Extension rates, crustal melting, and core complex dynamics

Rey, Patrice; Teyssier, Christian; Whitney, Donna L.

doi:10.1130/g25460a.1

Cited by 167 publications

(156 citation statements)

References 28 publications

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“…Patterns (or modes) of continental extension primarily depend on the rheological layering of the lithosphere (Analytical models: Buck, 1991;Analogue models: Allemand and Brun, 1991;Brun, 1999;Tirel et al, 2006;Numerical models: Lavier et al, 1999;2000;Tirel et al, 2004a;Wijns et al, 2005;Gessner et al, 2007;Gueydan et al, 2008;Rey et al, 2009a;2009b;Huet et al, 2011;Wang et al, 2015;Wu et al, 2015;Wu & Lavier, 2016). For a general appraisal of lithosphere rheology and its effects on large-scale geodynamics see Burov (2007a;2010;.…”

Section: Modes Of Extension As a Function Of Lithosphere Rheologymentioning

confidence: 99%

“…A first category of these models simulates only the deformation of the brittle-ductile crust above a non-deformable flat base representing the A C C E P T E D M A N U S C R I P T Tirel et al, 2004a;Rey et al, 2009a;2009b andHuet et al, 2011;Wang et al, 2015).…”

Section: Crustal Core Complexesmentioning

confidence: 99%

“…In models that integrate phase transitions controlled by pressure, temperature and the local amount of free fluid that comes from both external (meteoric) and local (dehydration) sources show a strong positive feedback between the asymmetry of the tectonic structures and the depth of penetration of meteoric fluids. From a general point of view, it must be noted that all models involving some type of strain softening favor asymmetric strain localization and the development of a rolling hinge type detachment, even in models where displacements are applied symmetrically and whatever the type of localizing perturbation (Lavier et al, 1999;2000;Lavier and Buck, 2002;Wijns et al, 2005;Gessner et al, 2007;Rey et al, 2009a;2009b;Tirel et al, 2009;Mezri et al, 2015;Schenker et al, 2012;Wang et al, 2015;Wu et al, 2015;Wu and Lavier, 2015). This suggests that strain softening could play a dominant role in the development of detachments and therefore in the evolution of core complex models.…”

Section: Comparison Of With Other Numerical Modelsmentioning

confidence: 99%

“…Consequently, more work on natural systems complemented by laboratory experiments would be necessary to produce realistic laws of strain softening that could be successfully implemented in numerical models. In models using a pre-existing fault as an upper crust perturbation to localize deformation (Skelton and Koyi, 2001;Rey et al, 2009a;2009b), the dip of the detachment and therefore the asymmetry of the core complex are determined by the dip of the pre-existing fault. The difficulty inherent to such initial condition is to justify how and why a solitary normal fault would be created in the upper crust prior to core complex development.…”

Section: Comparison Of With Other Numerical Modelsmentioning

confidence: 99%

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Crustal versus mantle core complexes

et al. 2018

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Contrary to what is commonly believed, it is argued from analogue and numerical models that detachments that accommodate exhumation of core complexes do not initiate at the onset of extension but in the course of progressive extension when the exhuming ductile crust reaches the surface. In models, convex upward detachments result from a rolling hinge process. A C C E P T E D M A N U S C R I P TMantle core complexes develop in either the oceanic lithosphere, at slow and ultra-slow spreading ridges, or in continental lithospheres, whose initial Moho temperature is lower than 750°C, with "sub-Moho mantle-dominated" strength profiles. It is argued that the mechanism of mantle exhumation at passive margins is a nearly symmetrical necking process at ACCEPTED MANUSCRIPTA C C E P T E D M A N U S C R I P T 2 lithosphere scale without major and permanent detachment, except if strong strain localization could occur in the lithosphere mantle. Distributed crustal extension, by upper crust faulting above a décollement along the ductile crust increases toward the rift axis up to crustal breakup.Mantle rocks exhume in the zone of crustal breakup accommodated by conjugate mantle shear zones that migrate with the rift axis, during increasing extension.

