The Bajgan Complex in the North Makran Domain (Makran Accretionary Prism) comprises disrupted meta-ophiolitic sequences originating from oceanic crust protoliths. They include ultramafic and mafic cumulates, isotropic gabbros, plagiogranites and basalts. Ultramafic–mafic cumulates and plagiogranites exhibit compositions akin to rocks formed in mid-ocean ridge settings. Isotropic gabbro and basalt protoliths can be subdivided into three distinct geochemical types. Type-1 rocks are sub-alkaline (Nb/Y < 0.1) with low Th, Nb and Ta contents and LaN/YbN ratios <1, resembling those of normal mid-ocean ridge basalts (N-MORB). Type-2 rocks display slight enrichment in Th, Ta, Nb (Nb/Y = 0.36–0.45) and LaN/YbN = 2.12–3.20, resembling the chemistry of enriched (E-) MORB. Type-3 basalts show an alkaline nature (Nb/Y = 0.88–1.82), significant Th, Ta and Nb enrichment, and high LaN/YbN ratios (7.01–20.08), resembling the chemistry of alkaline basalts (ocean island basalts, OIB). Petrogenetic modelling indicates that N-MORB protoliths originated from a depleted MORB mantle source, whereas E-MORB and OIB protoliths were generated from partial melting of sub-oceanic depleted sources that underwent varying degrees of OIB-type enrichment. The Bajgan meta-ophiolitic protoliths were formed within a Late Jurassic to Cretaceous oceanic basin influenced by mantle plume activity and plume–ridge interaction.

Supplementary material: Field photographs, micrographs, rocks sampled, analytical methods and results, and supplementary tables are available at

Thematic collection: This article is part of the Ophiolites, melanges and blueschists collection available at:

You do not have access to this content, please speak to your institutional administrator if you feel you should have access.