE monsoon) in Holocene in core 31/1 (western bay), in which the enhanced contents of the clays of the Himalayan sources are observed (smectite < 40% I + C > 50%). These findings have implications for climate regulated influence of fluvial processes over the areas, hitherto, considered unaffected by the Indian peninsular fluvial sources
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References
Agnihotri R, Dutta K, Bhushan R and Somayajulu BLK 2002 Evidence for solar forcing on Indian monsoon during the last millennium;Earth Planet. Sci. Lett. 198 521–527.
Biscaye P E 1965 Mineralogy and sedimentation of recent deep-sea clays in the Atlantic Ocean and adjacent seas and oceans;Bull. Geol. Soc. America 76 803–832.
Chauhan O S 2003 Past 20,000-year history of Himalayan aridity: Evidenced from oxygen isotope records in the Bay of Bengal;Curr. Sci. 84 90–93.
Chauhan O S, Borole D V, Gujar A R, Antonio M, Mislanker P G and Rao Ch M 1993 Evidences of climatic variations during Late Pleistocene-Holocene in the eastern Bay of Bengal;Curr. Sci. 65(7) 558–562.
Chauhan O S, Patil S K and Suneethi J 2004 Fluvial influx and weathering history of the Himalayas since Last Glacial Maxima; isotopic, sedimentological and magnetic records from the Bay of Bengal;Curr. Sci. 87(4) 509–515.
Chauhan O S, Rajawat A S, Pradhan Y, Suneethi J and Nayak S R 2005 Weekly observations on dispersal and sink pathways of the terrigenous flux of the Ganga-Brahmaputra in the Bay of Bengal during NE monsoon;Deep-Sea Res;Part II,52 2018–2030.
Chauhan O S, Suneethi J and Sukhija B S 2001 Sedimentary environments in the middle Bengal Fan during Late Quaternary;Spec. Publ. GSI 65(III) 279–282.
Chauhan O S and Suneethi J 2001 18 ka BP records of climatic changes, Bay of Bengal: Isotopic and sedimentological evidences;Curr. Sci. 81 1231–1234.
Emmel F J and Curray J R 1984 The Bengal submarine Fan, Northeastern Indian Ocean;Geo-Mar. Lett. 3 119–124.
Folk R L 1966 A review of grain size parameters;Sedimentology 6 73–98.
Ittekkot V, Nair R R, Honjo S, Ramaswamy V, Bartsch M, Mangani S and Desai B N 1991 Enhanced particle flux in Bay of Bengal induced by injection of fresh water;Nature 351 385–387.
Kolla V and Rao N M 1991 Sedimentary sources in surface and near surface sediments of the Bay of Bengal;Geo-Mar. Lett. 10 125–136.
Konta J 1985 In: Mineralogy and chemical maturity of suspended matter in major river samples under SCOPE/UNEP, Transport of carbon and minerals in major world rivers; Part III; (eds) Degens T and Kempe S, Mitteilungen aus dem Geologisch — Paleontol-ogischen Institut der Universitat Hamburg, pp. 569.
Kudrass H R, Hofmann A, Doose H, Emeis K and Erlenkeuser H 2001 Modulation and amplification of climate changes in Northern Hemisphere by Indian summer monsoon during the past 80 Ky;Geology 29 63–66.
Levitius S, Burgett R and Boyer T P 1994 In: World Ocean Atlas: Salinity NOAA Atlas NESDIS 3; US Department of Commerce, Washington DC, Vol. 3.
Passega R 1964 Grain size representation by CM pattern as a geological tool;J. Sedim Geol. 34 830–847.
Sarkar A, Ramesh R, Bhattacharya S K and Rajagopalan G 1990 Oxygen isotope evidence for a stronger winter monsoon current during the last glaciation;Nature 343 549–551.
Shetye S R, Gouveia A, Shenoi S S C, Sundar D, Michael G S and Nampoothri G 1993 The western boundary current in the seasonal subtropical gyre in the Bay of Bengal;J. Geophys. Res. 98 945–954.
Shetye S R, Shenoi S S C, Gouveia A D, Michael G S, Sundar D and Nampoothri G 1991 Wind driven coastal upwelling along the western boundary of the Bay of Bengal during southwest monsoon;Continent. Shelf Res. 11 1397–1408.
Sirocko F, Sarnthein M, Erlenkeuser E, Lange H, Arnold M and Duplessy J C 1993 Century-scale events in monsoonal climate over the past 20000 years;Nature 364 322–324.
Stuiver M and Reimer P J 1993 Extended14C data base and revised calibration 3.014C age calibration program;Radiocarbon 35 215–230.
Subramanian V 1987 Environmental geochemistry of Indian rivers;J. Geol. Soc. India 29 205–220.
Tiwari M, Ramesh R, Somayajulu B L K, Jull A J T andBurr G S 2005 Early degalcial (∼ 19–17 ka) strengthening of northeast monsoon;Geophys. Res. Lett. 32 L19712.
Van der Borch C C, Sclater J G and others 1974 Site 218 initial report deep sea drilling project, (Washington DC: Govt. Printing Office)22 325–348.
Varkey M J, Murthy V S N and Suryanarayana A 1996 Physical oceanography of the Bay of Bengal and Andaman Sea;Oceanography and Mar. Bio. 34 1–70.
Weaver C E 1989Clays, Muds and Shales; (Amsterdam: Elsevier) p. 819.
Weber M E, Wiedicke H M, Kudrass H R, Hubscher C and Erlenkeuser H 1997 Active growth of the Bengal Fan during sea level rise and highstand;Geology 25 315–318.
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Chauhan, O.S., Vogelsang, E. Climate induced changes in the circulation and dispersal patterns of the fluvial sources during late Quaternary in the middle Bengal Fan. J Earth Syst Sci 115, 379–386 (2006). https://doi.org/10.1007/BF02702050
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DOI: https://doi.org/10.1007/BF02702050