Density, temperature, and rheological models for the southeastern Canadian Cordillera: implications for its geodynamic evolution

Lowe, C; Ranalli, Giorgio

doi:10.1139/e93-007

Cited by 31 publications

(21 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The crust beneath the Foreland belt is thicker (41 km) than beneath the Omineca belt (34 km) (ZELT and WHITE, 1993). Moho temperature is modelled to be 300°C higher beneath the Omineca belt (1100-1200 K) than beneath the Foreland belt (850-950 K) (LowE and RANALLI, 1993 The base of the crust beneath the Foreland belt has a brittle rheology (LowE and RANALLI, 1993).…”

Section: Tectonic Setting and Previous Geophysical Resultsmentioning

confidence: 99%

The BC87 Dataset: Tectonic Setting, Previous EM Results, and Recorded MT Data.

Jones

1993

J. geomagn. geoelec

View full text Add to dashboard Cite

As part of project LITHOPROBE, magnetotelluric data were acquired at twenty-seven sites along a 150 km east-west profile in southeastern British Columbia straddling the complex tectonic boundary between ancestral North American rocks and those of the easternmost accreted terranes. These data, named the BC87 dataset, display complex effects due to both three-dimensional induction and galvanic scattering at virtually all scale sizes, from that of the electrode array (<50 m) to that of the large plutonic Nelson batholith (150x50 km surface extent). The dataset was distributed widely in order to compare and contrast different schemes for extracting the underlying predominant two-dimensional structure, and to test differing interpretational algorithms on data from a complex crystalline terrane. The MT data are shown, and the tectonic setting described. Also, seismic and previous EM studies of the region are described.

show abstract

Section: Tectonic Setting and Previous Geophysical Resultsmentioning

confidence: 99%

The BC87 Dataset: Tectonic Setting, Previous EM Results, and Recorded MT Data.

Jones

1993

J. geomagn. geoelec

View full text Add to dashboard Cite

show abstract

“…6, for a 350 km long cross-section of the southeastern Canadian Cordillera (Lowe & Ranalli 1993). The cross-section includes both thinned continental lithosphere (the Omineca Belt, expressed at the surface by tectonically inverted metamorphic core complexes) and cratonic lithosphere (the Foreland Belt and basinal sedimentary cover).…”

Section: Rheological Profiles (Strength Envelopes)mentioning

confidence: 99%

“…Stipple in the temperature section indicates asthenosphere; dashed line the seismic Moho.In the two-dimensional rheological profile, brittle and ductile regions are denoted by heavy and light stipple, respectively; distances from the SW end of the cross-section are marked in the one-dimensional profiles. Tectonic regime: normal faulting, strain rate 10 -15 s -1 (fromLowe & Ranalli 1993).…”

mentioning

confidence: 99%

Rheology of the lithosphere in space and time

Ranalli

1997

165

141

View full text Add to dashboard Cite

The rheology of the lithosphere is a factor of primary importance in the kinematics and dynamics of mountain belts. This paper attempts to clarify the role of rheology in orogenesis, by applying simple physical principles to the analysis of tectonic processes. The emphasis is on broad generalizations leading to order-of-magnitude estimates. Since the rheology of lithospheric materials is strongly dependent on temperature, the discussion opens with a review of continental and oceanic geotherms and an assessment of their reliability. Then the brittle (frictional) and ductile (high-temperature creep) properties of the lithosphere are considered. In the brittle field, particular attention is paid to the problem of fault reactivation, which is shown to be more likely in extensional than in compressional regimes. In the ductile field, a summary of creep parameters for the most common lithospheric materials is presented. The central concept of rheological profiles (strength envelopes), essential to the estimation of the depth variations of lithospheric rheology, is discussed with reference not only to its applicability but also to its limitations (a two-dimensional example from the Canadian Cordillera is given). Processes related to the rheological properties and layering of the lithosphere — gravitational collapse in thickened and softened crust, tectonic inversion following the detachment of a lithospheric root, lower crustal ductile flow with consequent relaxation of Moho topography — are analysed semi-quantitatively, mainly to show that they are indeed likely to be important players in geodynamics. Finally, in a brief Archaean detour, some possible important differences between present-day and Archaean oceanic lithosphere are examined, and the conclusion is reached that in all likelihood plate tectonics, although at different rates, has been the main agent of orogenesis during most of the history of the planet.

show abstract

“…Besides this depth-dependent rheology of the continental lithosphere, significant lateral variations arise from different crust structures and thermal regimes. These variations provoke rheological anisotropy, a main factor controlling the behaviour of the lithosphere (Lowe and Ranalli, 1993;Cloetingh and Burov, 1996;Hyndman and Lewis, 1999;Lankreijer et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Thermal and mechanical structure of the central Iberian Peninsula lithosphere

Tejero

Ruíz

2002

Tectonophysics

View full text Add to dashboard Cite

The central Iberian Peninsula (Spain) is made up of three main tectonic units: a mountain range, the Spanish Central System and two Tertiary basins (those of the rivers Duero and Tajo). These units are the result of widespread foreland deformation of the Iberian plate interior in response to Alpine convergence of European and African plates. The present study was designed to investigate thermal structure and rheological stratification in this region of central Spain. Surface heat flow has been described to range from f 80 to f 60 mW m À2 . Highest surface heat flow values correspond to the Central System and northern part of the Tajo Basin. The relationship between elevation and thermal state was used to construct a one-dimensional thermal model. Mantle heat flow drops from 34 mW m À2 (Duero Basin) to 27 mW m À2 (Tajo Basin), and increases with diminishing surface heat flow. Strength predictions made by extrapolating experimental data indicate varying rheological stratification throughout the area. In general, in compression, ductile fields predominate in the middle and lower crusts and lithospheric mantle. Brittle behaviour is restricted to the first f 8 km of the upper crust and to a thin layer at the top of the middle crust. In tension, brittle layers are slightly more extended, while the lower crust and lithospheric mantle remain ductile in the case of a wet peridotite composition. Discontinuities in brittle and ductile layer thickness determine lateral rheological anisotropy. Tectonic units roughly correspond to rheological domains. Brittle layers reach their maximum thickness beneath the Duero Basin and are of least thickness under the Tajo Basin, especially its northern area. Estimated total lithospheric strength shows a range from 2.5Â10 12 to 8Â10 12 N m À1 in compression, and from 1.3Â10 12 to 1.6Â10 12 N m À1 in tension. Highest values were estimated for the Duero Basin. Depth versus frequency of earthquakes correlates well with strength predictions. Earthquake foci concentrate mainly in the upper crust, showing a peak close to maximum strength depth. Most earthquakes occur in the southern margin of the Central System and southeast Tajo Basin. Seismicity is related to major faults, some bounding rheological domains. The Duero Basin is a relative quiescence zone characterised by higher total lithospheric strength than the remaining units. D

show abstract

Density, temperature, and rheological models for the southeastern Canadian Cordillera: implications for its geodynamic evolution

Cited by 31 publications

References 78 publications

The BC87 Dataset: Tectonic Setting, Previous EM Results, and Recorded MT Data.

The BC87 Dataset: Tectonic Setting, Previous EM Results, and Recorded MT Data.

Rheology of the lithosphere in space and time

Thermal and mechanical structure of the central Iberian Peninsula lithosphere

Contact Info

Product

Resources

About