Testing absolute plate reference frames and the implications for the generation of geodynamic mantle heterogeneity structure

Description of Resources - Shephard et al. (2012)

This file provides a detailed description of all of the files that make up the data collection associated with the publication: Shephard, G. E., Bunge, H. P., Schuberth, B. S., Müller, R. D., Talsma, A. S., Moder, C., & Landgrebe, T. C. W. (2012). Testing absolute plate reference frames and the implications for the generation of geodynamic mantle heterogeneity structure. Earth and Planetary Science Letters, 317, 204-217. doi: 10.1016/j.epsl.2011.11.027

Note: For information on file formats and what programs to use to interact with various file formats, see "File Formats and Recommended Programs”.

This data collection includes both the rotations and topologically closed polygons* for each of the 5 absolute reference frames that were tested in the publication. They are to be loaded in GPlates (http://www.gplates.org).

*Topologically closed plate polygons are constructed from the intersection of ridges, transforms, subduction zones and other plate boundary geometries. These 'resolved topologies' are valid at 1 Myr intervals. The plate boundary geometries and plate polygons have been assigned plate reconstruction IDs to allow them to be reconstructed using the supplied rotation files. 

The files associated with this data collection include:

• Hybrid hotspot model (Moving and Fixed hotspots) (HHS)

* Caltech_Global_20110311HHS.gpml (37 MB) - topologically closed plate polygons and plate boundary geometries

* Caltech_Global_20110412HHS.rot (287 KB)- global rotation model

• Fixed hotspot model (FHS)

* Caltech_Global_20110311FHS.gpml (36.8 MB) - topologically closed plate polygons and plate boundary geometries

* Caltech_Global_20110412FHS.rot (291 KB) - global rotation model

• Hybrid hotspot and palaeomagnetic model (PMG)

* Caltech_Global_20110311PMG.gpml (35.9 MB) - topologically closed plate polygons and plate boundary geometries

* Caltech_Global_20110412PMG.rot (287 KB) - global rotation model

• Subduction reference frame model (SUB)

* Caltech_Global_20110311SUB.gpml (36 MB) - topologically closed plate polygons and plate boundary geometries

* Caltech_Global_20110412SUB.rot (287 KB) - global rotation model

• Hybrid hotspot and TPW-corrected palaeomagnetic model (TPW)

* Caltech_Global_20110311TPW.gpml (36.8 MB) - topologically closed plate polygons and plate boundary geometries

* Caltech_Global_20110412TPW.rot (287 KB)- global rotation model

Project files (.gproj) are included for each .gpml/.rot pair.

This article has additional supplementary data available with the online publication.

Additional notes:

*.rot contains the rotations for all plates and topological polygons.

Each model is specific according to the African Plate (Plate ID 701) rotations. The rotations for all other plates are the same across each of the five models with the exception of cross-overs involving Pacific/Panthalassa plates for times earlier than 83.5Ma; these must be absolute reference frame specific and were re-calculated for each model. Programs used to calculate the new finite rotations include "adder" and "seaflow" 

*.gpml and .shp files contain continuously closing plate polygons i.e. from plate boundaries, from 140 Ma to present-day in 1 million year increments. 

These files differ slightly from those used in the paper, but are the most up-to-date version (as at May 2011) and are based on an updated model, Seton et al. (2012).

They are specific to each of the five absolute reference frames. 

Note on velocity calculations in GPlates:

GPlates calculates the velocity within each plate based on the stage rotation for that time period and averages for that respective period. For this reason, the velocities of a plate do not change incrementally within the time period and then abruptly change according to the next time period/stage rotation. 

This is also why there appears to be a "jump" in velocity magnitude and direction between 140 and 139 Ma.