黑龙江多宝山—铜山斑岩铜(钼)矿床绿帘石矿物成分特征及其成矿指示意义

Mineral composition of epidote in Duobaoshan—Tongshan porphyry Cu-Mo deposit,Heilongjiang and its implications for mineralization

运用电子探针和LA-IPC-MS分析多宝山及铜山岩体中绿帘石的主、微量成分,结果表明多宝山铜(钼)矿床斑岩体的绢英岩化带含矿样品中绿帘石富Al2O3、SiO2,贫Fe OT,青磐岩化带中绿帘石则富TiO2;铜山矿床斑岩体的青磐岩化蚀变带中绿帘石富含MnO、Fe OT,贫Al2O3和SiO2。多宝山斑岩体中蚀变带及铜山地区中的绿帘石均富集LREE和LILE (Th、U、Sr、Sm),亏损HREE和HFSE(Nb、Zr、Hf)。绿帘石Ps值与样品的含矿性呈负相关,即含矿绿帘石的Ps值明显低于无矿绿帘石的Ps值,青磐岩化带中绿帘石的Ps值集中在26~34之间。多宝山含矿样品中绿帘石的Cu含量高于距成矿中心较远的多宝山和铜山的无矿绿帘石Cu含量。笔者认为斑岩铜矿床中蚀变绿帘石的成分特征可以反映矿化热液的特征,具有指示矿化的潜力。

The main and trace components of epidote in Duobaoshan and Tongshan deposits were analyzed by electron probe and LA - IPC - MS. The results show that the epidote in the phyllic alteration zone ore-bearing samples of porphyry in the Duobaoshan copper deposit are rich in Al 2O 3 and SiO 2 , poor in FeO T, while the epidote in prophylitic zone is rich in TiO 2 .In the Tongshan deposit, the epidote in the propylitic alteration zone is rich in MnO and FeO T, but the contents of Al 2O 3 and SiO 2 are low. In terms of trace elements, both Duobaoshan and Tongshan porphyry deposits are rich in LREE and LILE(Th,U,Sr,S), poor in HREE and HFSE (Nb,Zr,Hf). Negative correlation is observed between Ps value of epidote and mineralization. That is, the Ps values of epidote in the ore-bearing samples are lower than the Ps of epidote in the ore-free samples, and the Ps value of the epidote in the propylitic alteration zone is between 26 and 34. Cu content in ore-bearing epidote is also significantly higher than that of the Cu-free epidote which is far away from the metallogenic center of Duobaoshan and Tongshan. It is suggested that the composition of the altered epidote in the porphyry copper deposit can reflect the characteristics of mineralized hydrothermal fluids and can be a potential indicator of mineralization.