Zircon U-Pb Ages and Nd Isotopic Characteristics of Susong Group in Dabie Orogenic Belt: Source and Provenance of Susong Terrene(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2016年第01期
- Page:
- 21-33
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Zircon U-Pb Ages and Nd Isotopic Characteristics of Susong Group in Dabie Orogenic Belt: Source and Provenance of Susong Terrene
- Author(s):
- LI Jun-hui; YU Yang; WEI Long-meng; HU Zhao-ping; CHEN Fu-kun
- School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, Anhui, China
- Keywords:
- crustal evolution; structure provenance; Precambrian; U-Pb age; Nd isotope; Susong Group; Yangtze Block; Dabie orogen belt
- PACS:
- P597
- DOI:
- -
- Abstract:
- Susong Group or Susong rock complex is the major rock unit of Susong terrene in the southern part of Dabie ultrahigh-pressure orogenic belt. Rocks of this group undergo high-pressure metamorphism and have complex origins or sources, and hence, the provenance and evolution history of Susong terrene are still debated. Zircon U-Pb ages and whole-rock Nd isotopic data for gneisses, schists and metabasic rocks of Susong Group were presented to place geochemical characteristics of Susong Group, and the evolution of the crust and provenance of Susong terrene were discussed. Zircons separated from two gneiss samples yield U-Pb ages of 750 to ~770 Ma, suggesting as evidence for a magmatic event in Neoproterozoic. Initial εNd values of whole-rocks of the gneisses range from -7.3 to -1.6. Detrital zircons from two schist samples give a wide range of U-Pb ages, clustering around Late Archean (2 700 Ma to ~2 800 Ma), Paleoproterozoic (2 000 Ma to ~2 500 Ma), Mesoproterozoic (1 100 Ma to ~1 500 Ma) and Neoproterozoic (700 to ~800 Ma), implying Neoproterozoic sedimentary rocks as their protoliths. Initial εNd values of whole-rocks of the schists vary from -20.2 to -1.4, when calculated back to 750 Ma, suggesting complex rock components in the source area. Similar distribution patterns of detrital zircon U-Pb ages are also commonly recorded in the basement or sedimentary cover rocks exposed in Yangtze Block. The Neoproterozoic magmatic rocks are widely distributed in Susong Group, ultrahigh-pressure metamorphic terrenes of Dabie-Sulu orogenic belt and the continental margins of Yangtze Block, indicating that Susong high-pressure metamorphic terrene is of a Yangtze affinity and has had similar history of the crustal evolution.
Last Update: 2016-01-30