Collaborative Research: Linking High 3He/4He to Other Isotopic Systems in Baffin Island Lavas

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Rare volcanic rocks with isotopically light helium (i.e., high 3He/4He ratios) are thought to contain material that ascended in plumes from early formed and long isolated reservoirs at the base of Earth's mantle. Lavas erupted on Baffin Island in arctic Canada have the highest 3He/4He ratios found in any terrestrial rocks and thus afford the best opportunity to investigate the stratification and long-term evolution of the deep Earth. This project will employ novel geochemical techniques to study a suite of high 3He/4He lavas collected on Baffin Island in 2018. The primary objective of the project is to improve our understanding of helium behavior in magmatic settings. Combined with a thorough petrologic and geochemical assessment of the samples, our results will provide new insights about deep Earth processes. This collaborative project will support graduate students and highly specialized technical support staff at Woods Hole Oceanographic Institution and California Institute of Technology. The project team also will partner with a Massachusetts-based rehabilitation center to provide employment opportunities to local residents. All results will be published in peer-reviewed journals, as well as translated into Inuktitut and shared with the Baffin Island Inuit communities that assisted with fieldwork.Understanding the composition and the long-term evolution of the deep Earth relies on an ability to link high 3He/4He ratios to other chemical components in volcanic rocks. This study will investigate helium (de)coupling from other elements by combing detailed petrographic and geochemical observations with precise 3He/4He measurements. The project will utilize innovative techniques including helium diffusion experiments, X-ray computed tomography, laser ablation micro-drilling, and single-grain crushing to investigate helium mobility in olivine crystals, which are the primary hosts of helium in the lavas. To fill knowledge gaps about Baffin Island lava geochemistry, researchers also will measure 186Os, 182W, and heavier noble gas (Ne, Ar, and Xe) isotopic abundances. This comprehensive geochemical assessment of these understudied lavas will offer a fresh perspective on enigmatic deep Earth processes. This collaborative project will support graduate students and highly specialized technical support staff at Woods Hole Oceanographic Institution and California Institute of Technology. Project members will partner with a Massachusetts-based rehabilitation center to provide employment opportunities to local residents. All results will be published in peer-reviewed journals, as well as translated into Inuktitut and shared with the Baffin Island Inuit communities that assisted with fieldwork.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.