Late Quaternary vegetational and climatic changes from tropical peats in southern India - An extended record up to 40,000 years BP

Geeta Rajagopalan, R. Sukumar, R. Ramesh, R. K. Pant, G. Rajagopalan

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108 Citations (Scopus)

Abstract

Stable carbon isotope ratios of peats dated (by 14C) back to 40 kyr BP from the montane region (> 1800 m asl) of the Nilgiris, southern India, reflect changes in the relative proportions of C3 and C4 plant types, which are influenced by soil moisture (and hence monsoonal precipitation). From prior to 40 kyr BP until 28 kyr BP, a general decline in δ13C values from about - 14 per mil to - 19 per mil suggests increased dominance of C3 plants concurrent with increasingly moist conditions. During 28-18 kyr BP there seems relatively little change with δ13C of - 19 to - 18 per mil. At about 16 kyr BP a sharp reversal in δ13C to a peak of - 14.7 per mil indicates a clear predominance of C4 vegetation associated with arid conditions, possibly during or just after the Last Glacial Maximum. A moist phase at about 9 kyr BP (the Holocene Optimum) with dominance of C3 vegetation type is observed, while arid conditions are re-established during 5-2 kyr BP with an overall dominance of C4 vegetation. New data do not support the occurrence of a moist phase coinciding with the Mediaeval Warm Period (at 0.6 kyr BP) as suggested earlier. Overall, the climate and vegetation in the high altitude regions of the southern Indian tropics seem to have responded to past global climatic changes, and this is consistent with other evidences from India and other tropical regions.

Original languageEnglish
Pages (from-to)60-63
Number of pages4
JournalCurrent Science
Volume73
Issue number1
Publication statusPublished - 10 Jul 1997
Externally publishedYes

ASJC Scopus subject areas

  • Multidisciplinary

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