百色盆地东部坳陷北部陡坡带那读组层序特征及岩相古地理演化

The sequence characteristics and evolution of sequence-based lithofacies and paleogeography in Nadu Formation in the north scarp zone of the eastern depression of Baise basin,Guangxi,China

结合钻井岩心、测井、野外露头等地质资料以及前人的研究成果，将百色盆地东部坳陷北部陡坡带东段那读组划分为1个超长期、4个长期、8个中期和数十个短期旋回层序。以2个长期旋回层序（LSC3-LSC4对应的2个沉积层序）为单位，编制了那一期的岩相古地理图。结果表明：在那一期主要发育扇三角洲前缘-浅湖、半深湖亚相；扇三角洲平原亚相不发育，仅分布在研究区的西北部和东北部，沿断裂呈窄带状分布；扇三角洲前缘、浅湖、半深湖亚相较发育，分布在研究区中部和东南部的广大地区。

On the basis of the comprehensive study of cores, log wells, outcrops and the conclusions of other papers, the authors have explored the lithofacies and paleogeographic features and the evolution of the Paleogene Nadu Formation in the eastern sector of the north scarp zone of the eastern depression of Baise basin. According to the high-resolution sequence stratigraphic theory, the Nadu Formation is divded into one super long-term sequence cycles, four long-term sequence cycles, eight medium term sequence cycles and tens of short-term sequence cycles in this area. 2 sequence-based lithofacies and paleogeography maps of No. 1 phase of the Nadu Formation have been drawn up taking two long-term cyclic sequences （two sedimentary sequences corresponding to LSC3 and LSC4） as a unit. The results show that during the No. 1 phase of the Nadu Formation fan delta front-shallow, the deep lake subfacies developed, and the fan delta plain did not developed and was only distributed over the northwest and northeast of the study area and along with the fault as a narrow strip. The fan delta front, shallow lake, and semi-deep lake developed well and were mainly located in the central and southeast vast region of the study area.