Domain State Diagnosis in Rock Magnetism: Evaluation of Potential Alternatives to the Day Diagram
Domain State Diagnosis in Rock Magnetism: Evaluation of Potential Alternatives to the Day Diagram
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DOI：
10.1029/2018jb017049
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发表时间：
2019-06
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影响因子：
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通讯作者：
A. Roberts;P. Hu;R. Harrison;D. Heslop;A. Muxworthy;H. Oda;Tetsuro Sato;L. Tauxe;Xiang Zhao
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文献类型：
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作者：
A. Roberts;P. Hu;R. Harrison;D. Heslop;A. Muxworthy;H. Oda;Tetsuro Sato;L. Tauxe;Xiang Zhao
在岩石磁学中，Day图被广泛用于磁畴状态诊断。最近的研究表明，由于10组原因，它从根本上是模糊的。这种模糊性突出了在岩石磁学研究中采用合适的替代方法来识别磁性矿物组分的畴状态的紧迫性。我们评估了10种潜在的替代方法，并得出结论，四个有价值的识别数据趋势，但是，像日图，他们受到使用的散装参数，妥协域状态诊断复杂的样本。基于剩磁曲线和磁滞回线分解的三种方法，当由独立数据监督以避免解的非唯一性时，提供了有价值的组件特定信息，可以通过推断与域状态联系起来。基于一阶反转曲线图的另外三种方法提供了具有不同有效性的直接域状态诊断。在评价的候选方法中，具有环境重要性的高磁化率赤铁矿和针铁矿的有效性各不相同。这些矿物主要出现在古地磁环境中的非相互作用的单畴粒子组合中，因此畴状态诊断对于亚铁磁性矿物更为关键。按照正常的岩石磁性程序单独处理高磁化率组分，可以集中在诊断亚铁磁性矿物组合中的磁畴状态这一更棘手的问题上。我们建议远离基于体参数的非诊断方法，并采用提供明确的组件特定域状态识别的方法，其中各种基于一阶反转曲线的方法提供诊断信息。
The Day diagram is used extensively in rock magnetism for domain state diagnosis. It has been shown recently to be fundamentally ambiguous for 10 sets of reasons. This ambiguity highlights the urgency for adopting suitable alternative approaches to identify the domain state of magnetic mineral components in rock magnetic studies. We evaluate 10 potential alternative approaches here and conclude that four have value for identifying data trends, but, like the Day diagram, they are affected by use of bulk parameters that compromise domain state diagnosis in complex samples. Three approaches based on remanence curve and hysteresis loop unmixing, when supervised by independent data to avoid nonuniqueness of solutions, provide valuable component‐specific information that can be linked by inference to domain state. Three further approaches based on first‐order reversal curve diagrams provide direct domain state diagnosis with varying effectiveness. Environmentally important high‐coercivity hematite and goethite are represented with variable effectiveness in the evaluated candidate approaches. These minerals occur predominantly in noninteracting single‐domain particle assemblages in paleomagnetic contexts, so domain state diagnosis is more critical for ferrimagnetic minerals. Treating the high‐coercivity component separately following normal rock magnetic procedures allows focus on the more vexing problem of diagnosing domain state in ferrimagnetic mineral assemblages. We suggest a move away from nondiagnostic methods based on bulk parameters and adoption of approaches that provide unambiguous component‐specific domain state identification, among which various first‐order reversal curve‐based approaches provide diagnostic information.