渤海海域沙一、二时期碳酸盐岩沉积特征及主控因素分析

Sedimentary characteristics and controls of the carbonate rocks during the deposition of the first and second members of the Shahejie Formation in the Bohai sea area

渤海海域沙一、二时期湖相碳酸盐岩分布广泛。根据其沉积特征可划分为台地型、斜坡型、水下隆起型和混合沉积型4大类及相应的亚相、微相,其中位于湖平面之下浪基面之上的各类浅水湖泊碎屑滩(生物滩、陆屑滩)储层最为发育。该时期渤海海域为温暖潮湿的北亚热带气候、封闭的微咸水-半咸水的环境。古地貌特征为影响碳酸盐岩发育和富集分布规律的主控因素,周边陆源碎屑供给能力则影响碳酸盐岩的发育程度。

The lacustrine carbonate rocks occurred on a wide range of scales in the Bohai sea area during the deposition of the first and second members of the Shahejie Formation, and may be grouped into four sedimentary facies types, including the carbonate platform, carbonate ramp, subaqueous uplift and mixed silieiclastie-carbonate facies types. The shallow lacustrine organic bank and terrigenous elastic beach reservoirs are best developed in the horizons between the lake level and wave base. During the deposition of the first and second members of the Shahejie Formation, the Bohai sea area was then in the warm humid subtropical climates and enclosed saline and brackish environments. The palaeogeomorphological features and terrigenous supply capacity are believed to be the main controlling factors for the development and distribution of the carbonate rocks in the Bohai sea area.