The Basin and Range Province as a Composite Extensional Domain

The Basin and Range province is a composite Cenozoic taphrogen with a present configuration and internal geometry derived from superimposed multiple phases of extensional deformation driven by varied geodynamic impulses. Different components of the composite taphrogen derive from: (a) post-orogenic Late Paleocene to Middle Miocene slab rollback beneath overthickened crust of the Sevier-Laramide orogen, to induce migratory arc magmatism, tectonic denudation of Cordilleran metamorphic core complexes within associated domains of crustal extension, and belts of backarc rifting including pre-Middle Miocene phases of the Rio Grande rift; (b) Eocene transrotational tectonism that pivoted and displaced crustal elements of the Paleogene forearc in the Pacific Northwest; (c) late Early Miocene and younger crustal extension in the northwestern Basin and Range province (Numic subtraphrogen including segments in the Great Basin, Southeast Oregon Plateau, and Idaho-Montana border regions) as structural accompaniment to...