Plate Tectonics Rotation Control Window

Opens with Rotate continents button on main MICRODEM toolbar.

The program will draw a map, with subdued boundaries. 

Edit boxes on the top control the parameters for the current rotation.

Memo Box lists results of the rotations.

Option Radio buttons control the rotation mode in operation. Depending on the mode selected, controls will be enabled or disabled.

  • Current vectors for a single plate, in the reference frame of the current rotation model
  • Past total poles--rotations to move a continent back to a former position in a single step. This may not be how the plate actually moved, which would have to use stage poles.
  • Arbitrary rotation--select the pole and rotation angle, and move a continent.
  • Two plate motions--pick two plates and a location on their boundary, and get the rates between them.  This could be convergence as well as spreading or transform.  If the point is not on the plate boundary, GIGO.
  • Triple junction--pick three plates and their triple junction, and get the rates between them.  If the point is not the triple junction, GIGO.

Controls to the right of the option selection:

  • Velocity diagram: draw a velocity diagram graph for the spreading rates and triple junction options.
  • Label velocities:
  • Resultant vector: for two plate motions, you can plot either the motions of the two plates, or the resultant vector between the two.
  • Velocity scalebar: can appear on the map
  • Line: the color and line weight to draw the rotation.
  • Font to label
  • Velocity vector slider controls the size of the vectors.  The best value depends on the speed, the size of the map, and how close to the map edge you want to go.

Drop down boxes control the rotation model and plate to use. These will vary with the option selected by the radio buttons.

  • Current rotation model.
  • Plate: (one to three plates enabled, depending on the option)
  • Time (Ma): used for past total poles.
  • Continent: these are the blocks of continental crust.
  • Total poles model: Cox and Hart or Duncan and Richards

Map options

  • Modify projection
  • Redraw map: removes overlays you no longer need
  • Vector outlines: coastlines, rivers, national boundaries and cities.
  • Continental crust:
  • Plate boundaries:

Buttons along the bottom control the operations on the associated map.

  • Pick Pole: used for arbitrary rotations
  • Rotate: rotate the current continent, using the current pole. Only available for "Past total poles".
  • Show pole:  shows current pole of rotation, and its antipole.
  • Motion: pick the point for the spreading rates and triple junction options.
  • Track: show the current continent for all available times. Only available for "Past total poles".
  • Time: shows all continents for the selected time. Only available for "Past total poles".
  • Vectors: draws plate motion vectors for the current plate and model. Only available for "Current vectors".  Length will be determined by the model's rotation rate and rotation duration.  If the vectors are too short, increase the rotation duration.
  • Movie: select "Past total poles" for this to work.  It will create a movie using the current model.
  • Close

References on plate motions.

Plate motion data files

Last revision 2/5/2019