Abstract

Late-Variscan two mica + or - cordierite + or - Al-silicate-bearing plutonic rocks are widespread in the Calabrian-Peloritan Arc. The most important features of the Sila Batholith "peraluminous" granitic rocks, belonging to the northern sector of the Arc, are discussed in this paper. A comparison with similar plutonites, cropping out in the southern sector, is also made. The Sila two mica + or - cordierite + or - Al-silicate-bearing Main, Minor and Small Intrusions and Felsic Dykes, exhibit, as a whole, a complete plutonic range of grain-size, texture and fabric, and a compositional spectrum ranging from granodiorite to leucomonzogranite. Magmatic cordierite, andalusite, sillimanite and muscovite are ubiquitous in the above rocks which also contain mafic microgranular inclusions (autoliths) and/or metamorphic xenoliths. Modal and chemical comparisons with I- and S-type granitic rocks from Southern Australia (Chappel & White, 1982) show that the Sila two mica + or - cordierite + or - Al-silicate-bearing plutonites plot with the Sila calcalkaline biotite + or - amphibole-bearing intrusions, as a single magmatic suite, in the I-type field. The Sila magmatic suite shows characteristics typical of an Alumino-Cafemic association (Debon & Le Fort, 1982) with an aluminum saturation index (ASI) ranging from 1.00 to 1.51. REE patterns emphasize the genetic link between the two mica + or - cordierite + or - Al-silicate-bearing and biotite + or - amphibole-bearing granitic rocks, confirming previous conclusions reached by Messina et al. (1991). The crystallization condition of the different two mica + or - cordierite + or - Al-silicate-bearing bodies are related to geological setting and also to magma composition and water activity. Comparisons between the Sila two mica + or - cordierite + or - Al-silicate-bearing and biotite + or - amphibole-bearing intrusions, and similar rocks, cropping out in the southern sectors of the Arc, show that they exhibit the same bulk petrochemical features. This suggests a similar Variscan magmatic evolution in both sectors of the Calabrian-Peloritan Arc.

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