Garnets eclogite xenoliths

Clinopyroxenes in eclogite xenoliths have convex-upwards REE patterns that are LREE-enriched relative to HREE. (La) varies from slightly below 1 to —15, while (Yb) varies between 0.1 and 1.5 (Figure 50). As with garnet, Nb-Ta depletions and, to some extent, other HFSE abundances depend on the coexistence of rutile (Jacob and Foley, 1999 Rudnick et al., 2000 Barth et al., 2001). The relatively homogenous REE patterns of eclogitic clinopyroxene contrast markedly with the wide variety of REE patterns observed in peridotitic clinopyroxene. 

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... 

In noncratonic xenolith suites, eclogite is much scarcer and it is notable if this lithology is present. Pyroxenites and garnet pyroxenites are more common in noncratonic xenolith suites. 

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. 

MacGregor I. D. and Carter J. L. (1970) The chemistry of clinopyroxenes and garnets of eclogite and peridotite xenoliths from the Roberts Victor Mine, South Africa. Phys. Earth Planet. Int. 3, 391-397. 

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