Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6446171 | Quaternary Science Reviews | 2014 | 13 Pages |
Abstract
Vegetation and climate during later part of Late Pleistocene have been reconstructed from Ziro valley, Arunachal Pradesh, Eastern Himalaya based on pollen data along with carbon isotope and magnetic susceptibility data The study reveals that the area and the vicinity is occupied by mixed broad leaved - conifer forest and pine grass savanah at variable densities at least since 66,000yr BP. The phases of expansions and declines of Oaks with decline and increase of Pines and grasses probably occurred under increase (warm-moist) and decrease (cool-dry) of S.W. monsoon precipitation respectively. The increasing trend of S.W. monsoon and temperature is recorded during â¼44,000 to 34,000 cal yr BP synchronizing with the peat development, and which peaked at around 35,000 cal yr BP. This may link to the interstadial phase during the last major glacial cycle in the Himalayan region. It is also reflected in the decline of δ13C value indicating dominance of C-3 type of vegetation. The increased values of ÏFD%, and lower values ÏLF magnetic susceptibility, recorded during the phase of the peat deposit, further advocate's higher monsoon intensity. Impact of expansion of glacier felt with peak (LGM) around 20,000 cal yr BP is perceived. Tree line had moved to lower altitudes due to increased aridity and low temperature. During this time existence of savannah type of vegetation is also evident by the increase of C4 taxa. Decreased FD% and increased ÏLF susceptibility also indicate reduced S.W. monsoon intensity.
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Earth and Planetary Sciences
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Authors
Amalava Bhattacharyya, Nivedita Mehrotra, Santosh K. Shah, Nathani Basavaiah, Vandana Chaudhary, Indra Bir Singh,