Widespread Tissintite in Strongly Shock‐Lithified Lunar Regolith Breccias
Widespread Tissintite in Strongly Shock‐Lithified Lunar Regolith Breccias
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DOI：
10.1029/2020gl091554
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发表时间：
2021-03
影响因子：
5.2
通讯作者：
A. Zhang;Qin‐Ting Jiang;N. Tomioka;Yan‐Jun Guo;Jia‐Ni Chen;Yang Li;N. Sakamoto;H. Yurimoto
中科院分区：
文献类型：
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作者：
A. Zhang;Qin‐Ting Jiang;N. Tomioka;Yan‐Jun Guo;Jia‐Ni Chen;Yang Li;N. Sakamoto;H. Yurimoto
冲击岩化作用是从月球表面的细粒和多孔风化岩中形成岩石的基本过程。先前的研究已经基于实验和数值模拟限制了冲击石化过程中的潜在冲击压力。然而，冲击石化作用期间的压力和温度条件并没有直接从天然的月球角砾岩中推断出来。在这里，我们报告了在强烈冲击锂化的月球陨石中发现的广泛的组织岩，偶尔伴随着富含Si的陨石和柯石英。在熔融区，组织石英和柯石英共存，而斯石英不存在，表明存在4-8 GPa的冲击压力，这可能是弱冲击-石化作用和强冲击-石化作用的压力分界。同时，富Si的Al_2O_3的存在对晶间熔体施加了约2,300 K的温度约束。这一温度约束对于解释月球角砾岩强烈冲击岩化过程中挥发性和中等挥发性元素的行为以及反射磁化记录具有重要意义。
Shock‐lithification is a fundamental process of making rocks from fine‐grained and porous regoliths on the surface of the Moon. Previous investigations have constrained potential shock pressures during shock‐lithification based on experimental and numerical simulations. However, pressure and temperature conditions during shock‐lithification have not been directly inferred from natural lunar breccias. Here, we report the discovery of widespread tissintite in strongly shock‐lithified lunar meteorites, accompanied occasionally by Si‐rich corundum and coesite. The coexistence of tissintite and coesite and the absence of stishovite in molten regions indicate a shock pressure of 4–8 GPa, which might be the pressure boundary between weak and strong shock‐lithification. Meanwhile, the presence of Si‐rich corundum imposes a temperature constraint of ∼2,300 K for the intergranular melts. This temperature constraint has profound significance for interpreting the behaviors of volatile and moderately volatile elements and remanent magnetization records during strongly shock‐lithification of lunar breccias.