Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-12-01T02:50:53.075Z Has data issue: false hasContentIssue false
  • English
  • Français

Sharp Decrease in Summer Monsoon Strength 4000–3500 cal yr B.P. in the Central Higher Himalaya of India Based on Pollen Evidence from Alpine Peat

Published online by Cambridge University Press:  20 January 2017

Netajirao R. Phadtare
Netajirao R. Phadtare*
Affiliation:
Palynology Laboratory, Wadia Institute of Himalayan Geology, P.O. Box 74, Dehra Dun, 248 001, India, E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Age-constrained pollen data and magnetic susceptibility of an alpine peat profile from the Garhwal Higher Himalaya display a continuous record of climate and monsoon trends for the past 7800 yr. About 7800 cal yr B.P., dominance of evergreen oak (Quercus semecarpifolia), alder (Alnus), and grasses in the pollen record reflect a cold, wet climate with moderate monsoon precipitation. From 7800 to 5000 cal yr B.P., vegetation was progressively dominated by conifers, indicating ameliorated climate with a stronger monsoon. A warm, humid climate, with highest monsoon intensity, from 6000–4500 cal yr B.P. represents the mid-Holocene climatic optimum. Between 4000 and 3500 cal yr B.P., the abundance of conifers sharply decreased, with the greatest increase in evergreen oak. This trend suggests progressive cooling, with a decrease in the monsoon to its minimum about 3500 cal yr B.P. Two relatively minor cold/dry events at ca. 3000 and 2000 cal yr B.P. marked step-wise strengthening of the monsoon until ca. 1000 cal yr B.P. After a cold/dry episode that culminated ca. 800 cal yr B.P., the monsoon again strengthened and continued until today. A sharp decrease in temperature and rainfall at 4000–3500 cal yr B.P. represents the weakest monsoon event of the Holocene record. This cold/dry event correlates with proxy data from other localities of the Indian subcontinent, Arabian Sea, and western Tibet.

Keywords

palynologyalpine peatHolocenemonsoonGarhwal Himalaya
Type
Research Article
Information
Quaternary Research , Volume 53 , Issue 1 , January 2000 , pp. 122 - 129
Copyright
University of Washington

