Le métamorphisme Tardi-Crétacé à Éocène des zones internes de la cha??ne Indo-Birmane (Myanmar occidental) : implications géodynamiquesLate Cretaceous to Eocene metamorphism of the internal zone of the Indo-Burma range (western Myanmar): geodynamic implications |
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Authors: | Anne Socquet Bruno Goffé Manuel Pubellier Claude Rangin |
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Institution: | Laboratoire de géologie, CNRS UMR 8538, École normale supérieure, 24, rue Lhomond, 75231 Paris cedex 05, France |
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Abstract: | Metamorphic study on Triassic schists in the internal zone of the Indo-Burma range, essentially based on chlorite–mica equilibrium in metapelites, allows a P–T path to be quantified. During the prograde metamorphism, the geothermic gradient evolves from that of a ‘normal’ crust (30 °C km?1) to that of a thickened crust (18 °C km?1). The peak conditions are around 8 kbar and 450 °C. This thickening (25–30 km) is probably made in a wedge set up between the Late Cretaceous and the Eocene, in front of the obduction. The obtained cold retrograde path requires a mechanism allowing thermal re-equilibration, implying slow exhumation. It occurred along a shear zone that put into contact the micaschists of the core with the Triassic schists of the roof. To cite this article: A. Socquet et al., C. R. Geoscience 334 (2002) 573–580. |
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Keywords: | India–Asia collision Myanmar Rhakine range Kampetlet schists mica-chlorite thermobarometry Himalayan ophiolite collision Inde–Asie Myanmar Arakan schistes de Kampetlet thermobarométrie mica-chlorite ophiolite himalayenne |
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