Abstract:

Located in Qimantage area of Qinghai Province, Hutouya is a typical skarn lead-zinc polymetallic ore district consisting of both orthocontact and exocontact substyles. The basic geological characteristics and ages of petrogenesis and mineralization were studied. The ore-forming elements are quite complex, dominated by Fe, Cu, Sn, Mo, Pb and Zn. Mineralization occurs in the contact zone between the intermediate-acidic intrusive rock and the carbonate-bearing strata, the fault zone or discordant contact between strata of different epochs and the lithologic boundaries, showing obvious zonation of mineralization and alteration from the intrusive rock outwards. U-Pb dating of zircons from granodiorite and adamellite has yielded ages of (235.4±1.8) Ma and (219.2±1.4) Ma, respectively. Re-Os isotopic dating of molybdenite from the skarn Cu-Mo polymetallic ore and skarn molybdenite ore by ICP-MS has yielded isochron ages of (225.0±4.0) Ma and (230.1±4.7) Ma. These new age data, combined with data available, indicate that the ages of ores and related granites should be Middle to Late Triassic. Indosinian magmatism and mineralization occurred at the post-collisional stage of the orogen, corresponding to the late stage of the Late PaleozoicEarly Mesozoic tectonic event in eastern Kunlun orogenic belt.

Key words: skarn polymetallic deposit, U-Pb dating of zircon, Re-Os isotopic dating, isotopes, Hutouya, Qimantage, eastern Kunlun