Paleoclimate Variations Inferred from Organic Carbon Isotopic Composition in Hetao Plain in North China since Late Glacial Period

摘要

INTRODUCTION Although the paleoclimatic instability since late glacial period in Hetao plain in North China has long been the major concern, little is known about the millennial-scale variations and their relation to the global control factors (Jia et al., 1998). More high-resolution records are needed to investigate the potential links of such events among locations over the last climatic cycle (Chun et al., 2008). Hetao plain of Inner Mongolia is proposed to be a climatically sensitive area due to its location at the transitional zone between arid and semi-arid regions (Jia et al., 2003). The annual average temperature of the study area is 4-7 ℃ and the annual mean precipitation is approximately 180-200 mm. In summer, the study area is dominated by warmmoist southeasterly summer monsoon responsible for the annual rainfall events, whilst in winter it is largely controlled by the relatively dry-cold northwesterly winter monsoon from late fall to early spring (Chun et al., 2008).