Sedimentary response to orogenic exhumation in the northern Rocky Mountain Basin and Range province, Flint Creek basin, west-central Montana

2011 ◽  
Vol 48 (7) ◽  
pp. 1131-1154 ◽  
Author(s):  
Ryan A. Portner ◽  
Marc S. Hendrix ◽  
Jeremy C. Stalker ◽  
Dan P. Miggins ◽  
Steven D. Sheriff
Keyword(s):  
Rocky Mountain ◽  
Basin And Range ◽  
Basin And Range Province ◽  
West Central ◽  
Central Montana

Uniform-sense normal simple shear of the continental lithosphere

1985 ◽  
Vol 22 (1) ◽  
pp. 108-125 ◽  
Author(s):  
Brian Wernicke
Keyword(s):  
Simple Shear ◽  
Colorado Plateau ◽  
Rocky Mountain ◽  
Shear Zones ◽  
Basin And Range ◽  
Normal Faults ◽  
The West ◽  
Basin And Range Province ◽  
Lithospheric Thinning ◽  
Crustal Thinning

Geophysical studies suggest that the thin crust characteristic of the Basin and Range Province extends eastward beneath the west margin of the Colorado Plateau and Rocky Mountain regions. In Arizona and Utah, zones perhaps over 100 km wide may be defined, bounded on the west by the east limit of upper crustal normal faults that account for more that 10% extension and on the east by the east limit of thinning beneath the Colorado Plateau. A discrepancy exists within these zones between the negligible extension measurable in the upper crust and the substantial extension apparent from crustal thinning, assuming the "discrepant zone" crust was as thick as or thicker than the Colorado Plateau – Rocky Mountain crust prior to extensional tectonism.If various theories appealing to crustal erosion are dismissed, mass balance problems evident in the discrepant zones are most easily resolved by down-to-the-east normal simple shear of the crust, moving lower and middle crustal rocks that initially were within the zones up-and-to-the-west to where they now are locally exposed in the Basin and Range Province. West of the discrepant zones in both Arizona and Utah, east-directed extensional allochthons with large displacement are exposed. These geophysical and geological observations complement one another if it is accepted that the entire crust in both Arizona and Utah failed during extension on gently east-dipping, east-directed, low-angle normal faults and shear zones over a region several hundred kilometres wide.Large-scale, uniform-sense normal simple shear of the crust suggests the entire lithosphere may do the same. Such a hypothesis predicts major lithospheric thinning without crustal thinning will occur in plateau areas in the direction of crustal shear. In the case of the Arizona, Utah, and Red Sea extensional systems, and possibly the Death Valley extensional terrain, a broad topographic arch, typically 1500–2000 m higher than the extended terrain, is present, suggesting lithospheric thinning in areas predicted by the hypothesis.

The 6 November 1774 MI 6 Bolaños Graben Earthquake (Southern Basin and Range Province, West-Central Mexico): Macroseismic Observations and Neotectonic Implications

2020 ◽  
Vol 91 (5) ◽  
pp. 2473-2486 ◽  
Author(s):  
Max Suter
Keyword(s):  
Hot Springs ◽  
Basin And Range ◽  
Alluvial Fan ◽  
Central Mexico ◽  
Western Boundary ◽  
Basin And Range Province ◽  
Active Deformation ◽  
Ground Shaking ◽  
Southern Basin ◽  
West Central

Abstract The continental part of west-central Mexico is characterized by the active extensional tectonic regimes of the Trans-Mexican volcanic belt and the adjacent southern Basin and Range Province. The deformation of the latter is distributed over several topographically very pronounced grabens and half-grabens (width 10–20 km, length ≤200  km; throw 1–2 km), including the Aguascalientes, Juchipila, Tlaltenango, and Bolaños grabens. Here, an A.D. 1774–1775 earthquake series in that area is documented based on numerous contemporary sources. The 6 November 1774 mainshock caused moderate-to-severe damage in several communities of the Bolaños graben, including the silver mining town of Bolaños, and moderate damage to communities in the Tlaltenango graben, such as the administrative center of Colotlán. Based on the macroseismic intensity distribution, the epicenter was in the Bolaños graben. The preferred magnitude of the mainshock is ∼6.0±0.5. No major historical earthquake had been reported previously from this region. Existing ground-shaking hazard models may, therefore, give a false sense of security. In the Bolaños graben, motion along the graben-bounding faults and the observed tilting of the graben shoulders has to be mostly younger than the 19.9 Ma age of the youngest basalt of the graben-shoulder stratigraphy. Its correlation across the western master fault indicates a 1300 m throw and a vertical long-term slip rate of 0.07  mm/yr. The observations of alluvial fan deposits juxtaposed against the footwall ignimbrites along the western master fault of the Bolaños graben, the displacement of alluvial fan deposits along secondary faults within the graben, and the existence of hot springs along the western boundary fault all are indicative of active deformation, and so is evidently the A.D. 1774 earthquake.

Mineral resource areas of the Basin and Range Province of Texas

1983 ◽  
Author(s):  
Christopher D. Henry ◽  
J.G. Price ◽  
M.F. Hutchins
Keyword(s):  
Mineral Resource ◽  
Basin And Range ◽  
Basin And Range Province
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