新研究揭示稀土成矿关键因素

Core Viewpoint - The research team from the Guangzhou Institute of Geochemistry has identified the depth of carbonatite magma intrusion as a key factor controlling the extraordinary accumulation of rare earth elements (REEs) [1][2]. Group 1: Research Findings - The study published in the journal "Nature Communications" reveals that over half of the global rare earth reserves come from carbonatite, yet less than 10% of carbonatite bodies form economically viable rare earth deposits [1]. - High-temperature and high-pressure experiments simulated the cooling and crystallization process of carbonatite magma at depths of 6 to 20 kilometers, showing two distinct evolutionary paths based on pressure levels [1][2]. - At depths shallower than 10 kilometers (approximately 0.3 GPa), early crystallization of apatite occurs, which traps REEs in its structure, preventing their migration and accumulation [1][2]. Group 2: Implications for Rare Earth Deposits - At depths greater than 10 kilometers, olivine crystallizes first, consuming silicon and preventing apatite from forming a "cage" to lock in REEs, allowing for higher solubility of REEs in saline melts [2]. - The findings explain the distribution patterns of global carbonatite-type rare earth deposits, with world-class deposits like Baiyun Obo in China being located at depths greater than 10 kilometers [2]. - The research establishes a complete causal chain linking pressure, mineral crystallization sequence, melt properties, and REE enrichment, providing new insights for the exploration of carbonatite-type rare earth deposits [2].