Origin of eclogite and pyroxenite xenoliths from the Victor kimberlite, Canada, and implications for Superior craton formation

Subduction-related origin of eclogite xenoliths from the Wajrakarur kimberlite field, Eastern Dharwar craton, Southern India: Constraints from petrology and geochemistry

“…The samples have low Cr 2 O 3 (0.04-0.17 wt.%) and TiO 2 (0.04-0.25 wt.%). While there are no distinct low-MgO and high-MgO suites in this set of Indian samples as reported from some other kimberlite pipes (Koidu, Sierra Leone; Kaalvallei, South Africa; Kasai Craton, northern Angola; Victor, Jericho, and Diavik, all in Canada: Viljoen, 1994;Barth et al, 2001;Aulbach et al, 2007;Smart et al, 2009;Smit et al, 2014), the kyanite-bearing samples are, on average, richer in grossular whereas the bimineralic eclogites have higher almandine. One kyanite eclogite (KL2-9) shows higher than 50% grossular component, and is thus a grospydite .…”

“…5a, b). Abundances are typical for eclogite xenoliths worldwide (Jacob, 2004;Tappe et al, 2011;Pernet-Fisher et al, 2014;Smart et al, 2014;Smit et al, 2014) except for sample KL2-33, which has anomalously high HREE abundances for an eclogite (ca. 350 times chondritic; Fig.…”

“…Eclogite xenolith suites from a number of cratons worldwide are often considered as residues of TTG melt formation incorporated into the lithosphere along convergent margins (Ireland et al, 1994;Rollinson, 1997;Jacob and Foley, 1999;Smit et al, 2014;Pernet-Fisher et al, 2014;Tappe et al, 2011). For example, eclogite xenoliths brought up from the subcratonic lithosphere by kimberlites in the Kaapvaal craton are interpreted to be remnants of the oceanic basin between the Witwatersrand and the Kimberley blocks, which collided at 2.93-2.88 Ga along the Colesberg magnetic lineament (Moser et al, 2001;Schmitz et al, 2004).…”

“…Eclogite xenoliths are usually interpreted either as fragments of subducted oceanic crust representing gabbroic or basaltic protoliths or oceanic crustal cumulates emplaced tectonically into the lithospheric mantle (Shervais et al, 1988;Taylor and Neal, 1989;Neal et al, 1990;Jerde et al, 1993;Jacob et al, 1994;Viljoen et al, 1996;Snyder et al, 1997;Jacob and Foley, 1999;Barth et al, 2001;Shirey et al, 2001;Jacob, 2004;Usui et al, 2006;Nikitina et al, 2014), or as high-pressure, magmatic cumulates (MacGregor and Carter, 1970;Hatton, 1978;Smyth et al, 1989;Viljoen et al, 1996;Snyder et al, 1997;Barth et al, 2002;Taylor et al, 2003;Heaman et al, 2006;Appleyard et al, 2009;Jacob et al, 2009). Some eclogites have been linked to partial melting and melt-mantle reaction processes associated with subduction, representing residues of tonalite melt extraction from basaltic crust (Ireland et al, 1994;Rollinson, 1997;Jacob and Foley, 1999;Barth et al, 2002;Rapp et al, 2003;Smart et al, 2009;Tappe et al, 2011;Pernet-Fisher et al, 2014;Smit et al, 2014).…”

Thermoelastic Properties of Eclogitic Garnets and Omphacites: Implications for Deep Subduction of Oceanic Crust and Density Anomalies in the Upper Mantle

“…However, density anomalies with larger values like those beneath the Tarim and Himalayas (larger than 0.06 g/cm 3 ) may result from eclogites with higher Fe contents. Actually, mantle eclogite originated from the subduction can be modified by partial melting and reaction with the surrounding peridotite to form low‐Fe eclogite (e.g., Smit et al, ; Yaxley & Green, ). Therefore, based on this study, the density anomalies with different values in the upper mantle of Asia can be explained by eclogites with various Fe contents.…”