Geological Characteristic And Origin Of Lead-Zinc Deposits In Qianjindongshan, Heilongjiang Province

Yichun - Yanshou mineralization belt is an important Mo, Cu, Pb, Zn, Au, Ag polymetallic mineralization belt in Heilongjiang province and even our country. Its geostructure position is in the connection spot of Songnen - Xiaohingganling block and the Jiamusu block. It has experienced a number of tensions and amalgamates in the long history of geological development evolutionary process; the tectonic magmatic activity grew extremely. The complex geologic structure environment has formed this area rich mineral resource. Qianjin area located at Yichun– Yanshou mineralization belt middle, west take Xunke - Tieli– shangzhi fault as, east near the Jiamusu block. Qianjindongshan lead-zinc deposit is Pb, Zn, Cu, and Fe polymetallic ore deposit which was recent discovered and investigated in recent years, the ore deposit scale medium, the mineralization geological condition was superior, the sign of ore-prospecting to be obvious, which demonstrated that it had the good prospecting potential.This article deeps research ore deposit geological feature, the geochemistry characteristic, the mineralization geological condition and the mechanism of the ore controls, based on the analysis of the mineralization geology background, discuss this area's metallogenic material source, the mineralization type and the characteristic and the mechanism of the mineralization concentrates, then determines the origin of the ore deposit and establishes the mineralization pattern. The studies show that mainly strata of ore district are Middle Ordovician Xiaojingou group and Upper Triassic Fengshantun group, and Xiaojingou group is the main ore bearing strata of the skarns ore deposit. The lead-zinc mineralization grew in the contact zone of Fengshantun group and the intrusion or nearby the fissure between layers of the wall rocks. Comprehensive studies indicate that ore texture primarily include solid solution separation texture, crushed texture, skeleton crystal texture, erosion and idiomorphic–auotriomorphic granular textures and so on. The structures primarily include brecciated, massive and disseminated-vein disseminated.The results show that ore body of lead-zinc polymetallic located in granite, granite-prohyry, quartz porphyry and Xiaojingou group or the intrusion contact zone of Fengshantun group and nearby the fissure between layers of the wall rocks as resembles layered, vein, lenticular and the lens shape. The occurrence and distribution of ore bodies in ore deposit were controlled by NE, NW, NWW trending fracture structure. Wall rock alteration is strong and dominated by garnet, wollastonitization, diopside, epidotization, actinolite, tremolite and silicfication. Skarn has obvious zonation. Cu, Fe mineralizations have closely relation with silicfication, garnet skarn, wollastonite skarn and diopside skarn. Lead-zinc mineralizations have closely relation with epidotization, actinolite and silicfication.Our studies showed that tectonic-magmatic activties in Mesozoic period provide necessarily wide space and source. Statistical analysis result of metallogenic elements indicated that granite-prohyry, quartz porphyry and monzonitic granite have important controlling effect to Pb, Zn, Cu, Ag polymetallic ore-forming, which are important resources of metallogenic material and ore-forming hydrothermal fluid. Xiaojingou group and Fengshantun group stratums also provide partial metallogenic material source.The studies show that the area polymetallic deposits belong to middle-high temperature- middle-low temperature hydrothermal deposit. Qianjindongshan Cu, Fe, Pb, Zn, Ag mineralization have characteristic of skarn type deposit. Xilingnanshan and Xilingdongshan Pb, Zn ore-forming belong to magmatic hydrothermalism origin.According to comprehensive research results, summarized the prospecting signs and determined the direction of further prospecting.