SECULAR TRENDS IN THE THERMAL EVOLUTION OF METAMORPHIC TERRAINS

Abstract

The thermal evolution of convergent orogens is sensitive to the deformation history of the mantle part of the lithosphere. If the dense mantle lithosphere thickens as a consequence of convergent deformation and remains attached during subsequent denudation of the thickened crust then high-pressure/low- to intermediate-temperature glaucophane schist assemblages will form during both thickening and denudation; the actual form of the P-T paths for a given deformation depending primarily on the initial thermal state of the lithosphere and, particularly, the ratio of the thickness of the crust and mantle lithosphere. However, if mantle lithosphere is thinned during convergence by processes such a..