Signatures of the Martian regolith components entrained in some impact‐melt glasses in shergottites
Signatures of the Martian regolith components entrained in some impact‐melt glasses in shergottites
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火星风化层成分的特征夹带在陨石中的一些冲击熔融玻璃中
DOI：
10.1111/maps.13177
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发表时间：
2018
影响因子：
2.2
通讯作者：
D. Garrison
中科院分区：
文献类型：
--
作者：
M. Rao;L. Nyquist;D. Ross;S. Sutton;P. Hoppe;C. Shih;S. Wentworth;D. Garrison
在辉玻无球粒陨石中的象鼻山（EET）79001、提森特、扎加米和舍戈蒂陨石的一些含火星大气气体的冲击熔融物（IM）中发现了火星风化层成分。硫的过量丰度为存在外源成分提供了有力的指示。抛光薄片（PTS）EET 79001,507（此处为#507）中高的硫丰度以及SO₃ - SiO₂的相关性与火星土壤中的情况相当。#507中来自岩性B的SO₃与FeO的相关性以及EET 79001,506（此处为#506）中来自岩性A的CaO和Al₂O₃的相关性表明，在冲击熔融前体中可能存在两种含硫酸盐的相。在#507的几个硫化物小球中测定的Fe/S（原子比）为1.02 - 1.34，与火成硫化物中测定的值（Fe/S = 0.92）不同，这表明#507中的大多数硫化物小球与火成硫化物无关。提森特玻璃中的Fe/S（原子比）范围从约0.5（黄铁矿）到>1.1，表明是含硫相的混合物。EET 79001和提森特玻璃中小球的S K - XANES光谱表明，硫以混合的无定形硫化物和亚硫酸盐形式存在。在EET 79001冲击熔融物中测定的δ³⁴S值和⁸⁷Sr/⁸⁶Sr（I）比值与以下观点一致：硫化物小球是在冲击加热过程中次生硫酸盐分解为亚硫酸盐，然后通过等熵冷却还原为硫化物的结果。这些结果表明，在一些辉玻无球粒陨石中存在外来的风化层成分，其中含有类似于火星土壤中存在的含硫物种的氧化含硫物质。
Martian regolith components are found in some impact melts (IM) containing Martian atmospheric gases in the shergottites Elephant Moraine (EET) 79001, Tissint, Zagami, and Shergotty. Excess sulfur abundances provide strong indicators for the presence of an exogenous component. High sulfur abundances and the SO3‐SiO2 correlation in polished thin section (PTS) EET 79001,507 (here #507) are comparable to those in Martian soils. Correlations of SO3 with FeO in #507 from Lithology B and of CaO and Al2O3 in EET 79001,506 (here #506) from Lithology A suggest the possible occurrence of two varieties of sulfate‐bearing phases in impact‐melt precursors. Fe/S (atomic) ratios of 1.02–1.34 determined in several sulfide blebs in #507 differ from those determined in igneous sulfides (Fe/S = 0.92), and suggest that most sulfide blebs in #507 are not related to igneous sulfides. Fe/S (atomic) ratios in a Tissint glass range from ~0.5 (pyrite) to >1.1 suggesting a mixture of sulfur‐bearing phases. S K‐XANES spectra of the blebs in EET 79001 and Tissint glasses show that sulfur occurs as mixed amorphous sulfide and sulfite. The δ34S values and the 87Sr/86Sr (I) ratios determined in EET 79001 impact melts are consistent with the proposition that the sulfide blebs result from decomposition of secondary sulfates into sulfites during shock heating followed by reduction to sulfides by isentropic cooling. These results suggest the presence in some shergottites of extraneous regolith components containing oxidized S‐bearing species resembling sulfur species present in Martian soils.
四价硫在硅酸盐熔体中的溶解机制：玻璃上硫 K Edge XANES 研究的证据
影响因子：
3.9
作者：
Backnaes;L. Stelling;Behrens;Göttlicher;Mangold;Verheijen;Beerkens;R. G. C;Deubener
通讯作者：
Deubener