【摘要】 柴西南英西地区下干柴沟组上段为一套湖盆含蒸发岩系。文章综合运用薄片、岩心、钻井、测井、化验分析等资料,对研究区下干柴沟组上段蒸发岩系沉积旋回特征进行了研究。研究表明,平面上由盆地中心向边缘呈现蒸发岩-混积型碳酸盐岩-碎屑岩的环带状分布,纵向上发育2个三级旋回及6个四级旋回期次。各级蒸发岩沉积旋回具有不对称的特征,即快速湖侵、缓慢湖退。总结出研究区的五种蒸发岩岩相组合类型。研究区蒸发岩为气候干旱、盆地基底快速沉降背景下,湖退时残留盐湖中以蒸发结晶为主具有一定水深的成因,并建立了沉积旋回发育模式。更多还原

【Abstract】 The upper member of the Lower Ganchaigou Formation in the Yingxi area, southwestern Qaidam Basin, is a set of evaporitebearing lacustrine series. Pate of thin section, cores, drillings logging as well as geochemistry were systematically used to study the characteristics of sedimentary cycles of the series in this paper. Results show a zonal distribution of evaporites to mixed carbonate rocks and to clastic rocks from the center to the margin of the basin laterally. Vertically, two third-order sedimentary cycles and six fourth-order sedimentary cycles were developed. Sedimentary cycles of all the levels are asymmetry with rapid transgression and slow regression. Five types of lithofacies combination of evaporites were identified. Evaporites were formed by evaporitive crystallization under a certain depth of lake water during regression, when there was an arid paleo-climate and rapid subsidence of the basin basement.The development model of sedimentary cycles in the study area is established accordingly.更多还原