GEOLOGY OF THE AGUA COMPRIDA GRANITE, SETUVA ANTIFORM, STATE OF PARANA, BRAZIL

The deformed granitoids of the Setuva Antiform are located at the Paranaense Shield, between the Apiai and Curitiba terrains, in the state of Parana, southern Brazil. The Setuva Antiform is an elliptical structure approximately E-W to NE-SW, subdivided in an inner portion, Agua Comprida Granitic Suite (ACGS), composed of variably deformed sienogranites and monzogranites; enveloped by an outer portion, Santana Sequence (SS), composed of biotite-white mica schists, quartzites and quartz veins. The Agua Comprida Granite (GAG) is the main porphyritic body, characterized by feldspar porphyroclasts. The magmatic paragenesis is composed of quartz, microcline, plagioclase and biotite. The accessory minerals are titanite, allanite, apatite, ilmenite and zircon. The secondary paragenesis is: (a) biotite II , white mica, titanite II, albite and epidote; and (b) chlorite, white mica, pyrite and rare carbonate. The rock fabric includes magmatic features, such as schlieren and feldspar imbrication, as well as deformed features, such as quartz ribbon, pressure shadow, core-mantle structure, tectonic perthite and twin. Zones of intense shear deformation and high fluid pressure are responsible for phyllonite, and quartz vein formation. The phyllonites form hydrothermal segregation bands composed of alternating white mica-biotite, quartz ribbon, and relicts of feldspar. Granites and related shear rocks present a prominent E-W mylonitic foliation (S-n), defined by levels of mica and quartz ribbons. S-n is affected by isoclinal and asymmetric folds, which develop an axial plane foliation (S-n(+)1). The granites of SGAC are from the high K calc-alkaline series, and metaluminous to peraluminous, revealing some magmatic fractionation.