Ore-controlling Structures Study On The Iron-lead-zine Polymetallic Deposit And Its Periphery In Dapai Village,Yongding County,Fujian Province

Located on the southeastern margin of the southeastern continent,southwestern Yunnan,after a series of late Paleozoic era,the Proterozoic Huaxia Paleozoic formation and cracking,the Early Paleozoic South China continent fold uplift,the Late Paleozoic intracontinental rift,and the strong tectono-magmatism since the Mesozoic Era Carbonate and coal-bearing clastic rock deposits with iron-lead-zinc polymetallic ore deposits,and a large amount of Late Mesozoic intrusive granite grouts.It is an important metallogenic concentration area in southeastern China.The Yongding Dapai ferrous-lead-zinc polymetallic deposit is located in the south of the Late Paleozoic depression in southwestern Yunnan,in the south of Datian-Longyan sub-level depression,and on the west side of Zhenghe-Dapu deep fault in Datian.The tectonic system of the mining area is complex,mainly including large-reversing inverted folds,shallow-thrust nappe structures,and detachment structures,as well as a series of fracture combinations.Previous studies on the ore-controlling structure of the deposits were few,and the thrust nappe structure was considered to be the main ore-controlling structure in the mining area.On the basis of extensive research on the literature and large row of borehole data,it is observed that the occurrence of orebodies is closely related to the nuclear limestone strata of the large-reversal inverted anticline,and the spatial distribution is also affected by the wrinkling morphology.Therefore,it is necessary to further study the ore-controlling structural system in the large-displacement mining area.In the field geological survey of the Dapai iron-lead-zinc polymetallic ore deposit and its periphery,this paper mainly studied the structural characteristics of the ore minerals and the characteristics of the wall rock alterations in the mining area.It is clear that the metallogenic stage of the deposit is divided into four phases,ie,early skarn.Stage,late skarn stage,quartz-sulfide stage,and epitaxial oxidation stage;an east-west length profile of 10 km is measured on the mining area and its periphery,and is referenced to seismic data at the same line location,from surface to underground A multi-level deep study of the structural framework of the mining area.It is clarified that the spatial distribution of orebody is mainly controlled by the axial direction of the near-NW to dual inverted anticline,and the whole body of the ore also tends to plunge northwards with the fold.The folding end space and the two-wing detachment space are the ore-bearing structures.The early NNE-fractured?F₁?zone and shallow thrust nappe structures provided the channel for the migration of ore-forming hydrothermal fluids.The EW fault?F₄?and NE fault?F₃?faults get through the early faults and orebodies,Become a broken ore structure;study the ore-forming structural plane in the mining area,and make clear that the major ore-forming structural planes in the mining area are the granite body and the Chuanshan-Qixia Formation limestone stratum contact zone and the Wenbishan Formation and Chuanshan-Qixia ash Inter-layer fracture zones in rock formations;summarizing the lithology and emplacement age and space of granites in the mining area,the granite associated with metallogenesis was considered to be an early Cretaceous granite intrusive rock mass of 132.35±0.83 Ma.Based on the above studies,combined with regional tectonic evolution and magma distribution characteristics,the ore-controlling structural model of the Dapai iron-lead-zinc polymetallic deposit was simulated.Finally,it is concluded that the ore-controlling structure of the Dapai iron-lead-zinc polymetallic ore deposit is mainly composed of double inverted anticlines,the thrust nappe structure and interlayer slip faults in the mining area provide favorable conditions for the ore-forming,and the ore body will be broken later.Finally,the characteristics of sedimentary-retrofitting iron-lead-zinc polymetallic ore deposits in the depression belts in southwestern are summarized,and the direction of prospecting is further specified.