Peraluminous xenoliths in kimberlite: Metamorphosed restites produced by partial melting of pelites

Geochemical and oxygen isotope signatures of mantle corundum megacrysts from the Mbuji-Mayi kimberlite, Democratic Republic of Congo, and the Changle alkali basalt, China

“…They overlap the chemical field of the ruby and Cr-bearing sapphire crystals of the Soamiakatra deposit in Madagascar, hosted in xenoliths of metagabbro and clinopyroxenite brought-up to the surface by the Ankaratra alkali basalts (Rakotosamizanany et al, 2014). They overlap also the fields of: ruby from the Chanthaburi-Trat and Pailin deposits hosted in alkali basalt fields from Thailand and Cambodia (Sutherland et al, 2009); Cr-bearing sapphires and ruby micro-inclusions hosted by corganite (Mazzone and Haggerty, 1989) and corgaspinite xenoliths (Exley et al, 1983) from Jagersfontein and Bellsbank kimberlites in South Africa; Cr-bearing sapphires found in kyanite eclogite xenoliths from the Roberts Victor mine kimberlite (Hatton, 1978).…”

High-pressure and ultrahigh-temperature metamorphism at Komateri, northern Madurai Block, southern India

“…The two minerals occur as porphyroblasts in the matrix of gedrite and retrograde cordierite. They discussed that such ''coarse-grained" garnet + corundum association was previously reported from corundum-bearing eclogites in kimberlite xenolith (e.g., Ater et al, 1984;Mazzone and Haggerty, 1989), mantle-derived rocks (e.g., Kornprobst et al, 1990;Morishita et al, 2001), and UHP metamorphic rocks (e.g., Enami and Zang, 1988). They further noted that garnet + corundum assemblages have also been rarely reported from pyroxene-free rocks, but are mostly from UHP metamorphic terranes (e.g., Enami and Zang, 1988;Zhang et al, 2004).…”

Highly aluminous xenoliths from kimberlites of Yakutia: mantle petrology remarks

“…It is more likely that corundum has a secondary origin in this case also. In their compositions these samples close to the xenoliths described as corganites by Massone and Haggerty (1989). Diamondiferous samples have been found in all varieties of these xenoliths except alkremites.…”

“…Such diversity of their origin and also the following evolution of eclogites in the process of partial melting and mantle metasomatism, which have been considered in a number of papers (Spetsius, 1995;Spetsius and Serenco, 1990;Spetsius and Taylor, 2003 and references therein), in their turn, determine the specific nature of these rocks in separate pipes. Based on highly enriched Sr isotope composition (87Sr/86Sr > 0.8), a crustal origin was proposed for alkremites whereby these rocks could represent the restites from subducted, melted pelitic sediments (Massone & Haggerty, 1989). The preliminary data on trace element content in garnet and high Lu/Hf ratio do not support this model (Nowell et al, this volume).…”