In Iran, units mapped as “coloured melange zones” consist of either melange terranes, ophiolite complexes, or ultramafic—mafic units, which are not complete ophiolitic sequences. These zones represent block margins that were active in Alpine times. Crystallization of the ophiolitic rocks, their emplacement at continental margins and the mixing of various rocks in melange are post-Paleozoic events that were considered from stratigraphical data to be pre-Upper Cretaceous to Cenozoic in age. Thirteen whole-rock and 30 mineral K-Ar ages were obtained from the ophiolitic complexes and from igneous and metamorphic rocks in the melange zones. Ophiolite crystallization, ocean-floor metamorphism and blueschist metamorphism in the south Baluchestan rocks appear to be of Campanian age. Ocean crust generation occurred at the same time in the Zagros Belt, but is perhaps slightly older in the East Iranian Ranges (north Baluchestan). Middle-grade metamorphic alteration of the exotic rocks of south Baluchestan and south Iran occurred at some time between (?) Late Jurassic to Late Cretaceous times (south Iran) and in the Campanian (south Baluchestan). There is evidence for an Early Eocene low-grade metamorphism in Baluchestan, perhaps of the same age as that in the Zagros Belt. Alkaline to calc-alkaline magmatism in the melange domain of north Baluchestan is Middle—Late Eocene, and Aquitanian. The formation of the melange, stratigraphically of Upper Cretaceous age in the Zagros Belt, may have occurred at the Cretaceous-Paleocene boundary in Baluchestan and continued possibly into post-Eocene times.