Instrumentation development for planetary in situ ⁴⁰Ar/³⁹Ar geochronology

Morgan, L., Davidheiser-Kroll, B., Munk, M., van Bibber, K., Harkness, P. , Lee, M., Wright, I., Gupta, S. and Mark, D. (2014) Instrumentation development for planetary in situ ⁴⁰Ar/³⁹Ar geochronology. In: Goldschmidt Conference, Sacramento, CA USA, 8-13 June 2014,

Abstract

The key to understanding the history of planetary and asteroidal bodies is the accurate and precise determination of the timescale over which they developed. Absolute dating of planetary materials remains a primary goal of planetary research. Given the success of recent unmanned missions to Mars (e.g., Spirit, Opportunity, Curiosity) in understanding geological processes, development of an <i>in situ</i> numerical dating instrument packages for future robotic missions is a logical next step. Several ongoing programs of research are seeking to develop instrument packages for <i>in situ</i> application of the K-Ar technique (e.g., [1,2]). For terrestrial rocks, the K-Ar method has largely been replaced by the ⁴⁰Ar/³⁹Ar technique, which can determine thermal histories and provide internal reliability assurance. The ⁴⁰Ar/³⁹Ar method is the most promising geochronometer for obtaining accurate ages and thermal histories for rocks on the Martian surface but relies on the ³⁹K(n,p)³⁹Ar reaction so that ³⁹Ar can be measured as a proxy for the parent element K. As the mass and power requirements of a nuclear reactor are not compatible with spaceflight, an alternative neutron source must be employed. Here, we examine the potential of ²⁵²Cf, which generates neutrons through its decay by spontaneous fission. We will present initial results from neutron modeling and technological considerations towards the development of an <i>in situ</i> dating package, including a ²⁵²Cf neutron source, a subcritical ²³⁵U neutron multiplier, quadrupole noble gas mass spectrometry, and sample drilling and handling strategies.

• Item Type: Conference Proceedings
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Morgan, Dr Leah and Mark, Professor Darren and Harkness, Professor Patrick
• Authors: Morgan, L., Davidheiser-Kroll, B., Munk, M., van Bibber, K., Harkness, P., Lee, M., Wright, I., Gupta, S., and Mark, D.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy; College of Science and Engineering > Scottish Universities Environmental Research Centre