伊川兵马沟组上段砂岩粒度特征及环境意义

Grain-size Characteristics and Environmental Significance of Sandstone in the Upper Section of Bingmagou Formation in Yichuan Area

豫西地区中元古界的沉积环境一直是人们研究的重点,但是并未单独针对兵马沟组上段发育的巨厚层砂岩进行沉积环境分析。通过实地踏勘并采集标本,采用多种粒度分析方法,在精细制作粒度概率值累积曲线,C-M图等的基础上,对豫西伊川地区兵马沟组上段发育的巨厚层砂岩进行沉积环境分析。粒度特征的分析结果表明:兵马沟组上段砂岩形成的沉积环境为扇三角洲前缘沉积,发育水下分流河道、支流间湾和河口沙坝等微相。

The Middle-Proterozoic sedimentary environment in western Henan has been a research focus. But there is no special literature devoted to research on sedimentary environment of the super-thick standstone of upper Bingmagou Formation. In this paper, by field reconnaissance and specimen collection, special research was carried out on sedimentary environment of the super-thick standstone of upper Bingmagou Formation in Yichuan Region in western Henan with several methods based on probability cumulative curve of grain size and C-M plot. The analysis results on grain-size characteristics indicate that the sedimentary environment of upper Bingmagou Formation is fan delta front, including microfacies of underwater distributary channel, bar between branches and mouth bar.