柴达木盆地达参1井自然伽玛曲线的R/S分析

Rescaled Range Analysis of Dacan 1 Core Natural Gamma Looging Curve in Qaidam Basin

在柴达木盆地达参 1井 ,应用自然伽玛曲线进行了 2 5万年以来基于年代的 R/ S分析 ,该时段分维数平均值为 1.2 2 9,与深海氧同位素曲线分维值 (1.2 2 )非常接近 ,证明了分数维提供了不同气候记录和不同代用指标之间对比的基础 .即达参 1井的自然伽玛曲线所反映的古环境变化类似于深海氧同位素曲线 ,其波动是受全球变化控制的 .基于深度的自然伽玛曲线 R/ S分析也表现出相似的规律性 ,支持了气候学的研究 .通过 R/ S分析辨别出时间序列的转折点 ,分别对应于自然伽玛值的阶段性变化 ,反映了气候变化的阶段性与构造运动的影响 ,以及沉积相与沉积环境之间的转换 ,表明自然伽玛曲线记录了丰富的环境变迁信息 .此外还表明 R/ S分析求分维数与时间间隔关系密切 ,在有足够序列长度支持并且分辨率许可的情况下 ,采用多种间隔求分维数 ,在此基础上讨论整个系统的分维数更为合理 .

This paper introduces R/S analysis to natural gamma logging curve of Dacan 1 core in Qaidam Basin. The analysis based on Age shows that mean value of the fractal dimension is 1.229 during the last 250 ka,which is close to the fractal dimension of marine isotope profile(1.22),it provides another evidence to fractal dimension affords the comparison basis of different climate record and different proxy record.The analysis based on depth shows similar regularity,which supports the analysis of Age.This method can identify some turning points,which corresponding to GR Value change.It shows the effect of tectonic event and climate change event,and the transform of sedimentary facies and sedimentary environment. It indicates that natural gamma logging curve can be regarded as one of the favorable proxies of environmental and climatic change.It also suggests that fractal dimension obtained from R/S analysis are closely related to sampling interval. With the support of sufficient sequence length and sufficient resolution,it is more reasonable to discuss fractal dimension based on manifold sampling interval.