IANIGLA   20881
INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
artículos
Título:
Geochemistry of K-feldspar and muscovite in rare-element pegmatites and granites from the Totoral pegmatite field, San Luis, Argentina
Autor/es:
J. C. OYARZÁBAL, M. A. GALLISKI AND E. PERINO
Revista:
Resource Geology
Editorial:
Blackwell Publishing
Referencias:
Lugar: Tokyo; Año: 2008
ISSN:
1344-1698
Resumen:
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Abstract: The geochemistry of K-feldspar for K, P, Sr, Ba,
Rb, Cs, Ga, and of muscovite for the same elements plus Nb and Ta, was used for
proving the parental relationships of S-type granites and LCT (Li, Cs, Ta)
rare-element pegmatites in the southernmost pegmatitic field of the Pampean
pegmatitic province in Argentina. The variation of K/Rb-Cs, K/Cs-Rb,
K/Rb-Rb/Sr, K/Rb-Ba in K-feldspar from the granites and pegmatites show that
they form an association with the evolutional sequence: granites"barren- to transitional pegmatites"beryl type, beryl-columbite-phosphate pegmatites"complex type of spodumente subtype pegmatites"albite-spodumente type "albite type pegmatites. This sequence reflects the
regional distribution of the different magmatic units. The Ta-Cs diagram for
muscovite reveals that none of the studied pegmatites exceed the threshold
established in previous studies for being considered with important tantalum
oxide mineralization.
The granites and pegmatites form a rare-element
pegmatitic field in which different magmatic units are petrogenetically linked
forming a continuous fractionation trend, extended from the less evolved
granitic facies to the most geochemically specialized pegmatites.