The Actively forming seafloor Sulfide mineralization in the Kolumbo volcano (ASK): source of metals in an arc-related magmatic-hydrothermal system

全球人口的快速增长以及能源和技术向低碳排放社会的重大转变，都大大增加并深刻改变了我们对原材料的需求。尽管循环经济有所改善，但获得新的初级原材料，包括关键原材料，至关重要。确保获得新原料的可能目标之一是形成于浅海火山弧中的岩浆-热液矿床，通常被称为热液-火山成因块状硫化物（VMS）混合矿床。这些矿床的贵金属（Ag、Au）、贱金属（Cu、Pb和Zn）和关键/痕量金属（As、Bi、Ga、Ge、Hg、Sb、Se、Te和Tl）富集程度不一。尽管具有经济意义，但它们的起源仍然没有很好地描述。矿床中富集金属的来源是一个长期存在的问题。与岩浆分异有关的挥发性损失通常被解释为火山弧中调动金属的有效机制，但在地壳中由海水衍生的热液流体循环过程中也调动了大量金属，可能是另一种金属来源。这两种作用在多大程度上促成了热液- vms混合型矿床的成矿作用尚不清楚。对一个活跃形成矿床的调查将提供有关金属来源及其地球化学路径的重要信息。位于希腊爱琴海火山弧5ma -present的Kolumbo浅海底弧-火山，拥有一个活跃的热液系统，目前形成As、Ag、Au、Hg、Sb和Tl含量高的VMS多金属矿化。科伦坡热液系统是目前已知的为数不多的与大陆边缘火山作用相关的浅热液- vms成矿作用混合活跃模拟类型之一。此外，基岩在邻近岛屿露头，代表了潜在的金属源区。因此，它是一个完美的天然实验室来研究整个系统从源到汇。该项目旨在利用一种创新的方法，同时关注Kolumbo多金属VMS矿床的金属汇和金属来源，来表征Kolumbo硫化物矿化中富集金属的来源。矿化烟囱、火山岩和来自科伦坡火山的基底岩性将使用最先进的整体岩石和原位分析结合数值模拟进行彻底研究。由于采用了在大陆边缘环境中积极形成矿床的整体方法，该项目在矿石地质学领域具有突破性意义，符合DOME特别优先方案的范围。生成的独特数据库将提供对地壳尺度上金属通量的深入了解。能够精确表征金属来源将对矿床形成的理解具有重要意义，不仅对Kolumbo，而且对混合热液- vms也具有重要意义。

Rapid global population growth and major energy and technological shifts towards low carbon emission society both highly increase and deeply modify our needs for raw materials. Despite improvement of a circular economy, access to new primary raw materials, including critical raw materials, is crucial. One of the possible targets to secure access to new raw materials are magmatic-hydrothermal ore deposits which form in shallow submarine volcanic-arcs and which are often referred to as hybrid epithermal-volcanogenic massive sulfide (VMS) deposits. These deposits are variably enriched in precious metals (Ag, Au), base metals (Cu, Pb and Zn) and critical/trace metals (As, Bi, Ga, Ge, Hg, Sb, Se, Te and Tl). Despite the economic significance, their genesis is still not well characterized. A long standing question is the source of the metals enriched in the deposits. Volatile loss associated with magmatic differentiation is commonly interpreted as an efficient mechanism for mobilizing metals in volcanic arcs but large mass of metals is also mobilized during seawater-derived hydrothermal fluid circulation in the crust and could represent an alternative metal source. The extent to which either of these processes contributes to mineralization in the hybrid epithermal-VMS deposits is not known. Investigation of an actively forming deposit will provide essential information about the sources of metals and their geochemical path. The Kolumbo shallow submarine arc-volcano, located in the 5 Ma-to-present Aegean volcanic arc in Greece, hosts an active hydrothermal system currently forming polymetallic VMS mineralization with high As, Ag, Au, Hg, Sb and Tl contents. The Kolumbo hydrothermal system represents one of the very few known hybrid active analogue style of epithermal-VMS mineralization associated with continental margin volcanism. Furthermore, basement rocks, representing the potential metal source areas, outcrop in the neighboring islands. As such, it is a perfect natural laboratory to investigate the entire system from source to sink. This project aims to characterize the sources of the metals enriched in Kolumbo sulfide mineralization using an innovative method which focuses both on the metal sink and the metal sources of Kolumbo’s polymetallic VMS deposit. Mineralized chimneys, volcanic rocks and basement lithologies from Kolumbo’s volcano will be thoroughly studied using state-of-the art whole rock and in-situ analyses coupled to numerical modelling. This project is ground breaking in the field of ore geology due to the holistic approach of an actively forming deposit in a continental margin environment and fits within the scope of the DOME Special Priority Programme. The unique database generated will provide insight into of metal fluxes at a crustal scale. Being able to precisely characterize the metal sources will have important implications on the understanding of ore deposit formation, not only for Kolumbo but also for hybrid epithermal-VMS.