『Abstract
　Rare earth element (REE) geochemistry and mineralogy have been studied in the weathered crusts derived from the Early Yanshanian (Jurassic) biotite granites of Dabu and Dingnan, as well as in the Indosinian (Permian) muscovite-biotite granite of Aigao in southern Jiangxi province, China, and the weathered crusts and clay sediments on biotite granites in the Sanyo belt, SW Japan, this is , Okayama, Tanakami, and Naegi areas. In all of the weathered crusts, biotite and plagioclase commonly tend to decrease toward the upper part of the profile, whereas kolinite and residual quartz and K-feldspar increase. The weathered crusts of the Dingnan granites and some Naegi granites, which are characterized by the enrichment in light REE (LREE) in C horizons, have higher total REE (ΣREE) content than the parent REE-enriched granites. Weathering of LREE-bearing apatite and fluorocarbonates in the Dingnan granites and allanite and apatite in some Naegi granites may account for the leaching of LREE at the B horizons. The leached LREE must result in subsequent enrichment of LREE in the C horizons. The enrichment is probably associated with mainly adsorption onto kaolinite and partly formation of possible secondary LREE-bearing minerals. In Japan it was found that REE mineralization occurs not in the weathered granitic crusts but reworked clay sediments, especially kaolinite-rich layers, derived mainly from the weathering materials of REE-enriched granitic rocks. The clay sediments are more enriched in LREE, which likely adsorbed onto kaolinite. Concentration of heavy REE within almost all the weathered crusts and clay sediments, however, may reflect mainly residual REE-bearing minerals such as zircon, which originated in the parent granitic rocks. The findings of the present study support the three processes for fractionation of the REE during weathering: (i) selective leaching of rocks containing both stable and unstable REE-bearing minerals; (ii) adsorption onto clay minerals; and (iii) presence of possible secondary LREE-bearing minerals.

Keywords: clay sediment; ion-adsorption-style REE deposit; mineral resources; Jiangxi Province; rare earth element; Sanyo Belt; granitoids; soil; weathered crust.』

1. Introduction
2. Geology
　2.1. Granitoids in southern China
　2.2. Granitoids of the Sanyo Belt
3. Samples and analyses
4. Results
　4.1. Occurrence of weathered crust and clay sediment
　4.2. X-ray diffraction identification of minerals
　　4.2.1. Weathered crusts of the Early Yanshanian granites in southern China
　　4.2.2. Weathered crust of the Sanyo granitoids
　　4.2.3. Clay sediment in the Tanakami and Naegi areas
　4.3. Chemical composition
　　4.3.1. Major elements
　　4.3.2. Rare earth elements and trace elements
　　4.3.3. Total REE content in weathered crusts and clay sediments
5. Discussion
　5.1. Relationships between major elements and constituent minerals in the weathered crusts
　5.2. REE behavior in the weathered crusts
　5.3. REE behavior in the clay sediments
　5.4. Possible controlling factors for enrichment of REE and comparison with ion adsorption-style deposit
6. Conclusions
Acknowledgments
References