COMPLICATED THERMAL HISTORY OF THE LITHOSPHERIC MANTLE OF THE ANABAR REGION: RECONSTRUCTIONS BASED ON XENOCRYSTS FROM KIMBERLITES

The thermal history and thickness of the lithospheric mantlebeneath the kimberlite fields of the Eastern Anabar shield and adjacent territories of the Siberian craton were reconstructed based on the composition of clinopyroxene xenocrysts from the concentrate of kimberlite heavy fraction and mantle...

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Main Authors: А. M. Dymshits, E. A. Gladkochub, S. I. Kostrovitsky
Format: Article
Language:English
Published: Russian Academy of Sciences, Siberian Branch, Institute of the Earth's crust 2024-10-01
Series:Геодинамика и тектонофизика
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Online Access:https://www.gt-crust.ru/jour/article/view/1914
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author А. M. Dymshits
E. A. Gladkochub
S. I. Kostrovitsky
author_facet А. M. Dymshits
E. A. Gladkochub
S. I. Kostrovitsky
author_sort А. M. Dymshits
collection DOAJ
description The thermal history and thickness of the lithospheric mantlebeneath the kimberlite fields of the Eastern Anabar shield and adjacent territories of the Siberian craton were reconstructed based on the composition of clinopyroxene xenocrysts from the concentrate of kimberlite heavy fraction and mantle xenoliths. Garnet and spinel peridotites are most abundant in the lithospheric mantle beneath the five studied fields of the Siberian craton. Almost in all fields, the Mg# index of clinopyroxene decreases through depth. In the oldest Chomurdakh kimberlite field, both TiO2 and FeO contents vary slightly. The titanium oxide values markedly vary from 0 to 0.6 wt. % in the Triassic fields. The high titanium oxide contents in minerals are indicative of deep­seated metasomatic transformations of lithospheric mantle blocks in the northern Yakutia kimberlite province. The geotherm was fitted to the PT data set in the Gtherm program with the model involved D. Hasterok and D. Champan. The thermal lithosphere beneath the studied fields retained the thermal thickness up to 260 km. In the period between 430 and 230 Ma, it underwent a significant metasomatic transformation resulting in the formation of high­Fe and high­Ti blocks. It appears, that the thermal thickness declined to 190–200 km only in the north of the Siberian craton during the Jurassic period. This assumption is verified by the values of lithosphere thickness beneath the northern Kuoika field.
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spelling doaj-art-b0ad255d8f8b42e98a1e95fcc7236ea82025-08-20T03:59:45ZengRussian Academy of Sciences, Siberian Branch, Institute of the Earth's crustГеодинамика и тектонофизика2078-502X2024-10-0115510.5800/GT-2024-15-5-0778779COMPLICATED THERMAL HISTORY OF THE LITHOSPHERIC MANTLE OF THE ANABAR REGION: RECONSTRUCTIONS BASED ON XENOCRYSTS FROM KIMBERLITESА. M. Dymshits0E. A. Gladkochub1S. I. Kostrovitsky2Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences ; Geological Institute of Kola Science Centre, Russian Academy of SciencesInstitute of the Earth’s Crust, Siberian Branch of the Russian Academy of SciencesInstitute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences ; Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of SciencesThe thermal history and thickness of the lithospheric mantlebeneath the kimberlite fields of the Eastern Anabar shield and adjacent territories of the Siberian craton were reconstructed based on the composition of clinopyroxene xenocrysts from the concentrate of kimberlite heavy fraction and mantle xenoliths. Garnet and spinel peridotites are most abundant in the lithospheric mantle beneath the five studied fields of the Siberian craton. Almost in all fields, the Mg# index of clinopyroxene decreases through depth. In the oldest Chomurdakh kimberlite field, both TiO2 and FeO contents vary slightly. The titanium oxide values markedly vary from 0 to 0.6 wt. % in the Triassic fields. The high titanium oxide contents in minerals are indicative of deep­seated metasomatic transformations of lithospheric mantle blocks in the northern Yakutia kimberlite province. The geotherm was fitted to the PT data set in the Gtherm program with the model involved D. Hasterok and D. Champan. The thermal lithosphere beneath the studied fields retained the thermal thickness up to 260 km. In the period between 430 and 230 Ma, it underwent a significant metasomatic transformation resulting in the formation of high­Fe and high­Ti blocks. It appears, that the thermal thickness declined to 190–200 km only in the north of the Siberian craton during the Jurassic period. This assumption is verified by the values of lithosphere thickness beneath the northern Kuoika field.https://www.gt-crust.ru/jour/article/view/1914clinopyroxenekimberlitesiberian cratonlithospheric mantlearcticthermobarometrygeotherm
spellingShingle А. M. Dymshits
E. A. Gladkochub
S. I. Kostrovitsky
COMPLICATED THERMAL HISTORY OF THE LITHOSPHERIC MANTLE OF THE ANABAR REGION: RECONSTRUCTIONS BASED ON XENOCRYSTS FROM KIMBERLITES
Геодинамика и тектонофизика
clinopyroxene
kimberlite
siberian craton
lithospheric mantle
arctic
thermobarometry
geotherm
title COMPLICATED THERMAL HISTORY OF THE LITHOSPHERIC MANTLE OF THE ANABAR REGION: RECONSTRUCTIONS BASED ON XENOCRYSTS FROM KIMBERLITES
title_full COMPLICATED THERMAL HISTORY OF THE LITHOSPHERIC MANTLE OF THE ANABAR REGION: RECONSTRUCTIONS BASED ON XENOCRYSTS FROM KIMBERLITES
title_fullStr COMPLICATED THERMAL HISTORY OF THE LITHOSPHERIC MANTLE OF THE ANABAR REGION: RECONSTRUCTIONS BASED ON XENOCRYSTS FROM KIMBERLITES
title_full_unstemmed COMPLICATED THERMAL HISTORY OF THE LITHOSPHERIC MANTLE OF THE ANABAR REGION: RECONSTRUCTIONS BASED ON XENOCRYSTS FROM KIMBERLITES
title_short COMPLICATED THERMAL HISTORY OF THE LITHOSPHERIC MANTLE OF THE ANABAR REGION: RECONSTRUCTIONS BASED ON XENOCRYSTS FROM KIMBERLITES
title_sort complicated thermal history of the lithospheric mantle of the anabar region reconstructions based on xenocrysts from kimberlites
topic clinopyroxene
kimberlite
siberian craton
lithospheric mantle
arctic
thermobarometry
geotherm
url https://www.gt-crust.ru/jour/article/view/1914
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AT eagladkochub complicatedthermalhistoryofthelithosphericmantleoftheanabarregionreconstructionsbasedonxenocrystsfromkimberlites
AT sikostrovitsky complicatedthermalhistoryofthelithosphericmantleoftheanabarregionreconstructionsbasedonxenocrystsfromkimberlites