North America region, 64 million years ago Lithgow-Bertelloni & Richards plate velocity vector field, IDV-computed divergence of vector field, and Ron Blakely's continental image; click for larger, or click here for Quicktime movie |
The GEON Integrated Data Viewer - Contents
INTRO
Introducing the GEON IDV
INSTALL
Download & Run the GEON IDV
YOUR DATA Data Formats for the IDV |
Tectonic Plate Velocity and Boundary Data and Displays in the IDV
The IDV is an excellent way to show and explore plate motions, in map or globe views, with time animation.
Today's Plate Motion Vectors (GSRM Plate Velocities)
Plate Motion Vectors in Geological Time, and IDV-computed Plate Boundaries from Divergence
Tectonic Plate Image Animation, 280 My BP to Today
Computing Plate Motion Divergence from GSRM and Historic Velocities
Plate Motion Data Quality Checking with the IDV
Data Formats for 2D and 3D Vector Grids in NetCDF for the IDV
Today's Plate Motion Vectors (GSRM Plate Velocities)
The Global Strain Rate Map (GSRM) Project created plate velocity models for no net rotation and each major plate. For more about the GSRM project, see the GEON IDV web page Global Strain Rate Map Data and Displays in the GEON IDV.
Data Sources Online:
The GSRM project made plate motion velocity vectors on 1 by 1 degree grids,i from 80 S to 80 N latitudes. Netcdf grid files of the data is provided here.
global plate velocities for no net rotation: No Net Rotation
global plate velocities relative to the indicated plates:
AN Antarctica OK Okhotsk CR Caroline PH Phillipine SO Somalia
IN India SA South America CO Cocos SC South China AR Arabia
PA Pacific AT Anatolia AU Australia NZ Nazca EU Eurasia
NU Nubia CP Capricorn TA Tarim AM Amuria RI Rivera
ST Scotia JF Juan de Fuca NA North America SU Sunda CA Caribbean
To see a velocity data source in the IDV, first "copy link location" for that URL. Enter that link location in the URLs entry box in the IDV Dashboard's Data Choosers window. Be sure to first choose Data Source Type of "Im feeling lucky" for netCDF gridded data. Click on Add Source.
In the "Fields " panel in the Dashboard's Field Selector tab, click on the little button left of "2D grid." Click on the little button left of "Derived." Click on either Vectors the list which appears. Finally click on the large "Create Display" button. The diplay control can be used to change vector size, color, and density on the plot.
GSRM NNR Velocities, southeast Asia. Click for larger view
...
plain map
...
divergence plot
Publication:
The Global Strain Rate Map (GSRM) data is provided by Corne Kreemer. See
Kreemer, C, A.J. Haines, W.E. Holt, G. Blewitt, and D. Lavalée,
"On the determination of a global strain rate model,"
Earth Planets Space, 52, 765-770, 2000; and Kreemer, C., W.E. Holt, and A.J. Haines, "An integrated global model of present-day plate motions and plate boundary deformation,"
Geophysical Journal International, 154, 8-34, 2003.
Publication Online:
See also http://gsrm.unavco.org/,
http://geodesy.unr.edu/cornekreemer/gsrm.htm, and
http://geodesy.unr.edu/publications/Kreemer_et_al_GSRM_2003.pdf
Plate Motion Vectors in Geological Time, and IDV-computed Plate Boundaries
Here is a data source of plate motion vectors from 170 My BP to 10 My BP.
The IDV includes computational ability using data sources. For 2D velocity vector grids you can compute the horizontal divergense, and examples are shown here. The color scale used has orange for divergence (spreading centers) and blue for convergence such as subduction zones. Intensity of color indicates speed of convergence or divergence. Inter-plate zones of deformation will also appear.
Past Plate Motion Vectors Data Source for the GEON IDV:
http://geon.unavco.org/unavco/geodynamics/Lithgow-Bertelloni_Richards_Mesozoic_Cenozoic_Plate_Velocities.ncEnter this URL link location into the IDV Data Chooser URLs window. In the "Fields " panel in the Dashboard's Field Selector tab, click on the little button left of "2D grid." Click on the little button left of "Derived." Click on either Vectors or Horizontal Divergence in the list which appears. Finally click on the large "Create Display" button.
Data Source Description: IDV data file (netCDF 2D grid) of tectonic plate motion velocity vectors in 11 time steps from 170 Mybp to 10 Mybp. (-170, -96, -94, -84, -74, -64, -56, -48, -43, -25, -10 Mybp)
Data Source Authors: C. Lithgow-Bertelloni and M.A. Richards
Data Source Publication: Lithgow-Bertelloni, C., and M.A. Richards, "The Dynamics of Cenozoic and Mesozoic plate motions," Reviews of Geophysics, vol. 36, no. 1, pages 27-78, 1998.
