Forum communication Vegetation response to South Asian Monsoon variations in Konkan, western India during the Late Quaternary: Evidence from fluvio-lacustrine archives K.P.N. Kumaran a, * , Ruta B. Limaye a , Sachin A. Punekar a, b , S.N. Rajaguru c , S.V. Joshi c , S.N. Karlekar d a Palynology and Palaeoclimate Laboratory, Palaeobiology Group, Agharkar Research Institute, G.G. Agarkar Road, Maharashtra, Pune 411004, India b Biospheres, Eshwari, 52/403, Lakshminagar, Parvati, Pune 411009, India c Department of Archaeology, Deccan College Post Graduate and Research Institute, Pune 411006, India d Department of Geography, Sir Parashurambhau College, Pune 411030, India article info Article history: Available online xxx abstract The palaeobotanical and palynological data along with physical proxies obtained from Konkan, western India, have been addressed while ascertaining the vegetation response to monsoon variations since Late Pleistocene (w53,000 yrs BP). The retrieved plant fossil assemblage, being a sensitive indicator of climate changes, has important implications in palaeoclimate study of the Late Pleistocene as it is the first of its kind in the entire 7500 km long coastline of India. The plant fossil assemblage of the lacustrine sediments forms potential evidence for the prevalence of wet evergreen forest in the Late Pleistocene (w44,000 yrs BP). This scenario was attributed to prevalence of an extended period of rainfall of both the Southwest (SW) and Northeast (NE) monsoon in Konkan, although the Indian subcontinent was under the influence of active tectonic processes. Numerous fossil plant taxa are now confined to freshwater Myristica swamps of Southeast Asia in general and that of southwestern India in particular suggesting that these areas maintain a similar monsoon trend to that existing prior to 44,000 yrs BP. On the other hand, the NE monsoon did not reappear during the Early Holocene, when the SW monsoon became strong along the Konkan coast. Many of the plant species of the fossil assemblage have been displaced from Konkan as a response to weakening of the monsoons since the Late Pleistocene and towards the Last Glacial Maximum (LGM). The aridity/reduced rainfall since Late Pleistocene, including the LGM, and limited terrestrial accumulation in the Early Holocene suggests an ecological shift and subsequent replacement of evergreen forest cover and a possible break in sedimentation. Palynological evidence of the Late Holocene (<3000 yrs BP) fluvio-lacustrine sediments reveals that the evergreen forest could not reappear/rejuvenate in Konkan due to such climatic stress, in contrast to southwestern India and Sri Lanka where extended rainfall was still prevalent. The hypothesis of an extended period of monsoonal rains prior to 44,000 yrs BP in the present humid tropical parts of Konkan holds significance, as data on paleosols and vertebrate fossils from the semi-arid/arid parts of western India indicate relatively wet climate and wetland flood plains. Ó 2012 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction The Late Quaternary vegetation dynamics of Peninsular India in response to monsoon variations are seldom addressed, due to lack of availability of exposures and potential signatures in sedi- mentary archives. Until now, the methodology applied to under- stand the monsoon variations, as far as the Indian subcontinent is concerned, has been through the study of foraminifera and carbon and oxygen isotopes (Geetha et al., 1997; Somayajulu et al., 1999; Sarkar et al., 2000; Srinivasan and Sinha, 2000; Gupta and Thomas, 2003; Sinha et al., 2006; Patnaik et al., 2009; Singhvi and Kale, 2009; Chauhan et al., 2010; Ramesh et al., 2010). Although the pollen signatures observed in the sediments of KonkaneKerala coast provided a reasonable account of the vegetation response to sea level changes and the climatic vicissitudes during the Holocene (Limaye, 2004; Kumaran et al., 2005; Nair et al., 2006; Limaye et al., 2007 , 2010), the paucity of information particularly on Pleistocene deposits remained a major gap towards understanding the impact of monsoon variations on biomes during the Late Quaternary. The presence of lateritic regolith over erosional surfaces of rocky uplands of Peninsular India, the preservation of rich vertebrate fauna in fluvial deposits of the Siwalik Ranges of NW India, and the occurrence of * Corresponding author. E-mail address: kpnkumaran@gmail.com (K.P.N. Kumaran). Contents lists available at SciVerse ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint 1040-6182/$ e see front matter Ó 2012 Elsevier Ltd and INQUA. All rights reserved. doi:10.1016/j.quaint.2012.03.010 Quaternary International xxx (2012) 1e16 Please cite this article in press as: Kumaran, K.P.N., et al., Vegetation response to South Asian Monsoon variations in Konkan, western India during the Late Quaternary: Evidence from fluvio-lacustrine archives, Quaternary International (2012), doi:10.1016/j.quaint.2012.03.010