Metasomatism

Meta-phosphorsiure, /. metaphosphoric acid -saure, /. meta acid, metasomatisch, a. metasomatic. meta-stabil, a. metastable, -st dig, a. in the meta position. 

Fig. 2.50. Plot of amphibole compositions on the Al203-Fe0 -Mg0 (AFM) diagram, together with the compositional range of amphibole in the hydrothermally metasomatized basalt from midocean ridges (Shinozuka et al., 1999).

Fig. 2.51. Plot of chlorite compositions on the diagram proposed by Hey (1954). The compositional range of chlorite in the metasomatized ba.salt from midocean ridges is taken from Humphris and Thompson (1978) (Shinozuka et al., 1999).

Blundy JD, Dalton JA (2000) Experimental comparison of trace element partitioning between clinopyroxene and melt in carbonate and silicate systems and implications for mantle metasomatism. Contrib Mineral Petrol 139 356-371... 

Chabaux F, Hemond C, Allegre CJ (1999) U- °Th- Ra disequilibria in the Lesser Antilles arc implications for mantle metasomatism. Chem Geol 153 171-185 Cheng H, Edwards RL, Hoff J, Gallnp CD, Richards DA, Asmerom Y (2000) The half-lives of nraninm-234 and thorinm-230. Chem Geol 169 17-33... 

Maury RE, Defant MJ, Joron J-L (1992) Metasomatism of the sub-arc mantle iirferred from trace elements in Philippine xenoliths. Nature 360 661-663... 

Yokoyama T, Kobayashi K, Kuritani T, Nakamura E (2002) Mantle metasomatism and rapid ascent of slab components beneath island arcs evidence from disequihbria of Miyakejima volcano,... 

The igneous processes which give rise to ore deposits are broadly classified into three types (i) magmatic concentrations and segregations, (ii) contact metasomatism, and (iii) hydrothermal processes. 

Metasomatic Deposits Esphinharas in Brazil, Ros Adams in Alaska, USA, as well as the Zheltye Vody deposit in Krivoy Rog area, Ukraine. 

Reed, M. H., 1977, Calculations of hydrothermal metasomatism and ore deposition in submarine volcanic rocks with special reference to the West Shasta district, California. Ph.D. dissertation, University of California, Berkeley. 

Thompson, J. B., Jr., 1959, Local equilibrium in metasomatic processes. In P. H. Abelson (ed.), Researches in Geochemistry, Wiley, New York, pp. 427M-57. 

Metasomatic deposits are altered albite and granatoids. These are low-grade ores. Of economic interest is the carbonatites, which contain up to 1% combined Ta/Nb. 

Migration of fluids in a porous matrix with solid-liquid fractionation results in a process much similar to the chromatographic separation of elements (DeVault, 1943 Korzhinskii, 1970, Hofmann, 1972). This mechanism has recently been revived in the context of mantle metasomatism by Navon and Stolper (1987), Bodinier et al. (1990), Vasseur et al. (1991), in the context of hydrothermal systems by Lichtner (1985) and, for stable isotopes, by Baumgartner and Rumble (1988). Only a simplified account of this model will be given here. Let

solid matrix and melt, respectively, and vHq the fluid velocity relative... 

Bodinier, J. L., Vasseur, G., Vernieres, J., Dupuy., C. Fabries, J. (1990). Mechanisms of mantle metasomatism Geochemical evidence from the Lherz orogenic peridotite. J. 

Guy, B. (1984). Contribution to the theory of infiltration metasomatic zoning the formation of sharp fronts a geometrical model. Bull. Mineral., 107, 93-105. 

Korzhinskii, D. S. (1970). Theory of Metasomatic Zoning. Oxford Clarendon Press. 

Metasomatized xenoliths studied by Nishio et al. (2004) show a diversity of Li isotopic compositions (ST i = -17.1 to +6.8), some of these correlated with variations in radiogenic... 

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