Relationship between Indosinian magmatic activity and Li−Be−rare metal mineralization in the eastern section of West Kunlun and its implications for prospecting

This paper is the result of mineral exploration engineering.

Objective This paper aims to investigate the relationship between the Li−Be−rare−metal mineralization and Indosinian magmatism in the eastern part of the West Kunlun Orogenic Belt through a comprehensive study of Indosinian magmatic activities and geochronology and geochemistry of granitic pegmatites. Furthermore, the relevant metallogenic regularity is summarized and the prospecting direction for rare metals is proposed.

Methods The geological background of the eastern part of the West Kunlun Orogenic Belt and the geological and geochemical characteristics of Indosinian magmas including their ages, lithological assemblages, whole−rock geochemistry, and isotopic characteristics (Hf, Nd, and Li, etc.) are summarized. The genetic link between the pegmatite−hosted Li−Be−raremetal mineralization and Indosinian magmatism is investigated.

Results The large−sized Indosinian Dahongliutan composite granite pluton in the eastern part of the West Kunlun Orogenic Belt which is mainly composed of quartz diorite, biotite monzogranite, and two−mica monzogranite (including garnet, tourmaline−bearing two−mica monzogranite) was derived from partial melting of the crust in a post−collision regime and controls the distribution of the granitic pegmatites. The chronological data, whole−rock geochemistry, and Nd−Hf isotope geochemistry suggest that the quartz diorite, biotite monzogranite, and two−mica monzogranite were likely derived from different magmas. In addition, the geochemical characteristics of minerals (such as garnet and tourmaline) and Li isotopes indicate that the two−mica monzogranite (garnet tourmaline two−mica monzogranite), garnet−bearing tourmaline muscovite granite pegmatite and spodumene−albite pegmatite were likely derived from the same magma source.

Conclusions The two−mica monzogranite, in particular garnet, tourmaline bearing two−mica monzogranite exhibit close relationship with the pegmatite−type rare metal deposits. The peripheries of Aktas and the 509 Daoban–Quanshuigou area are favorable locations for lithium−rich pegmatite prospecting.