地层学杂志

通过研究构造背景、野外露头、岩性组合、沉积构造、古生物特征和测井曲线特征,分析和总结鄂尔多斯盆地白垩系洛河组至环河华池组沉积相、相带分布范围和沉积特征。洛河组主要沉积了冲积扇相、风成沉积相、辫状河相和沙漠相;而在环河华池组主要沉积了湖相、三角洲相、曲流河相及风成砂岩夹层。平面上沉积相带的变化规律性较强,由盆地边缘的冲积相、冲积—河流相砾岩向盆内渐变为河流相—滨浅湖—半深湖相泥岩。沉积特征受构造运动影响和沉积相带控制,洛河组是从山缘向盆地内砂岩厚度迅速变薄、尖灭;环河华池组岩性变化表现为北粗南细、东粗西细,在北部砂体呈现东薄西厚,东北向西南增厚,在南部砂体呈近南北向展布,东薄西厚,南薄北厚。

The sedimentary facies and facies distribution of the Cretaceous Luohe and Huanhe-Huachi formations in the Ordos Basin are analyzed using regional structure, outcrop, drill core, lithological, sedimentary, palaeontological, and well log data. Major sedimentary facies in the Luohe Formation include alluvial fans facies, eolian facies,braided fluvial facies, and desert facies. Major sedimentary facies in the Huanhe-Huachi Formation include lacustrine facies, delta facies, meandering fluvial facies, and interbedded eolian sandstone facies. Alluvial facies and alluvial-fluvial conglomerate facies are found mostly in the margin of the Ordos Basin, whereas fluvial and lacustrine mudstone facies occur in the central Ordos Basin. This spatial pattern of facies distribution is controlled by the configuration of the basin. Sandstone beds of the Luohe Formation thin from the margin to the center of the basin. Sediments in the Huanhe-Huachi Formation coarsen to the north and to the east. In the northern part of the basin, sandstone beds thin to the east and to the northeast. In the southern part of the basin, sandstone bodies extend in the north-south direction and thin to the east and to the south.