- 责任者：Ruan Linsen (Faculty of Earth Resources ; China University of Geosciences ; Wuhan 430074 ; China) ; Zhao Pengda
- 刊名：Earth Science
- 出版年：2013
- 卷期：38(4)
- 页码：p.663-676
- issnNo：ISSN1000-2383
- isbnNo：CN42-1233/P
Located at the central of the Anning River discordogenic fault, the binding site of the Songpan-Garize orogenic belt and the Yangtze block, Dashuigou schiefer has attracted increasing attention of researchers regarding to its special tectonic site and the occurred tellurium deposit. In order to provide chronologic evidences for reconstructing tectonic and magmatic geo- chronic evolution of areas around Dashuigou and the western margin of the Yangtze block in Shichuan, as well as for locating time of Dashuigou sehiefer, zircon ages of the greenschist from Dashuigou were determined by SHRIMP U-Pb dating tech- nique. Five age groups of the zircons with different characteristics of inner texture and cosmetics are obtained and subdividedfrom the greenschist of Dashuigou schiefer which should contain great proportions of sediments in the protolith. Ages of 2 467--2 430 Ma from remained detrital magma zircons shows the mass transportation of Archaean-early proterozoic basement, whereas ages of 790. 5--762. 5 Ma probably represent the magmatic event around Dashuigou on the background of Rodinia crack and upwelling mantle in early neoproterozoic. Metamorphism and magmation generated by orogenics and post orogenics are documented by ages of 696.8--642.9 Ma from the magmatic zircons. Zircons of 262.0--220.0 Ma ages are inferred to have been originated from alkalic rock nearby related to the Emeishan movement. 216.5--167. 1 Ma ages of typical new growth and r~crystallized zircons caused by hydrothermal alteration reveal the post-magmatic hydrothermal activity. Dashuigou schiefer is probably allochthonic thrust sheet, and ages from magma zircons and those thermal genetics bound its general locating time to the interval from 220. 0 Ma to 167.1 Ma.