Formation and evolution of magmas due to sediment subduction: a case study of the submarine Paphsanias volcano, Aegean arc

沉积物再循环对俯冲带岩浆的形成和演化以及对大陆地壳生长的影响尚不清楚。俯冲沉积物的熔体混合到地幔中，导致玄武岩或安山岩岩浆的融化，这对大陆地壳的形成很重要。在爱琴海弧上存在高达8公里厚的沉积物沉积物，其中很大一部分是俯冲的，导致在弧熔岩中有强烈的沉积物特征。爱琴海岛弧最西端的火山之一是海底火山帕弗萨尼亚斯，它于1987年才被发现，显然在大约2000年前就活跃了。在2017年4月/ 5月的波塞冬512号巡航期间，我们计划首次使用遥控车辆（ROV） PHOCA探索这座火山，在这里我们申请ROV的租金。ROV可以对熔岩和火山碎屑岩进行详细的观察和地层采样，并了解喷发单元和潜在的热液活动。我们推测在帕弗萨尼亚斯火山喷发单元中存在丰富的火山玻璃，从而可以直接测定液体的组成及其挥发性含量。这将为沉积物俯冲和岩浆形成、混合和脱气以及喷发的过程提供重要的新见解。该项目将使人们更好地了解大陆的生长和位于雅典西南仅50公里处的帕弗萨尼亚火山的潜在火山危害。

The effects of sediment recycling on the formation and evolution of magmas at subduction zones and on the growth of the continental crust are poorly known. Melts of subducted sediments mix into the mantle and cause melting of basaltic or andesitic magmas that are important for the formation of the continental crust. Up to 8 km thick sediment deposits exist at the Aegean arc and signficant portions of these are subducted leading to a strong sediment signature in the arc lavas. One of the westernmost volcanoes of the Aegean arc is the submarine volcano Paphsanias that was found only in 1987 and that apparently was active some 2000 years ago. During cruise Poseidon 512 in April/May 2017 we plan to explore this volcano for the first time using the remotely operated vehicle (ROV) PHOCA and here we apply for the cost of the rental of the ROV. The ROV allows detailed observations and stratigraphic sampling of the lavas and volcaniclastic rocks as well as an understanding of eruptive units and potential hydrothermal activity. We suspect abundant volcanic glasses in the eruptive units of Paphsanias volcano so that the composition of liquids and their volatile contents can be directly determined. This will provide important new insights into the processes of sediment subduction and magma formation, of mixing and degassing as well as of eruption. This project will lead to a better understanding of continental growth and of potential volcanic hazards of the Paphsanias volcano that lies only 50 km SW of Athens.