Phase transition and melting in zircon by nanosecond shock loading

Takagi, S.; Ichiyanagi, Kouhei; Kyono, Atsushi; Kawai, Nobuaki; Nozawa, Shiro; Ozaki, Norimasa; Seto, Yusuke; Okuchi, Takuo; Nitta, Souma; Okada, Shingo; Miyanishi, Kohei; Sueda, Keiichi; Togashi, Tadashi; Yabuuchi, T.

doi:10.1007/s00269-022-01184-8

Cited by 5 publications

(3 citation statements)

References 35 publications

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“…It must be emphasized that the heterogeneous textures in the impactites suggest that the phase transformations reflect disequilibrium processes and temperatures derived from phase equilibrium processes might not be relevant for highly dynamic shock environments. For example, under certain shock-loading conditions, zircon directly produces a homogenous liquid without decomposition into oxides (Takagi et al 2022).…”

Section: Shock-induced Decomposition and Back Reactionmentioning

confidence: 99%

Nano- and micro-structures in lunar zircon from Apollo 15 and 16 impactites: implications for age interpretations

Kusiak

Kovaleva

Vanderliek³

et al. 2022

Contrib Mineral Petrol

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Meteorite impact processes are ubiquitous on the surfaces of rocky and icy bodies in the Solar System, including the Moon. One of the most common accessory minerals, zircon, when shocked, produces specific micro-structures that may become indicative of the age and shock conditions of these impact processes. To better understand the shock mechanisms in zircon from Apollo 15 and 16 impact breccias, we applied transmission electron microscopy (TEM) and studied nano-structures in eight lunar zircons displaying four different morphologies from breccias 15455, 67915, and 67955. Our observations revealed a range of shock-related features in zircon: (1) planar and non-planar fractures, (2) “columnar” zircon rims around baddeleyite cores, (3) granular textured zircon, in most cases with sub-µm-size inclusions of monoclinic ZrO2 (baddeleyite) and cubic ZrO2 (zirconia), (4) silica-rich glass and metal inclusions of FeS and FeNi present at triple junctions in granular zircon and in baddeleyite, (5) inclusions of rutile in shocked baddeleyite, (6) amorphous domains, (7) recrystallized domains. In many grain aggregates, shock-related micro-structures overprint each other, indicating either different stages of a single impact process or multiple impact events. During shock, some zircons were transformed to diaplectic glass (6), and others (7) were completely decomposed into SiO2 and Zr-oxide, evident from the observed round shapes of cubic zirconia and silica-rich glass filling triple junctions of zircon granules. Despite the highly variable effect on textures and Zr phases, shock-related features show no correlation with relatively homogeneous U–Pb or 207Pb/206Pb ages of zircons. Either the shock events occurred very soon after the solidification or recrystallization of the different Zr phases, or the shock events were too brief to result in noticeable Pb loss during shock metamorphism.

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Section: Shock-induced Decomposition and Back Reactionmentioning

confidence: 99%

Nano- and micro-structures in lunar zircon from Apollo 15 and 16 impactites: implications for age interpretations

Kusiak

Kovaleva

Vanderliek³

et al. 2022

Contrib Mineral Petrol

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“…At evaluated temperature around 1000–1500 K, the transition pressure decreases to 8 GPa, 31 which is similar to the simulated value. In addition, the zircon‐scheelite transition is usually considered to be a displacive or martensitic transition as it happens almost instantaneously, that is, at microsecond 32–35 or even nanosecond timescale 36 . However, there is opposite evidence for a reconstructive or diffusive mechanism due to the formation of granular reidite nanograins in meteorite‐impacted zircon 37 .…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the zircon-scheelite transition is usually considered to be a displacive or martensitic transition as it happens almost instantaneously, that is, at microsecond [32][33][34][35] or even nanosecond timescale. 36 However, there is opposite evidence for a reconstructive or diffusive mechanism due to the formation of granular reidite nanograins in meteoriteimpacted zircon. 37 Moreover, a metastable high pressure low symmetry (HPLS) phase (𝐼4 2 𝑑) has been recently found in zircon.…”

Section: Introductionmentioning

confidence: 99%

Phase transition of hafnon, HfSiO₄, at high pressure

Niu

Nan

et al. 2023

J Am Ceram Soc.

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The high-pressure behavior of hafnon has been systematically investigated by combining in situ synchrotron X-ray diffraction, Raman, high-resolution transmission electron microscopy (HRTEM) techniques, and theoretical simulations. Hafnon starts phase transition at 26.6 GPa and completes the transition to an irreversible scheelite phase (𝐼4 1 ∕𝑎, Z = 4, a 0 = 4.712 Å, and c 0 = 10.378 Å) at ∼45 GPa. The HRTEM observation of an interface between hafnon and scheelite phases allows atomic scale understanding of the transition process with a relationship of (200) h ‖(112) s , (002) h ‖(110) s //, and [010] h ‖[1 1 1] s . Hafnon shows a significantly lower transition pressure (∼12.6 GPa), as calculated from the relative enthalpies, than the measured pressure (∼26 GPa), indicating a kinetically hindered process involved in the transition. A high pressure low symmetry phase in hafnon (𝐼4 2 𝑑) is identified by the simultaneous appearance of two Raman modes (∼75 and 450 cm −1 ) at 26.6 GPa and their subsequent simultaneous disappearance at 36.7 GPa. These results are important to understanding the mechanism of the zircon-scheelite transition for both zircon and hafnon.

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