Equipment: MRI: Track #1 Acquisition of electron spin resonance spectrometer for radiation exposure dating

This Major Research Instrumentation Program (MRI) award supports the acquisition of an electron spin resonance (ESR) spectrometer and standalone X-ray irradiator that will be used for geological and archaeological dating at the Desert Research Institute (DRI) in Reno, Nevada. ESR dating is one of a family of ‘radiation exposure’ dating methods that relies on the accumulated radiation dose stored in a material to determine its age. Other methods in the family include optically stimulated luminescence (OSL) and thermoluminescence (TL), both of which are currently supported at DRI. ESR dating offers two main advantages over OSL and TL: (1) the method can be applied to a much wider range of materials including, but not limited to, quartz, tooth enamel, and carbonates, and (2) its applicable dating range spans the last 2 million years, far surpassing the capabilities of luminescence dating methods. Importantly, acquisition of this ESR spectrometer will establish DRI as one of only two North American institutions with ESR dating capabilities and will vastly increase the number of opportunities for research collaboration and innovation. This new instrumentation will also enhance DRI’s strong track record of undergraduate and graduate student research training and provide new opportunities to attract and train geochronologists from across North America. Acquisition of a Bruker EMXmicro continuous wave X-band ESR spectrometer and benchtop X-ray irradiator (X-ray Dose ESR Version, Freiberg Instruments) will enable a number of multi-disciplinary research projects that address questions spanning a variety of depositional environments and timescales over the Quaternary period. Some of these projects include: (1) defining the timescales and drivers of Quaternary terrace formations along the Rio Grande valley, New Mexico, (2) refining radiocarbon chronologies based on lacustrine shells, (3) paleohydrological modeling of mid- to late- Pleistocene pluvial lakes in the Great Basin, (4) constraining long-term slip rates and the timing of extension in the Great Basin, and (5) reconstructing Antarctic sedimentary provenance using paired ESR and luminescence analyses. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.