Use of the Ellipsoid of Variographic Anisotropy as a Kinematic Indicator in Rock Massifs Fractured by Faults - the Example of the Cana Brava Chrysotile Asbestos Deposit (Minaçu, GO)

• Main Authors: Carlos Eduardo dos Santos, João Carlos Biondi
• Format: Article
• Language: English
• Published: Universidade de São Paulo 2011-12-01
• Series: Geologia USP. Série Científica
• Subjects: Ellipsoid of anisotropy; Kinematic indicator; Chrysotile deposit; Cana Brava
• Online Access: http://ppegeo-local.igc.usp.br/pdf/guspsc/v11n3/v11n3a04.pdf

The parameters of a variogram depend on which direction it is calculated, such as the ellipsoid of variographicanisotropy, whose axes indicate the directions of higher, medium and lower continuity of the variable used to calculate thevariogram. Consequently, the ellipsoid can be used as a kinematic indicator, since the anisotropy ellipsoids of blocks ofthe same rock massif or mineralized body will be rotated if the blocks are also rotated. The chrysotile ore body of the CanaBrava Asbestos deposit is composed of 13 blocks separated by faults. Comparing the ellipsoids of variographic anisotropyof the variable amount of chrysotile in these 13 blocks, it was observed that, although they are displaced in relation to eachother, in most cases this displacement was not caused by rotation. As a result, it was possible to group some blocks togetherand use only six ellipsoids and their respective variograms to estimate the amount of chrysotile in the deposit.