彭水廖家槽地区灯二段微生物碳酸盐岩沉积建造

The Microbialites Deposition and Construction of 2^nd Member of Dengying Fm in Pengshui Liaojiacao Section

以彭水廖家槽剖面灯二段为研究对象。为明确彭水廖家槽地区灯二段微生物碳酸盐岩的沉积建造,通过剖面实测、薄片鉴定等手段对研究区灯二段微生物碳酸盐岩的岩石学特征、宏观建造、微观组构进行了研究。结果表明:(1)研究区岩石类型主要为凝块泥-粉晶白云岩、纹层叠层泥晶白云岩,葡萄花边状构造发育;(2)研究区微生物宏观建造发育多个微生物丘和微生物层,可见多个微生物丘叠置发育,累计厚度达96.9 m;(3)研究区微观组构以凝块组构和纹层叠层组构为主,还可见泡沫绵层组构、包覆组构和枝状组构,自下而上呈现纹层叠层-凝块-包覆-枝状-泡沫绵层-凝块组构的演化特征。

In this paper,the 2^nd member of Dengying Fm in Pengshui Liaojiacao section is taken as the research object.In order to make clear the microbialites deposition and construction of 2^nd member of Dengying Formation in study area,this paper use section measurement and thin section identification to analyze the petrological characteristics,macro formation and micro fabric.The following results were obtained.(1)The main types of rocks are agglomerate silty dolomite,laminated micrite dolomite,and a lot of dolostones with grape-lace shaped cement can be seen.(2)There are many microbial mounds and microbial layers on the macro scale.And most of microbial mounds are superimposed.The cumulative thickness of the microbial mounds is 96.9m.(3)The microfabrics are mainly composed of thrombolite and stromatolite,and spongiostromata,coating fabric and dendritic fabric are also found.From bottom to top,the evolution characteristics are thrombolite→stromatolite→coating fabric→dendritic fabric→pongiostromata→stromatolite.