The file body contains all data outside the file header. These are Moving Plate Rotation Sequences (MPRS) which are in turn composed of individual lines listing rotation parameters.

The moving plate rotation sequence (MPRS) specifies a block of rotations which all have the same moving plate id. It is denoted by a > flag at the start of each line and allows multi-line headers.

The introduction of a header for any moving plate rotation sequence follows the idea that most metadata is applied to a whole sequence of rotations and allows for better “bookmarking” in GPlates' rotation file editor or other external text editors. The rotation header sequence denominator is modelled as follows:

Template:

  > @MPRS:pid"PID1" @MPRS:code"XXX" @MPRS:name"Moving Plate name"

Compact version

   
  > @MPRS"288 | FLI | Falkland Islands"

Extended version

  > @MPRS:pid"288" @MPRS:code"FLI" @MPRS:name"Falkland Islands" @C"optional comment"

Multiline version

  > @MPRS:pid"288"
  > @MPRS:code"FLI"
  > @MPRS:name"Falkland Islands" 
  > @C"Optional comment" @AU"CHHEI"

Oftentimes the full moving plate rotation sequence is taken from a single author/publication. In that case, adding metadata to each rotation line would increase the possibility for mistakes.

The new rotation file format allows the user to specify metadata for a whole MPRS in the header which then applies to all rotations in that sequence:

  > @MPRS:pid"002" @MPRS:code"PHS" @MPRS:name"Pacific Hotspots" 
  002     2.580  53.7200  -56.880   -2.660  901 @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07" 
  002     5.890  59.6500  -66.050   -5.390  901 @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07" 
  002     8.860  62.8700  -70.870   -8.230  901 @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07" 
  002    12.290  65.3700  -68.680  -10.300  901 @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07" 
  002    17.470  68.2500  -61.530  -15.500  901 @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07" 
  002    24.060  68.7800  -69.830  -20.400  901 @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07" 
  002    28.280  67.7200  -70.800  -23.600  901 @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07" 
  002    33.540  66.5700  -68.730  -27.700  901 @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07" 
  002    40.100  65.4300  -64.250  -31.600  901 @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07"

can now be replaced with

  > @MPRS:pid"002" @MPRS:code"PHS" @MPRS:name"Pacific Hotspots" 
  > @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07" 
  002     2.580  53.7200  -56.880   -2.660  901
  002     5.890  59.6500  -66.050   -5.390  901 
  002     8.860  62.8700  -70.870   -8.230  901
  002    12.290  65.3700  -68.680  -10.300  901 
  002    17.470  68.2500  -61.530  -15.500  901
  002    24.060  68.7800  -69.830  -20.400  901 
  002    28.280  67.7200  -70.800  -23.600  901
  002    33.540  66.5700  -68.730  -27.700  901 
  002    40.100  65.4300  -64.250  -31.600  901

In case there are changes to individual rotations in the MPRS these can be done on line/rotation pole level and will overide the MPRS header data: Multiline comment metadata in @MPRS header

  > @MPRS:pid"002" @MPRS:code"PHS" @MPRS:name"Pacific Hotspots" 
  > @PP"PHS-PAC" @REF"Wessel.JGR.08" @C"Model WK08-A" @GTS"GeeK07" 
  002     2.580  53.7200  -56.880   -2.660  901
  002     5.890  59.6500  -66.050   -5.390  901 
  002     9.0    62.8700  -70.870   -8.230  901 @AU"CHHEI" @T"2012-05-03" @C"Changed time from 8.860" 
  002    12.290  65.3700  -68.680  -10.300  901
  002    17.470  68.2500  -61.530  -15.500  901 
  002    24.060  68.7800  -69.830  -20.400  901
  002    28.280  67.7200  -70.800  -23.600  901 
  002    33.540  66.5700  -68.730  -27.700  901
  002    40.100  65.4300  -64.250  -31.600  901

Given the above, the new 9.0 Ma rotation will carry the metadata specified on for the individual pole and only the specified pole metadata overrides the MPRS metadata (non-overridden metadata is still inherited from the MPRS).

We adopt the legacy PLATES rotation format which consists of 6 mandatory parameters specifying the stage pole of any given rotation. Backwards compatibility with PLATES rotation data The format has not changed andis fully compatible with legacy applications.

