Composition of the Lithospheric Mantle in the Siberian Craton: New Constraints from Fresh Peridotites in the Udachnaya-East Kimberlite

Melting phase relations of the Udachnaya-East Group-I kimberlite at 3.0–6.5 GPa: Experimental evidence for alkali-carbonatite composition of primary kimberlite melts and implications for mantle plumes

“…In our understanding, The P-T conditions of the source region can be constrained from the study of mantle xenoliths carried up by kimberlite magma. The deepest xenoliths are sheared (deformed) Gt-peridotites (harzburgite and lherzolite) with porphyroclastic textures (Green and Gueguen, 1974;Boyd and Nixon, 1975;Sobolev, 1977;Nixon, 1995;Ionov et al, 2010;O'Reilly and Griffin, 2010;Agashev et al, 2013). The interpretation of deformation features suggests that porphyroclastic texture results from the recrystallization of coarse xenoliths under a very high-stress and high strain-rate deformation (Mercier, 1979;Green and Gueguen, 1983).…”

The age and history of the lithospheric mantle of the Siberian craton: Re–Os and PGE study of peridotite xenoliths from the Obnazhennaya kimberlite

“…Also shown are peridotite xenoliths from the Udachnaya kimberlite in the central Siberian craton (small circles) after Ionov et al (2010) and Doucet et al (2012Doucet et al ( , 2013 including: spinel harzburgites (yellow), coarse garnet peridotites (red), deformed garnet peridotites (green). Also shown are primitive mantle (PM) after McDonough and Sun (1995) and the field of fertile offcraton garnet and spinel peridotite xenoliths from Vitim and Tariat in central Asia (fine dashed contours; (Ionov et al, 2005a;Ionov and Hofmann, 2007).…”

“…the only site that has provided large numbers of xenoliths suitable for bulk-rock chemical and isotopic studies and covering a large variety of rock types from a broad depth range in the mantle (e.g. Ionov et al, 2010). The Os isotope data have shown that the mantle beneath Udachnaya contains rare Archean components, like "megacrystalline dunites" and eclogites (Pearson et al, 1995a(Pearson et al, , 1995b.…”

Eight good reasons why the uppermost mantle could be magnetic

“…The origin of this magnetite (Figure 2) is crucial to the evaluation of the magnetic properties of the lithospheric mantle, as it has to be demonstrated it formed under mantle conditions. In general, Cr-rich spinel occurs as a primary phase in mantle peridotites formed at mantle depths (e.g., Ballhaus et al, 1991;Barnes and Roeder, 2001;Ionov, 2010;Ionov et al, 2010). As the Cr content of spinel increases, it is stabilized at increasing depths in the mantle and coexists with garnet (MacGregor, 1970;Neal and Nixon, 1985).…”