Regional characteristics, tilt domains, and extensional history of the later Cenozoic Basin and Range Province, western North America

Abstract

The Basin and Range province covers a large region of western North America and contains diverse late Cenozoic extensional structures, including metamorphic core complexes, detachment faults, strike-slip faults, and basin and range fault blocks. The central region of the Basin and Range province, extending from the northern Rocky Mountains in the western United States to Sonora, Mexico, contains local or regional areas characterized by moderate-to large-magnitude extension overprinted by basin and range faults that have produced major elongate mountain horsts or tilted blocks and intervening valleys underlain by grabens, half grabens, or downtilted blocks. In southeast Oregon and most the Mexican part of the Basin and Range province east of the Sierra Madre Occidental, the province is only slightly or moderately extended, and structures consist mainly of basin and range blocks produced by widely spaced high-angle normal faults. Strike-slip faults are most common in the western part of the Basin and Range province in the Walker Lane belt of Nevada and California, the Eastern Mojave shear zone of the Mojave Desert region, and parts of the Gulf of California region.Tilt domains in which the dip of stratified rocks and the tilt of mountains blocks are consistently, or fairly consistently, in one direction are characteristic of the Basin and Range province. These domains are commonly 50-200 km or more across in a direction perpendicular to the strike of stratified rocks and the trend of elongate mountain ranges and as much as 1,000 km across parallel to this direction. Tiltdomain boundaries (accommodation zones) consist of either (1) anticlinal boundaries where the strike of stratified rock and the trend of structural fault blocks is parallel to, and the dips or tilts are away from, the boundary; (2) synclinal boundaries where the strike of stratified rock and the trend of structural fault blocks is parallel to, and the dips or tilts are toward, the boundary; or (3) transverse boundaries at a high angle to the strike of stratified rocks and structural fault blocks. These transverse boundaries (transverse accommodation zones) mark areas across which the strike direction of Tertiary rocks and of mountain ranges remains essentially the same, but the dip or tilt direction reverses. Tilt-domain boundaries (accommodation zones) may correspond to areas of abrupt change in dip directions at individual faults or folds, or may be broad areas of structural change that are several kilometers to 20 km across.

Molecular systematics and radiation of western North American nymphophiline gastropods

“…1, Table 1) was similarly mapped onto the tree to evaluate geographical diversification of Pyrgulopsis. Geographical regions, whose characteristic physiography and structure generally date to the late Tertiary (Stewart, 1998), were chosen as the unit of analysis rather than major western drainage basins, which have been shown to be complex composites (e.g.. Belcher, 1975;Malde, 1991;Young, 2004).…”

Seismic anisotropy and mantle flow from the Great Basin to the Great Plains, western United States

“…Dipping strata, schists, or faulting all yield slow anisotropic symmetry axes perpendicular to the layering or fault planes. Stations RTS and MLC are both above normal faults that dip east, and MLC is in a domain of eastward Cenozoic tilting [Stewart, 1998], which would both yield anisotropy with a slow axis plunging westward. Station GAR lies near the border between a region of westward and one of eastward tilting [Stewart, 1998].…”

Estructura y geoquímica de un grupo de domos dacíticos del norponiente del campo volcánico de San Luis Potosí, México

“…El conjunto de lavas del CVSLP que formaron los domos presentados en la Figura 1, están relacionadas tectónicamente a la provincia de Cuencas y Sierras de México, considerada como continuación hacia el sur de la Provincia Basin and Range de los Estados Unidos de América (Henry y Aranda-Gómez, 1992;Stewart, 1978Stewart, , 1998Aranda-Gómez et al, 2000). La gran mayoría de estos domos están alineados en forma puntual a lo largo de sistemas NNW, NW-SE y NE-SW y éstos a su vez se encuentran afectados por un conjunto de fallas normales desarrolladas a principios del Oligoceno tardío, en patrones Tristán-González, 1986).…”