Rare earth elements diamonds

McKenzie D, O Nions RK (1995) The source regions of ocean island basalts. J Petrol 36 133-159 Meen JK, Eggler DH, Ayers JC ((1989) Experimental evidence for very low solubility of rare earth elements in C02-rich fluids at mantle conditions. Nature 340 301-303 Menzies M, Chazot G (1995) Fluid processes in diamond to spinel facies shallow mantle. J Geodynamics 20 387-415... 

Figure 6.41 Anassembly comprised of a cubic [Er4(p.3-0)(p.3-0H)3] + and a diamond-shaped [Er2( X3-0H)2] unit (left) showing of one unit of the nanosized 36-Er wheel-like structure (middle) and the two-dimensional network of wheel-shaped cationic cluster [Er36( X3-OH)3o( X3-0)6(BDC)6] + (right) [25]. (Reproduced from Z.P. Zheng, Cluster compounds of the f-elements, in K.A. Gschneidner, Jr., J.C.G. Biinzli, and V.K. Pecharsky (eds.). Handbook on the Physics and Chemistry of Rare Earths, volume 40, 2010, with permission from Elsevier.)...

The uneven distribution of elements across the face of the earth has shaped history - stimulating trade and encouraging exploration and cultural exchange, but also promoting exploitation, war, and imperialism. Southern Africa has paid dearly for its gold and the elemental carbon of its diamonds. Many rare but technologically important elements, such as tantalum and uranium, continue to be mined from poor regions of the world under conditions (and for reasons) that some consider pernicious and hazardous. 

Carbon is the 17th most common element in Earth s crust. Its abundance has been estimated to be between 180 and 270 parts per million. It rarely occurs as a diamond or graphite. Both allotropes are formed in the earth over millions of years, when dead plant materials are squeezed together at very high temperamres. Diamonds are usually found hundreds or thousands of feet beneath the earth s surface. Africa has many diamond mines. 

It must be concluded that the extensive research on rare gases in diamond has provided considerable information regarding isotopic effects in the mantle, perhaps related to environments unusually enriched in trace elements. However, it appears that no constraints regarding mantle rare gas components in the early Earth have been obtained. 

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