Multi-proxy evidence for Late Pleistocene-Holocene climatic and environmental changes in Lop-Nur,Xinjiang,Northwest China

A 10.35-m-long sediment core from the Luobei depression in Lop-Nur,Xinjiang,Northwest China,provides detailed information about environmental changes during the Late Pleistocene.The samples taken every 5 cm of the core were analyzed for 10 environmental proxies,including magnetic susceptibility,granularity,chroma,carbonate and loss on ignition(LOI),and pH value.The chronology data are provided by the uranium/thorium disequi-librium dates.The sediments of the section were deposited during the last 32000 years.The results of analysis of 10 proxies were examined using multivariate statistical analysis,and the principal components were calculated.According to the results,the Late Pleistocene sequence contains four climatic and environmental stages appearing in the cycles of cold-wet and warm-dry changes.During 10-9 ka BP,it was the earliest warm episode in the Holocene.Environmental changes in this district were restricted by global change,as suggested by the analysis of glacial-interglacial cycles.But it was different from the mutative trend of a monsoon region in East China because of its own characteristics,which was the situation of cold-wet and warm-dry climate-environment change.The candidate reason may be the uplift of the Tibet Plateau and the westerly wind circulation.