Rare Earth Elements and Yttrium Potentials of Neoproterozoic Peralkaline Siwana Granite of Malani Igneous Suite, Barmer District, Rajasthan

摘要

The bimodal volcano-plutonic association of Neoproterozoic Malani Igneous Suite of western Rajasthan has resulted in enrichment of rare earth elements (REE), especially heavy rare earth elements (HREE) due to fractionation during polychronous emplacement of riebeckite / aegirine bearing peralkaline granite in three phases. The modal mineralogy indicates bastnasite (La-Ce), parasite, La-Ce-Ba cebaite, cerianite, thorianite, carbocernaite, ancylite, strontianite, celestire, allanite, fergusonite, REE silicates, xenotime, monazite, REE clays and zircon in order of abundance. The distribution of minerals shows total REE minerals 2.04% in Gudanal (east), 2.23% in Gudanal (west), 2.15% in Meli and 2.5% in Bhatikhera. The end phase of magmatic activity represented by boss, dykes and veins of microgranite has rich potentials for HREE. Out of several blocks having preponderance of dykes/veins, Gudanal (east and west), Bhatikhera, Phulan and Meli areas are most promising. The HREE and yttrium abundance of Gudanal (west) is 0.33%, Gudanal (east), 0.22%, Bhatikhera as 0.31% and Phulan 0.93%. Majority of REE minerals are small in size (< 20 microns) occurring as carbonates, followed by phosphates, oxides and silicates and will warrant detailed bulk mineral processing test for the recovery of REE minerals and subsequent metallurgical tests.