Tectonic Evidence For Indosinian Mineralization Of The Wuxu Orefield In Hechi City

Wuxu ore field is an important polymetallic ore field in the southern part of the Danchi metallogenic belt.Wuxu mine area has been largely mined,proven minerals are molybdenum,lead,zinc,etc.So far,the South China region has been identified as Indosinian mineralization deposits are very rare,and most of the research is more dependent on isotopic chronology.Danchi metallogenic belt is affected by tectonic stress in southern China,and it has not been reported that there are geological and chronological evidence of Indosinian mineralization,and the cause of the largest ore field in the metallogenic belt has been debated for a long time.The view of the mineralization in indosinian has great geological significance to re-understand the genesis,metallogenic epoch and metallogenic prognosis of Danchi metallogenic belt.On the basis of previous work,this paper makes a detailed study on the Geological characteristics of orefield and metallogenic structure formation mechanism to the genesis and the metallogenic epoch of the Wuxu ore field.This article divides the stage of mineralization tectonics evolution and has achieved the following main understanding:1?Based on the analysis of the previous studies of Danchi metallogenic belt,It is found that the Wuxu anticline in the Wuxu ore field is the same as the Dachang anticline in Dachang ore field,all belong to the north east wing shelving,south west wing dipping or inverted half box decollement fold.Wuxu ore field is part of the decollement fold of Late Paleozoic caprock in the Dian-qian-gui border area of indosinian.2?The mudstone in Mid-Devonian period stratum of Wuxu ore field is sandwiched between the banded limestone and siltstone,by NE-SW regional tectonic stress,the carbonaceous clay occurs bedding layer shear and fold thrust in the middle of the ore field,forming a bedded thrust type brittle-ductile shear zone in the layer;The lithology of the upper limestone is more prone to cause interlayer cracks,when the stress increases to a certain extent,the interlayer fracture zone is formed.With the continuously strengthened tectonic stress of NE-SW,and the north west of blind thrust has been formed;The fault dip tend to be smaller when the thrust is extended to the soft rock,and finally to the layers of sliding and disappear,the decollement fold are formed at the end of the thrust in the deep formation.3?The mud rock series?D₂n?in the core of the Wuxu anticline is a brittle ductile detachment,the lead and zinc antimony ore vein of step left in bedding layer is developed,constitute the original ore body position of the large-scale lead-zinc antimony deposit of Jianzhu slope deposit;In the process of progressive detachment fold deformation,the closed flexure flow folds are formed by early bedded orebodies in the core of the fold and the layer.The ore body state is steeply steep,The veins are repeating in the flat,cross section,belongs to the structure-fluid vein mineralization structure.4?The formation and evolution of the veins in the Jianzhu slope deposit of Wuxu ore field are closely related to the evolution of the Wuxu anticline.The relationship between the orebody's position and the decollement fold in Indosinian is tectonic–coupling,It shows that the series of deposits in Wuxu ore field should be formed in Indosinian,Belonging to a metallotectonic series.