EA: Acquisition of an IRMS for sulfur isotope measurements

This grant will support the acquisition of a state-of-the-art mass spectrometer. The instrument will be used in Dr. Dottin’s research program as a new faculty member at Brown University in the Department of Earth, Environmental, and Planetary Sciences.

Sulfur, the sixteenth element on the periodic table, has 4 stable isotopes (32S, 33S, 34S and 36S). Ratios of these isotopes that are measured in a variety of rock materials often provide fingerprints associated with how the rock materials have been processed throughout geologic time. Such can also provide insights into the different planetary evolutionary processes that have occurred through time.

The proposed project focuses on the acquisition of a state-of-the-art instrument capable of measuring the ratios of sulfur isotopes at high precision. The instrument will primarily be used for research associated with (1) understanding the origin and evolution of sulfur in the deep Earth, (2) placing constraints on the evolution of Earth’s atmosphere, and (3) ultimately deconvoluting the complexities related to interactions among Earth’s atmosphere, surface, and interior.

The instrument also will be used as a teaching tool. It is anticipated that undergraduate students, graduate students, and postdocs will use the instrument for their respective projects. They will be trained in the operation and troubleshooting of the instrument.

The instrument also will be incorporated in upper-level undergraduate/graduate courses that will allow students exposure to gas source mass spectrometry and an opportunity to work in an isotope laboratory within a class setting.

The awarded proposal contains a request for an isotope ratio mass spectrometer (IRMS) that will be used to determine sulfur isotope compositions of rocks from a variety of Earth reservoirs. Acquisition of an IRMS will support the research program of PI (Dottin), who will begin an assistant professorship at Brown University July 1, 2023. The analytical tasks that will be accomplished with the state-of-the-art IRMS will broadly cover studying the quadruple isotopic composition of sulfur that exists in multiple earth reservoirs to identify the processes associated with the cycling of sulfur among the Earth’s interior, surface, and atmosphere, and the timescales on which these processes occur.

Specifically, Dottin plans to use the instrument to: (1) determine the nature and relative age of recycled components erupted among Ocean Island Basalts; (2) place detailed constraints on the sulfur isotope composition of the primordial mantle; and (3) to use S isotopes to track the evolution of Earth’s continental crust across the Archean-Proterozoic boundary. The instrument will contain state-of-the-art technology and can be fit with a unique set of collectors that will allow for the acquisition of high-precision measurements of the minor isotopes of sulfur.

Beyond the scope of strictly acquiring data, the instrument will be connected to efforts that are rooted in education, training, and diversification of the geosciences. The instrument requested will be used to support research performed by undergraduate students at Brown University and summer research undergraduate students actively recruited from HBCU’s and other minority-serving institutions.

Additionally, the instrument will be used as an educational/training tool. Graduate students will be trained in the proficient operation and maintenance of the instrument and the PI (Dottin) plans to develop courses that use the instrument as a teaching aid to expose a wide audience of students to gas source mass spectrometry and geochemistry laboratory applications.

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.