Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkhangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts
To provide new insights into the origin of megacrysts and metasomatism of the subcontinental lithospheric mantle (SCLM), we present a detailed petrographic and geochemical investigation of clinopyroxene-phlogopite xenoliths and clinopyroxene megacrysts from the Grib kimberlite (Arkhangelsk diamond p...
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Online Access: | https://doi.org/10.1016/j.lithos.2017.08.018 http://ecite.utas.edu.au/122157 |
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ftunivtasecite:oai:ecite.utas.edu.au:122157 2023-05-15T15:23:47+02:00 Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkhangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts Kargin, AV Sazonova, LV Nosova, AA Lebedeva, NM Tretyachenko, VV Abersteiner, A 2017 https://doi.org/10.1016/j.lithos.2017.08.018 http://ecite.utas.edu.au/122157 en eng Elsevier Science Bv http://dx.doi.org/10.1016/j.lithos.2017.08.018 Kargin, AV and Sazonova, LV and Nosova, AA and Lebedeva, NM and Tretyachenko, VV and Abersteiner, A, Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkhangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts, Lithos, 292-293 pp. 34-48. ISSN 0024-4937 (2017) [Refereed Article] http://ecite.utas.edu.au/122157 Earth Sciences Geology Igneous and Metamorphic Petrology Refereed Article PeerReviewed 2017 ftunivtasecite https://doi.org/10.1016/j.lithos.2017.08.018 2019-12-13T22:21:04Z To provide new insights into the origin of megacrysts and metasomatism of the subcontinental lithospheric mantle (SCLM), we present a detailed petrographic and geochemical investigation of clinopyroxene-phlogopite xenoliths and clinopyroxene megacrysts from the Grib kimberlite (Arkhangelsk diamond province, Russia). Clinopyroxene megacrysts and clinopyroxene from clinopyroxene-phlogopite xenoliths have similar petrography, major and trace element compositions, and are therefore classified as Cr-rich megacrysts. Geothermobarometry suggests that Cr-rich clinopyroxenes originate from within the SCLM (3.64.7GPa and 764922C). Phlogopite from clinopyroxene-phlogopite xenoliths have low-Ti and -Cr compositions that overlaps with phlogopite megacrysts from the Grib kimberlite. The clinopyroxene-phlogopite rocks within the SCLM are the main source for Cr-rich clinopyroxene and low-Ti phlogopite megacrysts in the Grib kimberlite matrix. Trace element compositions of studied Cr-rich clinopyroxenes have similar geochemical features to clinopyroxenes megacrysts occurrences worldwide and overlap with clinopyroxenes from phlogopite-garnet peridotite xenoliths from the Grib kimberlite. The strong depletion in Ti, Nb, Ta and to a lesser extent in Zr and Hf in clinopyroxene reflects equilibrium with Ti-oxides, such as ilmenite. The clinopyroxene-phlogopite xenoliths could be the final product of metasomatism of garnet peridotites within the SCLM beneath the Grib kimberlite. The calculated equilibrium of clinopyroxene melt compositions suggests that the metasomatic agents were derived from silicate-bearing kimberlite melts. The presence of veinlets infilled with kimberlitic mineral assemblages in clinopyroxene grains suggests that the clinopyroxene-phlogopite rocks experienced intense interactions with kimberlite melt after their formation, but before their entrainment into the host kimberlite magma. This interaction resulted in the formation of high-Ti and -Cr phlogopite and high-Ti clinopyroxene rims, zones and grains with spongy textures. Finally, we propose the sequence of metasomatic events that occurred in the SCLM and the subsequent formation of the Grib kimberlite. Article in Journal/Newspaper Arkhangelsk eCite UTAS (University of Tasmania) Lithos 292-293 34 48 |
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Open Polar |
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eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Geology Igneous and Metamorphic Petrology |
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Earth Sciences Geology Igneous and Metamorphic Petrology Kargin, AV Sazonova, LV Nosova, AA Lebedeva, NM Tretyachenko, VV Abersteiner, A Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkhangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts |
