Global deep‐time plate motion models have traditionally followed a classical rigid plate approach, even though plate deformation is known to be significant. Here we present a global Mesozoic–Cenozoic deforming plate motion model that captures the progressive extension of all continental margins since the initiation of rifting within Pangea at ~240 Ma. The model also includes major failed continental rifts and compressional deformation along collision zones. The outlines and timing of regional deformation episodes are reconstructed from a wealth of published regional tectonic models and associated geological and geophysical data. We reconstruct absolute plate motions in a mantle reference frame with a joint global inversion using hot spot tracks for the last 80 million years and minimizing global trench migration velocities and net lithospheric rotation. In our optimized model, net rotation is consistently below 0.2°/Myr, and trench migration scatter is substantially reduced. Distributed plate deformation reaches a Mesozoic peak of 30 × 106 km2 in the Late Jurassic (~160–155 Ma), driven by a vast network of rift systems. After a mid‐Cretaceous drop in deformation, it reaches a high of 48 x 106 km2 in the Late Eocene (~35 Ma), driven by the progressive growth of plate collisions and the formation of new rift systems. About a third of the continental crustal area has been deformed since 240 Ma, partitioned roughly into 65% extension and 35% compression. This community plate model provides a framework for building detailed regional deforming plate networks and form a constraint for models of basin evolution and the plate‐mantle system.
10 July 2004 in Geochemistry, Geophysics, Geosystems
Improving Earth Models: The geophysical processes responsible for shaping the planet's surface and interior need largescale simulations, but to achieve high resolution at these scales is costly and tends to focus on gradual processes such as plate tectonics. By using large parallel supercomputers,
Stadler
et al. (p. 1033 ; see the Perspective by Becker ; see the cover) have improved on a commonly used method—adaptive mesh refinement—to increase the resolution of global geodynamic models to the scale of a single kilometer and been able to reveal unexpected insights into localized processes, such as subduction zone mechanics, thermal anomalies in the lower mantle, and the speed of movement of oceanic plates.
19 July 2000 in Geochemistry, Geophysics, Geosystems
A three-dimensional model of mantle convection in which the known history of plate tectonics is imposed predicts the anomalous Cretaceous vertical motion of Australia and the present-day distinctive geochemistry and geophysics of the Australian-Antarctic Discordance. The dynamic models infer that a subducted slab associated with the long-lived Gondwanaland-Pacific converging margin passed beneath Australia during the Cretaceous, partially stagnated in the mantle transition zone, and is presently being drawn up by the Southeast Indian Ridge.
29 March 2003 in Geochemistry, Geophysics, Geosystems