粤西福湖岭混合岩及其原岩的地质年代学研究

为了深入认识华夏地块早古生代陆内造山作用相应的地壳再造过程,本文选取粤西福湖岭混合岩进行了详细的岩相学以及锆石U-Pb年代学研究。根据混合岩化程度,粤西福湖岭混合岩剖面由上而下可以分为3部分:混合岩化沉积变质岩、条带状混合岩和混合花岗岩。根据岩性与岩相学特征,福湖岭混合岩又可分为古成体、暗色体和浅色体。LA-ICP-MS锆石U-Pb定年结果及与区域上基底变质岩资料的对比研究表明,福湖岭混合岩的原岩(古成体)是形成于新元古代的变质沉积岩。粤西福湖岭混合岩的形成时代为441~435 Ma,是华夏地块早古生代陆内造山事件的重要产物。

Geochronology of Fuhuling migmatite and its protolith in western Guangdong

In order to further understand the crust reworking process related to the early Paleozoic intracontinental orogeny in the Cathaysia Block, this paper presents detailed studies of lithology, petrography and zircon U-Pb dating of the Fuhuling migmatites in western Guangdong Province. With the increasing migmatization, these rocks can be divided into three rock types: migmatized para-metamorphic rock, stromatic migmatite and migmatitic granite (diatexite). According to lithological and petrographic characteristics, the Fuhuling migmatites can be divided into three suites: paleosomes, melanosomes, and leucosomes. LA-ICP-MS zircon U-Pb dating results together with a comparison with the data of metamorphic basements from this region suggest that the protolith (paleosome) was meta-sedimentary rocks deposited in the Neoproterozoic, and the migmatization occurred at 441~435 Ma, related to the early Paleozoic intracontinental orogeny in South China.