| Plate tectonic theory and hotspot theory explain the presence of volcanism at plate boundaries and over mantle plumes such as Hawaii. However, there are linear intraplate volcanic ridges associated with free air gravity lineaments in the south central Pacific Ocean that are not explained by these two theories. The GLIMPSE experiment employed several geophysical techniques to explore the origin of two of these volcanic features: the Sojourn Ridge and the Hotu Matua Volcanic Complex.; Using data from bathymetric surveying, gravimetric surveying, body wave delay analyses, shear wave splitting analyses, seismic impulse responses determined from ambient seismic noise, and surface wave tomography, I find overwhelming evidence that a dynamic mantle component is required to produce the observed bathymetric, gravimetric, and seismic anomalies associated with the intraplate volcanism and gravity lineations. I show that models of small-scale convection or channelized asthenospheric return flow are likely, while lithospheric boudinage models or thermoelastic cracking models cannot completely explain all of the observations. |
