Mobilization of Metals in Oceanic core complex (MOMO): source to sink investigation of gabbroic-ultramafic hosted VMS deposits

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Mineral resources are of major importance for many industrial sector supply chains. Developing further mineral extraction within the European Union will be a necessity in the next decades. Classic ore deposits, however, are harder to discover, especially in Europe, despite worldwide massive exploration budgets, and unconventional ore deposits appears as new potential alternative. Among these are gabbroic-ultramafic hosted volcanogenic massive sulfide (VMS) deposits, which are part of the larger group of VMS deposits. These deposits are associated with Oceanic Core Complexes (OCC), uplifted, dome-like exposures of the lower oceanic crust that have been exhumed by tectonic extension along slow to ultra-slow oceanic spreading centers. These peculiar deposits show specific enrichment in Au-Cu-Co-Ni and are future potential polymetallic ore deposits mined either from land or from the seafloor. They have been, however, poorly characterized on-land partly because they were misclassified as hydrothermally altered magmatic ore deposits and partly because their genetic model remains poorly understood. In this project we propose to locate the source of the metals enriched in gabbroic-ultramafic hosted VMS deposits by investigating the ocean drilling program (ODP) Hole 735B located on the Atlantis Bank OCC, in the southwest Indian ridge and the Troodos ophiolite in Cyprus. The ODP Hole 735B recovers gabbroic rocks down to 1508 meters below seafloor (mbsf) and shows evidence for high temperature alteration zones where possible metal mobilization occurred during high temperature hydrothermal fluid circulation. Similarly, the Troodos ophiolite shows evidences for relics of OCC with seafloor-related high temperature hydrothermal alteration and associated massive sulfide mineralization. We also propose to determine the characteristics, extent and intensity of alteration halos and element dispersion related to ultramafic-hosted VMS mineralization from the western Limassol Forest complex within the Troodos ophiolite. The combined study areas are the perfect natural laboratories for implementing a mineral system approach from source to sink; essential for developing the genetic model of gabbroic-ultramafic hosted VMS deposits. Additionally, we will develop a preliminary exploration model for this deposit type.