Chalcophile and highly siderophile element behaviour in subduction zones: implication for global recycling of crustal 186Os-187Os signatures.

与广泛研究的俯冲相关的亲石元素和挥发性元素的再循环相反，俯冲带中亲硫元素（Se-Te）和高亲铁元素（HSE）的行为仍然缺乏约束，但仍然是矛盾的。该项目的目的是获得第一个全面的Se-Te-HSE和187 Os同位素数据集的蓝片岩和榴辉岩古俯冲岩石的连贯序列从爱琴海岛屿锡罗斯和锡弗诺斯（基克拉迪蓝片岩单元），以了解这些元素如何表现在高压低温俯冲相关的脱水过程中的洋壳。这些目标将通过结合Se-Te-HSE-187 Os分析全岩，硅酸盐和个别寄主矿物与活塞缸实验在压力和温度模仿典型的P-T俯冲路径。这些结果将有助于更好地了解Se-Te-HSE的地球循环和地球地幔中小规模和大规模187 Os-186 Os非均质性的起源，包括洋岛和洋中脊玄武岩的特征。

In constrast to the widely investigated subduction-related recycling of lithophile and volatile elements, the behavior of chalcophile (Se-Te) and highly siderophile elements (HSE) in subduction zones remains poorly constrained but is yet contradictory. This project aims at obtaining the first comprehensive Se-Te-HSE and 187Os isotope dataset on a coherent sequence of blueschist and eclogitic paleosubduction rocks from the Aegean islands of Syros and Sifnos (Cycladic Blueschist Unit) in order to understand how these elements behave during prograde high pressure-low temperature subduction-related dehydration of the oceanic crust. These aims will be achieved by combining Se-Te-HSE-187Os analyses on whole-rocks, silicates and individual host minerals with piston cylinder experiments at pressures and temperatures mimicing the typical P-T path of subduction. The results will contribute to a better understanding of the terrestrial cycle of Se-Te-HSE and of the origin of small and large-scale 187Os-186Os heterogeneities in the Earth mantle, including signatures in oceanic island and mid-oceanic ridge basalts.