贺兰山北段晚石炭世地球化学特征与沉积环境

Sedimentary environment and geochemical characteristics of northern part of Helan mountains

为研究贺兰山北段晚石炭世地球化学特征及沉积环境,以研究区内10个泥岩样为统计对象,分析泥岩中所含微量元素、稀土元素的变化规律,探讨两者对沉积环境的指示作用。结果表明:同一微环境中微量元素和稀土元素含量相近,不同微环境中微量元素含量差异明显;泻湖相泥岩中微量元素与潮坪相泥岩中微量元素分布明显不同。该区在晚石炭世为滨岸过渡环境,古气候条件温暖潮湿,这与古生态学、古生物化学相标志表征结果一致。该研究可为贺兰山地区的油气地质勘探提供基础资料。

This paper presents an attempt to investigate sedimentary environment and geochemical characteristics of mudrocks occurring in northern Helan mountains in the Late Carboniferous.The investigation involves using 10 mudstone samples as the target of statistics to analyze the law governing the changes of REE and trace elements in mudrocks and probe into the indication of the sedimentary environments by REE and trace elements.The result shows that,given similar content of trace elements and REE in the same microenvironment,significantly different content of trace elements among different microenvironments, and a distinct difference in distribution of trace elements found in mudstone between lagoonal facies and tidal-flat facies,the area is identified with shore transitional environment in the Late Carboniferous, with ancient climatic conditions found to be warm and humid,which is consistent with the signs of paleoecology and paleontology chemical facies.This study provides the basic reference for petroleum exploration in Helan mountain area.