Re-Os SULFIDE (BORNITE, CHALCOPYRITE, AND PYRITE) SYSTEMATICS OF THE CARBONATE-HOSTED COPPER DEPOSITS AT RUBY CREEK, SOUTHERN BROOKS RANGE, ALASKA

New Re-Os data for chalcopyrite, bornite, and pyrite from the carbonate-hosted Cu deposit at Ruby Creck (Bornite), Alaska, show extremely high lie abundances (hundreds of ppb, low ppm) and contain essentially no common Os. The Re-Os data provide the first absolute ages of ore formation for the carbonate-hosted Ruby Creek Cu-(Co) deposit and demonstrate that the Re-os systematics of Pyrite, chalcopyrite, and bornite are unaffected by greenschist metamorphism. Them Re-Os data show that the main phase of Cu mineralization predominantly occurred at 384 +/- 4.2 Ma, with an earlier phase possibly at similar to 400 Ma. The Re-Os data are consistent with the observed paragenetic sequence and coincide with zircon U-Pb ages from igneous rocks within the Ambler metallogenic belt, some of which are spatially mid genetically associated with regional volcanogenic massive sulfide deposits. The latter may suggest a temporal link between regional magmatism and hydrothermal mineralization in the Ambler district. The utility of bornite and chalcopyrite, in addition to pyrite, contributes to a new, understanding of Re-Os geochronology and permits a refinement of the genetic model for the Ruby Creek deposit.