IANIGLA   20881
INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Geochemistry of K-feldspar and muscovite in rare-element pegmatites and granites from the Totoral pegmatite field, San Luis, Argentina
Autor/es:
OYARZÁBAL, J.C., GALLISKI, M. A. AND PERINO, E.
Lugar:
San Salvador de Jujuy
Reunión:
Congreso; XVII Congreso Geológico Argentino; 2008
Institución organizadora:
Asociación Geológica Argentina
Resumen:
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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.