Revisited: The Ni isotopic compositions of ureilite metal and olivines.

重温：脲石金属和橄榄石的镍同位素组成。

• 批准号: 520770394
• 负责人: Dr. Andrea Patzer-Wilson
• 金额: --
• 依托单位: Abteilung Isotopengeologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/520770394?language=en
• 关键词: Revisited; Ni; isotopic; compositions; ureilite

This study is tailored to revisit and expand on the hypothesis of exogenous, impact-delivered ureilite vein material and follows up on the results of my recent work with ureilites. The working hypothesis is that the ureilite parent body (UPB) was a regular differentiated body consisting of a metal core, ultramafic mantle and a thin basaltic crust. The impactor was also large, incompletely solidified and possibly primarily metallic. Upon collision, a liquid metal phase from the impactor mixed with the silicate debris of the UPB and was injected into fractures and pore space (similar to the suggested formation of the pallasites). The exogenous carbon-metal component then sparked the reduction of olivine and, to a lesser extent, pyroxene. Depending on fragment size and pore space geometry, the reduction reaction varied from inside out and ceased quickly within a matter of days (see predecessor study). The Ni isotopic investigation proposed here is the last phase of the ureilite project I first presented in 2017 and started in August 2020. It is to follow up on my recent findings when exploring the reduction of ureilite olivines that took place contemporaneously with the catastrophic disruption of the UPB. The Ni isotopic fingerprints of ureilite olivines and vein metal will lead to crucial genetic constraints on their origins. If both constituents are confirmed to be unrelated, this would lend strong support to my earlier findings that ureilite olivines and vein metal are not co-genetic, providing the third and final line of evidence to my working hypothesis.

这项研究旨在重新审视和扩展外源性、冲击传递的尿素石脉材料的假设，并跟进我最近对尿素石的研究结果。工作假设是尿素岩母体（UPB）是一种规则分异体，由金属核、超镁铁质地幔和薄玄武岩地壳组成。撞击器也很大，未完全凝固，可能主要是金属的。碰撞后，来自撞击器的液态金属相与 UPB 的硅酸盐碎片混合，并被注入裂缝和孔隙空间（类似于建议的橄榄石形成）。然后，外源碳-金属组分引发橄榄石的还原，并在较小程度上引发辉石的还原。根据碎片大小和孔隙空间几何形状，还原反应从内到外发生变化，并在几天内迅速停止（参见先前的研究）。这里提出的 Ni 同位素研究是我于 2017 年首次提出并于 2020 年 8 月开始的 ureilite 项目的最后阶段。这是我在探索 UPB 灾难性破坏同时发生的 ureilite 橄榄石减少时的最新发现的后续。脲橄榄石和矿脉金属的镍同位素指纹将对其起源产生关键的遗传限制。如果这两种成分被证实是无关的，这将为我之前的发现提供强有力的支持，即橄榄石和矿脉金属不是同生的，为我的工作假设提供了第三条也是最后一条证据。