2015•Dixue qianyuanRequires access
The metallogenic regularity related to the tectonic and petrographic features of Pulang porphyry copper orefield,Yunnan,and its ore-controlling characteristics
Wenchan Li
Open publisher page 7 citations
Abstract
Geza arc is an important geological tectonic unit which formed in the Paleotethyan stage of theSanjiangarea in northwestern Yunnan.It is located in the southern tip of Yidun island-arc in the western margin of the Yangtze craton.In recent years,a series of deposits were newly found there,including the Pulang super-large sized copper deposit,Hongshan Hongniu large sized copper deposit,Xuejiping large sized copper deposit,and more than 10 small and medium sized porphyry-skarn copper deposits,which constituted a porphyry copper orefield and a copper resources exploration and development base.The research found that the formation of ore deposits closely corresponded to the tectonic evolution,and different deposits were formed in different developmental stages.The regional NW-trending main faults corresponding to the tectonic evolution controlled the rock belts distribution,and the secondary faults and fold controlled morphology and occurrence of the rock mass.Porphyry deposit is mainly distributed in the core of the anticline and the emplacement depth of mineralized porphyry is shallow;skarn copper deposit was mainly produced in the core of the syncline and the emplacement depth of the porphyry was relatively deep.Most mineralized porphyries were composite pluton and often had a volcanic rock cover on the top of the composite pluton,which indicated that volcanic magmatic activity had the inherited characteristics.The formation of the Pulang super-large sized porphyry copper deposit was strictly controlled by the intersection of NW trending structure and NEE structure,it formed atrinityporphyry mineralization system which included porphyry copper deposit inside rock mass,skarn copper deposit of the contact zone and the large vein copper ore bodies in surrounding rocks,and also include the lead-zinc deposit and epithermal gold(silver)deposit in the outer contact zone.