The magnetic susceptibility of Pleistocene paleosols as a Martian paleoenvironment analog
The magnetic susceptibility of Pleistocene paleosols as a Martian paleoenvironment analog
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DOI：
10.1016/j.icarus.2022.115210
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发表时间：
2022-08
期刊：
影响因子：
3.2
通讯作者：
B. Bradák;Á. Kereszturi;V. Steinman;C. Gomez;Diána Csonka;M. Hyodo;J. Szeberényi;Ágnes Novothny;Tamás Végh;Gabriella Barta;A. Medveďová;P. Roštínský;Enikő Mihály;Viviána Jó;E. Horváth
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文献类型：
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作者：
B. Bradák;Á. Kereszturi;V. Steinman;C. Gomez;Diána Csonka;M. Hyodo;J. Szeberényi;Ágnes Novothny;Tamás Végh;Gabriella Barta;A. Medveďová;P. Roštínský;Enikő Mihály;Viviána Jó;E. Horváth
这项工作旨在介绍和测试各种半定量场方法和环境磁测量，以帮助准备未来的火星行星任务。对于模拟观测，研究了土壤发育不同阶段黄土演替的古土壤，并将其用作模型来推断早期火星环境变化期间的环境变化。陆地土壤和沉积物环境中常用的方法，如土壤发育指数和低场和频率依赖的磁化率，介绍和评估作为潜在的代理约束古环境条件和气候变化在火星上几十亿年前。这些方法包括以下：1）低场磁化率，其可以帮助识别风化层（例如，古土壤），并提供了对风化强度程度的洞察; 2）频率依赖的磁化率可以限制纳米级的磁性贡献，包括一些可能的生物/细菌起源，但其指示成土作用程度的适用性有限;和3）低场磁化率的垂直分布，即，磁化率曲线的模式，似乎在指示沉积和成土环境之间的平衡很好。对磁化率曲线的分析可能有助于识别火星古土壤，描述土壤形成期和随后的沉积期之间的过渡期（诺亚纪-西方纪和西方纪-亚马逊纪过渡期），以及识别气候周期;因此，这些可以用作评估火星古气候变化的参考框架，例如，结果还表明，古土壤磁性增强的时间依赖性与成土期本身的长度相比似乎是非线性的，磁化率可以作为一个相对计时参数，它可以帮助限制火星上成土蚀变和土壤形成的持续时间。
This work aims to introduce and test various semiquantitative field methods and environmental magnetic measurements to help prepare future planetary missions on Mars. For analog observations, paleosols of loess successions in various stages of soil development were investigated and were used as models to infer environmental change during environmental change on early Mars. Methods commonly used in terrestrial soils and sediment environments, such as soil development indices and low field and frequency-dependent magnetic susceptibility, are introduced and evaluated as potential proxies to constrain paleoenvironmental conditions and climate change on Mars billions of years ago. These methods include the following: 1) low field magnetic susceptibility, which may aid in the identification of weathered horizons (e.g., palaeosols) and provide insight into the degree of weathering intensity; 2) frequency-dependent magnetic susceptibility can constrain nanoscale magnetic contributions, including some with possible biogenic/bacterial origin, but its applicability to indicate the degree of pedogenesis is limited; and 3) the vertical distribution of low field magnetic susceptibility, i.e., the pattern of magnetic susceptibility curves, seems to work well in the indication of the balance between the sedimentary and pedogenic environment. Analysis of magnetic susceptibility curves may contribute to the identification of Martian paleosols, the characterization of the transition period between the soil-forming and subsequent sedimentary periods (Noachian-Hesperian and Hesperian-Amazonian transitions) and the identification of climate cycles; thus, these may be used as a frame of reference for evaluating paleoclimatic changes on Mars to e.g., the Noachian warm Mars and”Snowball Mars” periods.The results also suggest that the time dependence of the magnetic enhancement of paleosols seems to be nonlinear compared to the length of the pedogenic period itself, and magnetic susceptibility may work as a relative chronometric parameter, which can help to constrain the duration of pedogenic alteration and soil formation on Mars.