A petrological and geochemical cross section of lower crust at the Wadi Gideah (Samail ophiolite) : implications for the crustal accretion at fast spreading mid ocean ridges Fast spreading mid ocean ridges crustal accretion Oman ophiolite Wadi Gideah layered gabbro major elements trace elements crystallographic preferred orientation axial melt lens. Schnell spreizende mittelozeanische Rücken Krustenbildung Oman Ophiolith lagige Gabbros Hauptelemente Spurenelemente bevorzugte kristallographische Orientierung axiale Schmelzlinse