Subduction dynamics and mineralization in the eastern Mediterranean region: an integrated study from the field to numerical modeling
IPGP - Îlot Cuvier
Séminaires Tectonique et Mécanique de la Lithosphère
IPG Paris, Tectonique et Mécanique de la Lithosphère
Subduction zones display a major economic interest, in terms of mineral resources, with mainly copper and gold deposits. While many studies focus on ore-forming physico-chemical mechanisms, the control of geodynamic processes on such deposits remains poorly investigated. In this study, we track 3D mantle and crustal processes that promote ore genesis along the eastern Mediterranean subduction zone since the late Cretaceous by providing (1) evidencing, on the field, the relations between mineralization and subduction-related tectonic structures, (2) characterizing the spatial and temporal distribution of ore occurrences and associated magmatism by performing a new kinematic reconstruction model of this region and (3) providing physical constrains on 3D subduction dynamics and associated magmatic evolution by performing 3D thermo-mechanical numerical modeling. We thus evidence that the geometry and kinematics of the subduction zone exert a first-order control on the metal content and typology of ore deposits in the eastern Mediterranean region. In the late Cretaceous, a steady-state subduction zone generated huge amounts of calc-alkaline magmas displaying a high Cu/Au ratio, then resulting in large porphyry Cu-deposits emplaced along the Balkans belt. Conversely, a fast retreating slab in the Oligocene-Miocene led to a smaller K-rich magma production with a low Cu/Au ratio, favoring the deposition of small Au-rich deposits in the Aegean-wester Anatolian region. Some exceptions exist, such as the giant K??lada? porphyry Au deposit (Turkey) which is spatially and temporally associated with a slab tearing event. We propose that this slab tear and associated asthenospheric flow would therefore locally promote the partial melting in the overlying lithospheric mantle, resulting in the deposition of major Au-rich deposits.