Lithospheric extension near Lake Mead, Nevada: A model for ductile flow in the lower crust

Kruse, Sarah; McNutt, Marcia; Morgan, Jason Phipps; Royden, L.; Wernicke, Brian P.

doi:10.1029/90jb02621

Cited by 172 publications

(123 citation statements)

References 39 publications

Supporting

Mentioning

117

Contrasting

Order By: Relevance

“…At the boundaries of the Tibetan plateau, a 15 km thick weak lower crust (viscosity of 10 18 -10 21 Pa s) can explain the gradients in surface topography (Clark & Royden 2000). In the Basin and Range province of the western United States, longwavelength gravity anomalies and topographies are consistent with a 25 km thick lower-crustal channel with a viscosity of 10 18 -10 20 Pa s (Kruse et al 1991).…”

Section: Ru S Ta L V I S C O S I T Y S T Ru C T U R Ementioning

confidence: 52%

“…This is similar to crustal channel flow driven by lateral topographic variations on the Earth's surface (e.g. Kruse et al 1991;McQuarrie & Chase 2000;Beaumont et al 2001Beaumont et al , 2006Grujic 2006). Second, crustal deformation arises from shearing of the deep crust by the underlying mantle (e.g.…”

Section: Surface Observables Of Mantle Dynamicsmentioning

confidence: 99%

“…The simplified structure provides a straightforward way to investigate the first-order physical mechanisms for crustal deformation (e.g. Kruse et al 1991;Clark & Royden 2000). The constant viscosity in each layer ensures that only vertical strength variations affect the dynamics.…”

Section: Numerical Model Setupmentioning

confidence: 99%

“…(d) Effective viscosity profiles assuming that the entire crust is felsic, with the rheology parameters of dry granite (Ranalli 1995). The red rectangle is the depth and viscosity of the inferred lower-crustal channel at the edge of Tibet (Clark & Royden 2000); the green rectangle shows the conditions for the lower-crust channel under Nevada (Kruse et al 1991); the blue line shows the depths and viscosity in the central Andean plateau (Gerbault et al 2005). The effective viscosity calculations use a strain rate of 10 −14 s −1 (solid lines) and 10 −16 s −1 (dashed lines).…”

Section: Ru S Ta L V I S C O S I T Y S T Ru C T U R Ementioning

confidence: 99%

“…This behaviour can be analysed in terms of a pressure/gravitationally driven channel flow within the weak mid-crust (cf. Kruse et al 1991). The presence of the dense root initially causes surface subsidence, which induces low pressures in the overlying crust relative to the adjacent regions.…”

Section: Mid-crustal Channel Modelmentioning

confidence: 99%

See 4 more Smart Citations

Crustal deformation induced by mantle dynamics: insights from models of gravitational lithosphere removal

Wang

Currie

2017

Geophysical Journal International

View full text Add to dashboard Cite

S U M M A R YMantle-based stresses have been proposed to explain the occurrence of deformation in the interior regions of continental plates, far from the effects of plate boundary processes. We examine how the gravitational removal of a dense mantle lithosphere root may induce deformation of the overlying crust. Simplified numerical models and a theoretical analysis are used to investigate the physical mechanisms for deformation and assess the surface expression of removal. Three behaviours are identified: (1) where the entire crust is strong, stresses from the downwelling mantle are efficiently transferred through the crust. There is little crustal deformation and removal is accompanied by surface subsidence and a negative free-air gravity anomaly. Surface uplift and increased free-air gravity occur after the dense root detaches. (2) If the mid-crust is weak, the dense root creates a lateral pressure gradient in the crust that drives Poiseuille flow in the weak layer. This induces crustal thickening, surface uplift and a minor free-air gravity anomaly above the root. (3) If the lower crust is weak, deformation occurs through pressure-driven Poiseuille flow and Couette flow due to basal shear. This can overthicken the crust, producing a topographic high and a negative free-air gravity anomaly above the root. In the latter two cases, surface uplift occurs prior to the removal of the mantle stress. The modeling results predict that syn-removal uplift will occur if the crustal viscosity is less than ∼10 21 Pa s, corresponding to temperatures greater than ∼400-500 • C for a dry and felsic or wet and mafic composition, and ∼900 • C for a dry and mafic composition. If crustal temperatures are lower than this, lithosphere removal is marked by the formation of a basin. These results can explain the variety of surface expressions observed above areas of downwelling mantle. In addition, observations of the surface deflection may provide a way to constrain the vertical rheological structure of the crust.

