HYDROCARBON ACCUMULATION AND OIL-SOURCE CORRELATION IN THE FRONT OF JIANGNAN-XUEFENG MOUNTAIN——SERIES 3 OF THE SOUTHERN STRUCTURE STUDIES

The Jiangnan-Xuefeng uplifted belt is a nappe formed by basement decoupling from southeast to northwest and from south to north at the end of Middle Triassic Indosinian movement.It caused the Middle Palaeozoic marine sedimentary basins to be deformed with the intensity decreasing progressively.A series of palaeo-asphalt oil pool of fracture-anticline type,such as Tongjiang Bankeng,Fenghuang Shuidatian,Alaying,Cili Nanshanping,Majiang,etc.,formed in the overthrust-fault curve folding belt(B zone) in the front of Jiangnan-Xuefeng mountain,in the Lower Palaeozoic.In overthrust fault,i.e.faulted unfurl folding belt(C zone),the oil pools of faulted unfurl anticline type and surface oil formed in the Upper Paleozoic strata in Chibi Beimencha,Cili Miaoshi,etc.Oil-source correlation shows that these palaeo-asphalt oil pools accept the oil from the Lower Camberian,Lower Silurian and Lower Permian slope facies source rock in the Early Palaeozoic cratonic marginal subsidence in Indosinian-Early Yanshan period.They migrate to platform and accumulate in the "X" type fracture belt and compressional anticline in the front of nappe.