豫西石千峰组研究新进展

NEW ADVANCE OF THE STUDY OF THE SHIQIANFENG FORMATION IN WESTERN HENAN

豫西石千峰组很发育,分布广泛,据钻井的岩芯及化石划为三段。下段:平顶山砂岩段;中段:双壳类泥灰岩段;上段:石膏钙核段。平顶山砂岩段的地质时代为晚二叠世,地层上可同华北石千峰组下部对比。平顶山砂岩段同下伏上石盒子组为整合接触,华北陆块南缘局部为不整合,称之海侵超覆。据石千峰组所含化石,说明华北陆块东南部晚二叠世为开阔海环境。

The Shiqianfeng Formation is well developed and widely distributed in western Henan. In accordance with the drill cores and fossils,the Shiqianfeng Formation can be subdivided into three members; i. e. the lower member Pingdingshan Sandstone,the middle member Lamellibranchiate Marl and the Upper member Gypsum Lime-Nodule. The Pingdingshan Member should be Late Permian in age and stratigraphically can be roughly correlated with the lower part of the Shiqianfeng Formation in North China. The Pingdingshan Sandstone Member conformarbly lies on the ' Shangshihezi Formation. Local disconformity, i. e. so-called, transgressive overlap occurs on the south margins of the North China. Fossils from the Shiqianfeng Formation suggests that there might be open marine conditions in the southeast part of the North China block during the Late Permian.