柴达木盆地第四纪古气候变化在物理测井自然伽玛曲线上的记录

利用物理测井曲线分析古气候变化，是近年发展起来的新领域。本文在对取芯井涩中6井多种气候指标分析的基础上，建立了涩中6井GR曲线古气候反演模式，将该模式引进到盆地东部唯一贯穿第四纪的钻孔---达参1井，利用该井高分辨率自然伽玛曲线建立了盆地东部地区2.85Ma以来的时间标尺，据此讨论盆地东部地区2.85Ma以来的古气候变化，表明盆地气候变化在大阶段上明显受到天文轨道周期的控制，但也具有明显的区域性特征。此外还与盆地西部大浪滩ZK-336孔进行了对比。表明柴达木盆地同时包含了高原隆升与全球性气候变化的信息，是古环境变迁的良好的信息载体。也证明了自然伽玛曲线是反映内陆干旱盆地气候与环境变化良好的代用指标。

Quaternary Palaeoclimatic Changes Recorded by Natural Gamma Logging Curve in Qaidam Basin

Using natural gamma logging curve to analysis palaeoclimatic change is the newly developed research field. Based on the analyses of a variety of palaeoclimatic indicators from the core samples of the Sezhong 6 well, we have established the model of inverse modeling of palaeoclimatic changes. This model has been further introduced into the Dacan 1 well — the only well drilling through the Quaternary in the eastern Qaidam Basin. The high-resolution natural gamma logging curve of the Dacan 1 well have been used to reconstruct the time scale of a period of 2.85Ma B.P. in the eastern Qaidam Basin. The palaeoclimatic changes in the eastern Qaidam Basin since 2.85Ma B.P. have also been discussed. In comparison with the record of ZK-336 well in the Dalangtan area of the western Qaidam Basin, it is suggested that the palaeoclimatic changes of the Qaidam Basin were controlled by the astronomic orbital periods, and these changes tend to behave obvious regional characteristics. It is shown that the current Qaidam basin is one of the best carriers of information such as the uplifting history of the Qinghai and Tibet plateau, the global climatic changes, and the global environmental changes. It is also indicated that the natural gamma-logging curve can be a good indicator of the environmental and climatic changes of the inland arid basin.