腾格里沙漠西北缘湖泊沉积记录的全新世中期气候环境

MID-HOLOCENE CLIMATE VARIATIONS FROM LAKE RECORDS OF NW TENGGER DESERT

通过腾格里沙漠西北缘青土湖沉积物粒度、有机碳、碳酸盐、碳氮比和有机质稳定同位素等多项沉积学气候代用指标及精确定年的综合分析，建立了该区域全新世中期9．0～3．0cal．kaBP的古气候演化序列。结果表明，9～7．8cal．kaBP期间，区域的水分条件和温度逐渐上升，植被状况好转，此阶段属于全新世早期向全新世暖湿期转变的过程；而在7．8～7．5cal．kaBP期间出现了显著的百年尺度的干旱事件，沉积物主要以砂质沉积为主，此时湖泊生产力显著下降；全新世期间最为暖湿的气候适宜期出现在7．5～5．0cal．kaBP；5．0cal．kaBP以来，该区域出现了较为明显的干旱化趋势。

QTL section of 6. 92 m depth is taken from Qingtu palaeolake, the terminal lake of Shiyang drainage located in NW Tengger Desert. Based on the detailed dating results, multi-proxy analysis of QTL section, including grain size, carbonate, TOC, C/N and δ13C of organic matter, was used to document regional climatic changes during 9 ～3 cal. kaBP. The climate evolution in the study area during 9 ～ 3 cal. kaBP is divided into four stages. ②from cold and dry to warm and humid during the period of 9～7.8 cal. kaBP, ③a significant drought interval of multicentennial scale between 7.8～7.5 cal. kaBP, ③Holocene optimum characterized by a warm and moist climate during the period of 7.5～5 cal. kaBP, ④from humid to dry during 5～3 cal. kaBP.