Can the lunar crust be magnetized by shock: Experimental groundtruth
Can the lunar crust be magnetized by shock: Experimental groundtruth
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DOI：
10.1016/j.epsl.2010.08.011
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发表时间：
2010-10-15
影响因子：
5.3
通讯作者：
Berthe, L.
中科院分区：
文献类型：
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作者：
Gattacceca, J.;Boustie, M.;Berthe, L.
自从第一次有证据表明月球地壳被磁化以来，人们提出了两种磁化机制来解释月球磁性：热剩余磁化（TRM）或冲击剩余磁化（SRM）。我们在这里首次实验性地获得了0.1-2 GPa范围内月球岩石的冲击剩磁，并讨论了它们对解释这些岩石的古地磁记录以及轨道数据揭示的磁异常分布的影响。在月海玄武岩上进行的受控磁场中的激光冲击实验表明，在环境场的存在下，这些岩石可以在低压（类似于0.1 GPa）下开始被磁化。在控制磁场中进行的1.8GPa的流体静力加载实验被用来将压磁恢复磁化（冲击恢复磁化的模拟物）赋予月海玄武岩和高地风化角砾岩。这些实验可以量化作为压力和环境场的函数的冲击剩磁。关于月球对极磁异常模型，我们的结果表明，月球土壤，风化角砾岩和大约40%的月球高地岩石（包括风化和冲击熔融角砾岩）可以被低压冲击磁化（
Since the first evidence of magnetized lunar crust, two mechanisms of magnetization have been suggested to account for lunar magnetism: thermoremanent magnetization (TRM), or shock remanent magnetization (SRM). We present here the first experimental acquisition of shock remanence by lunar rocks in the 0.1-2 GPa range, and discuss their implications for the interpretation of the paleomagnetic record of these rocks, as well as for the distribution of magnetic anomalies revealed by orbital data. Laser shock experiments in controlled magnetic fields performed on lunar mare basalts demonstrated that in the presence of an ambient field these rocks can be magnetized significantly starting at low pressure (similar to 0.1 GPa). Hydrostatic loading experiments up to 1.8 GPa in controlled magnetic fields were used to impart piezo-remanent magnetization (an analogue for shock remanent magnetization) to mare basalts and highland regolith breccias. These experiments allow quantifying the shock remanence as a function of pressure and ambient field.Regarding the lunar antipodal magnetic anomaly model, our results show that lunar soils, regolith breccia and about 40% of lunar highland rocks (comprising regolith and impact-melt breccia) in the upper crust can be magnetized by low pressure shocks (