Timing of ore-related magmatism in the western Alaska Range, southwestern Alaska

Ryan D. Taylor; Garth E. Graham; Eric D. Anderson; David Selby

doi:10.3133/ofr20141115

Timing of ore-related magmatism in the western Alaska Range, southwestern Alaska

Open-File Report 2014-1115

By: Ryan D. Taylor, Garth E. Graham, Eric D. Anderson, and David Selby

https://doi.org/10.3133/ofr20141115

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Abstract

This report presents isotopic age data from mineralized granitic plutons in an area of the Alaska Range located approximately 200 kilometers to the west-northwest of Anchorage in southwestern Alaska. Uranium-lead isotopic data and trace element concentrations of zircons were determined for 12 samples encompassing eight plutonic bodies ranging in age from approximately 76 to 57.4 millions of years ago (Ma). Additionally, a rhenium-osmium age of molybdenite from the Miss Molly molybdenum occurrence is reported (approx. 59 Ma). All of the granitic plutons in this study host gold-, copper-, and (or) molybdenum-rich prospects. These new ages modify previous interpretations regarding the age of magmatic activity and mineralization within the study area. The new ages show that the majority of the gold-quartz vein-hosting plutons examined in this study formed in the Late Cretaceous. Further work is necessary to establish the ages of ore-mineral deposition in these deposits.

Suggested Citation

Taylor, R.D., Graham, G.E., Anderson, E.D., Selby, D., 2014, Timing of ore-related magmatism in the western Alaska Range, southwestern Alaska: U.S. Geological Survey Open-File Report 2014-1115, Report: iv, 25 p.; Tables 1-4, https://doi.org/10.3133/ofr20141115.

ISSN: 2331-1258 (online)

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Additional publication details
Publication type	Report
Publication Subtype	USGS Numbered Series
Title	Timing of ore-related magmatism in the western Alaska Range, southwestern Alaska
Series title	Open-File Report
Series number	2014-1115
DOI	10.3133/ofr20141115
Year Published	2014
Language	English
Publisher	U.S. Geological Survey
Publisher location	Reston, VA
Contributing office(s)	Central Mineral and Environmental Resources Science Center
Description	Report: iv, 25 p.; Tables 1-4
Country	United States
State	Alaska
Other Geospatial	Alaska Range
Online Only (Y/N)	Y