Establishment of exploration methods of ion-adsorption type REE ores and evaluation of resources

重稀土元素主要产于风化花岗岩组成的离子吸附型稀土矿床中。本文旨在阐明离子吸附型稀土矿床的成因，发展稀土元素的找矿方法，评价稀土元素的资源潜力。稀土氟碳酸盐、褐帘石和钛铁矿是离子吸附矿的较好稀土源矿物。由于风化花岗岩的Ce亏损与离子交换型稀土元素的百分含量或浓度呈正相关，Ce异常是找矿的良好标志，测区风化壳厚度大多小于10 m。根据中国的定义，矿产资源估计为小型（<10 000吨）至中型（50 000 - 500 000吨）。

Heavy rare earth elements (HREE) are predominantly produced from ion-adsorption type REE (rare earth elements) deposits consisting of weathered granites. This study aims to elucidate the genesis of ion-adsorption type deposits, to develop an exploration method and to estimate a resource potential of REE.Occurrences and weathering susceptibility of REE-bearing minerals have important roles in the ore formation. REE fluorocarbonates, allanite and titanite are preferable REE-source minerals for the ion-adsorption ores. Since Ce depletion of weathered granite is positively correlated with percentage or concentration of ion-exchangeable REE, the Ce anomaly is a good indicator in exploration of the REE ores.Thickness of weathering crusts is mostly less than 10m in the surveyed areas. The mineral resources are estimated to small (<10,000 tonnes) to middle (50,000 - 500,000 tonnes) based on the definition of China.