Precise U–Pb ages of syn-extensional Miocene intrusions in the central Menderes Massif, western Turkey
Precise U–Pb ages of syn-extensional Miocene intrusions in the central Menderes Massif, western Turkey
复制标题
土耳其西部门德雷斯地块中部同伸展中新世侵入体的精确 U-Pb 年龄
作者：
J. Glodny;R. Hetzel
土耳其西部是经历过大陆地壳大规模扩张的地区。在这里，我们使用 U-Pb 测年报告了门德雷斯地块中部两个侵入体（图尔古特鲁和萨利赫利花岗闪长岩）的精确结晶年龄。两个侵入体都发生在地震活跃的 Alaşehir 地堑的南下盘，并同构造地位于一个从顶部到 NNE 的伸展剪切带中，该剪切带在逆行绿片岩相条件下很活跃。 16.1 ± 0.2 Ma（独居石、图尔古特鲁花岗闪长岩）和 15.0 ± 0.3 Ma（铜铝长石、萨利赫利花岗闪长岩）的 U-Pb 年龄证明，早到中中新世过渡时期，门德列斯地块中部的中地壳岩石的构造折返已经开始。结合已发表的地质年代学、结构和沉积学数据，新的 U-Pb 年龄表明至少自 16 Ma 以来一直持续延伸。没有令人信服的证据表明构造缩短存在于中新世晚期/上新世阶段。
Western Turkey is an area which has experienced large-scale extension of continental crust. Here we report precise crystallization ages of two intrusions in the central Menderes Massif, the Turgutlu and Salihli granodiorites, using U–Pb dating. Both intrusions occur in the southern footwall of the seismically active Alaşehir graben and were emplaced syntectonically in an extensional top-to-the-NNE shear zone which was active at retrograde greenschist-facies conditions. The U–Pb ages of 16.1 ± 0.2 Ma (monazite, Turgutlu granodiorite) and 15.0 ± 0.3 Ma (allanite, Salihli granodiorite) document that tectonic exhumation of middle-crustal rocks in the central Menderes Massif was already underway at the Early to Middle Miocene transition. Combined with published geochronological, structural and sedimentological data, the new U–Pb ages point to a continued extension since at least 16 Ma. There is no convincing evidence for a late Miocene/Pliocene phase of tectonic shortening.