大别山北部花岗质片麻岩锆石Pb-Pb年龄

Pb-Pb zircon ages of granitic gnesis in the North Dabie Mountains,Anhui province

大别造山带北部出露大量的花岗质片麻岩,大致可以划分两类:一类为石英闪长质→石英二长闪长质→石英二长质片麻岩;另一类为花岗闪长质→二长花岗质片麻岩。本文对其两类岩石选择有代表性的样品进行单颗粒锆石Pb-Pb年龄测定,分别获得595±27Ma(石英二长质片麻岩)和289±16Ma(二长花岗质片麻岩)年龄数据,这为进一步探讨大别山构造岩浆作用性质提供了依据,为揭示大别山晚古生代构造岩浆作用提供了线索。

There are a large number of granitic gnesis in the North Dabie Mountains. They are roughly divided into two types, One is made up of the quartz-dioritic gnesis, quartz-monzodioritic gnesis and quartz-monzonitic gnesis, the other is composed of the granodioritic gnesis and adamellitic gnesis. Pb-Pb single zircon ages are determined by using representative samples of two types. The results indicate that the quartz-monzonitic gnesis was formed later Proterozoic(595±27Ma), the adamellitic gnesis was formed later Paleozoic(289±16Ma). The data provide an important geological evidence for further discussion of structure-magmatism character in later Proterozoic era, and also provide a clue of structure-magmatism character of later Paleozoic era in the Dabie Mountains.