PT conditions and trace element variations of picroilmenites and pyropes from placers and kimberlites in the Arkhangelsk region, NW Russia

Afanasiev, V. P.; Ashchepkov, Igor; Verzhak, V.V.; O’Brien, Hugh; Palessky, S. V.

doi:10.1016/j.jseaes.2013.03.002

Cited by 29 publications

(9 citation statements)

References 82 publications

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“…Cr-diopside thermobarometry indicates a hot cratonic geotherm of approximately 45 mW/m 2 , which is not typical for the ADP lithospheric mantle. However, such high-temperature Cr-diopside grains are numerous in some kimberlites of the Terskii Coast and Finland [49]. The Cr-diopside sampling is continuous in the range of 60-160 km, with 12% of the grains originating from the diamond stability field.…”

Section: Discussionmentioning

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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Section: Discussionmentioning

confidence: 99%

Diamond Exploration Potential of the Northern East European Platform

Shchukina

Shchukin²

2018

Minerals

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“…The goal of this study was to determine the nature of olivine from two commercially diamondiferous pipes of the Arkhangelsk diamond province, Pioner skaya and V. Grib, the kimberlites of which show sig nificantly different geochemical and isotopic charac teristics and diamond contents (Parsadanyan, 1996;Arkhangel'skaya almazonosnaya…, 1999;Kononova et al, 2006;Bogatikov et al, 2007Bogatikov et al, , 2009Afanasiev et al, 2013;etc. ).…”

Section: Introductionmentioning

confidence: 99%

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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“…The high peaks in Nb, Ta, and Zr are characteristic for other kimberlitic ilmenites (Ashchepkov et al, 2012;Afanasiev et al, 2013). These peaks become lower for ilmenites with lower TiO 2 content having small depressions in DyTm.…”

Section: Variations Of the Trace Elements In Mineralsmentioning

confidence: 90%

“…The SW to NE transect from Kharamai through Anabar fields to the Kuoyka field, also having early Triassic kimberlites like Djanga, was obtained using Surfer 8 software similar to the procedure used for the Arkhangelsk kimberlite region and central part of Siberia (Afanasiev et al, 2013;Ashchepkov et al, 2014). It is somewhat similar to the mantle profile compiled for Siberia and other kimberlite provinces by Griffin et al (1999a).…”

Section: Swene Transect Through Mantle Beneath Kharamai Field and Primentioning

confidence: 99%

Comparison of mantle lithosphere beneath early Triassic kimberlite fields in Siberian craton reconstructed from deep-seated xenocrysts

Ashchepkov

Kuligin

Vladykin

et al. 2016

Geoscience Frontiers

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a b s t r a c tMantle xenocrysts from early Triassic kimberlite pipes from Kharamai, Ary-Mastakh and Kuranakh fields in the Anabar shield of Siberia revealing similar compositional trends were studied to estimate the superplume influence on the subcratonic lithosphere mantle (SCLM). Pressure-temperature (PT) reconstructions using monomineral thermobarometry for 5 phases show division of the SCLM beneath the Kharamai field into 6 units: pyroxenitic Fe-rich (1e2 GPa) and Mg-rich (2e3 GPa) layers; middle with two levels of Gar-Sp pyroxenites at w3 and 4e5 GPa; Gar-duniteeharzburgites w4.5e6.5 GPa subjected to Ilm-Px vein metasomatism; and a Mg-rich dunite lower part. In the Anabar shield (Ary-Mastakh, Dyuken and Kuranakh fields) mantle lithosphere is composed of three large units divided into two parts: upper part with amphiboles and phlogopite; two levels of pyroxenites and eclogites at 3 and 4 GPa, and a lower part composed of refertilized dunites. Diagrams showing P-Fe # Gar clusters for garnets and omphacites illustrate the differences between SCLM of these localities. Differences of Triassic SCLM from Devonian SCLM are in simple layering; abundance of Na-Cr-amphiboles and metasomatism in the upper SCLM part, thick pyroxenite-eclogite layer and lower part depletion, heated from SCLM base to 5.0 GPa.Kharamai mantle clinopyroxenes represent three geochemical types: (1) harzburgitic with inclined linear REE, HFSE troughs and elevated Th, U; (2) lherzolitic or pyroxenitic with round TRE patterns and decreasing incompatible elements; (3) eclogitic with Eu troughs, Pb peak and high LILE content. Calculated parental melts for garnets with humped REE patterns suggest dissolution of former Cpx and depression means Cpx and garnets extraction. Clinopyroxenes from Ary-Mastakh fields show less inclined REE patterns with HMREE troughs and an increase of incompatible elements. Clinopyroxenes from Kuranakh field show flatter spoon-like REE patterns and peaks in Ba, U, Pb and Sr, similar to those in ophiolitic harzburgites. The PT diagrams for the mantle sections show high temperature gradients in the uppermost SCLM accompanied by an increase of P-Fe # Ol upward and slightly reduced thickness of the mantle keel of the Siberian craton, resulting from the influence of the PermianeTriassic superplume, but with no signs of delamination.Ó 2015, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

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PT conditions and trace element variations of picroilmenites and pyropes from placers and kimberlites in the Arkhangelsk region, NW Russia

Cited by 29 publications

References 82 publications

Diamond Exploration Potential of the Northern East European Platform

Diamond Exploration Potential of the Northern East European Platform

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

Comparison of mantle lithosphere beneath early Triassic kimberlite fields in Siberian craton reconstructed from deep-seated xenocrysts

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