Anisotropia de susceptibilidade magnética do plúton Serra da Cai?ara, Batólito águas Belas-Canindé Alagoas, Nordeste do Brasil

摘要

The Anisotropy of Magnetic Susceptibility (AMS) technique was applied in the Serra da Cai?ara pluton, which is part of the?águas Belas-Canindé batholith, Pernambuco-Alagoas Domain of Borborema Province, Northeastern Brazil. The pluton has?high values of magnetic susceptibility (K) (90% of the values above 5 × 10 -3,/sup SI), typical of granites of the magnetiteseries.?The anisotropy degree (P) ranges from 1.025 to 1.320. The highest P values are associated with the margins of the body?and have a positive correlation with K. The pluton presents a mixed, slightly more oblate, fabric, with T values between?-0,822 and 0,823. In general, magnetic foliations and lineations are fairly uniform and have two preferred directions: NW-SE?(dominant, usually plunging to SW) and NNE-SSW, with a more varied plunge (usually associated with high P values). The?foliation and lineation of the hornblende quartz syenite facies have low to moderate dip and plunge, respectively, which agrees?with the regional fabric. The lineations mostly have SE plunging, indicating the magmatic flow’s direction. The hornblende?quartz alkali feldspar syenite facies (center of the body) has a discordant fabric, with flow from SW to NE and spreading to?NW. The observed structural magnetic structure is consistent with the structural framework of the region, which has two main?directions (NE-SW and NW-SE). Data suggest that the pluton intruded taking advantage of the regional foliation formed during?the convergent phase of the Brasiliano orogenesis. During the final crystallization phase, the pluton was affected by the?transcurrent phase of the Brasiliano event, mainly at the edges of the body, conditioning the NE-SW foliations and? lineations.