Plagioclase trace elements

In this case, trace element and carrier occupy the same structural position both in the solid phase and in the melt and are subject to the same compositional effects in both phases (i.e., extension of the cation matrix in the melt and amount of anorthite component in the solid). Figure 10.9A shows the effect of normalization the conventional partition coefficient of Sr between plagioclase and liquid varies by about one order of magnitude under equal P-T conditions, with increasing anorthite component in solid solution, whereas normalized distribution coefficient D is virtually unaffected. Figure 10.9B shows the same effect for the Ba-Ca couple. 

Figure 10,9 Effect of normalization on trace element distribution of Sr (A) and Ba (B) between plagioclase and silicate liquid. Distribution curves are based on various experimental evidence (Ewart et al., 1968 Ewart and Taylor, 1969 Berlin and Henderson, 1968 Carmichael and McDonald, 1961 Philpotts and Schnetzler, 1970 Drake and Weill, 1975). Ab albite Or orthoclase An anorthite.

Dudas M. I, Schmitt R. A., and Harward M. E. (1971). Trace element partitioning between volcanic plagioclases and dacitic pyroclastic matrix. Earth Planet. Set Letters, 11 440-446. 

Steele I. M., Hutcheon I. D. and Smith J. V. (1980b). Ion microprobe analysis of plagioclase feldspar (Cai xNaxAl2 xSi2+x08)- for major, minor and trace elements. VIII Int. Congr. X-ray Optics Micro analysis, Pendell Pub. Co, Midland, Michigan. 

The primitive mantle-normalized trace-element spider diagram of felsic rocks shows negative Sr and Eu anomalies that are indicative of either plagioclase restite or plagioclase fractionation resulting from a combination of the partial melting and fractional crystallization processes (Fig. 5), and later changed by hydrothermal alteration. 

Suspended solid surfaces (particles or colloids) in waters play a prominent role in controlling the concentration of dissolved trace elements. Most of these elements are eliminated by sedimentation after incorporation on to or into particles, generally by complexation with the surface sites. The most common inorganic particles and colloids are non-clay silicates (quartz, potash feldspar, plagioclase, opaline silica (diatoms)) clays (illite, smectite) carbonates (calcite, dolomite) Fe-Mn oxides (goethite, magnetite) phosphates (apatite) sulfides (mackinawite). Particles and colloids in a water body may be classified as a function of their origin ... 

Most trace elements have values of D< C 1, simply because they differ substantially either in ionic radius or ionic charge, or both, from the atoms of the major elements they replace in the crystal lattice. Because of this, they are called incompatible. Exceptions are trace elements such as strontium in plagioclase, ytterbium, lutetium, and scandium in garnet, nickel in olivine, and scandium in clinopyroxene. These latter elements acmally fit into their host crystal structures slightly better than the major elements they replace, and they are therefore called compatible. Thus, most chemical elements of the periodic table are trace elements, and most of them are incompatible only a handful are compatible. 

Rampone E., Piccardo G. B., Vannucci R., Bottazzi P., and Ottolini L. (1993) Subsolidus reactions monitored by trace element partitioning the spinel- to plagioclase-facies transition in mantle peridotites. Contrib. Mineral. Petrol. 115, 1-17. 

Bindeman I. N. and Davis A. M. (2000) Trace element partitioning between plagioclase and melt investigation of dopant influence on partition behaviour. Geochim. Cosmochim. Acta 64, 2863-2878. 

Drake M. J. (1972) The distribution of major and trace elements between plagioclase feldspar and magmatic silicate liquid an experimental study. PhD Thesis, University of Oregon Eugene, Oregon, USA (unpublished). 

Ginibre C., Worner G., and Kronz A. (2002b) Minor- and trace-element zoning in plagioclase implications for magma chamber processes at Parinacota volcano, northern Chile. 

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