萨恨托亥金矿床的地球化学异常特征

GEOCHEMICAL ANOMALY OF SAHENTUOHAI GOLD DEPOSIT IN XINJIANG,CHINA

新疆和静县萨恨托亥金矿床位于1∶50万萨恨托亥金异常、1∶20万金-白钨矿重砂异常和1:1万Au3异常中心域内,产于萨恨托亥压扭性断裂带中.上志留-下泥盆统大山口组第三岩性段的含铁白云石砂岩和泥灰岩是区域金异常的主要异常源.矿化(矿致)异常沿Ⅰ、Ⅱ、Ⅲ号断裂破碎蚀变带分布,金矿体产于Au3-2子异常内.元素组合为Au、Ag、As、Sb、Bi,该异常重现性好,异常元素之间相关性高,相互套合良好,属于多元素组合异常.矿床元素组合显示头晕特征,表明矿体处于矿床前缘部分.因此,深部可能存在规模更大、品位更高的矿体.

Sahentuohai gold field of Hejing Cou nty,Xingjiang lies in the Sahentuoh ai shearing fault belt inside the Sahentuohai-Dashankou foreland basin in Southern Tianshan on Tarim Pla te,with simple strata,gentle folds,developed faults and less magmatic activities.The 3rd lithologic member of Dashan kou formation,Upper Silurian-Lowe r Devonian and Saerming formation of Devonian a re dominant in the ore field.They are distributed in a NWW-trending zone a nd contacting each other by fault.The r ock association consists of metamorphic sandstone,ferriferous dolomi tic sandstone,sericitized siltstone,phyllitic s iltstone and phyllite.The orebody i s registered in the central area of 1:Sahen-tuohai Au anomaly,1:Au-scheelite h eavy concentrate anomaly and 1:Au 3 anomaly,and hosted in No.1,No.2and No.3faulted alterati on zones within Sahentuohai shearin g fault belt.The rocks in the fault belt are intensively fractured,with strong schistosity,fragmantation and mylonitization.The fractured alteration zone is the prin-cipal ore-controlling structure in the region.Quartz veins and carbonate-quartz veins are developed along the schistosity and fracture.The wall rock alterati ons are mainly ferrodolomitization,silicification,sericitization a nd pyritization,with minor chloritization.The metalliz ation are chiefly pyrite with a littl e chalcopyrite and galena.There is n o distinct de-marcation line between the ore body a nd wall rock.The mineralization is p ositively correlated to the alteration.The more comprehensive and stronger the alte rations are,the better the metalliz ation is.Conversely,the metalliza tion becomes weaker and gradually transits to normal wall rock.The ferroan dolomite s andstone and marl of the 3rd member of Dashankou formation are the major so urce of the regional Au anomaly.The g old orebody occurs in the Au 3-2 sub-anomaly with element composition of Au,Ag,A s,Sb and Bi.The anomaly presents a good recurrence,high correlation between the anomalous elements and multi-eleme nt composition.The element composition demonstrates the feature of fro nt halo,in-dicating that the orebody is in the fr ont part and there might be an even larger orebody with higher grade in the d eep.