Deformation, magmatism and water cycling in subduction zones

Subduction zones host the largest earthquakes and tsunamis on Earth and produce magmatism and addition to Earth’s crust. Significant volatile exchanges between the solid earth, ocean and atmosphere also occur at subduction zones. One focus of my research is understanding controls on these processes. Current projects are focused on the subduction zone offshore of the Alaska Peninsula and the Aleutian Island arc.

Seismic reflection image of Semidi Segment, offshore Alaska (Li et al., Geology, 2018)

Evolution of continental rift systems, from early-stage rifting to initiation of seafloor spreading

Continental rifting is a fundamental part of the plate tectonic cycle, yet many questions remain about the initiation of rifting, the distribution of strain throughout the lithosphere and through time, and the generation and distribution of magmatism. To address these questions, I study ancient and active rifts. Current projects include the Malawi (Nyasa) Rift in the East Africa Rift System, the Corinth Rift, Greece, and the Eastern Margin of North America, including the South Georgia Rift Basin and the rifted margin offshore North Carolina.

Estimated thickness of rift basin sediments
(Accardo et al, JGR, 2018)

Hotspot magmatism and lithospheric flexure

Although much of the magmatism on Earth occurs near plate tectonic boundaries, the oceanic floor is peppered with seamounts formed away from the mid-ocean ridge. The most prominent of these comprise chains formed above hotspots in Earth’s mantle. These volcanos provide insights into deeper Earth dynamics and the strength of oceanic plates. We focus on the Hawaii-Emperor Chain to examine these processes.

The Big Island viewed from the R/V Marcus G. Langseth