束鹿凹陷古近系沙三下段沉积相特征研究

Sedimentary facies in the lower part of the third member of the Palaeogene Shahejie Formation in the Shulu depression,Hebei

本文通过岩相特征、沉积构造特征、化石及地球化学特征,对束鹿凹陷古近系沙三下段的总体沉积特征进行了概述,将研究区的沉积相类型定为湖泊相。通过对研究区沉积微相的详细分析,认为厚层块状砂砾岩主要发育贫基质的碎屑流沉积,浊流沉积及颗粒流沉积少见;泥灰岩主要发育具有复杂沉积模式的混合沉积,细分为互层混合沉积、结构混合沉积和夹层混合沉积三种类型。通过对沉积相的平面展布特征的研究表明,研究区是以碎屑流沉积和混合沉积为主体的半深湖-深湖沉积体系。

The present paper deals with the sedimentary features of the lower part of the third member of the Palaeogene Shahejie Formation in the Shulu depression, Hebei on the basis of sedimentary facies and sedimentary structures, plant remains and geochemical signatures. The detailed study of the sedimentary microfacies has disclosed that the thick massive sandstone and conglomerate are dominantly composed of matrix-poor debris flow deposits with rare turbidity current deposits and grain-flow deposits. The marl mainly consists of the mixed deposits, which may be subdivided into the interbedded mixed deposits, structural mixed deposits and intercalated mixed deposits. In general, the study area displays, as indicated by the planar distribution of the sedimentary facies in the study area, the semi-deep lake and deep-lake depositional systems in which the debris flow deposits and mixed deposits are accentuated.