Geotectonic evolution of the Great Basin

The crust of the Great Basin has occupied a range of tectonic settings through geologic time. Archean and Paleoproterozoic crustal genesis preceded residence of Laurentia within the Mesoproterozoic supercontinent Rodinia, which rifted in the late Neoproterozoic to delineate the Cordilleran fl ank of Laurentia. Successive stages of Phanerozoic evolution included (1) early to middle Paleozoic miogeoclinal sedimentation along a passive continental margin, (2) late Paleozoic to earliest Mesozoic thrusting of oceanic Antler and Sonoma allochthons over the continental margin in response to episodic slab rollback beneath an offshore Klamath-Sierran islandarc complex, (3) Mesozoic to mid-Cenozoic arc-rear and backarc thrusting, together with pulses of interior magmatism, associated with development of the Cordilleran magmatic arc to the west where subduction and arc accretion expanded the continental margin, and (4) middle to late Cenozoic crustal extension, which involved initial intra-arc to backarc deformation and later transtensional torsion of the continental block inland from the evolving San Andreas transform system. Potential metallogenic infl uences on Great Basin tectonic evolution included transfer of substance from mantle to crust by magmatism and associated metasomatism, and reworking of crustal materials by both magmatism and intracrustal fl uid fl ow, the latter of which was induced both by thermal effects of magmatism and by reconfi guration of flrock masses during multiple episodes of Great Basin deformation.