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Science. 2010 Jul 16;329(5989):316-9. doi: 10.1126/science.1190366.

Cenozoic tectonics of western North America controlled by evolving width of Farallon slab.

Author information

1
School of Geosciences, Monash University, Melbourne, Victoria 3800, Australia. wouter.schellart@monash.edu

Abstract

Subduction of oceanic lithosphere occurs through two modes: subducting plate motion and trench migration. Using a global subduction zone data set and three-dimensional numerical subduction models, we show that slab width (W) controls these modes and the partitioning of subduction between them. Subducting plate velocity scales with W(2/3), whereas trench velocity scales with 1/W. These findings explain the Cenozoic slowdown of the Farallon plate and the decrease in subduction partitioning by its decreasing slab width. The change from Sevier-Laramide orogenesis to Basin and Range extension in North America is also explained by slab width; shortening occurred during wide-slab subduction and overriding-plate-driven trench retreat, whereas extension occurred during intermediate to narrow-slab subduction and slab-driven trench retreat.

PMID:
20647465
DOI:
10.1126/science.1190366
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