   PID1 FROMAGE POLELAT POLELON ANGLE PID2

New optional meta data attributes from the dictionary can be added to the individual lines. Rotation metadata attributes The optional attributes follow the structure layed out in Sec. and can consist of the following elements:

Attribute	Description
@PP	Abbreviated description of the relative plate motions, e.g. Africa-South America to @PP“SAM-AFR”, the abbreviated names have to adhere to the @MPRS:code from the MPRS.
@C	Free form comment
@GTS:id	Unique ID of the geological time scale used in identifying the magnetic anomaly picks. References the @GEOTIMESCALE:id in the file header
@AU	Abbreviation/ID of modification author. Alias which references @DC:contributor:id in the file header.
@DOI	Digitial object identifier for reference related to that individual rotation. Alias to @BIBINFO:doibase:doi. Citation key for reference related to that individual rotation.
@REF	Alias for @BIBINFO:bibliographyfile:citekey
@HELL	Set of attribute:value pairs for uncertainty parameters for this rotation. For details see Sec. .
@T	Modification date/time. Adhere to ISO standard (ie [YYYY]-[MM]-[DD]T[hh]:[mm]:[ss]).
@CHRONID	Magnetic anomaly chron ID. Alias to @GPML:MagneticAnomalyIdentification:polarityChronID and adheres to strict naming convention. The identifier used for magnetic picks evolved to be a combination of letters and numbers, of the form of (C/M)<number><combination of letters>. See the GPGIM for details.

For a complete list of attributes see GPlates GROT Format attribute list

Example:

  833    53.300 -14.1900  130.4100   -0.7200  801 @PP"LHR-AUS"  @DOI"10.1029/98JB00386" @CHRONID"C24o"

The Hellinger method allows to compute statistical uncertainties for rotations, representing them as a series of parameters and a 3D-covariance matrix. Hellinger Statistics attributes for individual rotations

These parameters are:

• total misfit (sum of squares of the weighted distances of data points to great circle segment) in [km]
• number of data points
• number of great circle segments
• number of degrees of freedom
• kappahat: quality factor which relates the uncertainties assigned to the data to their true estimates
• a 3 × 3 covariance matrix which needs to be divided by the factor kappahat to convert in square radians

An example matrix is given here obtained from the file satl.34 and running the hellinger1 program:

(                                    )
  8.71113084   - 4.33230877  -4.97091355
|| -4.33230877   4.01436998   3.23033819|| × 10-7
|( -4.97091355   3.23033819    3.6493551 |)
(1)

So far, Hellinger-fit criteria have not been explicity expressed in the rotation file. For the new standard, the Hellinger statistics need to be included explicity in the format expressed below. The complete Hellinger values can either be represented as coherent string with the some matrix values omitted due to the rotational symmetry of the matrix:

@HELL"r|(N,s)|dF|kappahat|(($x_1$,$x_2$,$x_3$)($y_2$,$y_3$)($z_3$))"

or as a separate set of arguments using the @HELL Parent:Children attributes:

• total misfit
• number of data points and segment length
• number of degrees of freedom
• Quality factor ^κ
• Covariance matrix, here we ONLY USE ¹⁾ due to the rotational symmetry of the matrix used.

Example:

Multi line version:

  @HELL:r"41.1911338"
  @HELL:Ns"75,16"
  @HELL:dF"40." 
  @HELL:kappahat"0.971082763"
  @HELL:cov"(8.71113084E-07,-4.33230877E-07,-4.97091355E-07) \ 
              (4.01436998E-07,3.23033819E-07)(3.6493551E-07)"

Compact single line:

  @HELL"""41.1911338 |75,16 | 40.| 0.971082763|\
   (8.71113084E-07,-4.33230877E-07,-4.97091355E-07) \ 
   (4.01436998E-07,3.23033819E-07)(3.6493551E-07)"""

Each rotation file should come with a companion bibliographic reference database in the ascii-based BibTeX format, see GROT: A new rotation file format for GPlates. The choice for BibTeX is driven by the fact that the format is text-based, accepted as one of the bibliographic data standards and many software tools allow to either directly use this format (BibDesk, JabREF) or import/export it (e.g. Endnote). At a future data the bibliographic information can possibly be incorporated consistently into the rotation file format without the need for two separate files.

Online resources:

• GPlates web site
• BibTeX resources
• Info about Dublin Core