Silicate and oxide inclusions in diamonds from the Finsch kimberlite pipe

Gurney, J.J.; Harris, Jeff W.; Rickard, R. S.

doi:10.1029/sp015p0001

Cited by 53 publications

(23 citation statements)

References 18 publications

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“…A widely held opinion is that the megacryst suite is formed by the metasomatic trans formation of peridotite under the influence of melts and/or fluids, including kimberlitic ones (Arndt et al, 2010;Pivin et al, 2009;etc.). The most important cri terion for distinguishing these mechanisms (fractional crystallization and metasomatic transformation) is interelement correlations corresponding to fraction ation trends; for instance, Cr/(Cr + Al) decreases in garnet with decreasing Mg# (Gurney et al, 1979), and Fe 2 O 3 increases in ilmenite with decreasing MgO (Agee et al, 1982). Megacrysts formed by the metaso matic activity of kimberlite melt in mantle peridotites are free of such correlations, and the garnet and cli nopyroxene compositions are more magnesian and poorer in Ti (Pivin et al, 2009).…”

Section: No 3 2015mentioning

confidence: 98%

Olivine from the Pionerskaya and V. Grib kimberlite pipes, Arkhangelsk diamond province, Russia: Types, composition, and origin

et al. 2015

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We report the first systematic study of different textural varieties of olivine (olivine from peridotite xenoliths, macrocryst type Ol I, and phenocryst type zoned Ol II) from two diamondiferous kimberlite pipes of the Arkhangelsk diamond province (V. Grib and Pionerskaya) differing in geologic setting, geochem ical and isotopic characteristics, and diamond content. Approximately 550 olivine analyses were obtained by the EPMA technique using the precise method of Sobolev et al. (2007) adapted at the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences . Olivines from the V. Grib moderate Ti kimberlites, which are similar to Group I kimberlites in geochemical and Sr-Nd isotopic characteristics and rich in diamond, are dominated by high Mg# low Ti Ol I formed owing to the fractional crystallization of a carbonate rich protokimberlite melt interacting with orthopyroxene bearing peridotite material; the fraction of high Ti Ol I produced by the metasomatic alter ation of peridotite under the influence of silicate aqueous fluids is significantly lower; and xenocrysts weakly affected by metasomatic agents (melts and fluids) occur in minor amounts. Olivines from the low Ti Pioner skaya kimberlites, which are similar to Group II kimberlites in geochemical and Sr-Nd isotopic character istics and show a moderate diamond content, are dominated by high Ti Ol I, and xenocrysts weakly affected by metasomatic agents are also abundant. In the kimberlites of both pipes, the cores of Ol II crystals are usu ally composed of low Ti olivine similar in composition to Ol I; both high Ti and low Ti olivine cores occur in the Pionerskaya pipe; whereas cores corresponding to high Ti Ol I were never found in the V. Grib pipe. The outer zones of olivine and small olivine grains in the groundmass show considerable variations in minor element contents within a narrow Mg# range. It is suggested that the high Ti rims of Ol II from the V. Grib and Pionerskaya kimberlites were produced by the late crystallization of kimberlite melt, and the low Ti rims on the outer zones of Ol II in the Pionerskaya kimberlites were formed by late stage equilibration with an aqueous fluid separated from the kimberlite melt and/or possible kinetic effects. Our study revealed the diver sity of olivine origin in the kimberlites and showed that there is no single mechanism of olivine formation.

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Section: No 3 2015mentioning

confidence: 98%

Olivine from the Pionerskaya and V. Grib kimberlite pipes, Arkhangelsk diamond province, Russia: Types, composition, and origin

et al. 2015

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“…Pyrope is considered to be the most important KIM, and its chemistry is one of the best tools used in diamond exploration for identifying kimberlites and determining their potential to host diamonds [22][23][24][25][26][27].…”

Section: Pyropementioning

confidence: 99%

Diamond Exploration Potential of the Northern East European Platform

Shchukina

Shchukin²

2018

Minerals

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Abstract:In this study, we assess the diamond exploration potential of the northern East European Platform based on aeromagnetic survey results and the morphologic and geochemical analysis of 1513 grains of kimberlite indicator minerals (KIMs), such as purple pyrope garnet, olivine, and Cr-diopside. These minerals were recovered from samples collected from modern river and stream sediments in four areas located in the north-eastern (within the Arkhangelsk Diamondiferous Province) and south-western (hundreds of kilometers outside of the Arkhangelsk Diamondiferous Province) parts of the Arkhangelsk region in the European part of Russia. All the studied areas are located within ancient cratons, including the Kola, Karelian, and Shenkursk cratons. Based on the major element compositions of the KIMs and thermobarometric calculations, this study confirms that the lithospheric mantle beneath the studied areas is suitable for the formation and preservation of diamonds. The high percentage of KIMs with primary magmatic grain surface morphologies is evidence of the presence of local kimberlite sources within all of the studied areas. The significant amount of diamond-associated KIMs indicates that the potential sources are diamondiferous. Hence, the results suggest that the studied areas can be recommended for further diamond prospecting activity with a high probability of discovering new diamondiferous kimberlites.

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“…In either case, however, it needs to be explained how the solar noble gas can be transported without contamination by atmospheric and radiogenic components into the diamond stable regions; >45 kbar, >1000°C [Bundy, 1980;Gurney et al, 1979].…”

mentioning

confidence: 99%