Fate of the continental lithospheric mantle during the continent to ocean transition in a magma-rich environment - Insights from the East Greenland margin

When continents split and a new ocean forms, large volcanic eruptions can occur. These eruptions create thick layers of lava mixed with sediment known as seaward dipping reflectors (SDRs). These features are common along continental margins and can host large mineral deposits. But, the mechanisms that generate the large volumes of magma for SDRs remain unclear. Hotspot mantle plumes from deep within the Earth are often invoked as the source of this magma. An alternative hypothesis is that formation of SDRs involves the continental lithosphere. This study focuses on East Greenland, a unique place where both igneous dikes onshore and offshore SDRs occur. The study will compare the geochemistry of these two features to trace the origin of the magma. New computer models using the geochemical results will show how continental lithosphere contributes to magma production during rifting. Findings will be integrated into a new course on the Energy Transition, helping students connect Earth Science with technology. The project also supports undergraduate and graduate researchers in geochemistry. Students develop Earth Science skills relevant to the challenges of the 21st century economy. This project will strengthen Michigan State University’s analytical geochemistry lab, a key resource for scientific and industrial partners in the Great Lakes region. This project is co-funded by the Marine Geology and Geophysics and Chemical Evolution of the Solid Earth and Volcanology Programs. When continents split to form new oceans, upwelling magma will generate subaerial basalt flows, intercalated with sediments, known as seaward dipping reflectors (SDRs). Large volumes of basaltic magmas are needed to explain the formation of SDR layers greater than 10 km thick. Typically, the large volume of basalt is attributed to mantle plume related melt. However, the continental lithosphere also may play a crucial role in melt production. This study will test the hypothesis that the continental lithospheric mantle impacts magma generation processes during the continent to ocean transition in East Greenland by addressing five questions: (1) What is the temporal evolution of magmatism along the East Greenland margin? (2) Is there a link between the SDRs and the East Greenland coastal dike swarm? (3) Is there evidence for a mass contribution from a depleted component, located within the continental lithospheric mantle, which manifests in magmatism during the continent to ocean transition? (4) Is there evidence for a mass contribution from an enriched component, located within the continental lithospheric mantle, which manifests in magmatism during the continent to ocean transition? (5) What is the lithology of the upper mantle and its melting dynamics? This geochemical study will use dike samples from the East Greenland coastal dike swarm and IODP drillcore samples of SDRs to address analytical gaps, apply new mantle melting models, and add Hf and Os isotopic data to constrain the origin of depleted mantle components. Findings will be integrated into a new training course on the Energy Transition, helping students connect Earth Science with new technologies. The project also supports undergraduate and graduate researchers who will form the core of the project. This project will strengthen Michigan State University’s analytical lab, a key resource for scientific and industrial partners in the Great Lakes region. By revealing how continents break apart and oceans begin, this research not only advances scientific knowledge but also helps train the next generation of scientists that will work at the intersection of Earth processes and the challenges of the 21st century economy. 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.