40Ar/39Ar Thermochronology for Submilligram Samples Using a Ta Platform Microfurnace, With Illustrations From the Bushveld Complex

Abstract

Abstract We present a method for 40Ar/39Ar step‐heating measurements on anhydrous K‐bearing minerals. Samples placed in dimples on Ta foil platforms are heated indirectly with a laser while temperatures are measured with a two‐color pyrometer. The system provides a simple, inexpensive, and reliable means for the heating of samples as small as a few to tens of micrograms. Results for plagioclase separates from the Rustenburg Layered Suite of the circa 2.06 Ga Bushveld Complex closely match previously published data.

Keywords

• thermochronology
• geochronology
• Bushveld