Elizabeth King

Postdoctoral fellow
University of British Columbia

I am a postdoctoral fellow working with Dr. Dominique Weis towards optimizing the analysis of iron isotopes using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). Iron is an abundant element within the Earth’s crust and the accurate measurement of the isotopic composition of various reservoirs can elucidate geochemical processes in both high- and low- temperature geochemistry. However, interferences during sample uptake severely limit the applicability of the iron isotope system. For this research, I will be collaborating with Nu Instruments to determine whether sample precision can be improved using a new collision cell MC-ICP-MS.

My prior work focuses on the mechanisms that fractionate molybdenum (Mo) isotopes during low-temperature biogeochemical cycling (Ph.D., Oregon State University, 2017). Molybdenum is a “non-traditional” stable isotope that has been traditionally used as a paleoredox tracer in marine sediments. The utility of the Mo isotope system as a paleoredox proxy relies on the assumption that there is no fractionation in the terrestrial environment. However, my research determined that there in, indeed, fractionation occurring as Mo is liberated from primary minerals and cycles throughout soils prior to entering rivers and eventually the ocean. In order to successfully determine the mechanisms fractionating Mo, I had to develop a program to measure Mo isotopes on the Nu Plasma MC-ICP-MS at Oregon State University. This extensive training will be useful for my appointment within MAGNET. Aside from Mo, I also have experience measuring Sr isotopes on a TIMS (for my undergraduate research project to tease apart carbonate and silicate weathering endmembers (B.S., Boston University, 2012).