REE Abundance and REE Minerals in Granitic Rocks in the Nanling Range, Jiangxi Province, Southern China, and Generation of the REE‐rich Weathered Crust Deposits

Abstract

Studies of Mesozoic granites associated with rare earth element (REE)-rich weathered crust deposits in southernmost Jiangxi Province indicate that they have high-K to shoshonite compositions and belong to ilmenite-series I-type granites. Of the studied rocks at 59 -292 ppm of bulk REE content, the highest are seen in the biotite granites of Dingnan (358, 429 ppm) and mafi c biotite granite of the Wuliting Granite (344 ppm) near the Dajishan tungsten mine, both areas where weathered-crust REE deposits occur. REE-bearing accessory minerals in these granites are mainly zircon, apatite and allanite, and REE-fl uorocarbonates are common. REE enrichment occurs in the rims of apatite crystals, and in fl uorocarbonates that occur along grain boundaries of and cracks in major silicate minerals, and in fl uorocarbonates that replaced altered biotite. It is therefore thought that a major part of the REE content of these granites was concentrated during deuteric activity, rather than during magmatic crystallization. The crack-fi lling REE-fl uorocarbonates could subsequently have been easily leached out and deposited in weathered crust developed during a long period of exposure.

An Overview on the Possibility of Scandium and REE Occurrence in Sulawesi, Indonesia

“…Generally, the weathered crusts show a higher concentration of total REE and REE + Y compared to their parent rocks as reported by Maulana et al (2014). This result indicates that weathered crusts were enriched in REE, consistent with enrichment of REE in weathered granitic crusts reported from many areas (Ishihara et al, 2008;Imai et al, 2013). However, the Palu weathered crust only shows a small enrichment of REE compared to the Mamasa weathered crust.…”

“…The bedrock in Petea profile contains of 40.8 wt% SiO 2 , 34.8 wt% of MgO,8.7 wt% Fe 2 O 3 , 0.2 wt% Ni, and 9.8 ppm Sc. In relation to this, the weathering profile shows a decreasing content of SiO 2 and MgO, and an increasing trend of Kadarusman et al, 2004;Maulana, 2009 and variation of REE in the weathered granitic crusts in the studied area are summarized in Figure 5. Generally, the weathered crusts show a higher concentration of total REE and REE + Y compared to their parent rocks as reported by Maulana et al (2014).…”

“…Sc occurrence in Sulawesi was firstly reported by Kadarusman et al (2004) and Maulana et al (2015) from bulk rock composition of ultramafic rocks. It is reported that Sc content is abundant in pyroxenite from Bantimala Complex, South Sulawesi (Maulana et al, 2015).…”

“…Nevertheless, REE are heavily dependent on some weathered crust deposits in China (ex. Bayan Obo Deposit and highly weathered granitic rocks from southern China) (Ishihara et al, 2008). These conditions have led to the growing concern that the world may soon face a shortage of Sc and REE resources.…”

Geochemical characteristics determinedby multiple extraction from ion-adsorption type REE ores

“…See Tables 2 and 3 for the experiment conditions. Whole-rock content data are from Murakami and Ishihara (2008). n.a., not analyzed.…”