Sr-Nd isotopic study of the plagiogranites from Oman ophiolite, Oman

Abstract

From the examination of Sr and Nd isotopic signature, igneous rocks in the Oman ophiolite are variously contaminated with seawater as described by McCullogh et al. (1980; 1981). In the case of rocks from the Lasail and Suhaylah complex, they are characterized by rather higher ε_Sr values than the mantle array. The gabbronorite from the Lasail complex shows the lowest value of ε_Sr, and probably retains magmatic ε_Sr values with negligible seawater contamination. This suggests that the gabbronorite magma has produced by the melting of the rocks with higher ε_Sr values than those of MORBs, e.g., the axis stage rocks interacted with seawater. On the other hand, the biotite granites intruding into mantle sequence at Wadi Fizh are considered to be produced by partial melting of continental materials during the emplacement stage on the Arabian continental margin.