新疆东天山玉海斑岩铜矿锆石SHRIMP U-Pb年龄及构造意义

摘要

新疆东天山玉海铜矿是2011年新疆有色地质勘查局704队新发现的铜矿床,现已达到中-大型矿床规模。成矿岩体地质特征、岩石地球化学特征、矿体地质特征及蚀变分带表明,玉海铜矿具有斑岩型铜矿特征,其赋矿岩体为一套形成于洋陆俯冲环境的富钠的闪长岩-花岗闪长岩。含矿岩石锆石SHRIMP U-Pb年龄为(422.3±4.0) Ma,这也是在东天山觉罗塔格成矿带首次发现的早古生代斑岩铜矿。结合区域构造演化特点和康古尔塔格构造带中的古洋壳残片证据,认为其符合北天山洋自奥陶纪至早石炭世一直俯冲消减的说法,对早古生代东天山的构造演化给出更进一步的数据支持。对于相同类型矿床的发现与勘查具有较好的启示作用。%The middle-large sized Yuhai copper deposit in Eastern Tianshan Mountains of Xinjiang was discovered in 2011 by No. 704 Geological Party of Xinjiang Nonferrous Bureau. The characteristics of geology, petrology geochemistry, orebody geology and alteration zoning show that the Yuhai copper deposit belongs to the porphyry Cu type, with ore-bearing intrusion being a set of sodium rich diorite-granodiorite bodies formed under the condition of ocean-continental subduction. Zircon SHRIMP U–Pb dating shows that the age of Yuhai intrusive rock is (422.3±4.0) Ma. This is the first discovery of an intrusive rock of early Paleozoic in the Jueluotage metallogenic belt. These data, combined with the regional tectonic evolution and the ancient oceanic crust of the Kangur tectonic belt, support the argument that North Tianshan Ocean was under the subcution state from the Ordovician to early Carboniferous, and this conclusion provides evidence for tectonic evolution of Eastern Tianshan Mountains of early Paleozoic. The results achieved by the authors provide better tectonic implications for guiding exploration of Yuhai type copper deposits in this region.