Plate tectonic theory was extremely successful in providing a framework for understanding deformation and volcanism at plate boundaries, and allowed us to understand how continent motions through time are a natural result of heat escaping from Earth's deep interior. Plate tectonics also provided a scientific framework for earthquake and volcanic hazard assessment and hydrocarbon exploration. Plate tectonics is, however, an incomplete theory: For instance, we lack a generally accepted mechanism that explains plate tectonics in the framework of mantle convection, and the origin of intra-plate volcanism such as hotspots and Large Igneous Provinces are controversial. Commonly, a deep mantle plume origin is assumed, but alternative models exist.

Linking surface and lithospheric processes to the mantle is extremely challenging and is only now becoming feasible due to better constraints on deriving ancient longitudes before the Cretaceous, much improved seismic tomographic images, better understanding of the dynamics of true polar wander and recent advances in mineral physics. Dramatic improvement in computational capacity and numerical methods that efficiently model mantle flow while incorporating surface tectonics, plumes, and subduction, have emerged to facilitate further study, and the principal CAS objectives was to (1) Develop a Global Subduction Absolute Reference Frame, and (2) Link Surface and Deep Processes.