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Section: Modes Of Extension As a Function Of Lithosphere Rheologymentioning

confidence: 99%

Section: Crustal Core Complexesmentioning

confidence: 99%

Section: Comparison Of With Other Numerical Modelsmentioning

confidence: 99%

Section: Comparison Of With Other Numerical Modelsmentioning

confidence: 99%

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Crustal versus mantle core complexes

et al. 2018

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“…The most fundamental tectonic consequence of these variations is the development of a rheologically weak layer in the lithosphere [e.g., Teyssier, 2001a, 2001b;Rosenberg and Handy, 2005;Regenauer-Lieb et al, 2006]. Recent geodynamic models that incorporate the effects of anatexis during orogeny emphasize the large-scale mobility of the partially molten crust [Beaumont et al, 2001[Beaumont et al, , 2006Clark and Royden, 2000;Vanderhaeghe et al, 2003;Rey et al, 2009]. The orogenic middle crust is typically characterized by abundant migmatite [e.g., Brown, 1994;Vanderhaeghe, 2009], and migmatites therefore preserve the record of crustal melting and viscoplastic flow processes in orogens.…”

Section: Introductionmentioning

confidence: 99%

Viscoplastic flow in migmatites deduced from fabric anisotropy: An example from the Naxos dome, Greece

et al. 2010

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[1] Many migmatites represent crystallized partially molten crust and therefore record the mechanisms and pathways of orogenic crustal flow. Field and microstructural methods may be insufficient to characterize the planar and linear elements of rock fabric in migmatites due to obscured flow fabrics or protracted deformation. In the Naxos dome (Greece), we test the anisotropy of magnetic susceptibility (AMS) as a tool for recovering mineral fabric symmetry and the kinematic axes of flow in migmatites. Measurements of 155 migmatite samples yield dominantly low values (<300 × 10 −6 [SI]) of bulk magnetic susceptibility (K m ) consistent with biotite being the dominant carrier of the AMS. Higher values of K m , thermomagnetic, hysteresis, and microstructural data, however, suggest a ferromagnetic contribution from magnetite in a subset of samples (N = 15). Using electron backscatter diffraction (EBSD) analysis, we establish the correspondence of the biotite subfabric with the AMS and structural fabric of the Naxos migmatites. EBSD data from biotite suggests that magnetic lineation in these dominantly paramagnetic migmatites arises from a zone axis orientation of biotite crystals organized about the direction of viscoplastic flow. Over a range of spatial scales, migmatitic foliation and magnetic foliation are well correlated. The magnetic lineation recovered by AMS displays a coherent organization despite the heterogeneous structure and composition of the Naxos migmatites. These data suggest that the apparent complexity of migmatites masks a simpler flow regime controlled by bulk viscoplastic flow. Furthermore, our study demonstrates the utility of the AMS method for studying the dynamics of partially molten orogenic crust.

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Low‐temperature thermochronologic record of Eocene migmatite dome emplacement and late Cenozoic landscape development, Shuswap core complex, British Columbia

et al. 2014

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Exhumed mid-to-lower crustal rocks offer an opportunity to determine the mechanisms, conditions, timing, and consequences of the ascent of hot rocks from deep to shallow crustal levels. We used results of low-T thermochronology (zircon and apatite (U-Th)/He, apatite fission track) to document the very shallow emplacement (<2 km) of high-grade metamorphic rocks and to determine the timing and rates of Cenozoic cooling, exhumation, and subsequent incision of the Thor-Odin migmatite dome of the Shuswap metamorphic core complex, British Columbia (Canada). Samples collected at high elevation in the dome (>1800 m) have preserved Eocene fission-track ages and evidence of rapid cooling (≥60°C/Myr). This Eocene cooling event corresponds to rapid exhumation by upward flow of partially molten crust and final exhumation by detachment faulting. Samples collected below 1800 m in elevation display a wide range of apatite fission track ages (43-15 Ma) and track length distributions that reflect prolonged residence in the apatite partial annealing zone. These age-elevation relations imply that the dome rocks reached the near surface (<2 km) during initial upward flow and tectonic exhumation in the Eocene and that little erosion of the Eocene surface has occurred since that time. Thermal modeling of the lowest elevation samples (≤~600 m) and intrasample apatite (U-Th)/He age variations reveal enhanced erosion and relief production at the onset of continental glaciations at~3 Ma. Our work illustrates the dynamic links between deep and shallow crustal processes and the evolution of topography in a deeply incised hot orogen.

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Extension rates, crustal melting, and core complex dynamics

Cited by 167 publications

References 28 publications

Crustal versus mantle core complexes

Crustal versus mantle core complexes

Viscoplastic flow in migmatites deduced from fabric anisotropy: An example from the Naxos dome, Greece

Low‐temperature thermochronologic record of Eocene migmatite dome emplacement and late Cenozoic landscape development, Shuswap core complex, British Columbia

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