Porphyry-Cu deposits of Turkey

Abstract

Turkey, located within the western Tethyan-Eurasian Belt contains numerous porphyry copper deposits formed by the subduction, collision and post-collisional events during the closure of NeoTethys Ocean between the latest Cretaceous and late Miocene. These porphyry systems and associated epithermal and skarn deposits are associated with the subduction and post-subduction magmatic rocks emplaced along arc-parallel belts as in eastern Pontides and arc transverse extensional terranes as in the western Anatolian province (WAP) and Southeastern Anatolian Orogenic Belt (SEAOB). The porphyry deposits are formed in magmatic-arc (Pontides, Aegean and Bitlis-Zagros subduction), post-collisional settings (Pontides, WAP, SEAOB) after continental collision (Central Anatolian Crystalline Complex), and extensional arc setting (WAP). The porphyry Cu systems begin in the Late Cretaceous at the north, and generally young southward, where paired Late Cretaceous and Eocene metallogenic episodes are present in the eastern Pontides, WAP and SEAOB. The dominance of ages between ca. 83 and 70 Ma broadly coincides with the final stages of Late Cretaceous magmatism at the Pontides and SEAOB. The available ages are indicative of epidocity and a limited period of formation for porphyry Cu systems in these belts, and comparable to the metallogenic evolution of Turkey. The Eocene porphyry systems in discontinuous belts across Turkey reflect collisional to post-collisional processes. The number of known porphyry deposits in porphyry belts is related to the level of erosion. Therefore, the magmatic belts with fewer known porphyry may indicate too shallow or too deep crustal levels for their exposure. The estimates of numbers of undiscovered deposits combined with grade and tonnage models in Monte Carlo simulation revealed a lower density of known porphyry deposits in the Pontides, WAP and SEAOB relative to well-explored provinces around the world. This suggests that undiscovered deposits are likely present in Pontides, WAP and SEAOB.