INVESTIGADORES
SPALLETTI Luis Antonio
artículos
Título:
Composición, procedencia y marco tectónico de sedimentitas eojurásicas (Formación Nestares) del sudeste de la Cuenca Neuquina
Autor/es:
SPALLETTI, L.A.; MERODIO, J.C.; MATHEOS, S.D.
Revista:
Revista de la Asociación Geológica Argentina
Editorial:
Asociación Geológica Argentina
Referencias:
Lugar: Buenos Aires; Año: 1992 vol. 47 p. 277 - 286
ISSN:
0004-4822
Resumen:
Sandstone detrital modes and petrofacies studies of the Lower Jurassic Nestares Formation indicate derivation from granitoid rocks located in the continental block of the North Patagonian Massiff. Sandstone compositions also indicate that the sediments accumulated near the craton, on the passive flank of the back-arc basin. Sandstone petrofacies clearly differ from those of the basinal sediments, which were derived from a magmatic arc located to the west. Geochemical and mineralogical composition of shales support these conclusions and show a significant degree of compositional maturation. The low sandstone maturation combined with the high maturation of the shales suggests an intermediate degree of chemical weathering of the source rocks, under humid conditions. The sandstones have concentrated de primary constituents of the source rocks whereas shales tend to be composed of resistates and secondary minerals resulting from alteration of granitoids.
