Laboratory Technician Support: Enhancing High-Precision 40Ar/39Ar Dating at the OSU Argon Geochronology Laboratory

Oregon State University, Corvallis OR

Investigators

Abstract

The OSU Argon Geochronology Laboratory has employed K/Ar and 40Ar/39Ar dating methods at Oregon State University (OSU) since 1969. Our user-base is ever-growing and ranges from students, post-docs and collaborators at OSU to many clients and collaborators throughout the U.S. and internationally. Over the last decade, we have substantially upgraded our facility and we now have in operation two new ARGUS-VI multi-collector mass spectrometers. Applying the ARGUS-VI to modern-day 40Ar/39Ar geochronology has provided us with a quantum leap forward in precision, accuracy and throughput of analyses. Our analytical precision is 10x improved using 60-95% less material. In addition, with two fully-automated ARGUS-VI instruments now online, we are projecting to carry out more than 70,000 analyses/year on ~1,300 samples from ~130 different research or educational projects. With this proposal, we will hire an experienced geochronologist with an MS or PhD degree and experience in 40Ar/39Ar geochronology. The successful candidate is envisioned to expand our expertise beyond our current research areas and would double our capacity for supporting the in-creasing number of NSF-funded geochronology projects in our laboratory. Recent research made possible through the ARGUS-VI instruments in the OSU Argon Geochronology Laboratory include the high-precision dating of (i) Late Pleistocene and Holocene sanidine and volcanic samples as young as a few thousand years, (ii) magnetic reversals and excursions in terrestrial lava flow records, (iii) low-potassium basalts from ocean crust, bonitites and tholeiites, (iv) ultra-low-potassium clinopyroxene, and (v) terrestrial volcanic centers younger than 5 Ma to improve our understanding their eruptive histories and related geohazards. These five examples of our recent advances, provide an exciting foundation for growing our research enterprise over the next decade. The new 40Ar/39Ar geochronology technician will play a critical role in building out those research avenues, while bringing to OSU research interests and skill sets that significantly expand our laboratory?s research portfolio.