Activity of aqueous fluids in the early solar system - characterization and formation timescales of the earliest water-bearing phases in chondritic samples

该项目旨在揭开原始太阳系样本中最不为人所知的成分之一的起源和形成时间：与星云和/或母体水库以及碳酸盐等相关相反应的含水矿物，如托吉林石和陨石。几十年来，陨石研究中的一个基本争论一直在激烈地讨论：球粒陨石中观察到的所有水蚀变是否都是在最终吸积后与陨石母体上的液态水(就地)反应的结果，或者这些矿物中至少有一重要部分在并入最终母体之前与水反应(吸积前蚀变)？因此，必须通过结构和同位素分析区分吸积前环境和仅有小行星形成的环境。这个项目的基本重要性是研究同一颗粒上不同的同位素体系(氧和D/H同位素，包括碳酸盐的锰铬同位素)和矿物学细节，以便区分不同的水活动性储集层，并确定不同的水合相和碳酸盐的形成时间尺度。这项建议中的技术完全是原位的，将结合使用二次离子质谱仪(SIMS)对单个相进行的同位素分析和高分辨率透射电子显微镜(TEM)的结构确定。

This project aims to unravel the origins and formation timescales of one of the least understood components in primitive solar system samples: hydrous minerals like tochilinite and cronstedtite that have reacted with a nebular and/or parent body water reservoir and related phases like carbonates. Since decades a fundamental controversy in meteorite research is heavily discussed: Does all aqueous alteration observed in chondrites is the result of a reaction with liquid water (in-situ) on the meteorite parent body after final accretion or has at least an important fraction of these minerals reacted with water before incorporation into the final parent body (pre-accretionary alteration)? It will therefore be essential to distinguish a pre-accretionary from an asteroidal-only formation environment by means of structural and isotopic analyses. The fundamental importance of this project is to study different isotope systems (O- and D/H-isotopes including Mn-Cr-isotopes for carbonates) and mineralogical details on the same grains in order to distinguish between different reservoirs of aqueous activity and to define different formation timescales of hydrous phases and carbonates. The techniques in this proposal are exclusively in-situ and will combine the isotopic analysis of individual phases by secondary ion mass spectrometry (SIMS) with structure determinations by high resolution transmission electron microscopy (TEM).