柴达木盆地自然伽玛曲线与古里雅冰芯记录的末次间冰期以来气候环境变化过程的对比

Correlation of Environmental and Climatic Change Between Qaidam Basin Gamma Ray Logging Curve and Guliya Ice Core δ^(18) O Record Since the Last Interglacial Cycle

采用柴达木盆地达参 1井自然伽玛 (GR)曲线进行古气候反演 ,分析了GR曲线记录的末次间冰期以来的环境变迁过程 .表明GR曲线忠实地记录了构造运动及气候变化的影响 ,与古里雅冰芯、格陵兰冰芯所记录的气候事件均能较好对应 .表明柴达木盆地同时包含了高原隆升和全球性气候变化的信息 ,是反映古气候变化良好的信息载体之一 ,是反映内陆干旱盆地环境与气候变化良好的代用指标 .

The Qaidam basin is a very large, arid, intermountain, sedimentary basin in western China. It is located to the north of the Tibetan Plateau. Core Dacan-1 was extracted from the east of the Qaidam Basin, due to great thickness, high continuity and fine material composition, the resolution of the core is high, which provides the necessary and sufficient basis for studying the Quaternary paleoclimatic changes in the basin. A natural gamma ray(GR) logging curve of Borehole Dacan-1 was used to inverse paleoclimate change in the basin. The process of environmental change during the last interglacial cycle has been revealed. The variation of GR logging curve can reflects environmental and climatic change, and it can be matched well with those recorded in Guliya ice core and Greenland ice core. The consistency confirms that the ancient global climate change is comparable, and the climate system has its own evolution process. During the transition of warm stage to cool stage, GR logging curve shows the same characteristics with Greenland ice corerecords,ut is opposite to the Guliya ice coreδ 18 Orecord. This difference shows that different proxy indicators in different regions may have its own characteristics, and it may own different sensibility and reflect regional factors. GR logging curve also reveals regional environmental change in the Qaidam Basin, which well reflected uplift of the Tibetan Plateau, and can be confirmed by the Guliya ice core δ 18 O record and other correlative studies. Tectonic and climatic events can be identified by the variability of GR logging curve. This suggests that GR logging curve is a sensitive proxy indicator of environmental and climatic changes. It also indicates that the Qaidam Basin, one of the inland paleo-lake is a well information carrier of climatic and environmental change, and it may faithfully record the process and stages of the uplift of Tibetan Plateau. GR logging curve reflects the combined actionof tectogenesisand climatic change. When properly defining the reflection of tectogenesis, more comparable climatic change information can be obtained. Based on the environmental and climatic information deduced from the GR logging curve in the Qaidam Basin, lacustrine deposits of longer time interval and shorter time scale can be extrapolated.