准南大黄山二叠系芦草沟组油页岩相控成矿模式

Mineralization model of oil shale controlled by facies in Lucaogou Formation of Permian,Dahuangshan,Zhunnan

采用沉积岩石学、沉积学、有机岩石学、层序地层学及有机地球化学对准南大黄山油页岩进行研究。研究结果表明:准南大黄山油页岩属腐泥型和腐殖腐泥型成因类型,主体发育在半深湖—深湖环境,缺少陆生植物输入,缺失底栖生物。凝灰质的存在指示火山营养物质促进了藻类和其他浮游生物的繁衍。表层水体有机质繁衍旺盛,底层水体闭塞滞流且咸化缺氧,提供了巨厚优质油页岩特殊的分层水体悬浮加积与持续成矿的条件。含矿岩系由低水位体系域、水进体系域、高水位体系域和水退体系域构成,油页岩发育于不同的体系域,其中水进体系域的湖泛期和高水位体系域的整个加积过程更有利于油页岩沉积成矿。

Base on the sedimentology, organic petrology, sequence stratigraphy and organic geochemistry ,oil shale was analyzed in the studied area. Its origin types are sapropelic and humosapropelic, which mainly developed in semi-deep lake and deep lake. Land plant and benthon in this sedimentary environment were rare,and the tuffaceous indicates that volcano nutritive substance improved the propagating of algae and other plankton. Organic matter propagated quickly in surface water and the bottom water is stagnant and anoxic with high salinity,therefore,this especial water condition (suspension and aggradation of layering water body and continuous mineralization) was advantaged to the formation of the thick oil shale. The rock series is composed of lowstand systems tract(LST) , transgressive systems tract ( TST) , highstand sys-terns tract ( HST) and regressive system tract ( RST). The oilshale developed in different system tracts,and the lake floodingof TST and aggradation of HST were the advantaged tracts for theformation of the oil shale.