Can the magmatic conditions of the Martian nakhlites be discerned via investigation of clinopyroxene and olivine crystallographic slip-systems?
Can the magmatic conditions of the Martian nakhlites be discerned via investigation of clinopyroxene and olivine crystallographic slip-systems?
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DOI：
10.1002/essoar.10508274.1
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发表时间：
2021-10
期刊：
影响因子：
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通讯作者：
S. Griffin;Luke Daly;S. Piazolo;L. Forman;Benjamin E Cohen;Martin R. Lee;P. Trimby;Raphaël Baumgartner;G. Benedix;B. Hoefnagels
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文献类型：
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作者：
S. Griffin;Luke Daly;S. Piazolo;L. Forman;Benjamin E Cohen;Martin R. Lee;P. Trimby;Raphaël Baumgartner;G. Benedix;B. Hoefnagels
变形是一个几乎无处不在的过程，在几乎所有自然形成的岩石中观察到，地球和外星。大面积电子背散射衍射（EBSD）是一种技术，使滑移系统（塑性变形的一种形式）能够在与代表性纹理分析（[？] 100晶）。广泛的实验室和对自然发生的样品的研究已经确定了艾德优惠的外部参数，用于地幔条件下橄榄石和单斜辉石中特定的滑移系特征。对来自16块不同火星赤霞岩陨石的21个大面积EBSD数据集的橄榄石和普通辉石（高钙单斜辉石）中的滑移系统进行了分析和评估。当研究样品内的高变形区和低变形区时，21个截面中的10个截面表现出低变形区和高变形区之间的滑移系图案的移位。在低形变区内识别出的次级特征艾德被推断为与侵位形变有关。因此，这些样品显示出冲击和定位特征。变形模式的两个主要制度的变形所观察到的变化表明nakhlite喷出物陨石坑的非均匀采样。我们的发现表明，冲击变形在整个Nakhlites中普遍存在，并且在解释明显较低变形区域内的晶体滑动变形时需要非常小心。
Deformation is a near ubiquitous process that is observed within nearly all naturally forming rocks, terrestrial and extra-terrestrial. Large area electron backscatter diffraction (EBSD) is a technique that enables slip-systems (a form of plastic deformation) to be inferred at a comparable scale to representative texture analysis ([?]100 crystals). Extensive laboratory and studies on naturally occurring samples have identified preferential extrinsic parameters for specific slip-system signatures within olivine and clinopyroxene for mantle conditions. Slip-systems in both olivine and augite (high Ca-clinopyroxene) for 21 large area EBSD datasets sourced from 16 different Martian nakhlite meteorites were analysed and assessed against these parameters. When investigating the high and low deformation regions within the samples 10 of the 21 sections exhibited a shift in the slip-system patterns between the low and high deformation regions. The secondary signatures identified within the low deformation regions are inferred to relate to emplacement deformation. Thus, these samples exhibit both shock and emplacement signatures. The observed variations in deformation patterns for the two main regimes of deformation indicate heterogeneous sampling of the nakhlite ejecta crater. Our findings indicate that shock deformation is prevalent throughout the nakhlites, and that great care needs to be taken when interpreting slip-deformation of crystals within apparent lower deformation regions.