AgeGrid dataset: age, spreading rates and spreading asymmetry of the world's ocean crust

Full description

The EarthByte Group presents four open-access companion datasets (grids). Four companion digital models of the age, age uncertainty, spreading rates and spreading asymmetries of the world's ocean basins are presented as geographic and Mercator grids with 2 minute resolution. The datasets include data from all the major ocean basins as well as detailed reconstructions of back-arc basins.

The age, spreading rate and asymmetry at each grid node is determined by linear interpolation between adjacent seafloor isochrons in the direction of spreading. Ages for ocean floor between the oldest identified magnetic anomalies and continental crust are interpolated by geological estimates of the ages of passive continental margin segments. The age uncertainties for grid cells coinciding with marine magnetic anomaly identifications, observed or rotated to their conjugate ridge flanks, are based on the difference between gridded age and observed age. The uncertainties are also a function of the distance of a given grid cell to the nearest age observation, and the proximity to fracture zones or other age discontinuities.

Asymmetries in crustal accretion appear to be frequently related to asthenospheric flow from mantle plumes to spreading ridges, resulting in ridge jumps towards hotspots. EarthByte Group also uses a new age grid to compute global residual basement depth grids from the difference between observed oceanic basement depth and predicted depth using two alternative age-depth relationships. The new set of grids helps to investigate prominent negative depth anomalies, which may be alternatively related to subducted slab material descending in the mantle or to asthenospheric flow. A combination of digital grids and the associated relative and absolute plate motion model with seismic tomography and mantle convection model outputs represent a valuable set of tools to investigate geodynamic problems.

Grid data, images and supporting documentation is available from the EarthByte website.  Images are available in .JPEG and .PDF format. Grid datasets may be read using GPlates, an open source software application developed in partnership with the EarthByte Group. For further information please refer to the associated publication and the EarthByte website.