29 September, 2020 A global dataset of present-day oceanic crustal age and seafloor spreading parameters Updates: 1 September, 2021: Added xyz files for age. 30 June, 2022: Added the age_misfit grid at 6 minute resolution References Seton, M., Müller, R. D., Zahirovic, S., Williams, S., Wright, N., Cannon, J., Whittaker, J., Matthews, K., McGirr, R., (2020), A global dataset of present-day oceanic crustal age and seafloor spreading parameters, Geochemistry, Geophysics, Geosystems, doi: 10.1029/2020GC009214 and Müller, R. D., Zahirovic, S., Williams, S. E., Cannon, J., Seton, M., Bower, D. J., ... & Russell, S. H. (2019). A global plate model including lithospheric deformation along major rifts and orogens since the Triassic. Tectonics, 38(6), 1884-1907. ### Version 2020.1 ### age_misfit.2020.1.GeeK2007.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age grid misfit (Myrs) between the age grid and age constraints. 6 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). age.2020.1.GeeK2007.1m.nc NetCDF-4 formatted file (compatible with GMT5 and above). The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age of oceanic crust (Myrs). 1 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). age.2020.1.GeeK2007.2m.nc NetCDF-4 formatted file (compatible with GMT5 and above). The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age of oceanic crust (Myrs). 2 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). age.2020.1.GeeK2007.2m.grd NetCDF-3 formatted file. The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age of oceanic crust (Myrs). 2 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). age.2020.1.GeeK2007.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age of oceanic crust (Myrs). 6 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). age.2020.1.GeeK2007.6m.grd NetCDF-3 formatted file. The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age of oceanic crust (Myrs). 6 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). age.2020.1.GTS2012.1m.nc NetCDF-4 formatted file (compatible with GMT5 and above). The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age of oceanic crust (Myrs). 1 minute resolution, gridline-registered. Timescale used is (Ogg 2012). age.2020.1.GTS2012.2m.nc NetCDF-4 formatted file (compatible with GMT5 and above). The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age of oceanic crust (Myrs). 2 minute resolution, gridline-registered. Timescale used is (Ogg 2012). age.2020.1.GTS2012.2m.grd NetCDF-3 formatted file. The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age of oceanic crust (Myrs). 2 minute resolution, gridline-registered. Timescale used is (Ogg 2012). age.2020.1.GTS2012.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age of oceanic crust (Myrs). 6 minute resolution, gridline-registered. Timescale used is (Ogg 2012). age.2020.1.GTS2012.6m.grd NetCDF-3 formatted file. The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the age of oceanic crust (Myrs). 6 minute resolution, gridline-registered. Timescale used is (Ogg 2012). full_rate.2020.1.GeeK2007.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the full spreading rate (mm/yr). 6 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). full_rate.2020.1.GTS2012.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the full spreading rate (mm/yr). 6 minute resolution, gridline-registered. Timescale used is (Ogg 2012). full_rate_bands.2020.1.GeeK2007.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is a number denoting the spreading mode based on Dick et al. (2003). 6 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). full_rate_bands.2020.1.GTS2012.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is a number denoting the spreading mode based on Dick et al. (2003). 6 minute resolution, gridline-registered. Timescale used is (Ogg 2012). asym.2020.1.GeeK2007.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the spreading asymmetry (%). 6 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). dir.2020.1.GeeK2007.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the spreading direction (deg). 6 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). obliq.2020.1.GeeK2007.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is the spreading obliquity (deg). 6 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). conf.2020.1.GeeK2007.6m.nc NetCDF-4 formatted file (compatible with GMT5 and above) The geographic grid spans longitudes from -180 to +180 and latitudes from 90 N to -90 N. Z value is a number representing confidence. 6 minute resolution, gridline-registered. Timescale used is Geek and Kent (2007). All grid file names follow the convention to use: ${data}.${year.version_number}.${timescale}.${grid_spacing}.{grid_extension} where: data = age, rate, asymmetry, direction, obliquity, etc year.version_number = year of the grid release followed by a version number for that release timescale = timescale used generating the age grid grid_spacing = resolution of the grid in minutes grid_extension = for netcdf-4 grids we use the extension .nc and for netcdf-3 grid we used the extension .grd Higher resolution grids for full spreading rate, spreading asymmetry, spreading direction and spreading obliquity can be made on request. We also provide the following two files as text files (with the columns: Longitude | Latitude | Age) using the .xyz extension: age.2020.1.GeeK2007.6m.xyz age.2020.1.GTS2012.6m.xyz Colour palette (.cpt) files for each grid can be found in the cpt/ directory. Known Bugs: Gridding artefacts 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). Contribute: We welcome contributions. If you would like your work to be included in the next version of the age grid, please send us an email. Email: Maria Seton maria.seton@sydney.edu.au Dietmar Muller dietmar.muller@sydney.edu.au Sabin Zahirovic sabin.zahirovic@sydney.edu.au