SHRIMP U-Pb geochronologic data for Elkhorn Mountains Volcanics and Boulder batholith satellite plutons, western Montana, U.S.A.

These data are for a geochronologic study of Cretaceous Elkhorn Mountains Volcanics and several discrete satellite plutons adjacent to the Cretaceous Boulder batholith of western Montana. Zircon from the two volcanic units of the Elkhorn Mountains Volcanics and four samples of satellite plutons of the Boulder batholith were dated by sensitive high resolution ion microprobe (SHRIMP). When compared to ages for the Boulder batholith, the ages for the Elkhorn Mountains Volcanics in this study indicate that the volcanics are older than the Boulder batholith and not coeval as long thought. Ages for satellite plutons indicate that some are older than the volcanics and some were coeval with the Boulder batholith. These ages for the igneous rocks of the Boulder batholith region connect the igneous activity to structural history, crustal depths, and origins of epigenetic and porphyry mineral deposits. These SHRIMP U-Pb data are shared to meet open data requirements.