Description of Resources - Müller et al. (2008) [G-cubed publication] This file provides a detailed description of all of the files that make up the data collection associated with the publication: Müller, R. D., Sdrolias, M., Gaina, C., & Roest, W. R. (2008). Age, spreading rates, and spreading asymmetry of the world's ocean crust. Geochemistry, Geophysics, Geosystems, 9(4). doi: 10.1029/2007GC001743 Note: For information on file formats and what programs to use to interact with various file formats, see "File_Formats_and_Recommended_Programs.txt”. The age, age error, half-spreading rate and spreading asymmetry files span longitudes from 180 W to 180 E (i.e. -180 to 180 degrees) and latitudes from 90 N to -90 N. The residual basement files span longitudes from 0 E to 360 E and latitudes from 90 N to -90 N. The files associated with this data collection include: • Seafloor ages - The seafloor age data are provided in raster and vector format. Age units are in millions of years. * age.3.2.unscaled.txt (54.9 MB) - 2 minute resolution, columns are longitude, latitude, age * age.3.6.unscaled.txt (54.9 MB) - 6 minute resolution, columns are longitude, latitude, age * age.3.2.unscaled.nc (39.6 MB) - 2 minute resolution, short integer netCDF formatted file * age.3.6.unscaled.nc (6.4 MB) - 6 minute resolution, short integer netCDF formatted file * age.3.2.unscaled.numerical-raster.tif (26 MB) - 2 minute resolution, numerical raster, datum-WGS 1984 * age.3.6.unscaled.numerical-raster.tif (25.9 MB) - 6 minute resolution, numerical raster, datum-WGS 1984 * age.3.2.unscaled.colour-raster.tif (25.9 MB) - 2 minute resolution, colour raster, datum-WGS 1984 * age.3.6.unscaled.colour-raster.tif (25.9 MB) - 6 minute resolution, colour raster, datum-WGS 1984 * age.3.2.unscaled.kmz (319 KB) - 2 minute resolution * age.3.6.unscaled.kmz (328 KB) - 6 minute resolution • Seafloor age error - The seafloor age error data are provided in raster and vector format. Age units are in millions of years. * ageerror.3.2.unscaled.txt (55.6 MB) - 2 minute resolution, columns are longitude, latitude, age error * ageerror.3.6.unscaled.txt (55.6 MB) - 6 minute resolution, columns are longitude, latitude, age error * ageerror.3.2.unscaled.nc (38.2 MB) - 2 minute resolution, short integer netCDF formatted file * ageerror.3.6.unscaled.nc (6.8 MB) - 6 minute resolution, short integer netCDF formatted file * ageerror.3.2.unscaled.numerical-raster.tif (25.9 MB) - 2 minute resolution, numerical raster, datum-WGS 1984 * ageerror.3.6.unscaled.numerical-raster.tif (26 MB) - 6 minute resolution, numerical raster, datum-WGS 1984 * ageerror.3.2.unscaled.colour-raster.tif (25.9 MB) - 2 minute resolution, colour raster, datum-WGS 1984 * ageerror.3.6.unscaled.colour-raster.tif (25.9 MB) - 6 minute resolution, colour raster, datum-WGS 1984 * ageerror.3.2.unscaled.kmz (483 KB) - 2 minute resolution * ageerror.3.6.unscaled.kmz (483 KB) - 6 minute resolution • Seafloor spreading rates - These are seafloor 'half-spreading' rates measured in units of mm/yr. The seafloor spreading rate data are provided in raster and vector format. * rate.3.2.unscaled.txt (54.7 MB) - 2 minute resolution, columns are longitude, latitude, rate * rate.3.6.unscaled.txt (54.8 MB) - 6 minute resolution, columns are longitude, latitude, rate * rate.3.2.unscaled.nc (42.3 MB) - 2 minute resolution, short integer netCDF formatted file * rate.3.6.unscaled.nc (6.5 MB) - 6 minute resolution, short integer netCDF formatted file * rate.3.2.unscaled.numerical-raster.tif (25.9 MB) - 2 minute resolution, numerical raster, datum-WGS 1984 * rate.3.6.unscaled.numerical-raster.tif (26 MB) - 6 minute resolution, numerical raster, datum-WGS 1984 * rate.3.2.unscaled.colour-raster.tif (25.9 MB) - 2 minute resolution, colour raster, datum-WGS 1984 * rate.3.6.unscaled.colour-raster.tif (25.9 MB) - 6 minute resolution, colour raster, datum-WGS 1984 * rate.3.2.unscaled.kmz (524 KB) - 2 minute resolution * rate.3.6.unscaled.kmz (487 KB) - 6 minute resolution • Seafloor spreading asymmetry - These data indicate relative proportions