Age, spreading rates, and spreading asymmetry of the world's ocean crust

Type Article
Date 2008-04
Language English
Author(s) Muller R1, Sdrolias M1, Gaina C2, Roest WalterORCID3
Affiliation(s) 1 : Univ Sydney, Sch Geosci, EarByte Grp, Sydney, NSW 2006, Australia.
2 : Geol Survey Norway, Ctr Geodynam, N-7491 Trondheim, Norway.
3 : IFREMER, Dept Geosci Marines, F-29280 Plouzane, France.
Source Geochemistry Geophysics Geosystems - G3 (1525-2027) (American Geophysical Union), 2008-04 , Vol. 9 , P. NIL_18-NIL_36
DOI 10.1029/2007GC001743
WOS© Times Cited 1159
Keyword(s) Seafloor spreading, Geodynamic, Plate kinematic, Ocean floor, Digital isochrons
Abstract 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 arc min 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 are 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 toward hot spots. 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 three 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 represents a valuable set of tools to investigate geodynamic problems.
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