Publication online: http://www.agu.org/pubs/crossref/1998.../97RG02282.shtml
Data Source IDV data Type: 2D NetCDF grid of parameters vn and ve for 11 time steps
Format conversion for IDV use: Allen McNamara and UNAVCO, converted to netCDF <
Sample IDV Displays:
Lithgow-Bertelloni and Richards Plate Velocity vectors and divergence, 64 My BP, North America
Quicktime movie of Lithgow-Bertelloni and Richards Plate Velocity vectors and divergence, 170-10 My BP, North America
Lithgow-Bertelloni and Richards Plate Velocity vectors and divergence, 64 My BP, India
Quicktime movie of Lithgow-Bertelloni and Richards Plate Velocity vectors and divergence, 170-10 My BP, India
Lithgow-Bertelloni and Richards Plate Velocity vectors and divergence, 170 My BP, 90W
Quicktime movie of Lithgow-Bertelloni and Richards Plate Velocity vectors and divergence, 170-10 My BP, 90 W
Lithgow-Bertelloni and Richards Plate Velocity vectors and divergence, 170 My BP, 30E
Quicktime movie of Lithgow-Bertelloni and Richards Plate Velocity vectors and divergence, 170-10 My BP, 30 East
Lithgow-Bertelloni and Richards Plate Velocity vectors and divergence, 170 My BP, 120E
Quicktime movie of Lithgow-Bertelloni and Richards Plate Velocity vectors and divergence, 170-10 My BP, 120 East
Tectonic Plate Image Animation, 280 My BP to Today
Use this bundle file http://geon.unavco.org/unavco/geodynamics/RBlakey_280MyBP_plate_animation.xidv to create a globe display of tectonic plates motion for the past 280 M years. Simply add the url of this "bundle file" to the IDV "Dashboard" window, Data Choosers panel, URLs entry box, click "Add source," and the display should be made.
The paleoplate images are made and provided online by Professor Ron Blakey Department of Geology, Northern Arizona University, Flagstaff, Arizona. The particular images used are paleogeographic map images in rectangular format. Note that the IDV maps the rectangular images to the 3D globe.
Quicktime Movie of Ron Blakey's plates, Atlantic side of globe, 280-0 My BP
Ron Blakey, plates, 65 My BP 
Computing Plate Divergence from GSRM Velocities and the Lithgow-Bertelloni & Richards Historic Plate Motions
cite "Wier, Stuart (2007). Computing Plate Divergence from GSRM Velocities and the Lithgow-Bertelloni & Richards Historic Plate Motions with the GEON IDV, accessed [date], from the UNAVCO web site http://geon.unavco.org/unavco/IDV_datasource_plates.html#divergence
The divergence of a vector field, del dot v, indicates where rigidity (incompressibility) of the plates breaks down -- positive divergence is spreading, negative is subduction or other crustal shortening processes. This is one way to show plate boundaries and their character, and to show intra-plate zones of deformation. Divergence also indicates where rigidity is violated by a velocities inside what should be a rigid plate. The IDV includes computational services, both as single formula and as user-defined computer programs.
Divergence was computed for the GSRM global velocity field of current plate motions, and the Lithgow-Bertelloni & Richards historic plate motions from 280 My BP to 10 My BP. Some results are shown here. The color scale used has orange for divergence (spreading centers) and blue for convergence such as subduction zones. Intensity of color indicates speed of convergence or divergence.
GEON IDV globe view of 'horizontal divergence' of the GSRM 'no net rotation' velocity field, Americas. Red and orange areas are positive divergence (crustal extension or spreading), and blue areas are negative divergence, crustal contraction or subduction . Note that divergence is not the same as the second invariant of strain rate.
Current Plate velocities from GSRM and IDV-computed horizontal divergence; click for full size
Current Plate velocities from GSRM and IDV-computed horizontal divergence; click for full size
Current Plate velocities from GSRM and IDV-computed horizontal divergence; Europe
Current Plate velocities from GSRM and IDV-computed horizontal divergence; south-western Pacific
Current Plate velocities from GSRM and IDV-computed horizontal divergence; Nasca Plate
Lithgow-Bertelloni & Richards plate velocity vector field, 64 My BP, IDV-computed divergence of vector field,
and Ron Blakely's continental image.
click for larger, or click here for Quicktime movie for from 280 My BP to 10 My BP, centered on 90 West latitude. L-B_R_Plate_Velocity_vectors_180E_diverg.mov L-B_R_Plate_Velocity_vectors_diverg_90W.mov L-B_R_Plate_Velocity_vectors_90E_diverg.mov
Quicktime movie for from 280 My BP to 10 My BP, centered on 90 East latitude.
Quicktime movie for from 280 My BP to 10 My BP, centered on 180 East latitude.
Plate Motion Quality Checking with the IDV
The divergence of the Lithgow-Bertelloni & Richards plate motion model for 94 My BP
shows significant positive divergence, extension, across the North Pacific
plate (yellow area), at odds with the rigid plate concept:
Data Formats for 2D and 3D Vector Grids in NetCDF for the IDV
NetCDF (binary file) a NetCDF 2D velocity grid for the IDV for one time and one depth:
http://geon.unavco.org/unavco/geodynamics/GSRM_velocity_NNR_with_time.nc
CDL (ASCII file):
For more details, see
NetCDF Data for the GEON IDV
.
Plate velocities and IDV-computed horizontal divergence; North Pacific, 94 My BP
Use these files as models of NetCDF file formats for your velocity data. Note you must use the variable
names "vn" and "ve" for north positive and east-positive velocity components. Add a new variable "vz" for
positive up components; for 3D velocities.
(The data is GSRM Plate Motion Vectors (no net rotation) ).
http://geon.unavco.org/unavco/geodynamics/GSRM_velocity_NNR_with_time.cdl
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