Genesis of the carbonatite-syenite complex and REE deposit at Maoniuping, Sichuan Province, China: Evidence from Pb isotope geochemistry

• Xu Cheng

  Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences

• Zhang Huan

  Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences Graduate School, Chinese Academy of Sciences

• Liu Congqiang

  Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences

• Qi Liang

  Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences

• Li Wenbo

  Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences

• Guan Tao

  Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences

抄録

The Maoniuping REE deposit is the second largest light rare earth elements deposit (1.45 million tons of REE₂O₃) in China, located in the Panxi rift, Sichuan Province. It is a vein-type deposit hosted within, and genetically related to the Himalayan alkalic carbonatite-syenite complex. The initial ²⁰⁶Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios from the Maoniuping carbonatites are similar to syenites, which, however, show more radiogenic ²⁰⁷Pb/²⁰⁴Pb ratios. This could not only be attributed to contamination by crustal materials. The Pb-Pb isotope plots from carbonatites and syenites define a linear array between EM1 and EM2. It suggests their sources were located in a heterogeneous lithospheric mantle and produced by the mixture of EM1 with EM2. The initial ²⁰⁶Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios from fluorites, galenas, pyrites and feldspar are similar to carbonatites and syenites, and different from granites. Their ²⁰⁷Pb/²⁰⁴Pb ratios also plot to between syenites and carbonatites. This suggests the REE ore-forming fluids were derived from carbonatite and syenite magmas. The Pb isotopic results are consistent with a model for REE deposition involving mixing of the F-rich, syenite-derived fluid with Ca-, CO₂-bearing fluid evolved from carbonatite magma. The early fluorites have higher ²⁰⁷Pb/²⁰⁴Pb ratio than the later ones, which shows that the REE ore-forming fluids were not contaminated by country rocks fluids.

収録刊行物

• ＧＥＯＣＨＥＭＩＣＡＬ　ＪＯＵＲＮＡＬ

  ＧＥＯＣＨＥＭＩＣＡＬ　ＪＯＵＲＮＡＬ 38 (1), 67-76, 2004

  一般社団法人日本地球化学会

キーワード

• genesis
• carbonatite
• syenite
• Pb isotope
• Maoniuping REE deposit

詳細情報

• CRID: 1390282679528264576
• NII論文ID: 130003904739
• NII論文ID: 10012847977
• NII書誌ID: AA00654975
• DOI: 10.2343/geochemj.38.67
• ISSN: 18805973
• ISSN: 00167002
• NDL書誌ID: 6899925
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I6899925
• Web Site: http://www.jstage.jst.go.jp/article/geochemj1966/38/1/38_1_67/_pdf
• 本文言語コード: en
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