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Journal Articles Earth and Planetary Science Letters Year : 2014

Strain heating in process zones; implications for metamorphism and partial melting in the lithosphere

Abstract

Since the late 1970s, most earth scientists have discounted the plausibility of melting by shear-strain heating because temperature-dependent creep rheology leads to negative feedback and self-regulation. This paper presents a new model of distributed shear-strain heating that can account for the genesis of large volumes of magmas in both the crust and the mantle of the lithosphere. The kinematic (geometry and rates) frustration associated with incompatible fault junctions (e.g. triple-junction) prevents localisation of all strain on the major faults. Instead, deformation distributes off the main faults forming a large process zone that deforms still at high rates under both brittle and ductile conditions. The increased size of the shear-heated region minimises conductive heat loss, compared with that commonly associated with narrow shear zones, thus promoting strong heating and melting under reasonable rheological assumptions. Given the large volume of the heated zone, large volumes of melt can be generated even at small melt fractions.
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Dates and versions

insu-03581127 , version 1 (19-02-2022)

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Maud H. Devès, Stephen R. Tait, Geoffrey C. P. King, Raphaël Grandin. Strain heating in process zones; implications for metamorphism and partial melting in the lithosphere. Earth and Planetary Science Letters, 2014, 394, pp.216-228. ⟨10.1016/j.epsl.2014.03.002⟩. ⟨insu-03581127⟩
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