Plate Tectonics Rotation
Opens with Rotate continents button
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.
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
junction--pick three plates and their triple
junction, and get the rates between them. If the point is
not the triple junction,
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
- 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
- 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
- Modify projection
- Redraw map: removes overlays you no longer need
- Vector outlines: coastlines, rivers, national boundaries and
- 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
- 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.
References on plate motions.
Plate motion data files
Last revision 2/5/2019