Rare earth element distributions among coexisting granulite facies minerals, Scourian complex, NW Scotland

Autor: C. Pride, G. K. Muecke
Rok vydání: 1981
Předmět:
Zdroj: Contributions to Mineralogy and Petrology. 76:463-471
ISSN: 1432-0967
0010-7999
DOI: 10.1007/bf00371488
Popis: The major rock-forming mineral phases (pyroxenes, plagioclase, garnet, hornblende) of a suite of granulite-facies gneisses from the Scourian complex, NW Scotland, have been analyzed for their rare earth element (REE) content. Although host rock compositions range from felsic to ultramafic, REE abundances and patterns for each mineral group show only limited variation. The REEs exhibit regular and consistent distribution patterns for each mineral which suggest, together with major element and textural considerations, that the observed distribution coefficients approach equilibrium. Total REE content follows the sequence hornblende>clinopyroxene>garnet>plagioclase >orthopyroxene and mass balance calculations show that even in the felsic gneisses>60% of the REEs reside in the major rock-forming minerals. Comparisons of both relative REE abundances and distribution coefficients with those in other rock types reveal a striking resemblance with patterns observed in mineral-liquid pairs of dacitic rocks. These similarities may have arisen during a partial melting episode in which granite-granodiorite melts were generated and removed from the Scourian complex; leaving a residuum which is severely depleted in the incompatible elements, including the REEs.
Databáze: OpenAIRE
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