• journal_title：Geology
• Contributor：David Selby ; Robert A. Creaser ; Craig J.R. Hart ; Cameron S. Rombach ; John F.H. Thompson ; Moira T. Smith ; Arne A. Bakke ; Richard J. Goldfarb
• Publisher：Geological Society of America
• Date：2002-
• Format：text/html
• Language：en
• Identifier：10.1130/0091-7613(2002)030<0791:ATOSAG>2.0.CO;2
• journal_abbrev：Geology
• issn：0091-7613
• volume：30
• issue：9
• firstpage：791

New Re-Os molybdenite dates from two lode gold deposits of the Tintina Gold Belt, Alaska, provide direct timing constraints for sulfide and gold mineralization. At Fort Knox, the Re-Os molybdenite date is identical to the U-Pb zircon age for the host intrusion, supporting an intrusive-related origin for the deposit. However, ⁴⁰Ar/³⁹Ar dates from hydrothermal and igneous mica are considerably younger. At the Pogo deposit, Re-Os molybdenite dates are also much older than ⁴⁰Ar/³⁹Ar dates from hydrothermal mica, but dissimilar to the age of local granites. These age relationships indicate that the Re-Os molybdenite method records the timing of sulfide and gold mineralization, whereas much younger ⁴⁰Ar/³⁹Ar dates are affected by post-ore thermal events, slow cooling, and/or systemic analytical effects. The results of this study complement a growing body of evidence to indicate that the Re-Os chronometer in molybdenite can be an accurate and robust tool for establishing timing relations in ore systems.