Kimberlites eclogite xenoliths

Peridotitic lithologies comprise more than 95% of the mantle lithosphere (Schulze, 1989). Thus, macrodiamonds in kimberlite are believed to come from mostly peridotitic hosts that break up during the sampling or transport that accompanies kim-berlitic volcanism. Sobolev (1974) and Hatton and Gurney (1979) noted the dichotomy that peridotite xenoliths greatly outnumber eclogite xenoliths and peridotitic silicate inclusions in diamond... 

Jacob D. and Jagoutz E. (1994) A diamond-graphite bearing eclogite xenolith from Roberts Victor (South Africa) implications for petrogenesis from Pb-, Nd-, and Sr isotopes. In Kimberlites, Related Rocks and Mantle Xenoliths (eds. H. O. A. Meyer and O. H. Leonardos) CPRM Spec. Publ. CPRM, Brasilia, vol. 1, pp. 304-317. 

Smith C. B., Gurney J. J., Harris J. W., Robinson D. N., Shee S. R., and Jagoutz E. (1989) Sr and Nd isotopic systematics of diamond-bearing eclogite xenoliths and eclogite inclusions in diamond from southern Africa. Kimberlites and Related Rocks. Spec. Pub. Geol. Soc. Austral., no. 14, vol. 2, pp. 853-863. 

Meyer H. O. A. and Brookins D. G. (1971) Eclogite xenoliths from Stockdale Kimberlite, Kansas. Contrib. Mineral. Petrol. 34, 60-72. 

Helmstaedt H. and Schulze D. J. (1988) Eclogite-facies ultramafic xenoliths from Colorado Plateau diatreme breccias comparison with eclogites in crustal environments, evalation of the subduction hypothesis, and implications for eclogite xenoliths from diamondiferous kimberlites. In Eclogite and Eclogite Facies Rocks (ed. D. C. Smith). Elsevier, New York, pp. 387-450. 

Robinson D. N., Gurney J. J., and Shee S. R. (1984) Diamond eclogite and graphite eclogite xenoliths from Orapa. Botswana. In Kimberlites II. The Mantle and Crust-Mantle Relationships (ed. J. Kornprobst). Elsevier, Amsterdam, pp. 11-24. 

Viljoen K. S., Smith C. B., and Sharp Z. D. (1996) Stable and radiogenic isotope study of eclogite xenoliths from the Orapa kimberlite, Botswana. Chem. Geol. 131, 235—255. 

Rollinson, H.R., 1997b. Eclogite xenoliths in West African kimberlites are residues from Archaean granitoids. Nature, 389, 173-6. 

Studies of mantle xenoliths have confirmed the view from seismology that peridotite is volumetrically the dominant component of the Earth s shallow mantle (<400 km) (see Chapter 2.02). This is because xenolith suites in almost all tectonic environments are dominated by peridotites. Even at localities where other lithologies such as eclogite dominate the intact xenolith suite, mineral concentrate studies show that peridotite dominates the inventory of entrained mantle material (Schulze, 1989). Major- and trace-element studies of mineral concentrates from mined kimberlites have also been used to illustrate... 

An unusual variety of ultrahigh pressure xenoliths has been described from the Jagersfon-tein kimberlite (Haggerty and Sautter, 1990 Sautter et ai, 1991). These xenoliths (type XIII, Table 1) comprise four-phase Iherzolite, discrete garnets, or iron-rich Iherzolites with eclogitic affinities (Sautter et ai, 1991). Their key... 

Figure 49 Bulk analyses of eclogite and alkremite (alkremite-corgaspinite-corganite Table 1) xenoliths from kimberlites compared with massif eclogites and Archean basalts and komatiites (open field). Data sources Kushiro and Aoki (1968), Sobolev (1974), Mazonne and Haggerty (1989), Hills and Haggerty (1989), Taylor and Neal (1989), Ireland et al. (1994), Pyle and Haggerty (1994), Snyder et al. (1993), Jacob et al. (1994), and Jacob and Foley (1999). Outlined field is for Archean basalts and Komatiites taken from Ireland et al. (1994).

Helmstaedt H. and Schulze D. J. (1979) Garnet clinopyrox-enite—chlorite eclogite transition in a xenolith from Moses Rock further evidence for metamorphosed ophiohtes under the Colorado Plateau. In The Mantle Sample Inclusions in Kimberlites and other Volcanics (eds. E. R. Boyd and H. O. A. Meyer). American Geophysical Union, Washington, DC, pp. 357-365. 

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