The Geological Characteristics And Genesis Of The Hongyuan Porphyry Mo (Cu) Deposit From West Junggar

The Hongyuan porphyry Mo (Cu) deposit, discovered in2010, is located in the WestJunggar region of Xinjiang of northwest China. The rock type of the Hongyuan plutonincludes granodiorite and Monzogranite. The deposit is hosted within the Karamaygranodiorite porphyry that intruded into Early Carboniferous sedimentary strata andJiafusaersu pluton. The southern Darbut teoctonic magmatic metallogenic belts is theimportant part of the huge Central Asia metallogenic domain. The belt is located in thecollage zone between Tangbale composite trench-arc belt and Junggar central block andhas the predominant metallogenic capacity because of the extensive magmatim and strongtectonic activity. Recent years, preliminary studies in terms of field geological mapping,mineral resources surveys, structural geology, and petrography, geochemistry andgeochronology of several key plutonic bodies in west Junggar have allowed us to findsome new ore occurrences including Tuketuke porphyry copper(molybdenum) deposit,Hongyuan porphyry molybdenum (copper) deposit and Hongshan porphyrycopper(molybdenum) deposit reported in this paper, and to characterize these porphyrydeposits. Consenquently, the southern Darbut teoctonic magmatic metallogenic belts canbe presented in west Junggar based on the spatial and temporal distribution and therock-type of ore-bearing intrusive bodies for these ore occurrences associated with theBaogutu copper-gold deposit in the Western segment of the belt.Combing the previous study results, this paper researches the deposit using petrology,structural geology, mineral deposit geology, radioisotope dating and tracing, major andtrace elements in terms of the metallogenic system theory.LA-ICPMS U-Pb method was used to date the zircons from the peraluminous A-typegranodiorite samples of the porphyry. Analyses of12spots of zircons from thegranodiorite samples yield a U-Pb weighted mean age of302.20±3.1Ma300.80±3.6M (2).Re-Os dating for five molybdenite samples obtained from two prospecting trenches andthree outcrops in the deposit yield a Re-Os isochron age of294.6±4.6Ma (2). TheRe-Os isochron age of the molybdenite is consistent with the U-Pb age of the granodioriteporphyry.The joint and fissure of the porphyry control the scale, morphology, grade andoccurrences of the orebodies. The Quartz-sericite zone, propylitic alteration zone from thecenter to rim of the porphyry suggested the alteration intensity increase from the center tothe outer. The pluton suffered from the alteration of planar limonite, intensive development of malachite, molybdenite mineralization and rock joints and fractures are observed in thepluton everywhere. The thickness Cu (Mo) mineralization type is fine veined, Leagueporphyritic and disseminated; the alteration of wall rock related to mineralization aremainly potassic, chlorite, sericite, epidote petrochemical. These general characteristicsindicate that the Hongyuan Mo (Cu) deposit is typical porphyry deposit. Low initial Sr (Sri)and Sr-Nd isotopic composition of the porphyry demonstrated the contamination of themantle material in the magmatism and mineralization.The Hongyuan Mo (Cu) deposit are different from the Baogutu Au(Cu) depositrelated to the adakitic porphyry which are discovered early in this belt. The results providea new significance information for the exploration of new porphyry deposits.