新疆香山杂岩体的成岩与成矿时序

新疆东天山香山地区镁铁-超镁铁杂岩体中产有香山中中型铜镍矿和香山西大型铜镍-钛铁矿床.杂岩体可分为辉长岩类、超镁铁质岩类和钛铁辉长岩类.野外证据表明三者具有先后侵位关系.本文通过对香山杂岩体不同岩相年代学资料梳理,补充了定年数据,获得香山杂岩体侵位年龄为283.2±2.1Ma,验证了不同岩石系列的侵位时序.此外,锆石年龄数据还记录了本地区曾经发生过的构造-岩浆热事件.利用角闪石40Ar/39Ar测年结果,并结合锆石U-Pb测年结果推测香山西岩体侵位较深,香山中岩体侵位较浅,进一步推测西岩体剥蚀量较大,而中岩体剥蚀量较小.结合野外穿插关系,厘定了杂岩体侵入-成矿事件的时序.

The timing order of mineralization and diagenesis for Xiangshan complex rocks, Xinjiang

The mafic-ultramafic complex in the Xiangshan area of the eastern Tianshan Mts., Xinjiang, produces the medium-sized mid-Xiangshan Cu-Ni deposit and the large-scale western-Xiangshan Cu-Ni-(V)-Ti-Fe deposit. These complex rocks are composed of gabbro, ultramafic rocks and Ti-Fe gabbro. Field evidence indicates that these complex rocks intrude successively. This paper aims to prove their intruded order through combing age data of various rock series, and complementing the dating data. We suggest that the complex rocks intrude at 283.2±2.1Ma, and report some data recording tectonic-magmatic thermal event. Using the results of hornblende ⁴⁰Ar/³⁹Ar age data, we insist that the western-Xiangshan rocks are hypogene, but the mid-Xiangshan rocks are hypabyssal, with the results of U-Pb zircon data. Thus, we believe that the erosion amount of the western-Xiangshan rocks is big, but that of the middle-Xiangshan rocks is small. Combing the field evidence, we determined the emplacement and mineralization timing orders of complex rocks in Xiangshan area.