徐州地区山西组沉积相与沉积环境分析

Sedimentary Facies and Sedimentary Environment on Shanxi Formation in Xuzhou

本文对徐州孟庄地区2-1#井、2-2#井,郑集地区3-2#井、3-4#井的岩芯进行观察描述和岩石薄片的镜下分析,得出徐州地区山西组的沉积环境特点。徐州地区山西组是华北地台在石炭—二叠纪陆表海向东南方向退出时形成的海陆过渡相,属于陆表海环境下的河控三角洲沉积,根据岩石组合特征分为上下两段。下段为水下沉积部分,由泻湖—前三角洲沉积亚相、三角洲前缘的远砂坝、河口坝、分流间湾和水下分流河道等微相组成。上段水上沉积部分,由三角洲平原的水上分流河道、天然堤、泛滥平原—沼泽等微相组成。

In this paper, information of well 2 - 1 and well 2 - 2 in Mengzhuang region, well 3 - 2 and well 3 - 4 in Zhengji region, is considered as the source data to study the sedimentary environmental features of Shanxi forma- tion in Xuzhou city, using the methods of core observation and microscopic analysis of rock slices. From the study, some conclusions are obtained. Shanxi formation of Xuzhou city is a transitional facies formed when epeiric sea of north china platform ebbed to southeast in permo - carboniferous period, belonging to the river - dominated delta of transitional facies environment. According to the rock assemblage characteristic, Shanxi formation can be divided into two sections, the lower section with the sedimentary part Under water, and the upper section for depositing above water. The lower section is made up of lagoon - predeha sedimentary sub - facies and microfacies such as distal bar, mouth bar, interdistributary and underwater distributary channel. The upper section is consisted of the microfacies as above - water distributary channel, natural levee and flood plain - swamp.