US EPA

1289348 

Book/Book Chapter 

Major types and regional metallogeny of rare metal deposits in the Altay Mountains, Xinjiang 

Wang, D; Xu, Z; Zou, T; Chen, Y; Wang, L 

2003 

International Association on the Genesis of Ore Deposits 

International (III) 

10 (2003) 

117-130 

The Chinese Altai are well known for their abundance of rare metal deposits. Located in the northwestern part of China, the Altay Mountains are mainly products of Hercynian orogeny and, to a lesser degree, Caledonian orogeny. The rare metal deposits located in Altai and Fuyun counties appear to have formed throughout a variety of a orogenic stages. In this paper, we classify most of the rare metal deposits in the Altay Mountains into three types: (1) rare metal deposits hosted by pegmatites within and/or located along the contact zones of mafic or alkalic intrusive rocks, which are rich in Nb, Ta, Be, and Li; (2) rare metal and beryl gem deposits hosted within granites or in adjacent contact zones; and (3) rare metal-bearing muscovite deposits within Proterozoic metamorphic rocks. The high (super 3) He/ (super 4) He values (1.80-2.54X10 (super -6) ) of the rare metal-rich pegmatites, typically greater than those of their mafic host rocks (1.39-2.55X10 (super -6) ), indicate the rare metals were concentrated into the magmas during anatectic melting of the Altai accretionary prism. A few new absolute dates (220 Ma; Ar-Ar method). The deposits within the metamorphic rocks formed during earlier Caledonian orogenic events. 

beryllium ores; Mesozoic; classification; ore bodies; metal ores; IGCP; noble gases; host rocks; tectonics; helium; mineral deposits, genesis; Altai Mountains; isotope ratios; Paleozoic; structural controls; Asia; orogenic belts; northwestern China; lithium ores; plutonic rocks; granites; Xinjiang China; niobium ores; tantalum ores; pegmatite; stable isotopes; Far East; China; absolute age; mineral assemblages; He-4/He-3; metallogeny; isotopes; dates; geochemistry; Ar/Ar; intrusions; veins; igneous rocks