Age, spreading rates and spreading symmetry
of the world's ocean crust
(Version 3, September 2008)

Please cite the source when using these data:

The authors present four companion digital models of the age, age uncertainty, spreading rates and spreading asymmetries of the world's ocean basins as geographic and Mercator grids with 2 minute resolution. The grids 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.

The authors also use the 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 these 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.

Version 3 (posted 9/25/2008) contains the following changes:

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.

Adjustment to the location of chron M25 in the westernmost Pacific (Pacific-Izanagi) and to the age assigned to the Pacific triangle

Minor COB modifications around back-arc basins to minimise over-interpolation artifacts from the adjacent subducting ocean floor

A gridding artifact in the Bay of Bengal, eastern India and in the southern Indian Ocean, east of the Enderby Basin was fixed.

Inclusion of the Komandorsky Basin and Bering Sea, North Pacific