浅析宁夏卫宁北山地区石炭纪地层沉积特征及演化规律

A brief analysis on sedimentary features and evolvement rules of Carboniferous strata in Weining North Mountain area of Ningxia

宁夏卫宁北山石炭纪地层发育良好,动、植物化石丰富,其岩石地层序列自上而下可划分为前黑山组、臭牛沟组、土坡组和太原组4个地层单位。通过对该地区石炭纪岩石地层特征、基本层序、沉积相和沉积特征演化规律分析,认为该地区石炭纪—早二叠世早期地层是在基底拗陷下沉、盆地范围不断扩大的构造背景条件下形成的。早石炭世以海进作用为主,沉积环境基本为半封闭的海湾,沉积相以碎屑岸线为主。晚石炭世—早二叠世早期整体演化为陆表海环境,海水时进时退(总体处于海退),发育进积类(建设性)受潮汐作用影响的三角洲。

The Carboniferous strata in Weining northern mountain of Ningxia developed well with rich animal and plant fossils,and its rock stratigraphic series from top to bottom can be divided into four stratigraphic units including Qianheishan Fm,Chouniugou Fm, Tupo Fm and Taiyuan Fm. Based on the analysis on the Carboniferous strata rock characteristics, the basic stratigraphic series, sedimentary phase and sedimentary evolvement characteristics, it can be concluded that the Carboniferous—the early Permian strata formed under the conditions of basal sinking and basin expanding. In the early Carboniferous,transgression played an important role in the formation of strata under the semi-closed bay sedimentary environment with clastic shoreline sedimentary facies. Until the later Carboniferous—early Permian, the sedimentary environment evolved into epicontinental sea with transgression-regression(overall regression) and developed into shallow water of river-dominated and tidal-affected delta.