Tectonic Triggers for Postsubduction Magmatic-Hydrothermal Gold Metallogeny in the Late Cenozoic Anatolian Metallogenic Trend, Turkey

Abstract

The newly defined, 1,500-km-long, late Cenozoic Anatolian metallogenic trend of Turkey is the central segment of the western Tethyan metallogenic belt and formed after the closure of the southern Neotethys Ocean. Mineral deposit discoveries along this trend show that the Oligocene to Miocene igneous units are highly prospective for gold-rich porphyry- and epithermal-style mineralization (~27 Moz) but that copper endowment is poor. However, the temporal and spatial constraints on late Cenozoic gold districts and isolated prospects and their tectonic affinity are poorly known, despite recent efforts. We herein provide new U-Pb and Re-Os age data and field observations from Miocene gold prospects and deposits throughout the Anatolian trend, which we interpret together with previously published age data in the region. We define nine new porphyry and epithermal districts: Simav, İzmir, Uşak, Bodrum, Konya, Aksaray, Kayseri, Tunceli, and Ağri. Gold-rich porphyry and epithermal systems peaked at (1) 25 to 17 Ma in eastern Anatolia, (2) 21 to 9 Ma in western Anatolia, and (3) 10 to 3 Ma in central Anatolia. The westward migration of porphyry and epithermal mineralization from eastern to central Anatolia is interpreted to reflect slab break-off propagation and gap opening after the onset of the Arabian continental collision. Conversely, the southwestward migration of the magmatic front and associated mineralization in western Anatolia resulted from the acceleration of the Aegean slab rollback and subsequent lateral tearing (15–8 Ma). Thus, the bulk of gold mineralization formed in response to the slab segmentation and thermal events at 25 and 15 Ma.

A Review of the Dynamics of Subduction Zone Initiation in the Aegean Region

“…The presence of slow velocity anomalies throughout the uppermost mantle beneath Anatolia and very slow velocities beneath eastern Anatolia have been explained by innovative ideas regarding how the mantle and lithosphere behave in terms of mantle upwelling, drip-style lithospheric delamination (Göğüş et al, 2017), or rollback (see discussion in Portner et al, 2018). Tomographic images of both the Hellenic and Cyrus arc have transformed ideas regarding how subducting slabs operate as they enter the deep mantle and their impacts on seismicity and the creation of transfer zones (e.g., Meighan et al, 2013), large volume magmatism (e.g., Cocchi et al, 2017), and controlling ore-forming process and mineral deposits (e.g., de Boorder et al, 1998;Rabayrol et al, 2019;Rabayrol & Hart, 2021). Changes in the subducting slab dynamics significantly affect plate dynamics, including plate motion and mantle dynamics (e.g., Gianni et al, 2019).…”

Metallogeny of the Tethyan Orogenic Belt: From Mesozoic Magmatic Arcs to Cenozoic Back-Arc and Postcollisional Settings in Southeast Europe, Anatolia, and the Lesser Caucasus: An Introduction

“…Miocene NS-oriented compression due to the motion of the Arabian plate explains the geometry of late epithermal overprints and left-lateral reactivation of faults and ore deposits. Rabayrol et al (2019a) have examined the geodynamic and magmatic framework of postsubduction porphyry-epithermal systems in Anatolia (Fig. 1).…”