Geological setting, nature and evolution of reduced intrusions and gold bearing quartz veins of the 4021 prospect, Goodpaster district, east-central Alaska ...

• Main Author: Dilworth, Katherine M.
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Alaska; Yukon
• Online Access: https://dx.doi.org/10.14288/1.0052562; https://doi.library.ubc.ca/10.14288/1.0052562

Gold deposits associated with Cretaceous reduced granitic rocks are common in Yukon and Alaska. The Liese zone and spatially related prospects in the Goodpaster district, eastcentral Alaska, are associated with an arcuate, easterly trending belt of Cretaceous reduced granite to tonalite that compose the older of two Early Cretaceous intrusive suites. A younger suite of calc-alkaline diorite rocks (-94 Ma) are slightly more oxidized and are unrelated to the gold mineralization. Both calc-alkalic suites have low magnetic susceptibilities and oxidation states. The older suite, which includes a phase of the Goodpaster Batholith, is weakly peraluminous and contains monazite and zircon. Biotite is common and hornblende is subordinate to absent. Older granitoids of the suite are deformed and syn- to- late kinematic to regional metamorphism at about 109-107 Ma (U-Pb; zircon and monazite). Post-kinematic intrusions of the suite are as young as 104 Ma (U-Pb SHRTMP-RG). Sulphide deposition at -104.3 Ma in the Liese ...