Portal de Periódicos da CAPES

Artigo Produção Nacional

BIBTEX RIS

Granitos peraluminosos intrusivos no Complexo Metamórfico Brusque: registro do magmatismo relacionado a colisão neoproterozóica no Terreno Tijucas, Itapema (SC)

2010; Sociedade Brasileira de Geologia; Volume: 40; Issue: 3 Linguagem: Inglês

10.5327/rbg.v40i3.1522

2317-4889

Ruy Paulo Philipp, Roberto Sacks de Campos,

Geochemistry and Elemental Analysis

Brusque Metamorphic Complex is one of main units of the Tijucas terrane in Santa Catarina. In Itapema region this complex is composed by metasedimentary association with subordinate presence of mafic and ultramafic metavolcanic rocks and peraluminous granites. The granites are exposing like bodies of centimeter to metric thickness and are intrusive in metapelites, mafic and calc-silicate schists. These units are tectonically intercalated and disposed according to a low angle foliation of northeast-southwest direction. The granites are concordant with the S 1 foliation and are positioned in conformity to axial surfaces of isoclinal F 1 folds. Its have a monzogranite composition with a K-feldspar, plagioclase and quartz, with subordinates quantities of muscovite and tourmaline, and biotite, garnet, monazite, zircon, apatite and opaques minerals as accessories. The main structure is a magmatic banding of centimeter thickness alternating regular and continuities levels with medium to coarse equigranular texture and levels with pegmatitic texture. The banding is originated by successive fulfilling of fractures by granite injections. Geochemical studies characterize the granites like a peraluminous magmatism related to high-K calc-alkaline series. Majors and traces elements patterns present low values for the ratios La N /Yb N (1.34 to 4.66), K 2 O/Na 2 O (0.86 to 1.72), CaO/Na 2 O (0.11 to 0.44) and low values of Rb, Sr, Zr e de ETR, very close to peraluminous granites of the others orogenic belts of Phanerozoic age. Compositions of this type are usually associated to rock generated by partial fusion of crustal sequences of pelitic composition with a formation of a granulitic residue. Structural relations between the positioning of the granitic bodies, metamorphism and deformation evolution related to Brusque Metamorphic Complex, associated to geochemical and geotectonic parameters are consistent with a magmatism generated by the anatexis related to collisional event of the end of Brasiliano Cicle.