40Ar/39Ar geochronologic data for study of country rock, Butte, U.S.A.
These 40Ar/39Ar thermochronologic data for biotite, hornblende, and K-feldspar from Butte granite country rock are for the study of the Butte mining district, U.S.A. Results of the study are described and interpreted in Lund and others (2018).