Absolute timing of sulfide and gold mineralization: A comparison of Re-Os molybdenite and Ar-Ar mica methods from the Tintina Gold Belt, Alaska

作者：Selby D^*; Creaser RA; Hart CJR; Rombach CS; Thompson JFH; Smith MT; Bakke AA; Goldfarb RJ

来源：Geology, 2002, 30(9): 791-794.

DOI：10.1130/0091-7613(2002)030<0791:ATOSAG>2.0.CO;2

• Re-Os
• molybdenite
• geochronology
• gold
• Alaska

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, Ar-40/Ar-39 dates from hydrothermal and igneous mica are considerably younger. At the Pogo deposit, Re-Os molybdenite dates are also much older than Ar-40/Ar-39 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 Ar-40/Ar-39 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.

• 出版日期2002-9