In order to quantify the Indian summer monsoon (ISM) variability for a monsoon dominated agrarian based Indian socio-economy, we used combined high resolution δ13C, total organic carbon (TOC), sediment texture and environmental magnetic data of the samples from a ~3 m deep glacial outwash sedimentary profile from the Sikkim Himalaya. Our decadal to centennial scale records identified five positive and three negative excursions of the ISM since last ~13 ka. The most prominent abrupt negative ISM shift was observed during the termination of the Younger Dryas (YD) between ~11.7 and 11.4 ka. While, ISM was stable between ~11 and 6 ka, and declined prominently between 6 and 3 ka. Surprisingly, during both the Medieval Warm Period (MWP) and Little Ice age (LIA) spans, ISM was strong in this part of the Himalaya. These regional changes in ISM were coupled to southward shifting in mean position of the Intertropical Convergence Zone (ITCZ) and variations in East Asian monsoon (EAM). Our rainfall reconstructions are broadly in agreement with local, regional reconstructions and PMIP3, CSIRO-MK3L model simulations.
A morpho-taxonomic study of leaf remains from the upper part of the Siwalik succession of sediments (Kimin Formation; upper Pliocene to lower Pleistocene) of Papumpare district, Arunachal Pradesh, India, revealed 23 species representing 20 genera belonging to 15 angiosperm families. The recovered fossil leaves are comparable to modern Bambusa tulda Roxb. (Poaceae), Mangifera indica Linn., Dracontomelum mangiferum Blume (Anacardiaceae); Chonemorpha macrophylla G. Don (Apocynaceae); Pongamia pinnata (L) Pierre., Millettia pachycarpa Benth., Dalbergia rimosa Roxb., Millettia extensa (Fabaceae); Macaranga denticulata Muell. Arg., Croton caudatus Geisel. (Euphorbiaceae); Combretum decandrum Roxb.
Diverse palynomorphs and phytoliths recovered from coprolites of ovi-caprids (sheep, goat) collected from Yang-Hai Tomb at Xinjiang Province, China, have been used to elucidate the dietary pattern of ancient livestock and to reconstruct the paleovegetation and paleoclimate of this part of northwest China ca. 2500 14C yr BP. Palynological and phytolith data suggest that a rich dry temperate vegetation prevailed in the area during the said period. Climatic conditions and grassland vegetation type of the area are explored using phytolith indices.
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