Thorsten Becker - Distinguished Chair in Geophysics, UT Austin: Downloads: Spreading aligned plate motion reference frame

Jackson School of Geosciences
The University of Texas at Austin

SA-RF APM

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Spreading-aligned absolute plate motion reference frame

In Becker et al. (2015), we argue that optimizing the match of absolute plate motions to spreading orientations provides for an improved absolute plate motion (APM) reference frame that can satisfy a number of constraints, including hotspot motions, and matches azimuthal anisotropy very well. Its net rotation amount is also broadly consistent with geodynamic estimates (e.g., Becker, 2006).

This new, spreading-aligned plate motion reference frame can be computed by adding a net rotation with Euler pole of 63.9E, 61.2S, 0.277 deg/Myr to a no-net-rotation (NNR) model. For our study, we used the NNR-MORVEL56 velocities of Argus et al. (2011).

Trench motions and slab rollback

Among the predictions of the new spreading-aligned APM model are a clearer separation of relative trench motions, as shown for Heuret and Lallemand (2005) rollback/advance estimates in the new reference frame (blue = advancing, red = retreating trench wrt. subducting plate). Also see the discussion of reference frames for trench motions in Becker and Faccenna (2009).

Here is the original data from Heuret and Lallemand's (2005) compilation of trench motions at

the SUbMAP web site of Heuret with complete references and such,

and when their trench motions are rotated into different reference frames:

Those two are plotted on this map:

Plate velocity model grids

For convenience, we here also provide global GMT/Netcdf .grd files with East and North velocities for the original velocities in NNR, and when moved into our spreading-aligned reference frame.

Original NNR version of NNR-MORVEL56 (Argus et al., 2011)

Spreading-aligned reference frame velocities of Becker et al. (2015)

References:

Argus, D. F., R. G. Gordon, and C. DeMets (2011), Geologically current motion of 56 plates relative to the no-net-rotation reference frame, Geochem. Geophys. Geosyst., 12, Q11001, doi:10.1029/2011GC003751.
Becker, T. W., Schaeffer, A. J., Lebedev, S., and Conrad, C. P.: Toward a generalized plate motion reference frame. Geophys. Res. Lett., 42, doi:10.1002/2015GL063695, 3188-3196, 2015. (PDF, supp. mat.)
Heuret, A., and S. Lallemand (2005), Plate motions, slab dynamics and back-arc deformation, Earth Planet. Inter., 149, 31–51.

Updated: November 11, 2024. (c) Thorsten Becker, 1997-2024.