Occurrence of tuite and ahrensite in Zagami and their significance for shock-histories recorded in martian meteorites

Gu, Lixin; Hu, Sen; Anand, M.; Tang, Xu; Ji, Jianglong; Zhang, Bin; Wang, Nian; Lin, Yangting

doi:10.2138/am-2022-8020

Cited by 5 publications

(5 citation statements)

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“…The FIB slices were then analyzed using a transmission electron microscope (TEM) of JEM-2100 equipped with an EDS operated at 200 kV at IGGCAS. The microstructures were studied using the high-resolution TEM imaging (HRTEM) and the selected area electron diffraction (SAED) followed the methods described by Gu et al (2022) and Tang et al (2020). Elemental mapping was performed using a FEI Tecnai F30 type of highangle annular dark-field scanning TEM (HAADF-TEM) equipped with four windowless X-ray detectors at 300 kV at the Peking University.…”

Section: Sample and Methodsmentioning

confidence: 99%

Formation mechanisms of ringwoodite: clues from the Martian meteorite Northwest Africa 8705

Zhang

Wang

et al. 2021

Earth Planets Space

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Ringwoodite and wadsleyite are the high-pressure polymorphs of olivine, which are common in shocked meteorites. They are the major constituent minerals in the terrestrial mantle. NWA 8705, an olivine-phyric shergottite, was heavily shocked, producing shock-induced melt veins and pockets associated with four occurrences of ringwoodite: (1) the lamellae intergrown with the host olivine adjacent to a shock-induced melt pocket; (2) polycrystalline assemblages preserving the shapes and compositions of the pre-existing olivine within a shock-induced melt vein (60 μm in width); (3) the rod-like grains coexisting with wadsleyite and clinopyroxene within a shock-induced melt vein; (4) the microlite clusters embedded in silicate glass within a very thin shock-induced melt vein (20 μm in width). The first two occurrences of ringwoodite likely formed via solid-state transformation from olivine, supported by their morphological features and homogeneous compositions (Mg# 64–62) similar to the host olivine (Mg# 66–64). The third occurrence of ringwoodite might fractionally crystallize from the shock-induced melt, based on its heterogeneous and more FeO-enriched compositions (Mg# 76–51) than those of the coexisting wadsleyite (Mg# 77–67) and the host olivine (Mg# 66–64) of this meteorite. The coexistence of ringwoodite, wadsleyite, and clinopyroxene suggests a post-shock pressure of 14–16 GPa and a temperature of 1650–1750 °C. The fourth occurrence of ringwoodite with compositional variation (Mg# 72–58) likely crystallized from melt at 16–18 GPa and 1750–1850 °C. The presence of the four occurrences of ringwoodite was probably due to their very fast cooling rates in and/or adjacent to the thin shock-induced melt veins and small pockets. In addition, the higher Fa-contents of the host olivine (Fa35–39) in NWA 8705 than those in ordinary chondrites (Fa16–32) makes the olivine–ringwoodite transformation prolong to a lower pressure.

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Section: Sample and Methodsmentioning

confidence: 99%

Formation mechanisms of ringwoodite: clues from the Martian meteorite Northwest Africa 8705

Zhang

Wang

et al. 2021

Earth Planets Space

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“…Merrillite and apatite are by far the most common phosphates; they are igneous in origin and typically occur as minor, late-stage phases included in, or interstitial to, mesostasis, feldspar, or maskelynite (shock-produced feldspar glass) (Figure 1) [25,27,29]. In rare occurrences, the high-pressure phosphate mineral tuite (γ-Ca3(PO4)2) has been identified in highly shocked martian meteorites associated with impact-produced melt pockets and veins (i.e., [83,84]. Finally, rare grains of monazite and several other REE phosphates have been discovered as inclusions in apatite in the basaltic regolith breccia meteorites [92].…”

Section: Meteorite Summary and Mineral Assemblagesmentioning

confidence: 99%

Section: Tuitementioning

confidence: 99%

“…The high-pressure phosphate mineral tuite is found in highly shocked martian meteorites [83,84]. It typically occurs as minute grains (~1-3 µm in size) associated with impact melt glasses and shock veins [83,84]. Tuite can form after either apatite or merrillite is subjected to high-pressure and temperature impact events and has been synthesized at 12-15 GPa and 1100-2300 °C [116,117].…”

