Pollen-based climate reconstruction from Ebi Lake in northwestern China, Central Asia, over the past 37,000 years

Abstract

Ebi (or Aibi) Lake is located in southwestern Junggar Basin in the Xinjiang Uygur Autonomous Region of northwestern China. In this study, we collected fossil pollen samples from the top 11.4 m of an Ebi core to reconstruct climate variability during the Late Quaternary. Results of a principal component analysis (PCA) of terrestrial pollen taxa from the Ebi core showed that four principal components explained 90.9% of the total variance. The chronology of the core section was determined based on five 14C dates obtained by accelerator mass spectrometry (AMS) and five dates obtained by optically stimulated luminescence (OSL). The studied section encompassed the Late Quaternary periods (37.6–3.6 cal ka). Environmental changes in Ebi Lake were divided into four stages based on significant pollen assemblage changes. From 37.6 to 34.5 cal ka, climate conditions were warm and dry. The climate became warmer and wetter between 34.5 and 28 cal ka and then deteriorated to cold and dry during 28 to 9 cal ka. High temperatures and dry conditions during the Early Holocene (11–9 cal ka) may have caused forest fires. From 9 to 3.6 cal ka, the climate was warm and wet; however, pollen data indicate that it was relatively drier between 6 and 4 cal ka. Available soil moisture during MIS 3 stage was less than that of the Holocene Optimum especially during 37.6–34.5 cal ka.