Ages of sediment-hosted Himalayan Pb-Zn-Cu-Ag polymetallic deposits in the Lanping basin, China: Re-Os geochronology of molybdenite and Sm-Nd dating of calcite

To define the metallogenic history of the study area, we dated nine calcite samples associated with copper sulfides from the Jinman Cu deposit by the Sm-Nd method and five molybdenite samples from the Liancheng Cu-Mo deposit by the Re-Os method. The calcite Sm-Nd age for the Jinman deposit (58 ± 5 Ma) and the molybdenite Re-Os age for the Liancheng deposit (48 ± 2 Ma), together with previously published chronological data, demonstrate (1) the Cu-Ag mineralization in the western Lanping basin mainly occurred in three episodes (i.e., ∼56-54, 51-48, and 31-29 Ma), corresponding to the main- and late-collisional stages of the Indo-Asian orogeny; and (2) the Pb-Zn-Ag (±Cu) mineralization in the eastern Lanping basin lacked precise and direct dating, however, the apatite fission track ages of several representative deposits (21 ± 4 Ma to 32 ± 5 Ma) may offer some constraints on the mineralization age.