Petrology of Santa Maria, Monte Pedral, Bom Jardim, Boa Esperança and Niterói Stocks in Serra do Catu Intrusive Suite, Sergipe State, NE Brazil

Monte Pedral, Boa Esperança, Santa Maria, Niterói and Bom Jardim Stocks are in the Northern part of the Sergipano Orogenic System. These five stocks consist of: alkali-feldspar syenite and alkali-feldspar quartz syenite (Monte Pedral); quartz alkali-feldspar syenite and alkali-feldspar granite (Boa Esperança); granite (Santa Maria); monzogranite, quartz monzonite and quartz monzodiorite (Niterói); granite, quartz monzonite, granodiorite, quartz monzodiorite and diorite (Bom Jardim). These rocks are porphyritic, with alkaline feldspar phenocrysts rich in multiple zonings. The presence of alkaline feldspar phenocrysts and abundance of mafic enclaves is a feature that distinguishes this magmatism from those of the other intrusive suites of Canindé Domain. Monte Pedral and Boa Esperança Stocks correspond to hypersolvus magmatism, while the other stocks (Bom Jardim, Niterói and Santa Maria) represent subsolvus magmatism. The U-Pb_Shrimp age of 611 ± 4 Ma obtained for Santa Maria Stock makes it possible to correlate the magmatism represented by the stocks with the oldest shoshonitic plutonism in the Southern Borborema Province. The brown mica in the studied rocks corresponds to biotite and phlogopite and indicates orogenic affinity for this plutonism. Mg-hornblende and tschermakite are the primary amphiboles in these rocks, which were crystallized under oxidizing conditions and depths ranging from 12 (3 kbar) to 26 (7 kbar) km. Geochemical data indicate that the magmas responsible for forming the studied stocks belong to shoshonite suites and evolve through fractional crystallization, with the contribution of mantle material, exhibiting geochemical signature (enrichment in light Rare Earth Elements) in relation to heavy ones, and negative anomalies in Ta, Nb, P, Sr and Eu, which are characteristics of magmas associated with subduction. (author)