From an extensive field study of the structural orientations within the Antalya ophiolite complex, a model for an oceanic ridge is proposed. The magmatic cumulate plane in ultramafic and mafic cumulates is restored to a horizontal orientation, and the strike of the ridge is chosen as the normal in this horizontal plane to the mineral lineation found in the foliation of the ultramafic tectonites. The lineation in these tectonites is the trace of the ductile-flow direction. It is parallel to the axis of folds developed in pyroxenite layers during ductile flow. Along the ridge strike, as defined above, the foliation has a 32° mean dip and is almost horizontal in the direction normal to the ridge strike. This suggests a mantle diapiric intrusion beneath the ridge. In the ultramafic tectonites, which are deformed in a dominantly rotational regime, the shear-flow plane has a somewhat more pronounced dip toward the ridge than does the foliation. The gabbro and pyroxenite veinlets, generated during the flow by partial melting of the peridotite, are intruded along planes containing the mineral lineation in tectonites. The isolated diabase dikes that cut all the members of the assemblage are principally subvertical with various trends and have nothing to do with the primary assemblage.

First Page Preview

First page PDF preview
You do not currently have access to this article.