Finite Strain Quantification in Cariris Velhos Metagranitoids of Alagoa Grande (PB)Sérgio Wilians de Oliveira Rodrigues

Abstract

The Cariris Velhos Metagranitoids are considered an important geological unit of the Transversal Zone (BorboremaProvince – NE Brazil). We evaluated the use of raw and processed digital images to obtain the deformation ellipsoid for theCariris Velhos Metagranitoids using the Inertia Tensor and Intercepts methods. The ellipsoid symmetry of the deformedfabric was very similar for both methods, the Inertia Tensor and Intercepts, although with different anisotropy values.The orientations of the ellipsoid axes are similar to the orientation of geological structures observed in the field (principalfoliations and mineral lineations). When analyzing the characteristics of the deformation ellipsoids obtained in this study,it is worth pointing out the strong orientation of the C-axis (foliation pole) and the predominance of ellipsoids associatedwith planar to planar- linear fabrics (flattening field). The deformation observed in the Cariris Velhos Metagranitoids isassociated with the development under transpressive stress of regional Brasiliano shear zones.

Keywords

• Strain analysis
• Deformation ellipsoid
• Inertia tensor
• Intercepts method
• Cariris Velhos Metagranitoids