Rare Earth Element (Summary Of Stephen B. Castor and James B. Hedrick Paper From Geological Perspective)
Exploration : Potential area of hard rock REE deposit mostly found in rock that older than Precambrian (underlain by Precambrian rock). In Placer deposit, REE deposit is associated with granitic rocks (some are Mesozoic - Phanerozoic) or high-grade metamorphic rocks (usually Precambrian), or both. Technique that can be use: 1. Radiometric exploration technique. 2. Geochemical prospecting using heavy mineral concentration of active stream sediments. 3. Multielement analytical techniques. 4. X-ray fluorescence or neutron activation analysis 5. Inductively coupled plasma (ICO) Spectroscopy. 6. Biochemical prospecting (Plant ash contain). 7. Surface exploration (trenching, pitting, and dredging). 8. Drilling that utilizing core sampling. 9. Absorption bands in the visible spectrum differentiation. 10. Geophysical methods of gravity surveys and airborne or magnetic surveys (sometimes using seismic surveys). Table 1. Known REE deposits Location Country Dis