show abstract

Section: Ru S Ta L V I S C O S I T Y S T Ru C T U R Ementioning

confidence: 52%

Section: Surface Observables Of Mantle Dynamicsmentioning

confidence: 99%

Section: Numerical Model Setupmentioning

confidence: 99%

Section: Ru S Ta L V I S C O S I T Y S T Ru C T U R Ementioning

confidence: 99%

Section: Mid-crustal Channel Modelmentioning

confidence: 99%

See 3 more Smart Citations

Crustal deformation induced by mantle dynamics: insights from models of gravitational lithosphere removal

Wang

Currie

2017

Geophysical Journal International

View full text Add to dashboard Cite

show abstract

Rayleigh wave dispersion measurements reveal low‐velocity zones beneath the new crust in the Gulf of California

Persaud

Luccio

Clayton

2015

Geophysical Research Letters

View full text Add to dashboard Cite

Rayleigh wave tomography provides images of the shallow mantle shear wave velocity structure beneath the Gulf of California. Low‐velocity zones (LVZs) are found on axis between 26 and 50 km depth beneath the Guaymas Basin but mostly off axis under the other rift basins, with the largest feature underlying the Ballenas Transform Fault. We interpret the broadly distributed LVZs as regions of partial melting in a solid mantle matrix. The pathway for melt migration and focusing is more complex than an axis‐centered source aligned above a deeper region of mantle melt and likely reflects the magmatic evolution of rift segments. We also consider the existence of solid lower continental crust in the Gulf north of the Guaymas Basin, where the association of the LVZs with asthenospheric upwelling suggests lateral flow assisted by a heat source. These results provide key constraints for numerical models of mantle upwelling and melt focusing in this young oblique rift.

show abstract

Crustal structure and extension mode in the northwestern margin of the South China Sea

Gao

McIntosh

et al. 2016

Geochem Geophys Geosyst

View full text Add to dashboard Cite

Combining multi‐channel seismic reflection and gravity modeling, this study has investigated the crustal structure of the northwestern South China Sea margin. These data constrain a hyper‐extended crustal area bounded by basin‐bounding faults corresponding to an aborted rift below the Xisha Trough with a subparallel fossil ridge in the adjacent Northwest Sub‐basin. The thinnest crust is located in the Xisha Trough, where it is remnant lower crust with a thickness of less than 3 km. Gravity modeling also revealed a hyper‐extended crust across the Xisha Trough. The postrift magmatism is well developed and more active in the Xisha Trough and farther southeast than on the northwestern continental margin of the South China Sea; and the magmatic intrusion/extrusion was relatively active during the rifting of Xisha Trough and the Northwest Sub‐basin. A narrow continent‐ocean transition zone with a width of ∼65 km bounded seaward by a volcanic buried seamount is characterized by crustal thinning, rift depression, low gravity anomaly and the termination of the break‐up unconformity seismic reflection. The aborted rift near the continental margin means that there may be no obvious detachment fault like that in the Iberia‐Newfoundland type margin. The symmetric rift, extreme hyper‐extended continental crust and hotter mantle materials indicate that continental crust underwent stretching phase (pure‐shear deformation), thinning phase and breakup followed by onset of seafloor spreading and the mantle‐lithosphere may break up before crustal‐necking in the northwestern South China Sea margin.

show abstract

Lithospheric extension near Lake Mead, Nevada: A model for ductile flow in the lower crust

Cited by 172 publications

References 39 publications

Crustal deformation induced by mantle dynamics: insights from models of gravitational lithosphere removal

Crustal deformation induced by mantle dynamics: insights from models of gravitational lithosphere removal

Rayleigh wave dispersion measurements reveal low‐velocity zones beneath the new crust in the Gulf of California

Crustal structure and extension mode in the northwestern margin of the South China Sea

Contact Info

Product

Resources

About