Pyrite Genetic Mineralography And Metallogenic Mechanism Of Mississippi Valley-type Pb-Zn Sulfide Deposits In Northern Fringe Of Qujiang-Renhua Basin

Fankou Lead-Zinc deposit, Yang Liutang Lead-Zinc deposit and Luocun pyrite deposit were the representative deposits in the northern fringe of Qujiang-Renhua basin. But each deposit had its salient features on deposit scale, ore fabric and enrichment. Fankou Lead-Zinc deposit was a super large enrichment Pb-Zn sulfide deposit; Yang Liutang Lead-Zinc deposit was a middle scale Pb-Zn sulfide deposit; because of small mineralized Pb-Zn in the deposit, Luocun Pyrite deposit was a single-type small sulfide deposit.Pyrite was the important sulfide mineral in these three deposits, and the pyrite generation showed corresponding variation with each deposit. In this paper the author wants to find whether these deposits were formed in an ore-forming fluid system or not by the genetic mineralogy of pyrite. Through the same and difference of the morphology features, the crystal structure and the chemic composition typomorphic characteristic of corresponding generation pyrite in these three deposits, it is showing that the pyrite in the northern fringe of Qujiang-Renhua basin belongs to the same ore-forming fluid system.There were some the relationship and differentia between pyrite deposit (Luocun Pyrite deposit) pyrite which was subjected to the superposition of Py hydrothermalism and pyrite Pb-Zn deposit (Fankou Lead-Zinc deposit, Yang Liutang Lead-Zinc deposit) pyrite which were subjected to the superposition of Py and Pb, Zn hydrothermalism. By the rare earth, trace element characteristics of Pb-Zn sulfide ore pyrite and pyrite Pb-Zn deposit pyrite, and geologic bodies inclusion enclave, isotopic characteristics of the deposit as its supplementary means, it is showing that the magmatic process did not participate in forming of the deposits; the sulfur of the mineralizing fluids may have derived from crust stratum sulfate, pyrite Pb-Zn deposits hydrothermalism were compounding of multi-source hydrothermalism. The forming and evolution of ores in the northern fringe of Qujiang-Renhua basin related to the MVT deposits, the multiplicate processes of metallogenesis, repeating and compounding of the metallogenetic processes and the multiplicate controlling factors.To summarize, the process of deposit mineralization experienced of Hercynian pyrite mineralization, early Indo-Chinese epoch pyrite hydrothermal, Early Yanshanian polygenetic compound ore-forming fluid superposition and alteration, and the diabase intrusive superposition.