Lead Isotopic Compositions of the Kohistan-Ladakh Terrane in NW Himalayan Syntax, Pakistan and their Tracer Significance

Served as an important part of northwest Himalayan syntax, the Kohistan-Ladakh terrane is characterized by the mixed source in the lead isotopic compositions. On the basis of previous studies, the lead isotopic compositions of the Kohistan-Ladakh terrane have been re-analyzed, and their H-H single-stage evolution model ages as well as characteristic parameters (such as, μ values, ω values, Th/U ratios, Δβ values and Δγ values) are calculated in this paper. The study results show that, the lead is mainly derived from the crust-mantle mixing substances, mixed with some crustal materials from Asian continent, and their types are similar to the subducted lead compositions that controlled by magmatism. The results indicated that their lead isotopic compositions displayed the DUPAL abnormal characteristics. Thus, it is speculated that the anomalous lead may come from Asian continent margin, which can serve as basic reference for studying magmatism and evolution in this area.