Chilean flat slab subduction controlled by overriding plate thickness and trench rollback
Por:
Manea V.C., Perez-Gussinye, M, Manea M.
Publicada:
1 ene 2012
Categoría:
Geology
Resumen:
How flat slab geometries are generated has been long debated. It has been suggested that trenchward motion of thick cratons in some areas of South America and Cenozoic North America progressively closed the asthenospheric wedge and induced flat subduction. Here we develop time-dependent numerical experiments to explore how trenchward motion of thick cratons may result in flat subduction. We find that as the craton approaches the trench and the wedge closes, two opposite phenomena control slab geometry: the suction between ocean and continent increases, favoring slab flattening, while the mantle confined within the closing wedge dynamically pushes the slab backward and steepens it. When the slab retreats, as in the Peru and Chile flat slabs, the wedge closure rate and dynamic push are small and suction forces generate, in some cases, flat subduction. We model the past 30 m.y. of subduction in the Chilean flat slab area and demonstrate that trenchward motion of thick lithosphere, 200-300
Filiaciones:
Manea V.C.:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Computat Geodynam Lab, Queretaro, Mexico
Manea M.:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Computat Geodynam Lab, Queretaro, Mexico
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