Holocene vegetation and climatic variations in Central India: A study based on multiproxy evidences |
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| Institution: | 1. Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow 226 007, UP, India;2. School of Earth and Environmental Sciences, Central University of Himachal Pradesh, PO Box 21, Dharamshala 176 215, HP, India;1. Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany;2. Department of Earth Sciences, Indian Institute of Science Education and Research, 741252 Kolkata, India;3. Institute for Earth- and Environmental Science, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476 Potsdam, Germany;4. Limnology and Fisheries Laboratory, Centre of Research for Development, University of Kashmir, India;5. Universität Hamburg, Institute of Biogeochemistry and Marine Chemistry, Hamburg, Germany;6. Indian Institute of Geomagnetism, Navi Mumbai, India;1. Wadia Institute of Himalayan Geology, 33 GMS Road, Dehradun, 248 001, India;2. Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur, 721302, India;3. Department of Geology, Savitribai Phule Pune University, Pune, 411 007, India;4. Department of Geology, H.N.B. Garhwal Central University, Srinagar, 246 174, India;1. Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow 226007, India;2. Centre of Advanced Study, Palaeobotany-Palynology Laboratory, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, India;3. Indian Institute of Tropical Meteorology, Pune;4. Department of Geology & Geophysics, Indian Institute of Technology, IIT Kharagpur, Kharagpur 721302, India;1. Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow 226007, India;2. Directorate of U.P. State Archaeology, Lucknow 226016, India |
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| Abstract: | Palynology, texture, mineralogy, geochemistry, and magnetic susceptibility analysis of a 2 m deep sediment core from Padauna Swamp, southeastern Madhya Pradesh infers that between 8600 and 7500 cal yr BP a warm and relatively less-humid climate prevailed with open tree-savannahs dominated by grasses followed by sedges, Artemisia and members of Chenopodiaceae/Amaranthaceae with scanty trees viz., Schrebera, Aegle marmelos and Sterculia urens. This is well supported by lower organic to carbonate carbon ratio, coarser texture having relatively low CIA and magnetic susceptibility values and presence of some primary minerals. Between 7500 and 6250 cal yr BP the tree-savannahs were succeeded by open mixed deciduous forests with the invasion of a few more trees viz., Madhuca indica, Holoptelea, Emblica officinalis, Mitragyna parvifolia and members of Anacardiaceae in response to onset of a warm and humid climate. A considerable rise in organic carbon generated from the degradation of plentiful biomass along with increase in clay content with signs of kaolinite and increase in immobile over mobile elements with slightly higher CIA and magnetic susceptibility values also suggest climatic amelioration. The presence of ruderal plants such as Artemisia, Cannabis sativa and Cheno/Am further infers initiation of human activities in the region. Between 6250 and 2800 cal yr BP, the mixed deciduous forests became more diverse and dense, subduing grasses and other herbaceous elements. Sporadic incursion of Shorea robusta (Sal) in forest floristic was recorded around 5000 cal yr BP. The overall change in the vegetation mosaic reflects that a warm and more-humid climate prevailed in the region, probably on account of invigoration of southwest monsoon. This observation is further corroborated by other proxy data showing a spurt in organic/inorganic carbon ratio, increase in clay content with matured mineralogy, significantly higher CIA and magnetic susceptibility values. Since 2800 cal yr BP onwards, the modern Sal dominated deciduous forests were established indicating continuation of warm and more-humid climate including timely arrival of SW monsoon coinciding with the shedding of Sal seeds as they are viable for a very short period. |
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| Keywords: | Holocene Palaeoclimate Palaeovegetation Multiproxy data Pollen analysis Central India |
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