Extensional Tectonics in the Basin and Range Province Between the Southern Sierra Nevada and the Colorado Plateau: The Basin and Range Province of Southern Nevada and Southeastern California June 30–July 7, 1989

10.1029/ft138 ◽  
1989 ◽  
Author(s):  
Brian P. Wernicke ◽  
J. Kent Snow ◽  
Gary J. Axen ◽  
B. Clark Burchfiel ◽  
Kip V. Hodges ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Colorado Plateau ◽  
Basin And Range ◽  
Extensional Tectonics ◽  
Basin And Range Province ◽  
Southern Nevada

scholarly journals Present-day motion of the Sierra Nevada block and some tectonic implications for the Basin and Range province, North American Cordillera

Tectonics ◽  
2000 ◽  
Vol 19 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Timothy H. Dixon ◽  
Meghan Miller ◽  
Frederic Farina ◽  
Hongzhi Wang ◽  
Daniel Johnson
Keyword(s):  
Sierra Nevada ◽  
North American ◽  
Basin And Range ◽  
Basin And Range Province ◽  
North American Cordillera ◽  
Tectonic Implications

Regional variation and frequency dependence of Qβ in the crust of the United States

1981 ◽  
Vol 71 (5) ◽  
pp. 1531-1538
Author(s):  
Brian J. Mitchell
Keyword(s):  
United States ◽  
Frequency Dependence ◽  
Colorado Plateau ◽  
The United States ◽  
Basin And Range ◽  
Small Degree ◽  
Eastern United States ◽  
Basin And Range Province ◽  
Period Range ◽  
Attenuation Coefficients

abstract Approximate Lg attenuation coefficient values are determined for paths in eastern North America at periods between 2 and 4 sec where no data were previously available. These new data, together with reported values at a period of 1 sec, are consistent with values predicted by a frequency-dependentent Qβ of the crust in which Qβ varies as ω0.2. The new data are inconsistent with values which would be predicted by models having prominent maxima or minima in Qβ−1 within the period range 1 to 5 sec. Lg attenuation coefficients were computed for the frequency-independent crustal Qβ models of Cheng and Mitchell (1981) for the Basin and Range Province and Colorado Plateau of the Western United States. The predicted values at 1 sec for the Colorado Plateau and Basin and Range Province are about twice as large, and three times as large, respectively, as those predicted for the Eastern United States. Recently reported values of Q for 1-sec Lg in those regions are consistent with the attenuation coefficients and Q values of Lg predicted by the Colorado Plateau and Basin and Range Province models. A model with a small degree of frequency dependence of Qβ would be consistent, but is not required by the data.

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.

Attenuation of Multiphase Surface Waves in the Basin and Range Province Part II: The Fundamental Mode

1993 ◽  
Vol 64 (3-4) ◽  
pp. 239-249 ◽  
Author(s):  
Brian J. Mitchell ◽  
Jai-kang Xie ◽  
Wen-jack Lin
Keyword(s):  
Attenuation Coefficient ◽  
Sierra Nevada ◽  
Particle Motion ◽  
Fundamental Mode ◽  
Wave Attenuation ◽  
Three Dimensional ◽  
Basin And Range ◽  
Basin And Range Province ◽  
Period Range ◽  
Mean Values

Abstract In order to investigate the large errors which sometimes characterize fundamental-mode attenuation coefficient determinations, we have made many such determinations in the Basin and Range province and have plotted particle motion for the observed three-component seismograms. Rayleigh wave attenuation coefficient values determined for four two-station paths across the Basin and Range province fluctuate between about −2.0 × 10−3km−1 and +3.0 × 10−3km−1 at periods between 6 and 33 s. Partide motion plots indicate that many of those determinations are contaminated by arrivals from non-great circle paths and from waves generated at heterogeneities along the path, factors which lead to systematic errors in the measured attenuation coefficient values. Attenuation coefficient determinations for the path MNV to ELK, which is within 20° of being normal to the structural trends of the Sierra Nevada and Great Valley, are, however, relatively free from such contamination. Mean values for that path decrease rapidly with period from about 3.0 × 10−3 to about 0.7 × 10−3km−1 between 6 and 10 s and then decrease slowly to about 0.3 × 10−3km−1 at 33 s. Standard deviations range between 0.2 × 10−3 and 0.3 × 10−3km−1 for most of the period range, but increase to about 0.4 × 10−3 at periods between 6 and 8 s. These results indicate that careful screening, based upon criteria such as three-dimensional particle motion, are necessary to obtain surface wave attenuation data of sufficient quality to use for inverting for crustal anelasticity in complex regions.

Sign in / Sign up

Export Citation Format

Share Document