Layering of the lithospheric mantle beneath the Siberian Craton

Autor(en)

I. V. Ashchepkov, N. N. Vladykin, T. Ntaflos, S. I. Kostrovitsky, S. A. Prokopiev, H. Downes, A. P. Smelov, A. M. Agashev, A. M. Logvinova, S. S. Kuligin, N. S. Tychkov, R. F. Salikhov, Yu. B. Stegnitsky, N. V. Alymova, M. A. Vavilov, V. A. Minin, S. A. Babushkina, Yu. I. Ovchinnikov, M. A. Karpenko, A. V. Tolstov, G. P. Shmarov

Abstrakt

Single-grain thermobarometric studies of xenocrysts were used to compile local SCLM transects through the major regions of kimberlite magmatism in Siberia and longer transects through the subcontinental mantle lithosphere (SCLM) beneath the Siberian craton. The mantle structure was obtained using P-Fe#, Ca in garnets, oxygen fugacity values fO

₂ and calculated temperatures T°C.The most detail transect obtained for the Daldyn field on the Udachnaya-Zarnitsa reveals layering showing an inclination of >. 35° to Udachnaya. Mantle layering beneath the Alakit field determined from the Krasnopresnenskaya-Sytykanskaya transect shows a moderate inclination from N to S. The inflection near Yubileinaya-Aykhal is also supported by the extreme depletion in peridotites with low-Fe sub-Ca garnets. Beneath the Malo-Botuobinsky field the sharply layered mantle section starts from 5.5. GPa and reveals step-like P-Fe#Ol trends for garnets and ilmenites. The deeper part of SCLM in this field was originally highly depleted but has been regenerated by percolation of protokimberlites and hybrid melts especially beneath Internationalnaya pipe.The three global transects reveal flat layering in granite-greenstone terranes and fluctuations in the granulite-orthogneiss Daldyn collision terranes. The mantle layering beneath the Daldyn - Alakite region may have been created by marginal accretion. Most of southern fields including the Malo-Botuobinsky field reveal flat layering. The primary subduction layering is smoothed beneath the Alakit field.Lower Jurassic kimberlites from the Kharamai-Anabar kimberlite fields reveal a small decrease of the thickness of the SCLM and heating of its base. The Jurassic Kuoyka field shows an uneven base of the SCLM inclined from west to east. SCLM sequences sampled at this time started mainly from depths of 130. km, but some pipes still showed mantle roots to 250. km. The garnet series demonstrates an inclined straight line pyroxenite P-Fe# trend due to interaction with superplume melts.

Organisation(en)

Department für Lithosphärenforschung

Externe Organisation(en)

Russian Academy of Sciences, Alrosa Stock Company, University of London

Journal

Tectonophysics

Band

634

Seiten

55-75

Anzahl der Seiten

21

ISSN

0040-1951

DOI

https://doi.org/10.1016/j.tecto.2014.07.017

Publikationsdatum

11-2014

Peer-reviewed

Ja

ÖFOS 2012

105105 Geochemie, 105120 Petrologie

Schlagwörter

ASJC Scopus Sachgebiete

Earth-Surface Processes, Geophysics

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/05f3f1e9-67eb-49e0-b956-e130530e9765