한국광물학회:학술대회논문집 (Proceedings of the Mineralogical Society of Korea Conference)
- 한국광물학회.한국암석학회 2003년도 공동학술발표회 논문집
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- Pages.54-54
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- 2003
Geochemistry of cordierite-bearing motasedimentary rocks, northern Yeongnam Massif: implications for provenance and tectonic setting
- Kim, Jeongmin (Korea Basic Science Institute) ;
- Moonsup Cho (School of Earth and Environmental Sciences, Seoul National University)
- 발행 : 2003.05.01
초록
The metasedimentary rocks together with various granitoids are the main constituents in Taebaeksan gneiss complex, northern Yeongnam Massif. Chemical compositions of sedimentary rocks may reflect the nature of the provenance and could be crucial for understanding the evolution of early continental crust. Previous workers have suggested that the provenance and tectonic studies based on the geochemistry of sediments are applicable to the Precambrian samples. In this study we analyzed the major, trace and REE elements of metasedimentary rocks to understand their provenance and tectonic setting during sedimentation. The overall geochemical characteristics of metasedimentary rocks are similar to those of average shale of the post-Archean. Major element chemistry indicates mature and sorted nature of the sediments. The degree of weathering in the source rocks the is not uniform, as inferred from a large scatter in chemical indices of weathering (CIW). The immobile trace elements such as Th, Sc, and REE can be used to discriminate various sedimentary processes. The Th/sc ratios (0.9 - 4.4) are larger than those of the upper crust and average shale, suggesting that the felsic source predominates. The contents of Ni and Cr and the variations in the ratio of compatible to incompatible elements are similar to the average post-Archean shale. Uniform chondrite-normalized REE pattern with the LREE enrichment (LaN/SmN = 4.9
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