Multi-proxy Data Analysis On Holocene Climate Changes In Western Arid China

As one of the most vitally important prineiples to predict the future environment what we are detending closely, the understanding of Holocene climate changes has attached extensive attentions of the world.The western arid zone in china is a region for interactions between westerly and monsoon climate, and responds sensitively to global climate change. Understanding the basic features of this region's Holocene climate changes will be benefit to understand the mechanism and reason of its climate change, thus to provide reference for the future climate forecast.Using the multi-taper method of spectrum analysis(MTM) and the wavelet analysis, wo analyze clay minerals data from the Dalianhai Lake, then compare them with many other climate proxies in this study. The main results of this study include the followings:(1) The background trend of the Smectite/(illite+chlorite)(s/i+c) and smectite/kaolinite(s/k) ratios time teries suggests that:The Holocene climate evolutionary process reflected by proxies of DaLianHai was primarily driven by the change of summer insolation of northern hemisphere .MTM and the wavelet analysis show that: there were periodicities of 194a,259a-261a,937a from 11000 to 5500 cal yr BP, quasi-periodicities of 242a-243a,336a-337a from 4500 to 0 cal yr BP . the wavelet analysis indicates that the major cycles of 242a-243a,336a-337a account for a large proportion in the interval of 4500-0 cal yr BP .The reconstruction of the main periodic signals shows that there are rapid climate changes in two intervals of 4500-3000 cal yr BP,1000-0 cal yr BP.(2) The humidity change in westerly zone is different from that of the monsoon zone.