Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Kyanite-bearing eclogite xenoliths from the Udachnaya kimberlite, Siberian craton, Russia. / Radu, Ioana Bogdana; Moine, Bertrand; Ionov, Dmitri и др.
в: Bulletin de la Societe Geologique de France, Том 188, № 1-2, 7, 2017.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Kyanite-bearing eclogite xenoliths from the Udachnaya kimberlite, Siberian craton, Russia
AU - Radu, Ioana Bogdana
AU - Moine, Bertrand
AU - Ionov, Dmitri
AU - Korsakov, Andrey
AU - Golovin, Alexander
AU - Mikhailenko, Denis
AU - Cottin, Jean Yves
PY - 2017
Y1 - 2017
N2 - Xenoliths brought up by kimberlite magmas are rare samples of otherwise inaccessible lithospheric mantle. Eclogite xenoliths are found in most cratons and commonly show a range of mineral and chemical compositions that can be used to better understand craton formation. This study focuses on five new kyanite-bearing eclogites from the Udachnaya kimberlite pipe (367+5 Ma). They are fine-to coarse-grained and consist mainly of "cloudy" clinopyroxene (cpx) and garnet (grt). The clinopyroxene is Al,Na-rich omphacite while the garnet is Ca-rich, by contrast to typical bi-mineral (cpx+grt) eclogites that contain Fe- and Mg-rich garnets. The Udachnaya kyanite eclogites are similar in modal and major element composition to those from other cratons (Dharwar, Kaapvaal, Slave, West African). The kyanite eclogites have lower REE concentrations than bi-mineral eclogites and typically contain omphacites with positive Eu and Sr anomalies, i.e. a "ghost plagioclase signature". Because such a signature can only be preserved in non-metasomatised samples, we infer that they were present in the protoliths of the eclogites. It follows that subducted oceanic crust is present at the base of the Siberian craton. Similar compositions and textures are also seen in kyanite eclogites from other cratons, which we view as evidence for an Archean, subduction-like formation mechanism related to craton accretion. Thus, contrary to previous work that classifies all kyanite eclogites as type I (IK), metasomatized by carbonatite/kimberlitic fluids, we argue that some of them, both from this work and those from other cratons, belong to the non-metasomatized type II (IIB). The pristine type IIB is the nearest in composition to protoliths of mantle eclogites because it contains no metasomatic enrichments.
AB - Xenoliths brought up by kimberlite magmas are rare samples of otherwise inaccessible lithospheric mantle. Eclogite xenoliths are found in most cratons and commonly show a range of mineral and chemical compositions that can be used to better understand craton formation. This study focuses on five new kyanite-bearing eclogites from the Udachnaya kimberlite pipe (367+5 Ma). They are fine-to coarse-grained and consist mainly of "cloudy" clinopyroxene (cpx) and garnet (grt). The clinopyroxene is Al,Na-rich omphacite while the garnet is Ca-rich, by contrast to typical bi-mineral (cpx+grt) eclogites that contain Fe- and Mg-rich garnets. The Udachnaya kyanite eclogites are similar in modal and major element composition to those from other cratons (Dharwar, Kaapvaal, Slave, West African). The kyanite eclogites have lower REE concentrations than bi-mineral eclogites and typically contain omphacites with positive Eu and Sr anomalies, i.e. a "ghost plagioclase signature". Because such a signature can only be preserved in non-metasomatised samples, we infer that they were present in the protoliths of the eclogites. It follows that subducted oceanic crust is present at the base of the Siberian craton. Similar compositions and textures are also seen in kyanite eclogites from other cratons, which we view as evidence for an Archean, subduction-like formation mechanism related to craton accretion. Thus, contrary to previous work that classifies all kyanite eclogites as type I (IK), metasomatized by carbonatite/kimberlitic fluids, we argue that some of them, both from this work and those from other cratons, belong to the non-metasomatized type II (IIB). The pristine type IIB is the nearest in composition to protoliths of mantle eclogites because it contains no metasomatic enrichments.
KW - Craton
KW - Eclogite
KW - Kyanite
KW - Mantle
KW - Siberia
KW - Xenolith
KW - SOUTH-AFRICA
KW - LITHOSPHERIC MANTLE
KW - PERIDOTITE XENOLITHS
KW - ROBERTS-VICTOR-KIMBERLITE
KW - OBNAZHENNAYA KIMBERLITE
KW - CONSTRAINTS
KW - PROGRESSIVE METASOMATISM
KW - OCEANIC-CRUST
KW - GEOCHEMISTRY
KW - RE-OS
UR - http://www.scopus.com/inward/record.url?scp=85026663846&partnerID=8YFLogxK
U2 - 10.1051/bsgf/2017008
DO - 10.1051/bsgf/2017008
M3 - Article
AN - SCOPUS:85026663846
VL - 188
JO - Bulletin - Societie Geologique de France
JF - Bulletin - Societie Geologique de France
SN - 0037-9409
IS - 1-2
M1 - 7
ER -
ID: 9068708