天山托木尔峰地区7500年来的气候变化

Climatic Changes in Tuomul Region,Tianshan Mountains During the Last 7500 Years

天山托木尔峰南坡的苏小堤黄土剖面表明,托峰地区全新世黄土开始沉积的时间不迟于距今7500年前.剖面以黄土与烧土交互迭置为特征,烧土层是受到烘烤作用的林下土壤层,黄土层别代表干燥和相对湿润的环境,据此恢复了托峰地区7500年来在10~3年和10~3-10~2年尺度上的气候波动,其中距今7000-3500年间的气候波动说明了全新世宜期气候的不稳定性。

Suxiaodi profile is at thewest bank of the Qiong Tailanriver, in the southern side ofMt.Tumul, Tianshan Moun-tains,The profile is charac-teristiced by the alternation ofLoess layers with bakedsoil Iayers. Based on theanalyses of the profile,some conclusions is made out bellow: 1. loess deposition inthis region at last began in7500 years B.P.2. The bakedsoil layer was the forest soilbefore it was producted bythe forest fire, The loesslayer and the baked soil layerrepresent the dry environmentand relative moist environment,respectively. The relative moistperiods in the scale of 10~3-10~2 years appeared around 6580,5730, 4810, 3545, and 715 yearsB. P and the relative moistperiod and the dry period thescale of in 10~3 years is dividedat 3500 years B.P. 3.The clim-atic fluctuations from 7000 to3500 years B.P. indicated theunsteadibility of the optemum.