| Titre | Temperature control of continental lithosphere elastic thickness, Te vs Vs |
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| Auteur | Hyndman, R D ;
Currie, C A; Mazzotti, S; Frederiksen, A |
| Source | Earth and Planetary Science Letters vol. 277, 2009 p. 539-548, https://doi.org/10.1016/j.epsl.2008.11.023 |
| Année | 2009 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20080031 |
| Éditeur | Elsevier BV |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.epsl.2008.11.023 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Sujets | croûte continentale; lithosphère; épaisseur de la croûte; études de la croûte; evolution de la croûte; structure de la croûte; manteau terrestre; déformation; interprétations tectoniques; évolution
tectonique; milieux tectoniques; temperature; regimes thermiques; tectonique |
| Illustrations | histogrammes; graphiques |
| Programme | Réduction des risques dus aux aléas naturels |
| Diffusé | 2009 01 01 |
| Résumé | (disponible en anglais seulement)
The elastic thickness of the continental lithosphere is closely related to its total strength and therefore to its susceptibility to tectonic deformation and
earthquakes. Recently it has been questioned whether the lithosphere thickness and strength are dependent on crustal and upper mantle temperatures and compositions as predicted by laboratory data. We test this dependence regionally by comparison in
northwestern North America of the effective elastic thickness Te, from topography-gravity coherence, with upper mantle temperatures mapped by shear wave tomography velocities Vs and other temperature indicators. The Te values are strongly bimodal as
found globally, less than 20 km for the hot Cordillera backarc and over 60 km for the cold stable Craton. These Te correspond to low Vs beneath the Cordillera and high Vs beneath the Craton. Model temperature-depth profiles are used to estimate model
Te for comparison with those observed. Only limited areas of intermediate thermal regimes, i.e., thermotectonic ages of ~300 Ma, have intermediate Te that suggest a weak lower crust over a stronger upper mantle. There are large uncertainties in model
Te associated with composition, water content, strain rate, and decoupling stress threshold. However, with reasonable parameters, model yield stress envelopes correspond to observed Te for thermal regimes with 800-900 °C at the Cordillera Moho and
400-500 °C for the Shield, in agreement with temperatures from Vs and other estimators. Our study supports the conclusion that lithosphere elastic thickness and strength are controlled primarily by temperature, and that laboratory-based rheology
generally provides a good estimate of the deformation behaviour of the crust and upper mantle on geological time scales. |
| GEOSCAN ID | 225070 |
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