XU Cheng1, SONG Wen-lei1, HE Cheng1, WANG Li-ze2
1. Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China;
2. China Petroleum Pipeline Bureau, Langfang Hebei 065000, China
Abstract: Rare earth elements (REE) are critical metals in the world. Exploration and study of the REE deposits become a hot issue. Exogenetic deposits are one of REE resource. The paper briefly overview geological features and origin of REE deposits from residual-diluvial, fluvial and beach placer, carbonatite and granitoid weathering crust. The weathering type REE deposits are formed by the chemical weathering processes of the REE-rich parent rocks. The initial REE-enrichment of the parent rocks is the premise for the formation of this type deposit, and the weathering crusts have inherited the REE distribution patterns of the primary rocks to a great extend. World presently has great demand for heavy REE (HREE). Granitoid weathering HREE deposits in Nanling region of South China are rare and attract many geologists. Weathering process is secondary extraction and enrichment. Primary HREE mineral formation is a key. However, the questions why the granites having potential to generate rare earth mineralization within weathering crusts mainly occurred and concentrated in Nanling region, and whether the LREE/HREE fractionation of the REE-rich granite is due to the discrepancy of their magma source or the differentiation of the magma during evolution, and how the HREE mineral formed, are still not clear and need more study.
Keywords: exogenetic REE deposits weathering crusts type placer deposits carbonatite granite
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Bulletin of Mineralogy, Petrology and Geochemistry Vol. 34, No.2, 2015, page 234-241