Molybdenum isotope anomalies in fine-grained refractory inclusions from Allende and Vigarano

阿连德和维加拉诺细粒难熔包裹体中的钼同位素异常

• 批准号: 248764757
• 负责人: Professor Dr. Thomas Kruijer
• 金额: --
• 依托单位: Institut für Geologische Wissenschaften
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/248764757?language=en
• 关键词: Molybdenum; isotope; anomalies; fine; grained

Nuclear isotope anomalies in meteorites and their components provide fundamental insights into the dynamical evolution and processing of matter in the solar nebula. Of particular interest in this respect are Ca,Al-rich inclusions (CAI), which, due to their antiquity, bear testimony to the earliest stages of disk evolution. Molybdenum isotopes are particularly well suited for investigating the origin of nucleosynthetic isotope heterogeneity in extraterrestrial materials. They possess the unique ability to distinguish between a deficit in s-process, and an excess in r-process Mo isotopes. In this study we aim to investigate the origin of nucleosynthetic isotope variations in CAI through an examination of Mo (and O) isotope heterogeneity. To this purpose we propose to conduct a systematic and comparative study on nucleosynthetic Mo isotope anomalies CAI from the carbonaceous chondrites Allende (CV3ox) and Vigarano (CV3red). A major focus of this study will be the investigation of Mo isotope anomalies in fine-grained refractory inclusions, some of which might be primary nebular condensates. Their genetic relation to coarse-grained (e.g., type B) CAI is largely unkwown. Specifically, we propose to: (i) explore the extent and origin of Mo isotope anomalies in fine-grained and coarse-grained CAI. (ii) examine the relationship between fine-grained and coarse-grained CAI by assessing as to whether these two groups of CAI exhibit systematically different Mo isotope systematics (i.e, r-excess vs. s-deficit), and (iii) investigate the origin of variable nucleosynthetic isotope anomalies in fine-grained CAI by assessing the effects of parent body and nebular processes on their isotope systematics. The effect of parent body alteration will be investigated through a comparative study of Mo isotope anomalies oxidized (Allende) and reduced (Vigarano) CV chondrites. The influence of nebular processes will be assessed through combined bulk Mo and in situ O isotope analyses on several CAI from Vigarano. This study will help to better establish the systematics and full extent of isotope anomalies in CAI, and will help to assess any genetic relationship between fine-grained and coarse-grained CAI. Ultimately, our study will provide new and firm constraints on the origin of nucleosynthetic isotope heterogeneity in the solar nebula during the earliest stages of solar system history.

陨石及其成分中的核同位素异常为研究太阳星云中物质的动力学演化和处理提供了基础。在这方面特别感兴趣的是Ca，Al丰富的包裹体（CAI），由于其古老性，见证了盘演化的最早阶段。钼同位素特别适合于研究地外物质中核合成同位素不均匀性的起源。他们拥有独特的能力，以区分赤字的s-过程，并在r-过程钼同位素过剩。在这项研究中，我们的目的是调查的起源，核合成同位素变化CAI通过检查钼（和O）同位素的异质性。为此，我们提出了一个系统的和比较研究的核合成钼同位素异常CAI从碳质辉长岩阿连德（CV 3 ox）和Vigarano（CV 3red）。本研究的一个主要重点将是调查钼同位素异常的细粒耐火包裹体，其中一些可能是初级星云凝聚。它们与粗粒（例如，类型B）CAI在很大程度上是未知的。具体而言，我们建议：（i）探讨钼同位素异常的范围和成因的细粒和粗粒CAI。(ii)检查细粒度和粗粒度CAI之间的关系，评估是否这两组CAI表现出系统不同的钼同位素系统（即，r-过剩与S-赤字），和（iii）调查的起源变量核合成同位素异常细粒度CAI通过评估母体和星云过程对它们的同位素系统的影响。将通过对氧化（阿连德）和还原（Vigarano）CV辉长岩的Mo同位素异常的对比研究，研究母体蚀变的影响。星云过程的影响将通过结合散装钼和原位氧同位素分析几个CAI从Vigarano进行评估。这项研究将有助于更好地建立CAI中同位素异常的系统和完整程度，并将有助于评估细粒和粗粒CAI之间的任何成因关系。最终，我们的研究将提供新的和坚定的限制在太阳系历史的最早阶段的太阳星云的核合成同位素异质性的起源。