皖北新元古代张渠组灰岩地球化学数理统计分析

Statistical Analyses of Geochemistry of the Limestone from the Neoproterozoic Zhangqu Formation in Northern Anhui Province

摘要: 地球化学在沉积学研究中发挥了重要作用。本研究以灵璧石国家地质公园新元古代张渠组灰岩为研究对象，在系统采样的基础上测试了其岩石地球化学组成，并进行了数理统计分析。结果表明，张渠组上下部灰岩中元素组成存在差异，主体表现出高的Ca含量，但其他元素含量相对较低，这种差异可能与其沉积环境变化有关。基于数理统计分析(相关性、聚类及因子分析)，10种元素被划分为3类：代表陆相的Al-K-Ti-Fe、代表海相的Ca-P和代表其他的Mg-Mn-Zr-Ni。在此基础上，构建出了用于探讨陆源、海相特征及陆海相对贡献的Al/Fe、Ca/P和Al/P比值，并被应用于张渠组沉积环境分析，发现张渠组上下部的海相环境无明显差异，但陆源贡献上变化显著。

Abstract: Geochemistry has played important roles for the research of sedimentary geology. In this study, the limestone from the Neoproterozoic Zhangqu Formation in the National Geological Park of the Lingbi Stone has been taken as a research object and the geochemistry of the rocks has been measured based on the systematic collection of samples, and then analyzed by statistical analyses. The results indicate that the geochemical compositions of the limestone rocks from the upper and lower formation are different with each other, and both of them are characterized by high Ca contents with low other elements, which is probably related to the change of the sedimentary environment. Based on the statistical analyses (including correlation, cluster and factor analyses), the 10 kinds of elements have been classified to be 3 categories: the Al-K-Ti-Fe (representing the terrigenous detrital), the Ca-P (representing the marine facies) and the Mg-Mn-Zr-Ni (other). And three ratios (Al/Fe, Ca/P and Al/P) have been constructed for the discussion of the terrigenous, marine characteristics and the contribution of terrigenous versus marine, which was then applied for the analyses of the sedimentary environment of the Zhangqu Formation, and then found that there was no significant change of the marine environment during the formation of the lower and upper Zhangqu Formation, but the terrigenous contribution changed significantly.