Southern Mongolian Alkaline Province

The Southern Mongolian Alkaline Province is well known for very high grade REE deposits associated with alkaline-carbonatite volcano-plutonic complexes (e.g. Lugiin Gol, Mushgai Khudag and Bayan Khoshuu; Samoilov and Kovalenko, 1983; Kynicky, 1996). The range of rock types, levels of erosion, styles of mineralisation and depth of drilling make it an outstanding example to use for comparison with European deposits. The complexes are controlled by E-W faults and formed in a continental rift environment, although post-collisional potassic magmatism has also been proposed (Munkhtsengel and Iizumi, 1999). REE deposits are predominantly associated with veins and brecciated alkaline rocks. The Bayan Khushu and Mushgai Khudag deposits are very similar and show relatively high concentrations of REE phosphates, and barite-celestine as well as fluorcarbonates with REE enrichment at depth (drilling down to a depth of 300 m), while the Lugiin Gol deposit is generally more uniform. It has an overall high content of REE and very detailed 3D maps created after drilling down to a depth of 1000 m.