Deconvolving Magmatic, Crustal and Atmospheric Gases in Yellowstone using a Coupled Noble Gas and Nitrogen Isotope Approach

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

The Earth’s surface is rich in volatile elements (e.g., H, C, N), providing the unique conditions that sustain life on our planet. However, the origin of terrestrial volatiles remains enigmatic, with considerable debate and uncertainty surrounding regarding volatile source(s) and the overall timing of planetary accretion. Analyzing the composition of primordial gases emanating from Earth's mantle represents one of the best avenues to determine the origin of terrestrial volatiles. The Yellowstone–Columbia River volcanic mega-province is one of the few volcanic localities on Earth where pristine, plume-derived magmatic gas reaches the surface and can be easily collected for analysis. Geochemical data from previous studies in Yellowstone suggest that gas vents are sourced from a deep-seated mantle plume, that is dominantly chondritic in origin. In this project, a comprehensive study of gas emissions from Yellowstone National Park (YNP) will be conducted. The aims are to: (i) investigate the nature and extent of the Yellowstone plume's interaction with the Archean-aged crustal basement, which will provide further insight into (ii) the source of the YNP plume, and the (iii) processes acting to obfuscate mantle source signals. Specifically, the proposed research will constrain the composition of YNP magmatic gases and their parental plume mantle source with unprecedented spatial and analytical resolution. The PIs will employ static noble gas mass spectrometry techniques, clumped N isotope measurements and the first ultra-high-precision (sub per mil (‰) precision) dynamic mass spectrometry measurements of magmatic gas to deconvolve mantle, crustal and atmospheric endmembers and to place firmer constraints on the origin of volatiles in the Yellowstone plume, which will help pinpoint the origin of volatiles on Earth. Questions pertaining to the origin of volatiles on Earth are of broad interest to the scientific community. Results from this study will provide insight into the relationship between mantle volatiles and Earth’s atmospheric composition, which is of direct relevance to understanding the drivers of Earth’s habitability and the subsequent evolution of life. Findings will be communicated to the scientific community through peer-reviewed publications and to the public through a multi-faceted outreach approach, including newsletter publications and field-based lectures that will be simulcast as a Facebook Live Event in coordination with YNP rangers. Further, the PIs will work with the YNP Exhibits Specialist to incorporate geochemical findings from this and other studies into a permanent “wayside exhibit” within the park. If possible, a short geochemical synopsis will also be included in the YNP welcome packet (distributed to the >4 million annual visitors). Additionally, an interactive website presenting a “Yellowstone Geochemical Trail Map.” will also be constructed and linked to the aforementioned wayside exhibit and entry brochure. 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.