This paper is the result of mineral exploration engineering.

Objective In recent years, great breakthroughs have been made in the prospecting of rare metals such as lithium, beryllium, niobium and tantalum in the Himalayan metallogenic belt. Based on the 1∶50000 mineral geological mapping, three different types mineralization have been identified: (1) The Gabo pegmatite type lithium deposit; (2) The Cimai skarn type Sn−Fe−Pb−Zn polymetallic deposit; (3) The Mucun tectonic-altered rock type Au deposit. The purpose of this paper is to find out the metallogenic age of typical rare metal deposits in the Himalayan belt, analyze the metallogenic relationship between dome structure, high differentiated granite and rare metal, and summarize the structural ore control regularity in the dome, so as to provide theoretical basis for regional rare metal prospecting and prediction.

Methods Based on the detailed field geological investigation, the dating of pegmatite monazite and the geological characteristics of typical deposits are studied in this paper, and the relationship between structure in the dome and metallogenesis of rare metals is investigated.

Results The Gobo lithium deposit is located at the northeast part of the Kulagangri Dome. Li−Be ore bodies are hosted by the marble in the middle unit of the Dome. Spodumene pegmatite yielded a monazite U−Th−Pb age of 23.1 Ma, which represents metallogenic age of the Gobo lithium deposit. The emplacement age of tourmaline granite in the north part of the Gabon mining area is 19.3 Ma, which is obviously later than the metallogenic age of lithium ore. The Cimai skarn type Sn−Fe−Pb−Zn polymetallic deposit is located at the south of the Gabon lithium deposit. At present, two mineralization types have been identified in the mining area: (1) Skarn type Sn−Fe bodies, which are mainly characterized by the symbiosis of cassiterite and magnetite, and belongs to a new type mineralization in the Himalayan belt; (2) Skarn−type Pb−Zn polymetallic ore bodies. Both type ore bodies are hosted in marble in middle unit of the Dome, and the U−Th−Pb age of pegmatite monazite closely related to ore-bearing skarn in the mining area is 23.0 Ma, representing its ore-forming age. The Mucun gold deposit is located in the Cover rocks in the southeast of the Kulagangri Dome, and the ore-bearing rocks are mainly a set of calcareous silty slate, and ore bodies are controlled by the northeast-strike and east−west strike faults. The mineralization in the Kulagangri Dome show a regular change from the high temperature magmatic type lithium beryllium rare metal deposit (Gabo) to the medium-high temperature skarn type tin-iron and lead-zinc deposit (Semai) to the low temperature tectonic-altered rock type gold deposit (Mucun). There are many events such as large-scale extensional detachment tectonic deformation, magmatic emplacement and high crystal differentiation of leucogranites, formation of syntectonic skarn, mineralization of Li−Be−Nb−Ta−Sn rare metals occurred at the same time at ca. 23 Ma.

Conclusions As a manifestation of the STDS in the north, both high differentiated leucogranites and large-scale detachment faults are the key factors for the mineralization of Li−Be−Nb−Ta−Sn rare metals in the Kulagangri Dome, which are also a necessary condition for finding new rare metal deposits in other typical dome structures in the Himalayan metallogenic belt.