Inverted metamorphic sequences are characterized by peak metamorphic temperatures that increase structurally upward, with isograds that are typically parallel to associated thrust faults. A fully coupled thermal-mechanical model for convergent orogens shows how an inverted sequence can be tectonically assembled in a crustal-scale ductile shear zone at moderate to high rates of synorogenic erosion. Model inverted sequences form by tectonic juxtaposition of points with widely differing initial positions that reach peak temperatures at different times and in different places within the model orogen, and thus do not represent metamorphic or thermal gradients. Inverted crustal isotherms are not required to produce model inverted isograds. Model results agree well with metamorphic pressure-temperature data from the Main Central Thrust zone of the central Nepal Himalayas.

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