Collaborative Research: Understanding the Processes and Timescales of Basalt Petrogenesis and Oceanic Crustal Construction at Slow-Spreading Mid-Ocean Ridges

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Mid-ocean ridges represent regions of the planet where volcanic activity is generating fresh oceanic crust and submarine mountain chains as two tectonic plates spread apart. This project will measure the chemical characteristics of volcanic rock produced along the planet’s largest extent of mid-ocean ridge, known as the Mid-Atlantic Ridge. The measurements will be used to understand which components of the mantle are melting and whether volcanic activity happens continuously or in pulses. This research will aid in understanding the larger evolution of the planet, as mid-ocean ridges serve as the dominant source of new crust on the Earth. Seventy-five percent of the Earth’s magmatic activity occurs at mid-ocean ridges. This work will also help to develop an interactive exhibit at the University of Wyoming’s Geological Museum titled “Earth’s Oceans: Now and in the Past”. This exhibit will help to inform the public, from preschoolers to senior citizens, of the importance of mid-ocean ridges in the formation and continuous resurfacing of the Earth. Mid-ocean ridges offer an opportunity to understand the isotopic and lithological composition and evolution of the Earth’s mantle, the subsurface melt processes which generate basaltic magmas, and the eruptive styles and frequency which give rise to fresh oceanic crust. While the melt processes and timescales of crustal construction are well-constrained at fast-spreading mid-ocean ridges such as the East Pacific Rise, slow-spreading ridges such as the Mid-Atlantic Ridge remain comparatively understudied. Furthermore, the Mid-Atlantic Ridge has been shown to erupt isotopically and geochemically enriched lavas, reflecting potentially lithologically heterogenous mantle source domains in the sub-ridge melting regime and potential nearby influences from upwelling mantle plumes. This research will constrain the mantle components which give rise to isotopically diverse oceanic crust along the 45°N segment of the Mid-Atlantic Ridge, the melting processes by which basaltic lavas are generated and transported to the surface, and the timescales of oceanic crustal construction that result in axial volcanic ridges. To achieve this, researchers will measure major and trace element abundances, radiogenic isotopic compositions, and U-decay series nuclides from a suite of basalt samples collected from the 45°N segment of the Mid-Atlantic Ridge. In addition, tomographic imaging from beneath MAR will be constructed and coupled with the chemical and isotopic interpretations. This multi-disciplinary data set will enhance the understanding of the mantle lithologies which melt beneath the slow-spreading Mid-Atlantic Ridge, the timescales and processes of how these melts are segregated, aggregated, and transported to the surface, and the temporal progression of fresh oceanic crustal construction along slow-spreading ridge segments. This work will help to provide the scientific community with a more complete, global understanding of the nature of the Earth’s mantle and how oceanic crust is constructed. This grant will also enhance the general public’s understanding of the Earth’s Mid-Ocean ridges by creating an exhibit at the University of Wyoming’s Geological Museum titled- “Earth’s Oceans: Now and in the Past”.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.