Geology, alteration, lithogeochemistry and hydrothermal fluid characterization of the Neoproterozoic Niblack polymetallic volcanic-hosted massive sulfide camp, southeast Alaska, USA ...

• Main Author: McNulty, Brian
• Format: Text
• Language: English
• Published: University of British Columbia 2014
• Subjects: Prince of Wales Island; Alaska
• Online Access: https://dx.doi.org/10.14288/1.0165874; https://doi.library.ubc.ca/10.14288/1.0165874

The Neoproterozoic Alexander terrane Niblack Cu-Au-Zn-Ag volcanic-hosted massive sulfide camp is on Prince of Wales Island, southeast Alaska. Multiple massive sulfide deposits occur at different stratigraphic levels in 565 ±1.25 Ma felsic volcanic strata. Host rocks are vent-proximal felsic pyroclastic volcanic breccia, lapilli tuff, coherent flows (Lookout deposit, Trio zone) and vent-distal felsic ash tuffs (Niblack Mine, Mammoth and Dama zones). New geochemical data and volcanic lithofacies indicate the host stratigraphy was deposited in a juvenile oceanic back-arc basin. Sub-seafloor mineralization (Lookout deposit, Trio zone) consists of 15-75% sulfide with disseminated to net-textured to semi-massive sulfide textures. These ores precipitated in unconsolidated water-laden vent-proximal felsic volcanic stratigraphy. Seafloor exhalative mineralization (Niblack Mine, Mammoth and Dama zones) is comprised of massive (>90%) poorly-banded sulfide. This type of sulfide precipitated on the paleo-seafloor in, ...