Advances in Earth Science
• Orginal Article •
), Yongsheng Wang
), Zhaoqi Hu
2, Qiao Bai
First author:Tian Ziqiang(1994-),male,Bozhou City,Anhui Province,Master student. Research areas include orogenic dynamics. E-mail:firstname.lastname@example.org
Ziqiang Tian, Yongsheng Wang, Zhaoqi Hu, Qiao Bai. LA-ICP MS Zircon U-Pb Dating of Metasedimentary Rocks in Dabie Orogenic Belt and Its Tectonic Implications[J]. Advances in Earth Science, 2018, 33(9): 945-957.
Low-grade metamorphic rocks concentrated in the Beihuaiyang unit and were sporadically in other units of the Dabie orogenic belt, whose coexistence with other rocks in the orogenic belt can provide evidence for the evolution of the Dabie orogenic belt. A small number of metasedimentary rocks crop out in the Shenqiao area, northeast of the North Dabie unit. In order to obtain the forming age and provenance of the low-grade metamorphic rocks and their relationship with the rocks in the North Dabie unit, detailed field observations, systematic microscopic identification and detrital zircon LA-ICP MS U-Pb dating were presented for metasedimentary rocks in the Shenqiao area. The results show that metasedimentary rocks in the Shenqiao area have similar petrological characteristics as low-grade metamorphic rocks of the Zhufoan Formation in the Foziling Group. The minimum age of detrital zircon is 431 Ma, which is also similar as the Foziling Group. All these reveal that these low-grade metamorphic rocks in the Shenqiao area may be a part of the Foziling Group. Detailed observations on thin-sections show that quartz are characterized by Subgrain Rotation (SGR) recrystallization and biotite has obvious growth rims, which indicates that the metasedimentary rocks experience an epidote-amphibolite facies metamorphic and deformation event. The rhythmic layers on the outcrop existed before experiencing low-grade metamorphism, during which the argillaceous layer in the protolith transferred to the darker layered biotite and the sandy layer to lighter and recrystallized quartz.