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Age, Spreading Rates and
Spreading Asymmetry of the World's Ocean Crust
We 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. We 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 our 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.
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Müller, R.D., Sdrolias,
M., Gaina, C. and Roest, W.R., 2008, Age
spreading rates and spreading asymmetry of the
world's ocean crust,
Geochemistry, Geophysics, Geosystems, 9, Q04006,
doi:10.1029/2007GC001743
This work is licensed under a Creative
Commons Attribution 3.0 Unported License.
Feedback
We welcome any feedback.
In particular, if you have data that you would
like to be included in the next version of the
agegrid, please send us an email. Send email
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