Mapeamento geológico e estudo das ocorrências de ferro do tipo skarn na região centro-este do arco magmático de Santa Quitéria-CE

Abstract

The study area is within the western portion of the municipaiity of Santa Quitéria , covering an area of 65 km 2 , the central-westem Ceará Central Domain Borborema Province . The mapping at 1:25,000 scale detail was carried out in various locations , such as Santo Antônio , Virginia and New Farm Farm Crispim , aims to describe the most representative rock types and their mineralization , and also perform structural, petrographic and mineralogy of the rocks observed in the area . The structural configuration of this region is marked by the existence of significant systems of ductile shear zones character, and with directions NE -SW , NNE- SSW and EW alignments marked by large geographical expression , characterized by Vauchez et ai . (1995 ) as a network of strike-slip faults developed during the performance of the Brasiliano orogeny . Supracrustal rocks such as marbie and metabasic rocks , migmatitic gneisses , granitoids and calcissilicate rocks were subjected to a first deformational / metamorphic event , where they were partially fused and features the type banding , foliation , lineation and foids were generated , followed by several events granitic intrusions of low angie and high angie ( thrust / trancorrências ) . This package was submitted to a second deformational / metamorphic event , which features such as brittle fractures , shear zones and faults were generated . During the granitic plutons intruded in orogênse sequences caicissilicates and carbonate rocks , resulting in halos of contact metamorphism , which later gave rise to the fluids of the skam type rocks . iron mineralization observed in the area are probably associated with these skams Manganese mineralization yet unknown origin were observed . The predominant degree of metamorphism corresponds to the mid-upper amphibolite facies , followed by corresponding to the greenschist facies metamorphic . Studies have confirmed the presence of some economically important minerais such as iron and manganese , but these were not considered economically viable. Given this scenario , the study area is formed by the association of supracrustal rocks , calcissilicáticas rocks , migmatitic gneisses , granitoids , skams , some mineralization of iron skarn type mineralization and manganese .