Testing hotspot fixity in the Indian and Atlantic oceans

Project Summary
We have developed a novel interactive evolutionary inversion approach for computing absolute tectonic plate motions and their uncertainties based on hotspot tracks through time. We use a modified criterion of fit for inverting hotspot-track data, following an approach previously developed by Chang and co-workers for relative plate motions. Using this method, we derive covariance matrices for absolute plate rotations for the last 120 million years for the first time, using dated hotspot tracks in the Atlantic-Indian oceans. This represents a major advance in quantitatively constraining paleogeographic maps for the last 130 million years. 

In our new methodology we model the motion of hotspot in the mantle flow field using an interactive evolutionary approach, by constraining the plate motion models to fit paleomagnetic constraints, and converge on an acceptable motion solution by varying unknowns over several generations of simulations.

Our hotspot motion model shows a large motion of the Indo-Atlantic hotspots for times before 70 million years before present, consistent with paleomagnetic constraints. The fixed and moving hotspot reference frames are not discernible over the level of uncertainty in such rotations for times younger than 60Myr, however, for older times the motion of the hotspots result in significant differences between the two models, resulting in substantial improvements in the positions of continents and oceans in palaeogeographic maps.

Project Participants
Prof Dietmar Müller
Dr Bernhard Steinberger