Caledonian Polygon Model

By Mathew Domeier (2016)

Visualization of the data requires the latest version of GPlates.  The data is contained in six files:

1. IR_TPW.rot is a standard format Gplates rotation file for 500-420 Ma. The header (top 7 lines) includes true polar wander (TPW) corrections from Torsvik et al. (2014).
2. IR_land.shp (and other extensions) is an ARC-GIS shapefile that contains select, present-day continent outlines (coastlines).
3. IR_ridge.gpml, IR_subduction.gpml and IR_transform.gpml are Gplates feature datafiles (in Gplates markup language format) containing the interpreted spreading ridge, subduction zone and transform plate boundaries, respectively.
4. IR_arbitrary-lines.gpml contains arbitrary polylines that are used to close the plate polygons once they reach the edge of the domain of interest of this paper. Note: these features are geologically meaningless.
5. IR_topos.gpml is a Gplates feature datafile (in Gplates markup language format) containing the topological plate polygons built from the ridge, subduction and transform plate boundary polyline files plus the arbitrary (plate-closure) polylines.

At Gplates start-up, select all the unzipped files (‘File’ > ’Open Feature Collection’). Gplates defaults to a mantle reference frame (Plate ID = 0) and reconstructions will be displayed as TPW corrected because of the header in the rotation file. To show reconstructions with respect to the spin axis (i.e. a paleomagnetic reference frame), change the anchored plate ID to 1: (‘Reconstruction’ > ‘Specify Anchored Plate ID’). For further information on Gplates and instructions on its use, visit

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