of crustal accretion (i.e., spreading asymmetry) on conjugate ridge flanks. Spreading asymmetry units are in percent, with 50% corresponding to roughly symmetric spreading (i.e. a distribution of 50% of accreted ocean crust on both conjugate plates). The seafloor spreading asymmetry data are provided in raster and vector format. * asym.3.2.unscaled.txt (54.3 MB) - 2 minute resolution, columns are longitude, latitude, asymmetry * asym.3.6.unscaled.txt (54.3 MB) - 6 minute resolution, columns are longitude, latitude, asymmetry * asym.3.2.unscaled.nc (42.5 MB) - 2 minute resolution, short integer netCDF formatted file * asym.3.6.unscaled.nc (6.3 MB) - 6 minute resolution, short integer netCDF formatted file * asym.3.2.unscaled.numerical-raster.tif (25.9 MB) - 2 minute resolution, numerical raster, datum-WGS 1984 * asym.3.6.unscaled.numerical-raster.tif (26 MB) - 6 minute resolution, numerical raster, datum-WGS 1984 * asym.3.2.unscaled.colour-raster.tif (25.9 MB) - 2 minute resolution, colour raster, datum-WGS 1984 * asym.3.6.unscaled.colour-raster.tif (25.9 MB) - 6 minute resolution, colour raster, datum-WGS 1984 * asym.3.2.unscaled.kmz (823 KB) - 2 minute resolution * asym.3.6.unscaled.kmz (827 KB) - 6 minute resolution • Seafloor residual basement depth - Residual oceanic basement depths were computed using different published age-depth relationships (see publication for more information), and these data are provided in raster and vector format. The 'GDH-1' model is from Stein and Stein (1992). The 'Crosby07' model is from Crosby's PhD Thesis (Cambridge, 2007). The 'Crosby' model is from Crosby et al. (2006). The 'PS77' model is from Parsons and Sclater (1977). Units are in meters and data have 5 minute resolution. * res_basement_gdh1_1.5.txt (55.5 MB) * res_basement_pm_crosby07_1.5.txt (55.6 MB) * res_basement_pm_ps77_1.5.txt (55.5 MB) * res_basement_tbl_crosby_1.5.txt (55.2 MB) * res_basement_GDH1_1.5.nc (18.7 MB) - gridline-registered grid * res_basement_PM_Crosby07_1.5.nc (18.7 MB) - gridline-registered grid * res_basement_PM_PS77_1.5.nc (18.7 MB) - gridline-registered grid * res_basement_TBL_Crosby_1.5.nc (18.7 MB) - gridline-registered grid * res_basement_GDH1_1.5.numerical-raster.tif (25.9 MB) - numerical raster, datum-WGS 1984 * res_basement_PM_Crosby07_1.5.numerical-raster.tif (25.9 MB) - numerical raster, datum-WGS 1984 * res_basement_PM_PS77_1.5.numerical-raster.tif (25.9 MB) - numerical raster, datum-WGS 1984 * res_basement_TBL_Crosby_1.5.numerical-raster.tif (25.9 MB) - numerical raster, datum-WGS 1984 * res_basement_GDH1_1.5.colour-raster.tif (25.9 MB) - colour raster, datum-WGS 1984 * res_basement_PM_Crosby07_1.5.colour-raster.tif (25.9 MB) - colour raster, datum-WGS 1984 * res_basement_PM_PS77_1.5.colour-raster.tif (25.9 MB) - colour raster, datum-WGS 1984 * res_basement_TBL_Crosby_1.5.colour-raster.tif (25.9 MB) - colour raster, datum-WGS 1984 * res_basement_GDH1_1.5.kmz (778 KB) * res_basement_PM_Crosby07_1.5.kmz (778 KB) * res_basement_PM_PS77_1.5.kmz (770 KB) * res_basement_TBL_Crosby_1.5.kmz (729 KB) • Colour palette files - These colour palette files can be used when visualing/plotting the gridded data. * age.cpt (4 KB) - for use with seafloor ages * ageerror.cpt (4 KB) - for use with seafloor age errors * rate.cpt (4 KB) - for use with seafloor half-spreading rates * asym.cpt (4 KB) - for use with seafloor spreading asymmetries * res_basement.cpt (4 KB) - for use with residual basement depths • Maps - Geographic maps displaying the different data sets. * Age_AgeError.jpg (1.4 MB KB) - Mollweide projection global maps of seafloor age and age error * indian_ocean.jpg (623 KB) - Mercator projection maps of seafloor ages, half-spreading rates and crustal accretion for the Indian Ocean * north_atlantic.jpg (623 KB) - Mercator projection maps of seafloor ages, half-spreading rates and crustal accretion for the North Atlantic * northeast_pacific_ocean.jpg (623 KB) - Mercator projection maps of seafloor ages, half-spreading rates and crustal accretion for the northeastern Pacific * rate_asym.jpg (1.6 MB