Lawn Of The Western Margin Of The Basin LANPING Tectonic Deformation Characteristics Of Copper And Developmental Mechanisms

The lancang river fault zone is located in the west Lanping basin, its growth presents the nature of multiphase and multi-stage,and obviously controls polymetallic metallogenic belt of the western margin of output which mainly copper.This selection of Maocaoping mining area belongs to the Yunlong county Gongguo town (the former town of Jiuzhou), located in Lanping basin west margin, the west close to the lancang river fault middle, belongs to the middle of the northeast margin of qinghai-tibet plateau "orogenic type" which is full of copper, lead and silver-polymetallic metallogenic belt.The area is representative tectonic position, to get the lancang river fault zone in the tectonic deformation characteristics and the mechanism has important significance.Through the field geological investigation, exploration, data acquisition, and comprehensive analysis and summary, tectonic deformation characteristics of the studied area, which set out its structural deformation sequence. Main research results and understanding are as follows:(1) The study area mainly outcropped strata have Pt2hm2, T3C,J2h,J3b,Klj,etc. And its appears strongly deformation.(2) The study area from west to east development of the fault of Lancang river in turn is part of the fracture and on the east side of F3, F4, F5, F2thrust nappe fault and fold structure.(3) The Maocaoping mining area of vein copper deposit is likely to exist two copper polymetallic metallogenic events (that is48-50ma,27-29ma), the former mainly for molybdenum, the later mainly for copper and silver, which are western of Lanping basin formed under the regional strike-slip tectonic background Himalayan thrust nappe process of the Lancang river fault zone, and the corresponding pressure by twist to a shear stress environment is related to the structure of the conversion process, and this is a generally think this area before and thrust nappe know about copper polymetallic mineralization (concentrated in Oligocene, development time is37-23ma).(4) Tectonic development and evolution in the study area is: 1) The late Paleozoic (Hercynian final or Indosinian epoch) under the action of drooping east-west tension, it is formed within the mining area also the most important of the area with deep faults control meaning, namely the lancang river fault, this basic structure is the first basic structure in the area. In Triassic, the developmental step fault from west to east, and north and south, is located in the lancang river fault found near the middle of a group, in parallel with the movement characteristics similar to those of the south-north fracture, such as F1, F2, belongs to secondary structure.Cretaceous the fracture stablely development. Phase indo-chinese and yanshan epoch, after repeatedly orchid basin subsidence, began to enter extrusion deformation, the transformation stage of Himalayan.2) During the early Himalayan, under the extrusion stress of NNW, Lancang River developed to right reverse slippery fracture. Meanwhile, due to the nappe extrusion, fracture east of several groups of nearly ns-trending fold, and the period of F3and F4fault belong to three times.3) Under the action of regional NW-SE compressional stress, and added material fracture on the granite rock mass due to the vertical extrusion, rock mass to the west indenting, distorted the Lancang river fault, to NNW to extending out of the mining area. F5fracture is roughly parallel to the F4faults; F6fault formation; Fold structure in the further development of evolution, fold towards to distortion of west, near the fold developed an array of secondary faults, small song, belong to construct four times. Granite rock mass fracture intrusion along the Lancang river, and nappe further evolution; At the same time, the Pt2hm2also from west to east in the form of geological body nappe in the Mesozoic sedimentary.4) During the late Himalayan, under the extrusion stress of regional NEE-SWW, the lancang river fault zone occurred right strike-slip again, fold was affected by partial right to walk of the phenomenon of the intermittent. Zone formed multiple sets of occurrence and the skeleton structure is obviously different from characteristics of conjugate joints, developed repeatly fold and fault, among that because fold nappe role further, develop into larger compound overturned anticline, belonging to the five constructs.