豫西、北地区“三山子灰岩”时代归属及成因意义

本文介绍了“三山子灰岩”的沉积厚度变化极大,在河南西部鲁山县辛集一带最薄仅28m,而到北部的渑池县厚度达360m。形成时代亦因地而异,最早开始于中寒武世张夏期,最晚止于早奥陶世亮甲山期。因此,认为“三山子灰岩”实际是一个倾斜和穿时的岩石地层单位。

AGE ASSIGNMENT OF THE "SANSHANZI LIMESTONE" IN WESTERN AND NORTHERN HENAN AND ITS GENETIC IMPLICATIONS

The "Sanshanzi limestone" is widely distributed in northern and western Henan. Its thickness is highly variable: it is the thinnest in Xinji,Lushan county,being only 28 m in thickness,while it is the thickest to the north in Rencun,Mianchi county,being 360 m thick. It is a complex geological body of dolomite. Its age varies from place to place,from the early Changxiaian age of the Middle Cambrian to the late Liangjiashanian age of the Early Ordovician. As a diachronous lithostratigraphic unit,it is an inclining mass of sedimentary rocks that formed in the process of marine regression during the Late Cambrian to Early Ordovician.