Paleovegetational history in the Kashmir basin, India, derived from ¹³C/¹²C ratio in paleosols

Abstract

The presence of a series of humus-rich layers, identified as paleosols in the loess sediments in the Kashmir basin in northwestern India indicate phases of climatic amelioration in the past. Stable carbon isotope ratios of the organic fraction of paleosols from three locations show that almost all the paleosols supported significant C₄-type vegetation which is characteristic of water stressed and relatively hot, dry environments. Limited measurements of stable carbon isotope ratio in modern soils show an estimated C₄-type vegetation contribution of less than 25%, which is tenable given the temperate climate of the basin today. In the light of some recently published TL (thermoluminiscence) dates for loess sedimentation in Kashmir, these findings suggest significant ecological changes most likely related to water stress and temperature there during the past 300 kyr (1kyr= 1000years).