Plume-lithosphere interaction and delamination at Yellowstone and its implications for the boundary of craton stability

Delamination of the lower lithosphere has occurred under different tectonic settings; strong lateral strength heterogeneities can result. Controls on the geometry of lithosphere delamination remain largely unknown. In this study, we examine plume-induced lithosphere delamination associated with the Yellowstone plume. We propose that interaction between the Yellowstone plume and western North American lithosphere led to delamination of the lower lithosphere beneath the Columbia River Basalt (CRB). The excess melting that occurred when this hole was being filled by Yellowstone plume material was the trigger for the CRB melting event. The lower lithosphere that was delaminated currently lies to the northeast of the CRB; it can be clearly identified in recent seismic tomographic models. We suggest that weak zones, either lithosphere-crossing faults or suture zones, or vertical weaknesses associated with hotspot tracks, acted as lateral boundaries for delamination of the lower lithosphere. Numerical model results indicate that the stronger regions where a weak MLD layer is absent also act as a barrier for delamination. Low stress ( 1MPa) and high strain rate at the lithospheric MLD promote delamination while higher stresses ( 100 MPa) in this region stop delamination.