The geochemical behaviour of Sn and In during mantle melting and crust formation

铟和锡是中度至高度挥发性和中度亲铁/亲铜元素族的一部分。在行星吸积过程中，这些元素被认为是在地核形成时被部分清除到地核中，另外，这些元素是由晚覆层传递到早期地球的。例如，铟是地球地幔中为数不多的比类似易挥发的亲石元素的丰度所预期的更丰富的元素之一，而锡似乎略有减少。然而，由于缺乏关于这些元素在主要陆相硅酸盐储层中分布的高质量数据，以及缺乏关于Sn和in在地质过程（例如地幔熔融和地壳形成）中的表现的系统研究，目前阻碍了对地幔丰度的足够准确估计。传统上，这样的估计是基于Sn/Sm和In/Y元素对，这些元素长期以来被认为是在火成岩过程中未分选的。然而，最近火成岩的Sn-In数据似乎表明，这些元素比例在一些重要的情况下是高度分异的，特别是在俯冲带。该项目旨在获得特征明确、精心挑选的橄榄岩和原始玄武岩的高精度in -Sn数据，以便对以下方面提供重要的认识：(1)地球硅酸盐储层和原始地幔中in和Sn的分布，(2)它们在地球主要分异事件中的行为，并评估in和Sn作为这些事件（如晚饰面）示踪剂的潜力。(3)控制Sn和In的富集/耗尽及其与类似不相容的微量元素（如Sm和Y）分离的过程。

Indium and tin are part of the moderately to highly volatile and moderately siderophile/chalcophile element group. During planetary accretion, these elements are thought to have been partially scavenged into the core as it formed and additionally delivered to the Early Earth by the Late Veneer. Indium, for example, is one of the very few elements that are more abundant in the terrestrial mantle than expected from the abundance of similarly volatile lithophile elements whereas Sn appears to be slightly depleted. However, the scarcity of high-quality data on the distribution of these elements in major terrestrial silicate reservoirs as well as the lack of systematic studies on how Sn and In behave during geological processes (e.g. mantle melting and crust formation), currently hamper sufficiently accurate estimates on the mantle abundances. Traditionally, such estimates were based on the Sn/Sm and In/Y element pairs that were long considered to be unfractionated during igneous processes. More recent Sn-In data for igneous rocks, however, appear to indicate that these element ratios are highly fractionated in some important cases, and especially in subduction zones. This project aims to obtain high-precision In-Sn data on well-characterized and carefully selected peridotites and primitive basalts in order to give important insights into (1) the distribution of In and Sn in the Earth's silicate reservoirs and the primitive mantle, (2) their behaviour during the major differentiation events of the Earth and assess the potential of In and Sn as tracers for such events, e.g., the Late Veneer, and (3) the processes that control the enrichment/depletion of Sn and In and their fractionation from similarly incompatible trace elements like Sm and Y.