Comment on “Mesoplates: Resolving a decades-old controversy”



Plate tectonics is primarily a geokinematic theory Additional new concepts or components are needed to provide insights and constraints for geodynamic modeling. Recently, in Eos (23 December 2003), Pilger has developed a new concept regarding the kinematics of the lithospheric plates and the underlying mesosphere. He proposed that three mesoplates under the lithosphere can provide a framework for resolving a decades-old controversy on hot spots and mantle plumes.

Geodynamic modelers are forced to establish the existence of these three mesoplates. We have attempted to verify the mesoplate hypothesis using satellite gravity signals for remote sensing the stresses in the mesosphere [Liu et al., 2003]. Our stress patterns of the mesosphere at 100 km depth as inferred from satellite gravity signals show that global stress concentrations are mainly restricted to the boundaries of the Hawaiian, Tristan, and Icelandic Mesoplate as defined by Pilger. From a mechanical perspective, mesoplates are more likely to behave plastically at the pressure and temperature at which they exist because they are subjected to sufficient mantle convection-generated stresses. Therefore, the boundaries of the three mesoplates have also provided a framework to explain the stress concentrations as the origin of historically large earthquakes. Furthermore, we have found that the mantle convection-generated stress concentrations also occur within the interior of the mesoplates. This finding could be applied to resolving another decades-old controversy on intraplate seismicity.