Discovery of cryptoexplosive breccia-type ore bodies and its prospecting signifi-cance in Bangpu porphyry Mo(Cu)polymetallic deposit,Xizang
The Bangpu deposit is a large porphyry-skarn Mo(Cu)polymetallic deposit in the East of the Gangdese metallogenic Belt.Authors of this paper discovered the cryptoexplosive breccia and diatreme for the first time in the east of the Bangpu ore deposit.Detailed drill core logging and studies on petrography and mineragraphy show that,the cryptoexplosive breccia can be divided into four facies zones:From shallow to deep and from center to the edge of diatreme,explosive facies,shattering facies,cracking facies and fissure facies.Breccia-type Pb-Zn-Cu ore bodies mainly occur in the fissure facies and cracking facies of breccia,and a small amount is in the shat-tering facies and explosive facies.Galena and sphalerite occur as veins,stockworks and bands in the fissure and cement of breccias.The rock-forming age of cryptoexplosive breccia is about～14 Ma,constrained by LA-ICP-MS U-Pb age of zircon in quartz monzonite porphyry breccia(14.51±0.12)Ma.This consists with the metallogen-ic ages of porphyry ore bodies(14.67±0.54)Ma～(14.11±0.31)Ma and skarn ore bodies(13.93±0.87)Ma.Their spa-tiotemporal distribution relationship suggests that the three types of orebodies belong to one common porphyry mineralized system.According to the distribution of different types of ore bodies in the porphyry metallogenic system,combined with the polycentric complex mineralization of the Gangdese metallogenic belt in the Tibetan Plateau,the discovery of cryptoexplosive breccia-type ore body indicates that there is probably another porphyry mineralization center in the eastern part of the Bangpu ore district.
万方数据
维普
