Identification and its significances of the Lalong Be-Nb-Ta-bearing albite granite in the Northern Himalaya, Tibet

The Lalong dome is one of the North Himalayan Gneiss Domes (NHGD), located between the well-studied Kangmar dome and the Cuonadong dome. On the basis of 1:50,000 geological survey for minerals, 1:10,000 geological mapping, detailed measured profiles and monazite U-Pb dating, a set of Be-Nb-Ta-bearing rare metal albite granite was first discovered and identified in the Lalong dome. The Lalong Be-Nb-Ta-bearing albite granite shows continuous zonings of granitic magma evolution. From inside out, two mica granite, white mica granite, pegmatitic granite, albite granite, and pegmatite were observed. The albite granite is characterized by high contents of Be, Nb, Ta, Li, Rb and Cs, and it is also rich in volatiles such as H₂O, P, F and B. A 21.3 Ma age was obtained by U-Pb dating for the monazite in the albite granite, which represented the crystallizing ager of the Lalong Be-Nb-Ta-bearing albite granite, implying an extensively magmatic activity in the northern Himalaya at that time. The identification of the Be-Nb-Ta rare metal albite granite in the Lalong dome not only opened an important prospecting prelude of albite granite type Be-Nb-Ta rare metal deposits, but vastly enriched metallogenic types of rare metals in the northern Himalaya.