KB) - Mollweide projection global maps of seafloor half-spreading rate and spreading asymmetry * residual_basement.jpg (385 KB) - Mollweide projection global maps of residual basement depths calculated using the models of GDH-1 (a), Crosby07 (b) and Crosby (c) [Figure 11 from the publication] * south_atlantic.jpg (623 KB) - Mercator projection maps of seafloor ages, half-spreading rates and crustal accretion for the South Atlantic * south_pacific_ocean.jpg (623 KB) - Mercator projection maps of seafloor ages, half-spreading rates and crustal accretion for the southern Pacific * west_pacific_ocean.jpg (623 KB) - Mercator projection maps of seafloor ages, half-spreading rates and crustal accretion for the western Pacific * Southern hemisphere centred seafloor age maps - orthographic projection: - age_ortho_1_135_-40.jpeg (995 KB) - age_ortho_2_90_-40.jpeg (914 KB) - age_ortho_3_45_-40.jpeg (910 KB) - age_ortho_4_0_-40.jpeg (951 KB) - age_ortho_5_-45_-40.jpeg (1 MB) - age_ortho_6_-90_-40.jpeg (1.1 MB) - age_ortho_7_-135_-40.jpeg (1.1 MB) - age_ortho_8_-180_-40.jpeg (299 KB) * Northern hemisphere centred seafloor age maps - orthographic projection: - age_ortho_1_135_40.jpeg (1.2 MB) - age_ortho_2_90_40.jpeg (1.2 MB) - age_ortho_3_45_40.jpeg (1.2 MB) - age_ortho_4_0_40.jpeg (1.2 MB) - age_ortho_5_-45_40.jpeg (1.2 MB) - age_ortho_6_-90_40.jpeg (1.2 MB) - age_ortho_7_-135_40.jpeg (1.2 MB) - age_ortho_8_-180_40.jpeg (316 KB) This article has additional supplementary data available with the online publication. Extra information from the original readme file associated with this data collection: All grid file names follow the convention to use two numbers to indicate the file version number followed by the resolution in minutes. Therefore age_3.2.nc corresponds to version 3 with 2 minute resolution. About .nc files: These are netCDF files adhering to the COORDS convention and may be used with any programs that supports such files, such as the GMT programs (eg grdreformat for converting the file to another format if desired, grdmath for division of the grids by 10 (for age, rate, asym and age error grids) and grdimage for plotting. GMT format file code is ns (short integer netCDF format). The 6 minute age, rate and asymmetry grids are provided for users who do not need high-resolution grids. This resolution corresponds to that of our previous age grid (from 1997). Convert short integer .nc files to default GMT grd files as follows (for example). grdmath age.3.6.nc=ns 0.01 MUL = age.3.6.grd=nf -V This example only works for GMT4.1 or above. For older versions of GMT, you may have to run grdreformat and grdmath separately. If you just want to convert a .nc file to xyz, run, for example grd2xyz age.3.2.nc=ns/0.01/0 > age.3.2.xyz The .nc files are gridline-registered (i.e. nodes are at gridline intersections). This differs from pixel-registered grids where nodes are centered on the grid boxes. Gridline-registered grids therefore have 1 row/column more than pixel-registrated grids. Known Bugs: Gridding artifacts exist around microplates (e.g. Bauer microplate), along fracture zones (e.g. Central Atlantic) and in areas with highly oblique spreading (e.g. South-West Indian Ridge). Minor interpolation artifacts along the margins of some back-arc basins. Fixes: 02-04-09: Fixed interpolation error in the rate grid along the prime meridin 11-11-09: Values in age.3.6.xyz that were 9.9920072e-15 were changed to 0.0 11-09-08: Spreading asymmetry for crust without a present day conjugate is included in this version of the grid due to several requests received by the authors. 11-09-08: Adjustment to the location of chron M25 in the westernmost Pacific (Pacific-Izanagi) and to the age assigned to the Pacific triangle 11-09-08: Minor COB modifications around back-arc basins to minimise over-interpolation artifacts from the adjacent subducting ocean floor 04-04-08: Gridding artifact in the Bay of Bengal, eastern India and in the southern Indian Ocean, east of the Enderby Basin was fixed. 04-04-08: Inclusion of the Komandorsky Basin and Bering Sea, North Pacific