塔河南盐下地区上奥陶统良里塔格组沉积环境分析

塔河南盐下地区上奥陶统良里塔格组主要为一套碳酸盐岩.通过对研究区28口钻井岩心的详细描述和3 200余块薄片的鉴定,确认其主要的岩石类型有微晶灰岩、生屑灰岩、藻粘结灰岩、藻球粒灰岩、鲕粒灰岩、含玄武岩屑灰岩.在这些碳酸盐岩中可见藻屑、苔藓虫屑、角石、海绵、棘屑、腕足、双壳、珊瑚、三叶虫等指示正常海相环境的生物.在综合分析其岩石学特征、自然伽马曲线、成像测井和地震资料的基础上,将研究区良里塔格组划分为开阔台地、台地边缘浅滩和台地前缘斜坡三种沉积环境.并讨论了良里塔格早、晚期沉积相的空间展布特征,编制了各时期的古地理图.为塔河南上奥陶统的油气勘探提供了地质指导.

Study on the sedimentary environment of the Upper Ordovician Lianglitage Formation in the south of Tarim River, China

The Upper Ordovician Lianglitage Formation mainly consistes of carbonates in the south of Tarim River of Xinjiang.In this paper,twenty eight cores are observed in detail,three thousand and two hundred slices are identified,then the authors thought rock types were as follows: calcipulverite,biolclastic limestone,algal binstone,algal pelleted limestone,oolilts,contain basalt clastic limestone.Biology,such as algal,bryozoa,goniolithon,sponge,echinodermata,brachiopod,bivalve,coral,trilobite,which are conserved in the carbonate of the Lianglitage Formation,indicates a normal shallow marine environment.Based on the integrative analysis of the natural gamma-ray log,imagery log,seismic data and petrology character,three types of sedimentary environments can be recognized in the Lianglitage Formation.They are open platform,marginal platform shoal and platform frontier slope.Based on this,the paleogeographic maps are mapped about early Baota stage and late Baota stage,respectively.At last,the authors describe the depositional facies distribution in space.This is very important for people to engage oil and gas exploration in study area.