中亚成矿域斑岩铜矿床基本特征

中亚成矿域发育许多大型和超大型斑岩铜矿床,是世界上重要的斑岩铜矿成矿域。我们对9个大型和超大型斑岩铜矿床进行了研究,包括地质特征、含矿岩体地球化学、SIMS锆石U-Pb定年和成矿流体成分等,结合前人成果,我们认为中亚成矿域斑岩铜矿床具有如下特点:(1)成矿时代为古生代和中生代,成矿高峰期为泥盆纪和石炭纪;(2)含矿岩浆为钙碱性中酸性岩浆和少量的碱性岩浆,含矿岩体为花岗闪长岩、闪长岩、英云闪长岩和少量的二长岩;(3)含矿岩浆大多数源于新生的洋壳,少量有古老的基底物质和围岩物质参与;(4)成矿构造背景主要为岛弧,少量为陆缘弧和岛弧向陆缘弧过渡的环境;(5)矿床可分为三类,包括斑岩型Cu-Au、Cu(Au,Mo)和Cu-Mo矿床;(6)成矿流体可分为两类,包括氧化性H2O-Na Cl-CO2-SO2体系和少量的还原性H2O-Na Cl-CH4-CO2体系;(7)成矿系统可分为三类,包括简单的斑岩系统和少量的斑岩-矽卡岩成矿系统和斑岩-浅成低温热液成矿系统。

Characteristics of the porphyry Cu deposits in the Central Asia Metallogenic Domain

The Central Asian Metallogenic Domain with many large and super-large porphyry Cu deposits is an important metallogenic domain of porphyry Cu deposits in the world. This study focuses on the geology, ages, ore-forming fluids, and elemental geochemistry for nine important porphyry Cu deposits in the Central Asian Metallogenic Domain on the basis of published data, our new ages, elemental data, fluids and detailed field work, and summarizes the characteristics of these deposits. These deposits have some characteristics as follow: (1) these deposits have a wide age range from Paleozoic to Mesozoic, but focus on Devonian and Carboniferous. (2) Most deposits are associated with calc-alkaline intermediate to felsic magma and minor with alkaline magma. The host rocks are dominant granodiorite, diorite, and tonalite and minor monzonite. (3) Most host magma from these deposits derived from the mantle, minor from the mantle with an involvement of crust or wall rocks. (4) Most deposits formed in the island-arc setting, minor in a continental-arc setting and in a transitional continental- to island-arc setting. (5) These deposits have been divided three types (porphyry Cu-Au, Cu (Au, Mo) and Cu-Mo deposits). (6) The ore-forming fluids from most deposits contain the dominant oxidized (H₂O-NaCl-SO₂-CO₂) and the fluids from minor deposits are the reduced (H₂O-NaCl-CH₄-CO₂) fluids. (7) The mineralization system has single porphyry system and minor porphyry-skarn and porphyry-epithermal systems.