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金湖凹陷西斜坡阜宁组第二亚段(E1f22)发育一套生物碎屑灰岩为主的灰砂岩混积地层,该地层属于层系混积地层。在前人研究基础上,通过对古气候、古盐度、沉积环境的分析,认为研究区阜宁组第二亚段沉积时期为亚热带气候,存在海侵事件,水体盐度较大,整体为一套碳酸盐岩坪沉积体系。沉积相垂向序列研究等发现阜宁组第二亚段发育两类沉积旋回,以下部为泥页岩、上部为生物碎屑灰岩或泥灰岩的沉积旋回及下部为粉砂岩、上部为生物滩坝灰岩的旋回,仅在局部发育少量全部为砂岩的小层,并且砂岩多数与断层的发育存在密切关系,从而提出了“Y”型同生断层输送碎屑沉积物模式。研究区灰砂混积岩沉积是在湖盆湖平面上升期,湖盆为咸化湖泊,存在形成沉积范围较广生物碎屑灰岩条件的大环境下,由于陆源碎屑不断堆积,断层断距不断减小直至消失,在碎屑岩顶部形成灰岩层,从而形成了灰砂混积岩。
The second sub-member of the Funing Formation (E1f22) in the west slope of the Jinhu Depression develops a set of bioclastic limestone-rich limestone mixed layers that belong to the stratigraphic mixed-layer formation. Based on the previous studies, through the analysis of palaeoclimate, paleosalinity and sedimentary environment, it is concluded that the sedimentary period of the second member of the Funing Formation in the study area is sub-tropical climate with transgression, and the salinity of the water body is large, A set of carbonate rock deposition system. Sedimentary facies vertical sequence study found that the second member of the Funing Formation developed two types of sedimentary cycles, the lower part is shale, the upper part is bioclastic limestone or marl, and the lower part is siltstone. The upper part is The cycle of the limestone in the bio-dams shows a small number of small sandstones that are all locally developed, and most of the sandstones are closely related to the development of the faults. Therefore, the “Y” type synsedimentary fault sediment transport model is proposed. Sandstone and alluvial sediment deposition in the study area is at the rising stage of the lake basin. The lake basin is a salinized lake. Under the environment of forming bioclastic limestone with a wide range of deposition, due to the continuous accumulation of terrigenous debris, From the ever decreasing to the disappearing, a limestone layer was formed on the top of the clastic rock, forming the sand-gravel mixed rock.