塔西北下寒武统肖尔布拉克组层序划分及台地沉积演化模式

发布时间：2019-05-29 05:36

【摘要】：基于野外露头观察和室内薄片鉴定工作,详细描述了塔里木盆地阿克苏地区下寒武统肖尔布拉克组微生物碳酸盐岩的展布特征,建立了层序地层格架,分析了肖尔布拉克期碳酸盐台地的演化过程。研究认为,肖尔布拉克组可分为两个三级层序:下部层序SQ1整体为一套波状微生物席,处于中-内缓坡沉积环境,对应缓坡型台地发育阶段;上部层序SQ2的海侵期是缓坡型台地向弱镶边台地的转变阶段,斜坡以风暴沉积为主,微生物岩不发育,而高地则以大型进积微生物礁建隆为主,主要通过丛状表附菌的自身骨架生长和微生物粘结方式成隆。高位期是弱镶边台地发育阶段,台缘和台内相分异明显。台缘区早期发育房室状表附菌层,晚期发育小型进积微生物礁群,由微生物粘结成礁,而台内区为低能微生物滩,缺乏高位早期建造,晚期以层纹石建造、泡沫绵层石和叠层石建造为主,其形成与粘性微生物席有关。
[Abstract]:Based on the field observation and indoor thin slice identification, the distribution characteristics of microbial carbonate rocks of the Lower Cambrian Shaobulak formation in Aksu area of Tarim Basin are described in detail, and the sequence stratigraphy framework is established. The evolution process of carbonate platform in Shaorbrak period is analyzed. It is considered that the Shaorbrak formation can be divided into two third-order sequences: the lower sequence SQ1 is a set of wavy microbial mats, which is in the middle-internal gentle slope sedimentary environment and corresponds to the development stage of gentle slope platform. The transgression period of the upper sequence SQ2 is the transition stage from the gentle slope platform to the weak edge platform. The slope is dominated by storm deposition, the microbial rocks are not developed, and the highlands are dominated by large progressive microbial reefs. Mainly through the cluster surface attached bacteria self-skeleton growth and microbial bonding mode to grow. The high stage is the development stage of the weak rimmed platform, and the phase difference between the platform edge and the platform is obvious. In the margin of the platform, a chamber-shaped ependymal layer was developed in the early stage, and a small progressive microbial reef group was developed in the late stage, which was bonded into a reef by microorganisms, while the inner part of the platform was a low-energy microbial beach, lacking of high early construction, and in the late stage, it was formed by laminar. Foam layer stone and stromatolite formation are mainly formed, and their formation is related to viscous microbial mat.
【作者单位】：中国石油勘探开发研究院;北京大学地球与空间科学学院;中国石化石油勘探开发研究院;
【基金】：中国石油天然气集团公司院级科技项目(2015yj-09) 国家科技重大专项(2016ZX05004-001)
【分类号】：P534.41

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