Study On The Multi-phase Fluid Activities Of Dengying Formation And Tectonic Uplift Of Micang Mountain Area

Fluid, as a leading edge of research project, has been very concerned by thedomestic and foreign geologists. However, the research about the fluid release intectonic disturbance and the relationship between tectonic and fluid has been veryweak. Multi-phase tectonic uplifts in Micang mountain tectonic belt interlaced withmulti-phase fluid fillings of Dengying Formation. Most of the documents did notexplore the relationships between tectonic uplifting and fluid filling. This weak pointwas selected by this paper. Paper researched from two different angles of tectonic andfluid; taken several sections in southern Micang Mountain as the research object; usedresearch tools such as sedimentology, geochronology and fluid geochemistry. Paperestablished the matching relationship between tectonic uplift and fluid filling.Tectonic uplift’s influence on fluid filling and zoning has been explored. Thefollowing conclusions have been reached:Study area has experienced the tectonic uplift before Dengying stage, tectonicuplift in Dengying stage, tectonic uplift in eopaleozoic, tectonic uplift in Indo-Chineseepoch, tectonic uplift in Yanshan epoch and tectonic uplift in Himalayan epoch. Thetectonic uplift before Dengying stage formed the paleo-uplift and control theevolution pattern of study area. Tectonic movements before the middle Triassic epochwere mainly characterized by marine vertical shock of the stretch background.Tectonic movements after the middle Triassic epoch were mainly characterized byterrestrial thrusting nappe of squeeze background. The tectonic in the Yanshan andHimalayan epoch were full thrusting nappe.Multi-phase tectonic upliftings, especially the full thrusting nappe in Yanshanand Himalayan epoch, formed the structure pattern with basal thrust belt, piedmontfault-fold structural belt and front monoclinic. Thrusting nappe started at the basal thrust belt and extended to the front monoclinic. The uplift rate reduced from thebasal thrust belt to the front monoclinic.Study area have multi-phase fluid fillings. The fluid fillings can be divided intothe first phase of epigenetic karst fluid, the second phase of brine water fluid, the thirdphase of bitumen, the fourth phase of ore-bearing hydrothermal fluid, the fifth phaseof brine water fluid, the sixth phase of bitumen, the seventh phase of brine water fluid,the eighth phase of epigenetic oxidation fluid. The third phase of bitumen was formedin the late middle Cambrian; the fourth phase of ore-bearing hydrothermal fluid wasformed about480Ma; the sixth phase of bitumen was formed in the LatePermian-Early Triassic.Tectonic uplift cause fluid release, fluid formed multi-generation minerals withinthe rock pores after it was destroyed. The tectonic uplift in late middle Cambriandestroyed the first phase of ancient petroleum pool, the tectonic uplift in late middleSilurian destroyed the first phase of ancient gas pool, the continue burial in LatePermian-Early Triassic caused the second phase of petroleum pool cracked to gas, thetectonic uplift in Yanshan epoch destroyed the second phase of ancient gas pool.The paleo-uplift before Dengying stage controlled the tectonic framework andfluid filling of study area. The first phase of epigenetic karst fluid was mainly formedin the middle area of paleo-uplift. The fourth phase of ore-bearing hydrothermal fluidoccurred differentiation in the slope of paleo-uplift, it formed thefluorineâ†'acerillaâ†'blende mineral zonation from the slope to edge of the uplift. Thecontent of bitumen, which comes from ancient petroleum pool, gradually decreasefrom the middle to the edge of paleo-uplift.