El Markh ophiolitic sequence is formed mainly of imbricated and dismembered ultramafic-mafic rocks including serpentinites, metagabbros, boninitic metagabbros and metabasalts.
The major and trace elements data indicate that the serpentinites and the metagabbroic-basaltic association are not related to each other by fractional crystallization of a common parental magma, but represent independently generated magmas. The gabbroic-basaltic association were produced by the remelting of a depleted residual mantle that had high Al2O3/TiO2 and CaO/TiO2 ratios. The high concentration of Cr and Ni in the serpentinites suggest that they were derived from a peridotite mantle material and that olivine fractionation played a minor role during the evolution of their magma. The proposed environment for the ophiolitic sequence was a spreading center near a subduction zone in an inter-arc, i.e. suprasubduction zone ophiolite (SSZ) or back-arc basin.