土耳其Pütürge变质地体晚白垩世岩浆作用与变质作用的年代学研究(英文)

Geochronology of the Late Cretaceous magmatism and metamorphism,Pütürge massif,Turkey

Pütürge变质地体位于新特提斯构造带南部的土耳其Anatolia逆冲推覆构造带内,形成于欧亚板块与阿拉伯板块之间晚白垩纪碰撞造山事件。Pütürge变质地体主要由变质泥质片岩及片麻岩、花岗质片麻岩、石英岩、角闪岩和大理岩组成,发育类似巴罗型递增变质带的变质带序列,变质程度达高绿片岩相至低角闪岩相。此前该变质地体一直缺乏精确的年代学约束,为此我们采用了二次离子质谱锆石U-Pb测年方法和黑云母40Ar/39Ar测年方法,对该变质地体进行了年代学研究。结果表明,区内花岗片麻岩原岩形成于84.2±1.1Ma,变质泥质片麻岩中黑云母40Ar/39Ar年龄所代表的变质时代为83.21±0.1Ma。这说明早白垩世期间岩浆侵入事件不久,Pütürge变质地体就发生了区域变质作用。

The Pütürge massif was developed within the south branch of Neotethys,and it is possibly one of the terranes within the Late Cretaceous collisional zone between the Eurasia and Arabian plates. Regional metamorphic rocks of the Pütürge massif mainly include metapelitic schist,metapelitic gneiss,granitic gneiss,quartzite,amphibolite and marble. A Barrovian-like prograde sequence is found in the metapelites in this terrane,and metamorphic peak of this massif reached upper greenschist to amphibolite facies conditions. SIMS U-Pb age of 84. 2 ± 1. 1Ma of the zircons was obtained from the metagranitic gneiss of the Pütürge massif suggests that the magmatism occurred at the Upper Cretaceous Santonian time,and 39 Ar /40 Ar age of the biotites separated from the metapelitic schist was determined to be 83. 21 ± 0. 069 Ma. These geochronological data suggest that the metamorphism occurred immediately after the magmatism.