Fundamental Magnetic Constants and Palaeomagnetic Recording Fidelity of Greigite (Fe3S4)

硅镁石 (Fe3S4) 的基本磁常数和古磁记录保真度

• 批准号: NE/G004617/1
• 负责人: Andrew Roberts
• 金额: $ 22.73万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG004617%2F1
• 关键词: Fundamental; Magnetic; Constants; Palaeomagnetic; Recording

Greigite (Fe3S4) is a strongly magnetic mineral that is being increasingly recognised in the geological record. It is widely associated with anomalous magnetizations that complicate analysis of Earth's magnetic field behaviour and environmental change in sedimentary sequences. In particular, the Arctic is a frontier region where active international efforts are being made to understand past variations in climate. The presence of greigite in Arctic sediments makes it difficult to determine if palaeomagnetic observations result from unique magnetic field variations at high latitudes or from anomalous field recording associated with strongly magnetically interacting clusters of greigite grains. Despite the increasing recognition of the importance of greigite in the geological record, and in contrast with other important terrestrial magnetic minerals, key fundamental magnetic parameters for greigite remain unknown. This makes it impossible to model micro-scale magnetic characteristics to test whether authigenic growth of greigite in clusters can explain the anomalous magnetizations commonly associated with greigite. Recent work in the PI's research group has enabled identification of 2 of the 3 key parameters required to undertake such modelling. We request funds to determine the remaining key parameter and to undertake modelling that will provide the basis for assessing the palaeomagnetic recording fidelity of greigite. This work will benefit the international palaeomagnetic community who seek to understand high latitude geomagnetic field behaviour and the palaeoclimate community who widely use palaeomagnetic records to construct chronologies of climate change. Greigite growth is also associated with gas hydrate formation. The proposed work could therefore also provide parameters that would enable greigite to be used as a tracer for the former presence of methane hydrates in sedimentary sequences.

闪锌矿(Fe3S4)是一种强磁性矿物，在地质记录中得到越来越多的认可。它广泛地与异常磁化作用有关，这些异常磁化作用使沉积序列中的地球磁场行为和环境变化的分析复杂化。特别是，北极是一个前沿地区，国际社会正在积极努力了解过去气候的变化。北极沉积物中云母的存在使人们很难确定古地磁观测是由高纬度独特的磁场变化造成的，还是由与强烈磁相互作用的云母颗粒簇有关的异常磁场记录造成的。尽管云母在地质记录中的重要性得到了越来越多的认识，而且与其他重要的陆地磁性矿物相比，云母的关键基本磁性参数仍然未知。这使得无法模拟微观尺度的磁性特征来测试团簇中灰岩的自生生长是否能解释通常与灰岩有关的异常磁化作用。PI研究小组最近的工作使进行这种建模所需的3个关键参数中的2个得以确定。我们请求提供资金，以确定剩余的关键参数，并进行建模，为评估火山岩的古地磁记录保真度提供依据。这项工作将有益于寻求了解高纬度地磁场行为的国际古地磁界和广泛利用古地磁记录建立气候变化年表的古气候界。云母的生长也与天然气水合物的形成有关。因此，拟议的工作还可以提供参数，使云母能够被用作沉积序列中以前存在的甲烷水合物的示踪剂。

项目成果

Critical single domain grain sizes in chains of interacting greigite particles: Implications for magnetosome crystals

• DOI: 10.1002/2013gc004973
• 发表时间: 2013-12
• 期刊: Geochemistry
• 影响因子: 3.7
• 作者: A. Muxworthy;W. Williams;A. Roberts;M. Winklhofer;Liao Chang;M. Pósfai