Mantle rocks kimberlites

Figure 4 Covariation of Cr/(Cr + Al) and Fe/(Fe -t-Mg) in spinels from mantle xenoliths in kimberlites and other volcanic rocks. The data points are representative of the extremities of fields for a database of 2.5 X 10 analyses (source Barnes and Roeder, 2001).

Figure 18 Primitive mantle normalized trace-element abundance patterns for whole-rock MARID xenoliths from kimberlites. Primitive mantle values used for normalisation in this plot and subsequent plots are those of McDonough and Sun (1995) (sources Pearson and Nowell, 2002 Gregoire et al, 2002).

Figure 20 Primitive mantle normalized extended PGE patterns (including rhenium) for cratonic whole-rock garnet peridotite xenoliths from the Letseng kimberlite (Lesotho) (sources Irvine, 2002 and Pearson et al., 2004).

Gunther M. and Jagoutz E. (1994) isotopic disequilibria (Sm/ Nd, Rb/Sr) between minerals of coarse grained, low temperature peridotites from Kimberely floors, southern Africa. In Kimberlites, Related Rocks and Mantle Xenoliths, Proc. 5th Int. Kimberlite Conf, Araxa, Brazil. CPRM. Spec. 

Haggerty S. E. (1989) Upper mantle opaque mineral stratigraphy and the genesis of metasomites and alkali-rich melts. In Kimberlites and Related Rocks. Geological Society of Australia Special Publication No. 14 (ed. J. Ross). Blackwell, Perth, vol. 2, pp. 687-699. 

Taylor L. A. and Neal C. R. (1989) Eclogites with oceanic crustal and mantle signatures from the Bellsbank kimberlite, South Africa Part 1. Mineralogy, Petrography, and whole rock chemistry. J. Geol. 97, 551-567. 

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. 

Kaapvaal peridotites and inferences on metasomatic interactions. In Kimberlites, Related Rocks, and Mantle Xenoliths, Proc 5th Int. Kimberlite Conf., Vol. 1, CPRM Spec. Publ. 1A (eds. H. O. A. Meyer and O. H. Leonardas). CPRM, Brasilia, vol. 1, pp. 336-353. 

There have been relatively few systematic descriptions of noble gas concentrations in rocks and minerals. In general, the He content is dependent upon the abundances of Th and U, the crystal density of host minerals and the permeability of the rock. Mantle-derived rocks and minerals seem to be relatively enriched in He, with high He/ He ratios. Thus, minerals and nodules in kimberlites can have He contents up to 2755 cm /g x 10 (phlogopite) and 350 cm /g x 10 (diamond) in contrast, many igneous rocks may contain <0.1 cm /g X 10 (Hoppe and Alexander, 1978). Very high concentrations of He can occur... 

Helmstaedt, H. Schulze, D. J. 1989. Southern African kimberlites and their mantle sample implications for Archean tectonics and lithosphere evolution. In Kimberlites and Related Rocks. Their Composition, Occurrence, Origin and Emplacement. Proceedings of the 4th International Kimberlite Conference, Perth, Australia 1986. Geological Society of Australia, Victoria, 358-360. 

---