江苏句容地区早石炭世大塘期高骊山组沉积类型与层序特征

Depositional types and sequence features in Kaolishan Formation of Early Carboniferous Datangian in Jurong,Jiangsu

江苏句容高骊山是早石炭世大塘期高骊山组出露较好的剖面。通过野外观测和镜下分析研究,显示高骊山组主要发育泥岩、硅质岩和砂岩。岩性组合显示高骊山组由4个岩性段组成:①粉砂岩段、②页岩段、③硅质岩和页岩互层段和④砂岩段。沉积类型分析显示,高骊山组主要发育滨海沉积、浅海-半深海沉积和三角洲沉积,可进一步识别出滨海泻湖、深水陆棚、三角洲前缘和三角洲平原等4种亚相,泻湖泥质沉积、深水泥质沉积和硅质沉积、间湾、水下河道、朵叶间、分流河道和河道间等7种沉积微相,以发育深水硅质沉积为特色。根据岩性和岩相变化,高骊山组是一个完整的三级沉积层序。该层序由低位体系域、海侵体系域和高位体系域组成。相对海平面变化分析显示,研究区在高骊山时期经历了一个三级海平面升降过程,控制了三级层序的发育。根据沉积构造分析,高骊山时期为挤压背景下的弧后前陆沉积。

Kaolishan Formation of Early Carboniferous stage Datangian is outcropped in Kaolishan of Jurong, Jiangsu Province. The Kaolishan Formation mainly developed in mudstone, siliceous and sandstone. The litho asso- ciations show that the Kaolishan Formation is composed of four lithologieal members including： ①siltstone, ② shale, ③ alternating siliceous and shale and ④sandstone. The main sedimentary types of Kaolishan Formation are coastal, shallow marine-bathyal and delta. Four subfaeies including coastal lagoon, deep water shelf, delta front and delta plain, and seven micro-facies including lagoon mud, deep water mud and silicious, inter-bay, underwa- ter channel, inter-lobe, interdistributary channel and interchannel; are further identified, which are characterized by deep water silicious in this area. Based on the ptrology and lithofacies change, the Kaolishan Formation can be