topic_facet |
Earth Sciences Geology Igneous and Metamorphic Petrology |
description |
To provide new insights into the origin of megacrysts and metasomatism of the subcontinental lithospheric mantle (SCLM), we present a detailed petrographic and geochemical investigation of clinopyroxene-phlogopite xenoliths and clinopyroxene megacrysts from the Grib kimberlite (Arkhangelsk diamond province, Russia). Clinopyroxene megacrysts and clinopyroxene from clinopyroxene-phlogopite xenoliths have similar petrography, major and trace element compositions, and are therefore classified as Cr-rich megacrysts. Geothermobarometry suggests that Cr-rich clinopyroxenes originate from within the SCLM (3.64.7GPa and 764922C). Phlogopite from clinopyroxene-phlogopite xenoliths have low-Ti and -Cr compositions that overlaps with phlogopite megacrysts from the Grib kimberlite. The clinopyroxene-phlogopite rocks within the SCLM are the main source for Cr-rich clinopyroxene and low-Ti phlogopite megacrysts in the Grib kimberlite matrix. Trace element compositions of studied Cr-rich clinopyroxenes have similar geochemical features to clinopyroxenes megacrysts occurrences worldwide and overlap with clinopyroxenes from phlogopite-garnet peridotite xenoliths from the Grib kimberlite. The strong depletion in Ti, Nb, Ta and to a lesser extent in Zr and Hf in clinopyroxene reflects equilibrium with Ti-oxides, such as ilmenite. The clinopyroxene-phlogopite xenoliths could be the final product of metasomatism of garnet peridotites within the SCLM beneath the Grib kimberlite. The calculated equilibrium of clinopyroxene melt compositions suggests that the metasomatic agents were derived from silicate-bearing kimberlite melts. The presence of veinlets infilled with kimberlitic mineral assemblages in clinopyroxene grains suggests that the clinopyroxene-phlogopite rocks experienced intense interactions with kimberlite melt after their formation, but before their entrainment into the host kimberlite magma. This interaction resulted in the formation of high-Ti and -Cr phlogopite and high-Ti clinopyroxene rims, zones and grains with spongy textures. Finally, we propose the sequence of metasomatic events that occurred in the SCLM and the subsequent formation of the Grib kimberlite. |
format |
Article in Journal/Newspaper |
author |
Kargin, AV Sazonova, LV Nosova, AA Lebedeva, NM Tretyachenko, VV Abersteiner, A |
author_facet |
Kargin, AV Sazonova, LV Nosova, AA Lebedeva, NM Tretyachenko, VV Abersteiner, A |
author_sort |
Kargin, AV |
title |
Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkhangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts |
title_short |
Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkhangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts |
title_full |
Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkhangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts |
title_fullStr |
Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkhangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts |
title_full_unstemmed |
Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkhangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts |
title_sort |
cr-rich clinopyroxene megacrysts from the grib kimberlite, arkhangelsk province, russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts |
publisher |
Elsevier Science Bv |
publishDate |
2017 |
url |
https://doi.org/10.1016/j.lithos.2017.08.018 http://ecite.utas.edu.au/122157 |
genre |
Arkhangelsk |
genre_facet |
Arkhangelsk |
op_relation |
http://dx.doi.org/10.1016/j.lithos.2017.08.018 Kargin, AV and Sazonova, LV and Nosova, AA and Lebedeva, NM and Tretyachenko, VV and Abersteiner, A, Cr-rich clinopyroxene megacrysts from the Grib kimberlite, Arkhangelsk province, Russia: relation to clinopyroxene-phlogopite xenoliths and evidence for mantle metasomatism by kimberlite melts, Lithos, 292-293 pp. 34-48. ISSN 0024-4937 (2017) [Refereed Article] http://ecite.utas.edu.au/122157 |
op_doi |
https://doi.org/10.1016/j.lithos.2017.08.018 |
container_title |
Lithos |
container_volume |
292-293 |
container_start_page |
34 |
op_container_end_page |
48 |
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1766354413267451904 |