Various mechanisms have been proposed for the dynamic cause and kinematic development of gneiss domes. They include (1) diapiric fl ow induced by density inversion, (2) buckling under horizontal constriction (i.e., extension perpendicular to compression), (3) coeval orthogonal contraction or superposition of multiple phases of folding in different orientations, (4) instability induced by vertic...

dehbid mylonite nappes associated with the tutak gneiss dome as the zagros hinterland involved-basement window in the zagros orogenic belt has significant components of dextral sense of shear along the mylonite nappes and are related to the high proportion of simple shear relative to pure shear deformation. kinematic vorticity analysis (wk) was made in order to determination of relative amounts...

In exhumed orogens, refractory mafic rocks have the potential to preserve a record of petrogenesis and high-pressure (HP) metamorphism that is commonly obliterated in quartzofeldspathic owing re-equilibration at high-temperature, low-pressure (LP–HT) conditions. Montagne Noire (France) migmatite dome, located foreland Variscan orogen, eclogite exposed both core margin dome. this study, we combi...

Field, structural, and metamorphic petrology investigations of Mabja gneiss dome, southern Tibet, suggest that contractional, extensional, and diapiric processes contributed to the structural evolution and formation of the domal geometry. The dome is cored by migmatites overlain by sillimanite-zone metasedimentary rocks and orthogneiss; metamorphic grade diminishes upsection and is defined by a...

• Mangodara forms a dome cored by tonalitic gneiss, mantled granodioritic gneiss. Gneiss-granitoids derive from partial melting of Birimian greenstones. Residual melt syntectonic gneiss genesis formed rare-metal pegmatites. We describe the geological context rare metal-bearing pegmatites district (South-West Burkina Faso, Paleoproterozoic West African Craton) and discuss their petrogenesis link...

Abst rac t -Large parts of the Central Eastern Desert of Egypt consist of Neoproterozoic nappes of ophiolite and island-arc volcanic rocks. Beneath these nappes metamorphic basement domes are exposed in tectonic w indows such as the Meatiq basement. The mineral and whole rock chemistry of amphibol i tes included in the teconical ly lowermost granitoid gneiss, within the metasedimentary cover of...

Fractured Gneiss aquifers present a challenge to hydrogeologists because of their geological complexity. Interpretation methods which can be applied to porous media cannot be applied to fractured Gneiss aquifers because flow and transport occur in fractures, joints, and conduits. In contrast, the rock matrix contribution to groundwater flow is not very important in Gneiss aquifers. Sodium chlor...