内蒙古柴胡栏子金矿区闪长玢岩锆石U——Pb定年及其地质意义

Zircon UPb Dating of Diorite Porphyrite and Its Geological Implications in Chaihulanzi Gold Deposit in Inner Mongolia

摘要:

内蒙古柴胡栏子金矿区断裂构造发育，岩浆岩类型复杂。本文在野外地质工作的基础上，通过锆石LAICPMS UPb同位素年代学研究，得到了矿区岩浆岩的形成时代，并对海西期的岩浆活动进行了讨论。闪长玢岩样品中存在(2447±13)Ma（MSWD=0.0108）的继承性岩浆锆石和(296.6±3.5)Ma（MSWD=0.58）的结晶岩浆锆石。认为结晶锆石的年龄代表了闪长玢岩的形成年龄；(2447±13)Ma的继承性岩浆锆石的存在说明了闪长玢岩在侵位过程中存在壳源物质的重熔和加入。

Abstract:

Faulted structures have developed well in Chaihulanzi gold mining area, and types of magmatic rocks are complex.On the basis of field geological work, through study on La ICP MS U Pb isotopic geochronology of zircon, the formation age of magmatic rocks in the mining area has been gained, and the magmatic activity of Hercynian period has been discussed.There are （2447±13）Ma (MAWD=0.0108) inherited magmatic zircons and （296.6±3.5）Ma (MSWD=0.58) crystalline magmatic zircons in diorite porphyrite samples. It is considered that the age of crystalline zircon represents the formation age of diorite porphyrite,and the existence of inherited magmatic zircon of （2447±13）Ma indicates that the remelting and addition of crust derived materials during the emplacement of diorite porphyrite.