Ar-40/Ar-39 Thermochronology For Submilligram Samples Using A Ta Platform Microfurnace, With Illustrations From The Bushveld Complex

We present a method for Ar-40/Ar-39 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.