Paleomagnetic Dating Constraints on the Genesis of the Leqingla Pb-Zn Deposit, South Tibet, China

The Leqingla deposit serves as a representative skarn-type Pb-Zn deposit in the Gangdese polymetallic belt, South Tibet, China. Although numerous studies have been conducted on this deposit, there is no consensus about its specific genesis, particularly concerning the timing of mineralization. Recent studies indicate that paleomagnetic dating techniques, employed on newly formed magnetic carrier associated with mineralized fluids, permit precise determination of mineralization timing. Hence, a systematic paleomagnetic and petrologic investigation was conducted on the host rock of the Leqingla deposit, which is characterized by the middle Permian Luobadui Formation sandstone. The results reveal that the dominant magnetic carrier in the host rock is hydrothermal authigenic pyrrhotite. The stable characteristic remanent components display maximum clustering when flattened to -5.5% ± 13.5% after tilt corrected. The obtained paleomagnetic pole (P_lat = 74.5°N, P_long = 222.5°E, at N = 8, A₉₅ = 2.9°) is consistent with that of the Pana Formation volcanic rock in the same area. Further combined with the chronological and geological evidences, we refer that the hydrothermal authigenic pyrrhotite in the host rock may record chemical remagnetization information acquired between 54-47 Ma. The magmatic activity (54-47 Ma) induced by the India-Asia collision is closely related to remagnetization and the formation of the Leqingla deposit.