百色盆地那坤地区古近系那读组湖相碳酸盐岩沉积特征及控制因素

Sedimentary Characteristics and Control Factors of Lacustrine Limestone of Nadu Formation of Paleogene in Nakun Area of Baise

百色盆地那坤地区古近系那读组发育一套湖相碳酸盐岩,综合研究表明碳酸盐浅湖为其主要沉积背景,从中划分出滨湖、浅湖、颗粒滩3个亚相及其若干个微相。其沉积相展布具有自南向北颗粒滩与浅湖相间分布的特征,位于那百隆起与那坤低潜山带北西段相衔接的部位滩核微相分布面积最大。沉积作用和微相展布规律主要受古气候、古地形及水动力状况等因素的控制。

A set of lacustrine limestones were developed in the Nadu Formation of Paleogene of Nakun Area in Baise Basin.The systematical study indicated that the depositional setting was carbonate shallow lake.The sedimentary facies of lacustrine limestones was divided into three subfacies such as coastal lake,grain bank and shallow lake and as well as various microfacies.Then several microfacies are recognized,and the sedimentary characteristics of each microfacies are studied in detail.The characteristics of sedimentary facies belts were the grain bank alternating with shallow lake from the south to north.The largest grain bank was located in north-west of the joint of Nabai Hunch and Nakun low buried-hill belt.Sedimentation and microfacies distribution rules controlled by paleoclimat,paleotopography and hydrodynamics conditions.