Isotopic composition of carbon in diamonds of diamondites: record of mass fractionation in the upper mantle 1 1Associate editor: B. Marty

Maruoka, Teruyuki; Kurat, G.; Dobosi, G.; Koeberl, Christian

doi:10.1016/j.gca.2003.10.007

Cited by 33 publications

(27 citation statements)

References 53 publications

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“…The isotopic compositions of carbon were measured at the Stable Isotope Lab of the Department of Geological Sciences (formerly the Institute of Geochemistry), University of Vienna, using a continuous flow isotope ratio mass spectrometer (CF-IR-MS; Micromass Optima; e.g., Preston and Owens 1985;Maruoka et al Forthcoming). The samples were weighed into 8 × 5 mm tin capsules, which were introduced by an autosampler into the combustion chamber heated at 1020°C with helium gas flowing at 100 ml/min, and were oxidized by a pulse of oxygen.…”

Section: Methodsmentioning

confidence: 99%

Carbon isotope fractionation between graphite and diamond during shock experiments

Maruoka

Koeberl

Matsuda

et al. 2003

Meteorit & Planetary Scien

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Abstract-Carbon isotopic compositions were measured for shock-produced diamond and shocked graphite formed at peak pressures ranging from 37 to 52 GPa. The δ 13 C values of diamonds produced in a sealed container were generally lower than that of the initial graphite. The differences in the carbon isotopic composition between initial graphite and shocked graphite/diamond may reflect kinetic isotopic fractionation during the oxidation of the graphite/diamond and/or analytical artifacts possibly induced by impurities in the samples. The pressure effect on the isotopic fractionations between graphite and diamond can be estimated from the δ 13 C values of impurity-free diamonds produced using a vented container from which gases, including oxygen, in pore spaces escaped during or after the diamond formation (e.g., 0.039 ± 0.085‰ at a peak pressure of 52 GPa). Any isotopic fractionation induced by shock conversion of graphite to diamond is too small to be detected in natural shock-induced diamond-graphite systems related to terrestrial impact cratering processes.

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Section: Methodsmentioning

confidence: 99%

Carbon isotope fractionation between graphite and diamond during shock experiments

Maruoka

Koeberl

Matsuda

et al. 2003

Meteorit & Planetary Scien

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“…The former process would imply a carbonatitic melt (rich in REE and alkalies), analogous to the assumed formation of framesite diamond, whose low δ 13 C values and trace element characteristics lead (Jacob et al 2000;Maruoka et al 2004) to suggest formation from a C-H fluid and carbonatite melt. It is important to note that the possibility of transitional position of framesites between carbonado and eclogitic diamonds has already been raised by Heaney et al (2005) and the lower end of the δ 13 C range of framesites overlaps with carbonado ( Fig.…”

Section: Hydrogen Isotope Compositions In Carbonado Diamond 65mentioning

confidence: 98%

Hydrogen isotope compositions in carbonado diamond: constraints on terrestrial formation

Demény

Nagy

Bajnóczi

et al. 2011

Central European Geology

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In this study we report the first hydrogen isotope composition analyses on carbonado diamond along with cathodoluminescence and scanning electron microscopic imaging, electron microprobe analyses, and stable (H and C) and radiogenic (Sr) isotope measurements. The hydrogen of bulk carbonado (consisting diamond and pore-filling minerals) yielded ~ -4‰, consistent with usual crustal or mantle-derived fluids. The diamond-related hydrogen component is about 70 ± 30 ppm and shows a D-depletion down to -200‰. Determined H isotope values -together with C isotope compositions -overlap the ranges for mantle-derived hydrocarbons. Textural characteristics and Sr isotope ratios of pore-filling florencite indicate that the carbonado was formed in a fluid-rich environment, underwent a significant high-temperature influence and finally suffered thorough alteration. Based on these observations, a terrestrial formation during interaction of mantle rocks/melts or subducted crustal materials and reduced C-H fluids seems to be more plausible than an extraterrestrial origin.

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“…On the other hand, kosmochlor-rich clinopyroxene with very high Cr 2 O 3 contents (10-11 wt%) is described only from the polycrystalline diamonds and has never been found as an inclusion in the single crystal diamonds [5]. Thirdly, the research of the natural polycrystalline diamonds has become an effective approach to analyzing the formation and origin of diamonds and investigating the major scientific issues in the deep earth such as the cratonic lithosphere remobilization [3][4][5][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

A Microscopy and FTIR and PL Spectra Study of Polycrystalline Diamonds from Mengyin Kimberlite Pipes

et al. 2012

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The results of a microscopy and FTIR and PL spectra study of the natural polycrystalline diamonds from the Mengyin kimberlite pipes show that they can be classified as the euhedral faceted polycrystalline diamonds (EFPCDs) and anhedral rounded polycrystalline diamonds (ARPCDs). Different diamond grains or their points were formed in different conditions or processes. They were not formed in diamond nucleation stage, but in the diamond growth period. They probably originated from the relatively deeper mantle and were formed in the environment like the peridotitic (P) type diamond single crystals. The EFPCDs did not undergo a remarkable dissolution process during their formation and were possibly fast formed shortly before the kimberlite eruption. The ARPCDs not only were formed at a higher temperature than the EFPCDs but also underwent a notable dissolution process and had been stored relatively longer in the mantle. Fluids or melts probably participated in the formation of the ARPCDs or modified them during the period of their storage in the mantle.

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Isotopic composition of carbon in diamonds of diamondites: record of mass fractionation in the upper mantle 1 1Associate editor: B. Marty

Cited by 33 publications

References 53 publications

Carbon isotope fractionation between graphite and diamond during shock experiments

Carbon isotope fractionation between graphite and diamond during shock experiments

Hydrogen isotope compositions in carbonado diamond: constraints on terrestrial formation

A Microscopy and FTIR and PL Spectra Study of Polycrystalline Diamonds from Mengyin Kimberlite Pipes

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