东准噶尔蒙西斑岩铜矿床双矿化蚀变系统的厘定及其找矿意义

Identification of Double Alteration-Mineralization System in the Mengxi Porphyry Copper Deposit,East Junggar and Its Significance for Prospecting

文章通过对东准噶尔蒙西矿床蚀变、矿化和元素分带特征的研究,厘定了蚀变类型及其时空分布规律,探讨了两期矿化蚀变所对应的斑岩体,初步建立了矿床成矿模型。结果显示蒙西斑岩铜矿区蚀变与成矿具双系统叠加结构:地表和浅部的钾化和铜钼矿化与花岗斑岩密切共生。矿区大面积绢英岩化-黄铁矿化-青磐岩化、深部发育的钾化磁铁矿化,及从上往下的Ag、Pb-Zn与Au垂向分带的矿化与深部发育的闪长玢岩有关。地表和浅部花岗斑岩及其伴生的钾化、铜钼矿化是花岗斑岩铜钼矿化蚀变系统的根部与残留,而闪长玢岩成矿系统以铜金矿化为特征。基于新建立的成矿模型与已有的勘探成果,推测深部存在隐伏的Cu-Au矿体。

Through researches on alteration,mineralization and element zoning characteristics of the Mengxi copper deposit in East Junggar,this paper redefines alteration types and spatial and temporal distribution,discusses relationships between alteration and porphyries,and finally develops a preliminary metallogenic model. The results show that alteration and mineralization in Mengxi porphyry copper deposit are consisted of two overprinted systems. The potassic alteration and Cu-Mo mineralization on the surface and in shallow depth is closely related to granitic porphyries,while widely distributed phyllic-pyritization-propylitization alteration,potassic alteration and magnetite mineralization in depth and vertical mineralization zoning of Ag,Pb-Zn and Au are closely related to dioritic porphyrite. Granitic porphyries and associated potassic alteration and Cu-Mo mineralization is possibly the root or residues of the granitic porphyries Cu-Mo mineralization system,and the dioritic porphyrite metallogenic system is characterized by Cu-Au mineralization.Based on the new genetic model and exploration results,it is proposed that there is possibly some buried Cu-Au ore bodies in the deep.