Geochemisry and Zircon U-Pb Geochronology of the Diorite Porphyry Associated with the Jinchang Cu-Au Deposit, hemas-microsoft-com:office:smarttags" />Heilongjiang Province
详细信息
- 责任者：Zhao Yusuo (State Key laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Yang Liqiang
- 刊名：Acta Petrologica Sinica
- 出版年：2012
- 卷期：28(2)
- 关键词：铜矿 ; copper ores ; 金矿 ; gold ores ; 闪长玢岩 ; diorite porphyry ; 黑龙江省 ; Heilongjiang Province
- 页码：p.451-467
- 图表：8 illus., 4 tables, 50 refs.
- 分类号：1001
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
The Jinchang Cu-Au deposit,a super-large ore deposit explored in the latest,is mainly of breccia-type ore body and is spatially closely associated with diorite porphyry which is apophysis like and porphyry structure with mainly plagioclase,hornblende and little pyroxene as phenocryst.Major element data show that the SiO2 content of diorite porphyry is 54.62%～67.82%,average as 60.33%;Al2O3 content is 14.52%～18.25%,an average of 16.62%,and ratio of K2O/Na2O is 0.06～0.31,less than 0.5.All these indicate that diorite porphyry belongs to sub-alkaline series and have a calc-alkaline evolutionary trend with a lower potassium content.While the LREE/HREE ratio of the porphyry diorite is relatively higher,between 5.06 and 14.24 with an average of 9.16 and the δEu of 0.85 to 1.46 shows a positive anomaly.Then,trace elements of porphyry diorite shows low Y and Yb,but high Sr.The ratio of Sr/Y is between 35.87 and 111.4,average as 57.57(>40) .Moreover,the primitive mantle-normalized trace element spider diagram shows that the diorite porphyry enriched in large ion lithophile elements(LILE) while depleted in high field strength elements(HSFE) ,especially Nb,Ta and Ti depletion,besides some enrichment of Pb.The geochemical data suggests that the diorite porphyry is probably adakitic rock and were produced by crustal contamination and fractionation of mafic magmas generated from partial melting of mantle source which had been metasomatismed by the subduction fluid.In addition,an 118.1±1.6Ma to 115.7±2.0Ma diagenetic age and an 118.1±1.6Ma mineralization age of diorite porphyry in Jinchang deposit,consistence with the 120～110Ma magmatic activities epoch in the eastern part of Jilin and Heilongjiang provinces,revealed that the Jinchang porphyry Cu-Au metallogenesis possiblely related to the Early Cretaceous subduction of the Pacific plate.It is potential to exploration the porphyry-epithemal system copper-gold deposit of the same period in the eastern part of Jilin and Heilongjiang provinces.
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