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bartlein, P.J., Edwards, M.E., Shafer, S.L., Barker, E.D. Jr., (1995). Calibration of radiocarbon ages and the interpretation of paleoenvironmental records. Quaternary Research 44, 417–424.Google Scholar
Bryson, R.A., Swain, A.M., (1981). Holocene variations of monsoon rainfall in Rajasthan. Quaternary Research 16, 135–145.Google Scholar
Caratini, C., Bentaleb, I., Fontugne, M., Morzadec-Kerfourn, M.T., Pascal, J.P., Tissot, C., (1994). A less humid climate since ca. 3500 yr B.P. from marine cores off Karwar, western India. Palaeogeography, Palaeoclimatology, Palaeoecology 109, 371–384.Google Scholar
Caratini, C., Fontugne, M., Pascal, J.P., Tissot, C., Bentaleb, I., (1991). A major change at ca. 3500 years B.P. in the vegetation of the Western Ghats in North Kanara, Karnataka. Current Science 61, 669–672.Google Scholar
Caratini, C., Rajagopalan, G., (1992). Holocene marine transgression marker on the Karnataka coast (India). Indian Journal of Marine Sciences 21, 149–151.Google Scholar
Fontes, J.C., Gasse, F., Gibert, E., (1996). Holocene environmental changes in Lake Bangong basin (Western Tibet). Part 1: Chronology and stable isotopes of carbonates of a Holocene lacustrine core. Palaeogeography, Palaeoclimatology, Palaeoecology 120, 25–47.CrossRefGoogle Scholar
Gasse, F., Arnold, M., Fontes, J.C., Fort, M., Gibert, E., Hue, A., Li Bingyan, , Li Yuanfang, , Liu Qing, , Melieres, F., Van Campo, E., Wang, Fubao, Zhan, Qingsong, (1991). A 13000 year climate record from Western Tibet. Nature 353, 742–745.Google Scholar
Gasse, F., Fontes, J.C., Van Campo, E., Wei, K., (1996). Holocene environmental changes in Bangong Co basin (Western Tibet). Part 4: Discussion and conclusions. Palaeogeography, Palaeoclimatology, Palaeoecology 120, 79–92.Google Scholar
Gergan, J. T, Choujar, R. K., (1997). Studies on Dokriani Bamak Glacier in U.P. Himalaya under the Himalayan Glaciology Programme.. Unpublished DST Scientific Report ES/91/06/91. .Google Scholar
Kotlia, B.S., Bhalla, M.S., Sharma, C., Rajagopalan, G., Ramesh, R., Chauhan, M.S., Mathur, P.D., Bhandari, S., Chacko, S.T., (1997). Palaeoclimatic conditions in Upper Pleistocene and Holocene Bhimtal—Naukuchiatal basin in south-central Kumaun, North India. Palaeogeography, Palaeoclimatology, Palaeoecology 130, 307–322.CrossRefGoogle Scholar
Merh, S.S., Chamyal, L.S., (1993). The Quaternary sediments in Gujarat. Current Science 64, 823–827.Google Scholar
Moore, P.D., Webb, J.A., Collinson, M.E., (1991). Pollen Analysis. Blackwell Scientific Publications, London.Google Scholar
Naidu, P.D., (1996). Onset of an arid climate at 3.5 ka in the tropics: Evidence from monsoon upwelling record. Current Science 71, 715–718.Google Scholar
Nakagawa, T., Yasuda, Y., Tabata, H., (1996). Pollen morphology of Himalayan Pinus and Quercus and its importance in palynological studies in Himalayan area. Review of Palaeobotany and Palynology 91, 317–329.Google Scholar
Nigam, R., (1993). Foraminifera and changing pattern of monsoon rainfall. Current Science 64, 935–937.Google Scholar
Polunin, O., Stainton, A., (1984). Flowers of the Himalaya. Oxford University Press, Delhi.Google Scholar
Sharma, C., Chauhan, M.S., Gupta, A., Rajagopalan, G., (1995). Vegetation and climate of Garhwal Himalaya during last 4000 years B.P. Symposium on Recent Advances in Geological Studies of Northwest Himalaya and Foredeep p. 90.Google Scholar
Sharma, M.C., Owen, L.A., (1996). Quaternary glacial history of NW Garhwal, Central Himalayas. Quaternary Science Reviews 15, 335–365.Google Scholar
Singh, G., Joshi, R.D., Chopra, S.K., Singh, A.B., (1974). Late Quaternary history of vegetation and climate of the Rajasthan Desert, India. Philosophical Transactions of the Royal Society of London 267, 467–501.Google Scholar
Singh, G., Wasson, R.J., Agrawal, D.P., (1990). Vegetational and seasonal climatic changes since the last full glacial in the Thar Desert, northwestern India. Review of Palaeobotany and Palynology 64, 351–358.Google Scholar
Stuiver, M., Reimer, P.J., (1993). Extended 14C data base and revised CALIB 3.0 14C age calibration program. Radiocarbon 35, 215–230.CrossRefGoogle Scholar
Van Campo, E., Cour, P., Sixuan, H., (1996). Holocene environmental changes in Bangong Co basin (Western Tibet). Part 2: The pollen record. Palaeogeography, Palaeoclimatology, Palaeoecology 120, 49–62.Google Scholar
Van Campo, E., Gasse, F., (1993). Pollen and diatom-inferred climatic and hydrological changes in Sumxi Co basin (Western Tibet) since 13,000 yr B.P. Quaternary Research 39, 300–313.Google Scholar
Van Geel, B., (1976). Fossil spores of Zygnemataceae in ditches of a prehistoric settlement in Hoogkerspel (The Netherlands). Review of Palaeobotany and Palynology 22, 337–344.Google Scholar
Wake, C.P., Mayewski, P.A., (1996). Himalayan Interdisciplinary Paleoclimate Project–Science and Implementation Plan. p. 96–1.Google Scholar
Williams, M.A.J., Clarke, M.F., (1984). Late Quaternary environments in north-central India. Nature 308, 633–635.CrossRefGoogle Scholar