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

Selby, D; Creaser, R.A; Hart, C.J.R; Rombach, C.S; Thompson, J.F.H; Smith, M.T; Bakke, A; Goldfarb, R.J

Authors

R.A Creaser

C.J.R Hart

C.S Rombach

J.F.H Thompson

M.T Smith

A Bakke

R.J Goldfarb



Abstract

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.

Citation

Selby, D., Creaser, R., Hart, C., Rombach, C., Thompson, J., Smith, M., …Goldfarb, R. (2002). Absolute timing of sulfide and gold mineralization: A comparison of Re-Os molybdenite and Ar-Ar mica methods from the Tintina Gold Belt, Alaska. Geology, 30(9), 791-794. https://doi.org/10.1130/0091-7613%282002%29030%3C0791%3Aatosag%3E2.0.co%3B2

Journal Article Type Article
Publication Date 2002-09
Deposit Date Mar 13, 2007
Journal Geology
Print ISSN 0091-7613
Electronic ISSN 1943-2682
Publisher Geological Society of America
Peer Reviewed Peer Reviewed
Volume 30
Issue 9
Pages 791-794
DOI https://doi.org/10.1130/0091-7613%282002%29030%3C0791%3Aatosag%3E2.0.co%3B2
Keywords Re-Os, Mmolybdenite, Geochronology, Gold, Alaska.