Continental margin deformation along the Andean subduction zone: Thermo-mechanical models

Gerbault, Muriel; Cembrano, José; Mpodozis, Constantino; Farías, Marcelo; Pardo, Mario

doi:10.1016/j.pepi.2009.09.001

Cited by 42 publications

(53 citation statements)

References 184 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We have thus chosen to setup our models for an already evolved collisional orogeny and acknowledge its disequilibrium de facto, as in fact other modelling studies do (eg. Yamato et al, 2008;Gerbault et al, 2009;Luth et al, 2013 ;Maierova et al, 2014, and references therein). We must then justify the initial shape, temperature and compositions of both the underplated subducting plate and the overriding orogenic prism.…”

Section: Model Setupmentioning

confidence: 99%

Crustal exhumation during ongoing compression in the Variscan Maures-Tanneron Massif, France-Geological and thermo-mechanical aspects

et al. 2018

Self Cite

View full text Add to dashboard Cite

The Maures-Tanneron Massif (MTM), together with Corsica and Sardinia, represent the Southeastern branch of the huge European Variscan belt. A continuous evolution from continental collision to exhumation is described from ca. 350 Ma to ca. 320 Ma, based on an extended compilation of available geological and geochronogical data. This geological compilation is complemented with thermo-mechanical modelling that tests the conditions under which deep-seated HP units can melt and exhume massively during continued convergence. We simulate in two-dimensions the development of gravitational instabilities in a partially melting crust, depending on rheological layering and heat sources, and accounting for temperature dependent elasto-visco-plastic rheologies. In order to reproduce PT exhumation patterns in the MTM, over the appropriate time-scale (>20 My) and spatial extent (>100 km), a best fit was obtained with a convergence rate of 0.5 cm/yr and moderate diffusive surface processes. The contribution of radiogenic heating in the pre-stacked felsic crustal units is crucial. A lateral alternation with mafic units is also required in order to prevent lateral spreading of the orogen. A low viscosity partially molten crust (10² Pa.s, thus rather felsic) accompanies crustal exhumation in a decoupled mode from the deeper mantle. A shallow asthenosphere below the orogen (LAB at ~70 km depth, eg. shallow slab break-off) produces too warm and sudden exhumation as opposed to a competent mantle lithosphere (120 km depth LAB) that restrains it. The MTM witnesses the typical competition between far-field plate convergence and internal body forces, and our study pleads for a progressive evolution of transpression towards perpendicular extension from ca. 320 Ma.

show abstract

Section: Model Setupmentioning

confidence: 99%

Crustal exhumation during ongoing compression in the Variscan Maures-Tanneron Massif, France-Geological and thermo-mechanical aspects

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…10c), Archimede's lithostatic stress reaction force is applied along the boundaries of the modeled mantle domain (e.g., simulating that the modeled domain is embedded in an infinite half space, as in e.g., Gerbault et al, 2009or Burov et al, 2005. The resulting state of stress displays even larger deviatoric stresses both in the eastern and western parts of the modeled mantle.…”

Section: Stress Field Resulting From Kinematic Conditions Imposed At mentioning

confidence: 99%

“…Within ~300 kyr of applied convergence from the right-hand side of the model (as in AM-2), f lexural deviatoric stresses up to 260 MPa (in red) develop inside the elastic plate; B. Model LM built with code "Parovoz" (modified from Gerbault et al, 2009). Here gravity is included and the mantle and overriding plate both behave according to thermally dependent elasto-visco-plastic laws.…”

Section: Stress Field Resulting From Kinematic Conditions Imposed At mentioning

confidence: 99%

“…Therefore we display model LM, which is built with the finite-differences code Parovoz (Poliakov and Podladchikov, 1992), and assumes conditions similar to those defined by Gerbault et al (2009), Dorbath et al (2008 and Sobolev and Babeyko (2005) when studying the influence of rheology on deformation along the Chilean margin over several millions years. This model considers subduction over a time-scale of 4 Myrs and assumes self-consistently defined temperature-dependent elasto-visco-plasic rheology.…”

