Petrographic, Mineralogical and Geothermometric Study of Garnet Hornfels from the Region of Iddeleh Silet Hoggar Occidental Algeria

Abstract

The emplacement of Neoproterozoic mafic-ultramafic complexes in the Iddeleh area, Silet Block (Western Hoggar) was associated with garnet hornfels facies contact metamorphism of the Pharusian I metapelites. EPMA data of garnet reveal formation temperatures as high as 900 °C. A later metamorphic event is manifested in the persistence of chlorite schist, in which the chlorite composition (Aliv contents) indicates a temperature range of 300–400 °C. It is, therefore, suggested that juxtaposition of the Silet terrane and the microcontinent LATEA was not the outcome of a collisional regime.