Fluid rock evolution of high T calc-silicate marbles: Constraints on the P-T-t history of a granulite facies terrain

GALLIEN, F.; MOGESSIE, A.; BJERG, E.; DELPINO, S.; CASTRO DE MACHUCA, B.

Oslo, Noruega

Congreso; International Geological Congress Oslo 2008; 2008

International Union of Geological Sciences

This study was carried out in the southern part of the Sierra de La Huerta, in the Province San Juan, NW-Argentina. The Sierra de La Huerta belong to the Western Sierras Pampeanas system and is part of a subduction related magmatic arc that experienced high grade granulite facies peak conditions at 860°C and 6-7 kbar in the Late Cambrian and Early Ordovician . The metacarbonate units of the La Huerta Range represent a heterogeneous sequence of layered impure dolomite-, calcite marbles respectively, 10-70 metres thick. High grade metamorphosed granulite-gneisses, migmatites and amphibolites represent the metamorphic basement which accommodates the marble units. The associated magmatic suite comprises tonalitic granodiorites, granites, gabbros - gabbronorites and pegmatites and is considered to be the advective heat source that leads to rather high temperatures at intermediate crustal levels.