Petrological and Tectonic Investigations of High Pressure Metamorphism in NE Oman

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Blueschists, type-C eclogites and other high pressure metamorphic rocks occur in the basement and continental platform deposits of the Saih Hatat culmination in northeastern Oman. The blueschists and eclogites constitute a coherent in situ terrain structurally overlain by two thrust piles containing lower-grade high pressure metamorphic assemblages. The entire sequence is overlain by the Semail ophiolite nappe. The tectonic setting of these high pressure metamorphic rocks is unique given their occurrence in a passive continental margin that has not undergone continent-continent collision and their structural relations to the unmetamorphosed Tethyan Semail ophiolite nappe. The NSF is requested to provide two-year support to continue a detailed field, petrological, geochemical and geochronological study of high pressure metamorphism in NE Oman. This study is aimed at (a) constraining the pressure-temperature conditions of metamorphism and reconstructing the pressure-temperature-time paths of the different structural terrains (b) developing petrogenetic grids for the various lithologies of the high pressure metamorphic rocks; and (c) establishing the ages of metamorphism and uplift rates of these domains. The results of this study will constrain the relationship between high pressure metamorphism and ophiolite emplacement in Oman and will be used to develop a tectonic model that will have sufficient temporal control on the large-scale tectonic events. The ultimate goal of this research is to explain why high pressure metamorphism developed in the absence of continent- continent collision or oceanic crust subduction beneath the continental margin.