Paleomagnetic data bearing on the timing of alteration associated with the emplacement of the Leqingla Pb-Zn deposit, South Tibet, China

The Leqingla deposit, situated in the Gangdese polymetallic belt of South Tibet, is a typical skarn-type Pb-Zn deposit. Although it has been the subject of extensive geologic studies, the timing and genesis of mineralization remain unresolved. Paleomagnetic dating, especially targeting remagnetized or newly formed magnetic minerals associated with mineralization, provides a valuable tool to address this issue. We conducted a comprehensive paleomagnetic and petrologic investigation of the middle Permian Luobadui Formation sandstone, the host rock of the deposit. A negative tilt test on pyrrhotite-bearing remanence directions suggests that the sandstone acquired a secondary magnetization after folding (post-Jurassic–Cretaceous). The calculated paleomagnetic pole (Plat. = 74.6°N, Plong. = 221.8°E, N = 8, A95 = 2.8°) closely matches the Eocene (54–47 Ma) pole of the Lhasa Block. Petrologic and magnetic evidence indicates pyrrhotite as the main remanence carrier, likely formed during hydrothermal activity associated with Pb-Zn mineralization. Thus, the remagnetization age likely reflects the mineralization event. Integrating geologic and chronologic constraints, we hypothesize that the Pb-Zn mineralization occurred between 54 Ma and 47 Ma, possibly triggered by magmatism during the main phase of the India–Asia collision.