Section: Tuitementioning

confidence: 99%

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Phosphates on Mars and Their Importance as Igneous, Aqueous, and Astrobiological Indicators

Hausrath,

Adcock,

Berger

et al. 2024

Minerals

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This paper reviews the phosphate phases in meteorites and those measured by landed spacecraft, what they reveal about past igneous and aqueous conditions on Mars, and important implications for potential prebiotic chemistry, past habitability, and potential biosignatures that could be detected in samples returned from Mars. A review of the 378 martian meteorites as of 2023 indicate that of the two most common phosphate minerals in Mars meteorites, merrillite and apatites, the apatite composition is largely F- and Cl-rich, with shergottites containing more OH. The phosphate concentrations examined across multiple missions show a relatively narrow range of phosphate, with higher concentrations observed in the Mount Sharp Group in Gale crater and Wishstone at Gusev crater and lower concentrations observed at Jezero crater floor and Jezero fan. Possible secondary phosphates detected on Mars, including Fe phosphates at Jezero crater and Gusev crater and Ca- and Al-bearing secondary phosphates, temperatures of formation of secondary phases and their dissolution rates and solubilities are reviewed and summarized. Despite this wealth of information about phosphates on Mars, due to their fine scale and relatively low concentrations, Mars Sample Return is needed to better understand phosphate and its implications for the igneous, aqueous, and astrobiological history of Mars.

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“…The instrument was operated at accelerating voltages of 10-15 kV with 1.6-13 nA beam currents. The mineral distribution map was constructed using Maps and Nanomin software [16]. The calculation method of mineral composition involves collecting BSE and X-ray signals at each point and comparing them with recipes of the database to recognize the minerals automatically.…”

Section: Backscattered Electron Imagingmentioning

confidence: 99%

Lunar Terrestrial Analog Experiment on the Spectral Interpretations of Rocks Observed by the Yutu-2 Rover

et al. 2022

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A visible and near-infrared imaging spectrometer (VNIS) loaded by the Chang’e-4 rover is the primary method for detecting the mineral composition of the lunar surface in the landing region. However, different data processing methods yield inconsistent mineral modes in measured lunar soil and rocks. To better constrain the mineral modes of the soil and rocks measured by Chang’e-4 VNIS, a noritic-gabbroic rock with a mineral composition similar to that of the lunar highland rocks is measured by scanning electron microscopy (SEM), the spare flight model of Chang’e-4 VNIS and TerraSpec-4 of ASD. Backscattered electron and energy dispersive spectrometry show that olivine, pyroxene, and plagioclase modal mineral abundances are 12.9, 35.0, and 52.2%, respectively. The estimated results of the spectrum by the Hapke radiative transfer model are 7.5, 39.3, and 53.2% for olivine, pyroxene, and plagioclase, respectively, which is consistent with to those of SEM mapping within error. In contrast, the estimated results of the modified Gaussian model are 29 and 71% for olivine and pyroxene, respectively, indicating the absence of plagioclase. Based on our implemented Hapke model, we decode the data of the two rocks detected by the rover on the 3rd and 26th lunar days of mission operations. The obtained results suggest that both rocks are norite or gabbro with noticeable differences. The first rock, with more olivine and pyroxene, may have been excavated from the Finsen crater. The second rock, with more plagioclase, may have been ejected from the southwestern edge of the Von Kármán crater, indicating the initial lunar crust.

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Occurrence of tuite and ahrensite in Zagami and their significance for shock-histories recorded in martian meteorites

Cited by 5 publications

References 75 publications

Formation mechanisms of ringwoodite: clues from the Martian meteorite Northwest Africa 8705

Formation mechanisms of ringwoodite: clues from the Martian meteorite Northwest Africa 8705

Phosphates on Mars and Their Importance as Igneous, Aqueous, and Astrobiological Indicators

Lunar Terrestrial Analog Experiment on the Spectral Interpretations of Rocks Observed by the Yutu-2 Rover

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