In Situ Potassium-Argon Geochronology Using Fluxed Fusion and a Double Spike

Hurowitz JA¹, Hecht MH¹, Zimmerman WF¹, Neidholdt EL¹, Sinha MP¹, Sturhahn W¹, Coleman M¹, McCleese DJ¹, Farley KA¹, Eiler JM¹, Rossman GR¹, Waltenberg K¹

¹California Institute of Technology ² Queensland University
Pasadena, CA, USA Brisbane, Australia

Abstract

A document highlights an Li-based fluxing agent that enables sample fusion and quantitative Ar-release at relatively low temperatures (900-1,000 C), readily achievable with current flight resistance furnace designs. A solid, double spike containing known quantities of Ar-39 and K-41 was developed that, when added in known amounts to a sample, enables the extraction of a Ar-40/K-40 ratio for age estimation without a sample mass measurement. The use of a combination of a flux and a double spike as a means of solving the mechanical hurdles to an in situ K-Ar geochronology measurement has never been proposed before. This methodology and instrument design would provide a capability for assessing the ages of rocks and minerals on the surfaces of planets and other rocky terrestrial bodies in the solar system.