An Electron-Microscope Study of Shock-Synthesized Diamond

Trueb, Lucien F.

doi:10.1063/1.1655823

Cited by 69 publications

(12 citation statements)

References 12 publications

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“…The largest craters on asteroid 4 Vesta, with a diameter of 400 to 500 km, could have formed from a 25-to 30-km impactor, with peak shock pressure during the compression stage lasting for 4 to 5 s (56). During the major impact event of UPB disruption, which is the most likely event in the history of ureilites to explain the majority of their shock features (17,21,32) Second, although the direct transformation of graphite to diamond may require higher pressures and/or longer duration of pressure than those of many shock events (44,45,58) the catalyzed formation of diamonds in metallic (Fe,Ni,Co)-C melts proceeds at notably lower pressures and higher reaction rates and has long been used in industrial production of diamonds (59)(60)(61)(62)(63)(64). Catalysis by metallic melts (referred to as the solvent method or solvent-catalysis in some literature) is likely to have been a significant factor in formation of diamonds in ureilites.…”

Section: Discussionmentioning

confidence: 99%

Impact shock origin of diamonds in ureilite meteorites

Nestola

Goodrich

Morana

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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The origin of diamonds in ureilite meteorites is a timely topic in planetary geology as recent studies have proposed their formation at static pressures >20 GPa in a large planetary body, like diamonds formed deep within Earth’s mantle. We investigated fragments of three diamond-bearing ureilites (two from the Almahata Sitta polymict ureilite and one from the NWA 7983 main group ureilite). In NWA 7983 we found an intimate association of large monocrystalline diamonds (up to at least 100 µm), nanodiamonds, nanographite, and nanometric grains of metallic iron, cohenite, troilite, and likely schreibersite. The diamonds show a striking texture pseudomorphing inferred original graphite laths. The silicates in NWA 7983 record a high degree of shock metamorphism. The coexistence of large monocrystalline diamonds and nanodiamonds in a highly shocked ureilite can be explained by catalyzed transformation from graphite during an impact shock event characterized by peak pressures possibly as low as 15 GPa for relatively long duration (on the order of 4 to 5 s). The formation of “large” (as opposed to nano) diamond crystals could have been enhanced by the catalytic effect of metallic Fe-Ni-C liquid coexisting with graphite during this shock event. We found no evidence that formation of micrometer(s)-sized diamonds or associated Fe-S-P phases in ureilites require high static pressures and long growth times, which makes it unlikely that any of the diamonds in ureilites formed in bodies as large as Mars or Mercury.

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Section: Discussionmentioning

confidence: 99%

Impact shock origin of diamonds in ureilite meteorites

Nestola

Goodrich

Morana

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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“…Lonsdaleite was first found in the environment as hard particles (Foote, 1891) in the Canyon Diablo meteorite, and only much later (Frondel & Marvin, 1967) was it found that these particles contain graphite, diamond and lonsdaleite. At the present time, the samples containing both lonsdaleite and diamond can be synthesized in a laboratory environment under conditions of high static (Kurdyumov et al, 1980;Britun et al, 2004;Blank et al, 1995) and dynamic (Trueb, 1968) pressures, and high temperatures (HPHT). Usually graphite is used as a precursor material in such experiments.…”

Section: Introductionmentioning

confidence: 99%

Polytypes and twins in the diamond–lonsdaleite system formed by high-pressure and high-temperature treatment of graphite

Kulnitskiy

Perezhogin

Dubitsky

et al. 2013

Acta Crystallogr Sect B

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As a result of the high-temperature and high-pressure treatment of graphite we obtained a powder containing diamond and lonsdaleite. The structure and properties of the powder were studied by transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS). It was found that the synthesized material contains not only diamond nanoparticles, but also some relatively large (up to several nanometers) fragments of lonsdaleite. 4H and 6H polytypes were found in some of the diamond particles. Incoherent twin boundaries were observed in the diamond particle containing fragments of lonsdaleite.

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“…Recently Masaitis [24] reported the same epitaxial growth on some Popigai impact diamonds. Also Trueb [25] found the same epitaxial growth forms on artificial impact diamonds.…”

Section: Discussionmentioning

confidence: 61%

Surface morphology and structural types of natural impact apographitic diamonds

Kvasnytsya

Wirth²,

Piazolo

et al. 2016

J. Superhard Mater.

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internal morphologies of natural impact apographitic diamonds (paramorphoses) have been studied. The (0001) surface morphology of the paramorphoses reflects their phase composition and the structural relationship of their constituting phases. Growth and etch figures together with the elements of crystal symmetry of lonsdaleite and diamond are developed on these surfaces. The crystal size of lonsdaleite is up to 100 nm, and that of diamond is up to 300 nm. Two types of structural relations between graphite, lonsdaleite, and diamond in the paramorphoses are observed: the first type (black, black-gray, colorless and yellowish paramorphoses)-(0001) graphite is parallel to (10 10) lonsdaleite and parallel to (111) diamond; the second type (milky-white paramorphoses)-(0001) graphite is parallel to (10 10) lonsdaleite and parallel to (112) diamond. The first type of the paramorphoses contains lonsdaleite-diamond-graphite or diamond-lonsdaleite, the second type of the paramorphoses contains predominantly diamond. The direct phase transition of graphite → lonsdaleite and/or graphite → diamond occurred in the paramorphoses of the first type. A successive phase transition graphite → lonsdaleite → diamond was observed in the paramorphoses of the second type. The structure of the paramorphoses of this type shows characteristic features of recrystallization.

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An Electron-Microscope Study of Shock-Synthesized Diamond

Cited by 69 publications

References 12 publications

Impact shock origin of diamonds in ureilite meteorites

Impact shock origin of diamonds in ureilite meteorites

Polytypes and twins in the diamond–lonsdaleite system formed by high-pressure and high-temperature treatment of graphite

Surface morphology and structural types of natural impact apographitic diamonds

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