Section: Long-term Flexural Stressesmentioning

confidence: 99%

“…First, the large stresses that develop in this model result from our assumption of purely visco-elastic behaviour in this case, in order to remain consistent with the other models of the present study. If rheologies were assumed fully elasto-visco-plastic as in e.g., Gerbault et al (2009), then the stresses would remain bounded by the yield strength and would not exceed ~400 MPa. However the strain and stress field still both develop a similar pattern to that displayed here.…”

Section: Long-term Flexural Stressesmentioning

confidence: 99%

See 2 more Smart Citations

Interseismic deformation at subduction zones investigated by 2D numerical modeling: case study before the 2010 Maule earthquake

Contreras

Tassara

Gerbault

et al. 2016

andgeo

Self Cite

View full text Add to dashboard Cite

ABSTRACT. We study interseismic deformation preceding the Mw8.8 2010 Maule earthquake by means of two-dimensional finite-element modeling. Our goal is to gain insight into the fundamental factors controlling elastic strain build-up and release in subduction zones, and to evaluate different modeling approaches of surface displacement as observed by GPS. We developed a linear elasticity solver that allows us to implement a realistic subducting plate geometry constrained by geophysical data. We test the influence of subducting plate thickness, variations in the updip and downdip limit of a 100% locked interplate zone, elastic parameters, and velocity reduction at the base of the subducted slab. We compared our modeled predictions with interseismic GPS observations along an EW profile crossing the Maule earthquake rupture area, in order to determine best fitting parameters. Our results indicate little inf luence of the subducting plate thickness at a given downdip limit, which itself has a strong influence on surface deformation. However, the fit to observations is achieved only after reducing the velocity at the base of the subducted slab below the trench region to 10% of the far-field convergence rate. We link this novel result to complementary numerical models that gradually evolve toward considering longer time-scales and complex rheology in order to evaluate the mechanical meaning of the above mentioned inferred kinematic conditions. This allowed us to link the velocity reduction at the base of subducting slabs with a long-term state of high flexural stress resulting from the mechanical interaction of the slab with the underlying mantle. Even a small amount of theses high deviatoric stresses may transfer towards the upper portion of the slab as strain energy that could participate into the mechanical loading of the megathrust and therefore in triggering large earthquakes there.

show abstract

Mechanical analysis of a natural example of onland gravity gliding: The role of river incision and deposition

2014

View full text Add to dashboard Cite

Gravity gliding implies rigid translation of a body down a slope where displacements are parallel to a tilted detachment plane. Although large-scale gravity gliding is commonly observed offshore, under conditions of high fluid overpressure and abundant upslope sedimentary supply, its occurrence on land is debated. We investigate the mechanical feasibility of such a process as well as the role of fluvial incision and sedimentation down the slope in the initiation of the gliding. We use a two-dimensional (2-D) finite element model combined with a 2-D failure analysis approach. The numerical models simulate the deformation and provide quantitative estimates of the failure criteria at the head and toe of the overburden. Analytical solutions approximate the numerical results by taking into account the fluvial incision and sedimentation, the internal friction angle, and the thickness and length of the overburden. Our models are based on a field example in the Andean foothills of Argentina, where gravity gliding of a 1000 m thick section is suspected above a crustal-scale anticline. The incision and sedimentation reduce and strengthen, respectively, the downslope resistance to contractional failure. The critical slope at which the gliding is initiated is reduced by fluvial incision and increased by sedimentation. We show that tectonic uplift may lead to large-scale gravity gliding on land where the overburden thickness is less than 2000 m. Incision facilitates and localizes the frontal shortening. Incision greater than 1000 m may trigger gliding for overburden up to 4000 m thick, while sedimentation thicker than 1000 m inhibits gliding. These results show that thin-skinned onland gravity gliding could be common in tectonically active regions where incision is important.

show abstract

Continental margin deformation along the Andean subduction zone: Thermo-mechanical models

Cited by 42 publications

References 184 publications

Crustal exhumation during ongoing compression in the Variscan Maures-Tanneron Massif, France-Geological and thermo-mechanical aspects

Crustal exhumation during ongoing compression in the Variscan Maures-Tanneron Massif, France-Geological and thermo-mechanical aspects

Interseismic deformation at subduction zones investigated by 2D numerical modeling: case study before the 2010 Maule earthquake

Mechanical analysis of a natural example of onland gravity gliding: The role of river incision and deposition

Contact Info

Product

Resources

About