河北宽城崖门子中元古界高于庄组地球化学特征及其沉积环境意义

GEOCHEMICAL CHARACTERS AND DEPOSITIONAL ENVIRONMENT OF THE MESOPROTEROZOIC GAOYUZHUANG FORMATION IN KUANCHENG COUNTY, HEBEI PROVINCE

摘要: 河北宽城崖门子剖面的高于庄组属于中元古界长城系，下伏长城系大红峪组，上覆中元古界蓟县系杨庄组，沉积年限200 Ma（1800~1600 Ma），共划分为4个亚组，自下而上为官地亚组、桑树鞍亚组、张家峪亚组和环秀寺亚组，为一套厚940 m的碳酸盐岩沉积地层.从常量元素和微量元素2个方面探讨了高于庄组的地球化学特征.通过对岩石样品测试结果的分析，各种元素含量在岩石地层界线附近变化较明显，说明地球化学特征可以辅助划分沉积地层或对已划分的地层界线进行优化.另外，据CaO/MgO、Ca/（Ca+Fe）和Sr/Ba比值及V、Ti元素特征分析，该研究区高于庄组为较干热气候下的海洋环境沉积.

Abstract: The Mesoproterozoic Gaoyuzhuang Formation in Kuancheng County, Hebei Province represents a succession of carbonate strata with 940 m in thick. Chemical analysis of rock samples from the Gaoyuzhuang Formation shows a distinct change in major and trace elements on the lithostratigraphic boundary of the strata, suggesting that such geochemical characters can be used as indicator while dividing sedimentary strata or optimizing lithostratigraphic boundary. Besides, based on the characters of CaO/MgO, Ca/(Ca+Fe), Sr/Ba and V and Ti of the strata, the Gaoyuzhuang Formation was deposited in shallow water and near coast conditions with more mud supply.