Oceanic Plateau Subduction

Oceanic plateaus fall within the category of large igneous provinces (LIPs). These structures lie 2-3 km above the seafloor and consist of very thick layers of basalt and harzburgite, which make the oceanic plateau buoyant. When these buoyant structures enter a subduction zone, they tend to resist subduction and become accreted to the upper plate. There are cases, however, when oceanic plateaus do subduct to great depths. The conditions that make this possible, as well as the resulting surface deformation, is something I found very intriguing.

In Alaska, the Yakutat oceanic plateau is colliding into the plate boundary corner, but seismic data also show that it is subducting to depths of ~150 km! It is hypothesized that the Yakutat plateau is responsible for causing the modern flat slab as well as far-field deformation and uplift of the St. Elias Mountains, which is the highest coastal mountain range on Earth. To test these hypotheses, I am currently working on adding in the compositional buoyancy of the Yakutat plateau into our 3D models of Alaska. Stay tuned for updates!