Peridotit xenoliths: a key to understanding exceptional depletion and re-enrichment of the lithospheric mantle beneath Greenland

地球不同的古大陆核在组成和结构上有很大的差异。然而，所有的地球动力学和环境，可以通过应用各种地球化学工具暴露的地壳样品或岩石圈地幔样品在零星的岩浆活动中携带的加密信息存档。格陵兰岛的南极部分一直是科学研究的热点，因为它被发现含有地球上最古老的地壳，并且下面的岩石圈具有显着的钻石潜力。我们手头上有一套新发现的新鲜金伯利岩夹带橄榄岩捕虏体，其岩性范围从纯橄榄岩到方辉橄榄岩和高度交代的伟尔岩。使用详细的岩相学和原位分析方法获取主要和微量元素，以及多种放射成因同位素系统学（Sr，Sm-Nd，Lu-Hf，Re-Os）矿物分离和原位，我们想解决以下问题，直接相关的早期地球动力学：（1）格陵兰地幔岩石圈异常耗竭的起源是什么？垂直（地幔柱）与水平（俯冲）过程在其形成过程中的作用是什么？(2)格陵兰的地壳和岩石圈地幔的形成是耦合的还是分离的？(3)地幔岩石圈再富集的性质和时间及其与区域构造活动的联系，特别是与含金刚石金伯利岩等低量熔体的形成的联系是什么？

The Earths different ancient continental cores (cratons) show significant differences in their composition and structure. However, all cratons archive encrypted information on early Earth dynamics and environments that can be decoded by applying a variety of geochemical tools to exposed crustal samples or to lithospheric mantle samples entrained during sporadic magmatism. The cratonic part of Greenland has been a hotspot of scientific investigation since it was discovered that it contains some of the oldest crust on Earth and that the underlying lithosphere has significant diamond potential. We have in hand a newly recovered suite of fresh kimberlite-entrained peridotite xenoliths that range in lithology from dunites to harzburgites and highly metasomatised wehrlites. Using a detailed petrographic and in situ analytical approach for the acquisition of major and trace elements, as well as multiple radiogenic isotope systematics (Sr, Sm-Nd, Lu-Hf, Re-Os) of mineral separates and in situ, we would like to address the following questions that are directly relevant to early terrestrial dynamics: (1) What is the origin of the exceptional depletion of the mantle lithosphere beneath cratonic Greenland and what was the role of vertical (plumes) vs horizontal (subduction) processes during its nascence? (2) Was the formation of the crust and lithospheric mantle in cratonic Greenland coupled or decoupled? (3) What are the nature and timing of re-enrichment of mantle lithosphere and its link to regional tectonothermal events, in particular the formation of low-volume melts, such as diamondiferous kimberlites?