Plutonism from Antarctica to Alaska

Geochemical evolution of granites from the Achala batholith of the Sierras Pampeanas, Argentina
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Published:January 01, 1990
The Achala batholith is a post-orogenic intrusion of probable Silurian age exposed in the Sierra de Cordoba in the eastern Sierras Pampeanas of central Argentina (31°6′S to 32°2′S; 64°29′W to 65°7′W). The batholith was emplaced into late Precambrian amphibolite- and granulite-facies metamorphic rocks. Five comagmatic granitoid facies, all monzogranite in composition, have been recognized. Geochemical data suggest these granitoids formed by a magmatic differentiation process that began with porphyritic and fine-grained facies B, C, and D, and ended with leucogranite facies A. Biotite-apatite enclaves that are interpreted as cumulates and tonalitic nodules occur in facies B. Less abundant rock types are quartz-muscovite greisens, feldspathic episyenites, pegmatites, and aplites. The granitoids have S-type chemical affinities and are consistent with a within-plate granite tectonic setting.
- alkaline earth metals
- amphibolite facies
- aplite
- Argentina
- batholiths
- chemical composition
- cumulates
- emplacement
- evolution
- facies
- geochemistry
- granites
- granulite facies
- greisen
- igneous rocks
- intrusions
- isotopes
- leucogranite
- metals
- metamorphic rocks
- metasomatic rocks
- mineral composition
- monzogranite
- Paleozoic
- Pampean Mountains
- pegmatite
- plutonic rocks
- S-type granites
- Silurian
- South America
- Sr-87/Sr-86
- stable isotopes
- strontium
- syenites
- tectonics
- textures
- Sierra de Cordoba
- Achala Batholith