2D thermomechanical modelling of continent–arc–continent collision

Dymkova, Diana; Gerya, Taras; Burg, Jean‐Pierre

doi:10.1016/j.gr.2015.02.012

Cited by 34 publications

(19 citation statements)

References 62 publications

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“…The model setup and parameter values are based on previous studies of subduction and collision that successfully reproduced the formation of (U)HP rocks (Dymkova et al, ; Faccenda et al, ; Sizova et al, ). The results of these models crucially depend on the incorporation of complex viscoplastic rheology, effect of fluids (water) and melt, which both reduce the strength of the rock, and major phase changes that affect the density.…”

Section: Methodsmentioning

confidence: 99%

Relamination Styles in Collisional Orogens

2018

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During continental collision, a part of the lower‐plate material can be subducted, emplaced at the base of the upper plate, and eventually incorporated into its crust. This mechanism of continental‐crust transformation is called relamination, and it has been invoked to explain occurrences of high‐pressure felsic rocks in different structural positions of several orogenic systems. In the present study we reproduced relamination during continental collision in a thermomechanical numerical model. We performed a parametric study and distinguished three main types of evolution regarding the fate of the subducted continental crust: (i) return along the plate interface in a subduction channel or wedge, (ii) flow at the bottom of the upper‐plate lithosphere and subsequent translithospheric exhumation near the arc or in the back‐arc region (“sublithospheric relamination”), and (iii) nearly horizontal flow directly into the upper‐plate crust (“intracrustal relamination”). Sublithospheric relamination is preferred for relatively quick convergence of thin continental plates. An important factor for the development of sublithospheric relamination is melting of the subducted material, which weakens the lithosphere and opens a path for the exhumation of the relaminant. In contrast, a thick and strong overriding plate typically leads to exhumation near the plate interface. If the overriding plate is too thin or weak, intracrustal relamination occurs. We show that each of these evolution types has its counterpart in nature: (i) the Alps and the Caledonides, (ii) the Himalayan‐Tibetan system and the European Variscides, and (iii) pre‐Cambrian ultrahot orogens.

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Section: Methodsmentioning

confidence: 99%

Relamination Styles in Collisional Orogens

2018

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“…The initial thermal structure of the continental lithospheres was a simplified linear profile defined by 0 • C at the surface, 1300 • C at the bottom of the lithosphere (70-140 km), and a 0.5 • C km -1 temperature gradient for the underlying mantle. Details of the procedures used in the model were already described in previous works [55,80,[82][83][84][85]. Here, we present a short summary.…”

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

Late Orogenic Heating of (Ultra)High Pressure Rocks: Slab Rollback vs. Slab Breakoff

et al. 2019

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Some (ultra)high-pressure metamorphic rocks that formed during continental collision preserve relict minerals, indicating a two-stage evolution: first, subduction to mantle depths and exhumation to the lower-crustal level (with simultaneous cooling), followed by intensive heating that can be characterized by a β-shaped pressure–temperature–time (P–T–t) path. Based on a two-dimensional (2D) coupled petrological–thermomechanical tectono-magmatic numerical model, we propose a possible sequence of tectonic stages that could lead to these overprinting metamorphic events along an orogenic β-shaped P–T–t path: the subduction and exhumation of continental crust, followed by slab retreat that leads to extension and subsequent asthenospheric upwelling. During the last stage, the exhumed crustal material at the crust–mantle boundary undergoes heating from the underlying hot asthenospheric mantle. This slab rollback scenario is further compared numerically with the classical continental collision scenario associated with slab breakoff, which is often used to explain the late heating impulse in the collisional orogens. The mantle upwelling occurring in the experiments with slab breakoff, which is responsible for the heating of the exhumed crustal material, is not related to the slab breakoff but can be caused either by slab bending before slab breakoff or by post-breakoff exhumation of the subducted crust. Our numerical modeling predictions align well with a variety of orogenic P–T–t paths that have been reported from many Phanerozoic collisional orogens, such as the Variscan Bohemian Massif, the Triassic Dabie Shan, the Cenozoic Northwest Himalaya, and some metamorphic complexes in the Alps.

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“…The geological data are also incorporated in some of the models, which focus mainly on the Barrovian-type metamorphism, timescales, and kinematics of metamorphic rocks exhumed in the Himalaya [Jamieson et al, 2004] or exhumation of UHP rocks during early stages of the collision [Beaumont et al, 2009]. Numerical models of ancient orogenies are still relatively rare and in the case of the European Variscides include only a handful of studies [e.g., Willner et al, 2002;Maierová et al, 2014;Dymkova et al, 2016]. Other considerations about their dynamics are inferred from generic-type models such as subduction wedge or gravity inversions [Gerya et al, 2000;Gerya and Stöckhert, 2006] or models designed for modern orogens [e.g., Beaumont et al, 2001].…”

Section: Tectonics Research Articlementioning

confidence: 99%