黑色页岩微量元素形态分析及地质意义

Sequential Extraction of Trace Elements and the Geological Significance of Fractions in Black Shales, West Hunan and East Guizhou

本文采用 4级不同形态逐级提取的方法研究了湘西上震旦统、下寒武统黑色页岩微量元素的物相分布特点。各形态微量元素含量和主要矿物电子探针分析结果表明 ,微量元素主要受控于有机质和硫化物含量的变化 ,较高的有机产率和缺氧的古海洋环境是影响黑色页岩中微量元素分布的决定因素。

The enrichment of the elements depends on the formation environment of black shales. The phases of trace elements can be as a marker of the genesis and the mineralization of black shales. The main minerals of upper Sinian and lower Cambrian black shales in west of Hunan are illite, quartz and sulfide, and the content of organic matter is about 5% to 14% The maturity of organic matter is high, and up to the metagenesis stage. The sequential chemical extractions of the four type phase are analyzed. The trace element partitioning phase and election microprobe analysis show that the enrichment of the elements are influenced by the content of organic matter and sulfide. The high production of organic matter and the anoxic environment are the main factors to control the scattering in trace elements in black shales.