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

矿产资源对许多工业部门的供应链具有重要意义。未来几十年，在欧盟内部进一步发展矿物开采将是必要的。然而，传统的矿床很难被发现，尤其是在欧洲，尽管世界各地都有大量的勘探预算，非常规矿床似乎是一个新的潜在选择。其中，辉长岩-超镁铁质火山岩块状硫化物（VMS）矿床是较大的VMS矿床群的一部分。这些矿床与海洋核杂岩（OCC）有关，OCC是沿慢速至超慢速海洋扩张中心的构造伸展所挖出的下洋壳隆起的圆顶状暴露物。这些奇特的矿床显示出特定的Au-Cu-Co-Ni富集，是未来有潜力的陆上或海底多金属矿床。然而，它们在陆地上的特征却很差，部分原因是它们被错误地归类为热液蚀变的岩浆矿床，部分原因是它们的成因模型仍然知之甚少。在这个项目中，我们建议通过调查位于亚特兰蒂斯海岸OCC、西南印度脊和塞浦路斯Troodos蛇绿岩的海洋钻探计划（ODP） 735B孔，来确定辉长岩-超镁铁质VMS矿床中富集金属的来源。ODP 735B孔恢复了海底以下1508米（mbsf）的辉长岩，并显示出高温蚀变带的证据，在高温热液循环过程中可能发生了金属动员。同样，Troodos蛇绿岩显示出与海底相关的高温热液蚀变和块状硫化物成矿作用的OCC遗迹。我们还建议在Troodos蛇绿岩中确定与利马索尔西部森林杂岩中超基性VMS矿化有关的蚀变晕和元素弥散的特征、程度和强度。综合研究区是实施从源头到汇的矿物系统方法的完美自然实验室；对于建立辉长岩-超镁铁质型VMS矿床的成因模式至关重要。此外，我们将开发该矿床类型的初步勘探模式。

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.