The role of mixing processes in andesite genesis - deep sediment recycling versus shallow crustal contamination

安山岩是活动大陆边缘的典型火山岩，平均大陆地壳具有安山岩成分。许多安山岩岩浆是由复杂的混合过程形成的，其中包括沉积物质，这些物质要么被俯冲到地幔楔中，要么被上升的岩浆吸收到地壳中。爱琴海弧代表了地球上沉积物循环率最高的俯冲带之一，岩浆显示了重要沉积物贡献的全岩石地球化学证据。为了确定岩浆源深度和混合过程，建议研究爱琴海弧中Methana/Aegina火山熔岩中橄榄石、角闪孔、斜辉石、斜长石等矿物的主微量元素和Sr-Nd-Hf-Pb-O同位素组成以及潜在的玻璃包裹体。矿物相允许深入了解不同末端成员在不同深度的混合过程，这可以通过热气压测定法确定。Methana/Aegina熔岩非常适合这样的案例研究，因为它们的地球化学描述很好，混合端元的极端成分变化很大，而且它们含有丰富的矿物相。

Andesites are the typical volcanic rocks at active continental margins and the average continental crust has an andesitic composition. Many andesitic magmas form by complex mixing processes involving sedimentary material that is either subducted into the mantle wedge or may be assimilated in the crust by the ascending magma. The Aegean arc represents the subduction zone with one of the highest sediment recycling rates on Earth and the magmas show whole-rock geochemical evidence of a significant sediment contribution. In order to define the depths of the magma sources and the mixing processes we suggest to study the major and trace element as well as Sr-Nd-Hf-Pb-O isotope composition of minerals like olivine, amphibole, clinopyroxene, and plagioclase and potential glass inclusions in lavas from the Methana/Aegina volcanoes in the Aegean arc. The mineral phases allow insights into the mixing processes of different end-members at different depths that can be determined by thermo-barometry. The Methana/Aegina lavas are well-suited for such a case study because they are geochemically well-described and variable with extreme compositions of the mixing end-members and they contain abundant mineral phases.