Shock metamorphism of clay minerals on Mars by meteor impact

Michalski, J.; Glotch, T. D.; Friedlander, L. R.; Dyar, M. D.; Bish, David L.; Sharp, T. G.; Carter, John

doi:10.1002/2017gl073423

Cited by 12 publications

(7 citation statements)

References 25 publications

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“…Shock processes can result in numerous types of changes to impacted phases ranging from deformation to melting. Shock metamorphism can also cause oxidation or reduction of multivalent elements like Fe and S within target materials depending on the bulk composition of the system, the physicochemical conditions of metamorphism, and the time over which those conditions persist (e.g., Bauer, 1979; Michalski et al., 2017; Rao et al., 2021; Taylor et al., 2004).…”

Section: Discussionmentioning

confidence: 99%

The Oxidation State of Sulfur in Apatite of Martian Meteorite—Shergotty

et al. 2023

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Apatite can incorporate sulfur in its reduced form (S2−) when apatite equilibrates with a silicate melt under reducing conditions. Incorporation of sulfate (S6+) has been observed in terrestrial apatite under oxidizing conditions. Thus, it has been suggested that the proportions of S6+/S2− in apatite may record the oxygen fugacity (fO2) during the formation and/or equilibration of apatite grains with a silicate melt in a wide variety of igneous and metamorphic rocks, including from Earth, Mars, the Moon, and in materials from the asteroid belt. Martian rocks, which record fO2 values intermediate between those recorded by rocks from the Moon and Earth, may have apatite that contains only S2− or mixtures of S6+ and S2−. Here, we present new measurements of the oxidation state of sulfur in apatite grains in the basaltic shergottite, Shergotty, which exhibits spectral features consistent with the presence of sulfide (S2−) structurally bound in apatite, and no evidence for the presence of sulfite (S4+) or sulfate (S6+). The presence of sulfide‐only apatite in Shergotty is consistent with other mineralogical records of fO2 in this meteorite, which are calculated from other late‐stage crystallizing phases like Fe‐Ti oxides as well as from early crystallizing phases like clinopyroxene (DEuCpx/melt) of ΔIW + 1.9 to ΔIW + 3.5. At these fO2 values, S is present in silicate melts as only S2−, and this suggests that the oxidation state of sulfur records and preserves the fO2 during the igneous crystallization of apatite reinforcing the idea that sulfur in apatite can be used as an igneous oxybarometer.

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Section: Discussionmentioning

confidence: 99%

The Oxidation State of Sulfur in Apatite of Martian Meteorite—Shergotty

et al. 2023

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“…38 The results indicated that the shock decreases the particle or crystallite size of clay minerals, resulting in an decrease in spectral contrast and loss of some of the spectral structure (2.17 μm) of shocked kaolinite. 38 The interpretation of such VNIR spectra may lead to deviations in the abundance and distribution of MCMs. 38 Studies of VNIR data on clay minerals has so far been qualitative, focusing on the detection of the presence/absence of various mineral phases.…”

Section: Detection Of Martian Clay Mineralsmentioning

confidence: 93%

“…38 The interpretation of such VNIR spectra may lead to deviations in the abundance and distribution of MCMs. 38 Studies of VNIR data on clay minerals has so far been qualitative, focusing on the detection of the presence/absence of various mineral phases. Quantitative analysis is difficult because the reflection signal is a nonlinear response to mineral abundance.…”

Section: Detection Of Martian Clay Mineralsmentioning

confidence: 99%

“…The VNIR spectra of MCM mixtures generally do not show a linear response because the effects related to grain size and differential scattering . Michalski et al (2017) studied the effect of shock metamorphism on the infrared spectra of clay minerals . The results indicated that the shock decreases the particle or crystallite size of clay minerals, resulting in an decrease in spectral contrast and loss of some of the spectral structure (2.17 μm) of shocked kaolinite .…”

Section: Detection Of Martian Clay Mineralsmentioning

confidence: 99%

“…Michalski et al (2017) studied the effect of shock metamorphism on the infrared spectra of clay minerals . The results indicated that the shock decreases the particle or crystallite size of clay minerals, resulting in an decrease in spectral contrast and loss of some of the spectral structure (2.17 μm) of shocked kaolinite . The interpretation of such VNIR spectra may lead to deviations in the abundance and distribution of MCMs …”

Section: Detection Of Martian Clay Mineralsmentioning

confidence: 99%

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Enigmatic Issues and Widening Implications of Research on Martian Clay Minerals

Zhong

Fiore

Chen

et al. 2022

ACS Earth Space Chem.

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Clay minerals are widespread in the Martian crust. Over the last few decades, accumulating data and research into the type, crystallinity, quantity, and distribution of Martian clay minerals (MCMs) has remarkably advanced the understanding of Martian geology, paleoclimate, environment, and the question of whether water, organic matter, and life exist there. Meanwhile, some issues remain enigmatic and arguable. To date, mineralogical data from orbiters and rovers have provided information regarding the distribution, composition, age, and geological evolution of MCMs. Several models for interpreting the formation of MCMs, including weathering, hydrothermal alteration, magmatic precipitation, and diagenesis, have been proposed. Nevertheless, the exact formation mechanism of MCM, remains unclear, primarily because of the lack of sufficient information on the chemical reactions and element cycles involved in the formation of clay minerals. Examination on the type, crystallinity, quantity, and distribution of MCMs indicates that Mars possibly had a warm and wet climate during the Noachian period. Since clay minerals possess abundant −OH groups in the layered structure and can host H 2 O in the interlayer space, MCMs are thought to be potentially large water reservoirs. Studies of MCMs and their interaction with organic matter are possibly conducive to finding answers to the question of whether or not on Mars life exists as clay minerals can preserve and enrich organic matter, catalyze the formation of biotic molecules, such as RNA oligomers, ribose, and amino acids, and even contribute to the assembly of vesicles. Future missions to Mars are recommended to set studies on MCMs with the key issues above and are expecting to lead to more exciting findings.

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