Resumo

CIOCCALE, Marcela A.; PASQUINI, Andrea I.  e  DEPETRIS, Pedro J.. Occurrence of silica speothems in granitic rocks of the Achala batholith, Sierras Pampeanas of Córdoba. Rev. Asoc. Geol. Argent. [online]. 2008, vol.63, n.3, pp.417-420. ISSN 0004-4822.

We are reporting on the occurrence of silica speleothems in granitic outcrops of the Achala batholith (Córdoba). Speleothems are accumulation forms which occur in environments dominated by erosive processes. They usually reach a thickness that varies between a few milimeters and 2 cm, and grow in fractures or in taffonis walls. Its morphology is varied and includes stalactites and flowstonetype speleothems. They are mainly composed of amorphous silica (opal-A) and mineral detritus (quartz, feldspar, and mica). PHREEQC modelling allows simulating the genesis of speleothems, progressively increasing the evaporation of meteoric water that flows through fractured zones.

Palavras-chave : Speleothems; Granitic rocks; Geochemical modelling; Opal-A; Argentina.

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