Record of vegetation and climate during Late Pleistocene–Holocene in Central Ganga Plain, based on multiproxy data from Jalesar Lake, Uttar Pradesh, India

Abstract

Pollen, organic–inorganic carbon ratio, clay mineral, texture analyses and radiocarbon dating of a 2.8 m sediment profile from Jalesar Lake demonstrate that from prior to 42,490 until 13,560 cal BP, the Central Ganga Plain supported grassland with scanty trees under a cool and dry climate. The sediments deposited during 13,560–5260 cal BP are palynologically barren and coarser in nature with increased inorganic/organic carbon ratio depicting the upwarping phase of the Ganga Plain. Between 5260 and 4760 cal BP, the immigration of more trees including Holoptelea, Acacia, and Bombax, accompanied by higher clay and organic carbon, indicate establishment of forest groves under an ameliorating climate. The debut of Cerealia pollen denotes the initiation of agricultural practices. Around 4760–3260 cal BP, forest groves became diversified, substantiated by higher clay with increasing kaolinite and organic carbon, indicating warm and humid climate owing to an active SW monsoon. The consistent presence of aquatics and rising trend of Cerealia pollen suggest lake expansion and acceleration in agricultural practices respectively. Between 3200 and 1200 cal BP, the forest groves became sparse, allowing coarser sediments with less organic carbon, which implies that climate became less humid. Since 1200 cal BP, diminution of arboreals signifies a weak SW monsoon.