Ultra-depleted, shallow cratonic mantle beneath West Greenland: dunitic xenoliths from Ubekendt Ejland

Formation of cratonic lithosphere: An integrated thermal and petrological model

“…Residues of dunite have been reported by Bernstein et al (2006;, indicating orthopyroxene exhaustion at melt fractions > 0.35 (Fig. 1a).…”

“…A notable exception may be rare garnet dunite residues (Spengler et al, 2006) expected of Al-depleted komatiites (Herzberg and Zhang, 1996;Walter, 1998). Moreover, olivine phenocrysts in many komatiites have Fo > 94 (Sobolev et al, 2007), significantly higher than the Fo 92-94 observed in olivines from cratonic mantle (Bernstein et al, 2006;Boyd, 1989;Gaul et al, 2000;Griffin et al, 2009;Lee and Rudnick, 1999) (Fig. 1a).…”

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

“…(b) Literature data on mantle xenoliths from Udachnaya: Re-Os T RD for whole-rock peridotites, "megacrystalline dunites" (Pearson et al, 1995a) and eclogites (Pearson et al, 1995b) and Lu-Hf T RD and isochron ages of clinopyroxene from spinel peridotites ; (c) Re-Os isochron ages for sulfide inclusions in diamonds from Siberian kimberlites including Udachnaya (Wiggers de Vries et al, 2013); (d) U/Pb ages of detrital zircons and model Sm-Nd ages (T DM ) for crustal basement rocks from the Siberian craton (Rosen, 2002;Rosen et al, 2005). (e) Age distribution plots (T RD ) for peridotite xenoliths from South Africa and North America: the Kaapvaal craton (continuous black line) (Carlson et al, 2004;Carlson et al, 1999;Irvine et al, 2001;Simon et al, 2007), the Slave craton (dashed line) (Aulbach et al, 2004;Irvine et al, 2003;Westerlund et al, 2006) and the North Atlantic craton (grey line) (Bernstein et al, 2006;Hanghøj et al, 2001;Wittig et al, 2008). The Re-Os model ages are calculated with chondritic mantle values after Walker et al (2002) as presented by Pearson and Wittig (2008).…”

Widespread refertilization of cratonic and circum-cratonic lithospheric mantle

“…Archean SCLM is distinctive in containing significant proportions of refractory harzburgites with minor lherzolites (Herzberg, 2004) and highly refractory dunites (Bernstein et al, 2006(Bernstein et al, , 2007, marking the most significant difference between Archean SCLM and that beneath younger terranes (Griffin et al, 1999a). The compositional variations significantly contribute to the difference in the density of SCLM of different ages.…”