Orefield Structure And Geochemistry In The FanKou Lead And Zinc Deposit

FanKou giant Pb-Zn ore deposit, Guangdong, is situated on the north of Quren structural basin in Nanling mineralization belt. The bearing-ore stratigraphy is the Devonian carbonate. The area has experienced many periods of tectonic activity associated with NNE, NE, NW and NWW trending faults. The morphology of the individual orebody is more complex and similar to melon-shape and bine-shape. Structure is most important ore-controlling factor for forming and orientation of orebodies in FanKou. The metallogenetic stages was recognized as pyrite stage and sphalerite-galena stage. The deposit is very similar to the typical MVT deposits, but there are also some differences.Based on structural analysis, geological characteristics of deposit, elements geochemistry, isotope geochemistry, structural ore-controlling model, genesis and metallogenic source of FanKou ore depositt, Guangdong are mostly investigated in this article. The main achieved advancements from this thesis are as follows:(1) A pre-mineralization, large-scale NWW trending faults have been firstly identified, which are cut-across by the NNE, NW-trending fault. The "broken turbostratic" was fault rocks formed during the period when NWW-trending faults were developing. It is the upper boundary of the orebodies and a block layer during upward migration of hydrothermal liquid along the principal channel.(2) Geological data shows that this area has experienced many periods of tectonic activity associated with NNE, NE, NWW and NW trending faults. Previously the NNE-NE faults were considered to be the ore-controlling structure, and continued to be active during the ore-formation period, while the NWW trending structure were suggested to be the thrusts prior to mineralization, and NW trending faults formed at the latest.(3) These sulfur isotopic compositions indicate that the ore-forming materials originate from seawater and Marine sulfate, also from other sources like magmatism. Sulfides formed in the earlier stage of mineralization provide part of the sulfur. The minerogenetic tempreture is mid-temperature. The lead isotopic compositions show that the ore-forming materials originate from the Uppercrust.(4) Pyrite formed in the multi-phase hydrothermal process. Arsenic-rich zone within Pyrite, is consistent with the arsenopyrite and chalcopyrite in the core of sphalerite, indicating that the high-temperature fluids was active late in the pyrite -formation period. Sphalerite formed in the low-temperature generally, and its color is irregular for some complex reasons.(5) FanKou Pb-Zn ore deposit is very similar to the typical MVT deposits, but there are also some differences. The main mineralization was the mixture of mid-low temperature fluids, mixing the magmatic hydrothermal.