Abstract

A short description of the regional geology of Iran is followed by new data concerning grade of metamorphism, palaeomagnetism, continental drift and radiometric age determinations.

Mineralization in Iran is considered in terms of four metallogenic epochs: Lower and mid-Cretaceous lead-zinc deposits in limestones, late Cretaceous chromium, copper and manganese associated with ophiolites, early Tertiary copper veins, skarns and porphyries and late Tertiary and Pleistocene porphyry copper deposits and lead-zinc veins.

Eight areas are examined as regional exploration targets. In the Yazd-Golpaigan area Lower and mid-Cretaceous stratabound lead-zinc ores of Mississippi Valley type are associated with magmatism related to the initial rifting of Gondwanaland. In western Azerbaijan Upper Cretaceous chromite ores in serpentinised dunite are regarded as part of a plate boundary environment. In northern Azerbaijan Oligocene granodiorite intrusions, related to porphyry copper deposits in Russia, have given rise to copper-molybdenum skarns. The Sabzevar zone is thought to be a 200 km wide area of oceanic crust. Cretaceous ophiolites with chromite deposits occur in its northern part, while the southern part contains chalcopyrite and pyrolusite ores in submarine lavas and sediments and low grade copper ores associated with Eocene island arc volcanism. Eastern Lut contains Cretaceous chromite deposits and lead-zinc-copper-gold veins possibly related to Plio-Pleistocene intrusions. The Neogene-Pleistocene portion of the central Iranian volcanic belt is a chain of large stratovolcanoes and granodiorite intrusions, apparently fault-controlled, which includes important porphyry copper deposits. The Oligocene volcanics of western Alborz contain veins with galena, sphalerite and chalcopyrite and a large hydrothermal alunite deposit. The flows and tuffs are intruded by granodiorite, granite and monzonite, with potential for porphyry-type copper ores.

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