Partial melting of rocks will yield geochemical and isotopic signatures in the melt that differ from the one in the residue. The major element composition is controlled by the phases forming the eutectic. The trace-element inventory is controlled by these phases and the solubility of accessory minerals in the melt. Finally, the isotopic composition of elements with radiogenic growth in melt and residue will depend on the distribution of these elements in minerals participating in melting and staying in the residue, the parent-to-daughter relation in these minerals, and the age of the material being molten… The uncoupling of trace-elements is important in migmatites and rocks affected by wall-rock assimilation. It provides a possibility to uncouple geochemical and isotopic fingerprints from the bulk-rock geochemistry.
Potassic and ultrapotassic rocks such as orogenic lamproites show a distinct uncoupling of major elements and trace elements, although for these rocks, the uncoupling is due to strongly contrasting trace element contents in the two contributing members. The rocks are derived from a mantle source (as seen from the composition of xenocrysts) and show trace element signatures and Sr-Nd-Hf-Pb isotopic compositions that reflect the subducted lithologies eventually giving rise to metasomatism and refertilization of the mantle. Regional variation of the metasomatic component of Mediterranean lamproites demonstrates that metasomatism is related to young subduction. Furthermore, the isotopic character of the metasomatic component does not provide age constraints on metasomatism, but represents a fingerprint of the crustal source of metasomatism.
Prelević, D., Akal, C., Foley, S.F., Romer, R.L., Stracke, A., and van den Bogaard P. (2012) Ultrapotassic mafic rocks as geochemical proxies for post-collisional dynamics of orogenic lithospheric mantle: the case of southwestern Anatolia, Turkey. J. Petrol., 53: 1019-1055. doi: 10.1093/petrology/egs008
Prelevič, D., Akal, C., Romer, R.L., and Foley, S.F. (2010) Lamproites as indicators of accretion and/or shallow subduction in the assembly of south-western Anatolia, Turkey. Terra Nova, 22: 443-452. doi: 10.1111/j.1365-3121.2010.00963.x
Franz, L. and Romer, R.L. (2010) Different styles of metasomatic veining in ultramafic xenoliths from TUBAF Seamount (Bismarck Microplate, Papua New Guinea). Lithos, 114: 30-53.
Prelevič, D., Stracke, A., Foley, S.F., Romer, R.L., and Conticelli, S. (2010) Hf isotope compositions of Mediterranean lamproites: mixing of melts from asthenosphere and crustally contaminated lithosphere. Lithos, 119: 297-312.
Preleviç, D. Foley, S.F., Romer R., Conticelli, S. (2008) Mediterranean Tertiary lamproites derived from multiple source components in postcollisional geodynamics. Geochim. Cosmochim. Acta, 72: 2125-2156.
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