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尺度：与星云和/或母体水库以及相关相（如碳酸盐）发生反应的含水矿物，如tochilinite和cronstedite。几十年来，在陨石研究中有一个基本的争议被大量讨论：在球粒陨石中观察到的所有含水蚀变都是在最终吸积后与陨石母体上的液态水（原位）反应的结果，还是至少有一部分这些矿物在并入最终母体之前与水反应（吸积前蚀变）？因此，通过结构和同位素分析来区分前增生环境和小行星形成环境是至关重要的。该项目的根本意义在于研究不同的同位素系统（碳酸盐的O-和D/ h同位素，包括mn - cr同位素）和同一颗粒上的矿物学细节，以区分不同的含水活性储层，并确定不同的水相和碳酸盐的形成时间尺度。本提案中的技术完全是原位的，将结合二级离子质谱（SIMS）对单个相的同位素分析和高分辨率透射电子显微镜（TEM）的结构测定。

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).