Resultados preliminares de los ángulos de extinción ondulante medidos en cuarzo de rocas provenientes de las Sierras Septentrionales, provincia de Buenos Aires

In Buenos Aires province there are numerous quarries of granites and metamorphic rocks which are used for various purposes. Different geotechnical tests, allow to characterize these materials and select which are the most appropriate according to the current regulations for each particular work. Preliminary petrographic study allows us to see compositions and textures of the rocks that may influence in their geotechnical response. Angle measurement undulating extinction quartz technique in particular, is used to estimate the possible reactivity of quartz against the alkali aggregate reaction. In this case, one of the available techniques for measuring this angle in order to compare the results of different lithologies was applied. Preliminary results presented here indicate that although most values are kept within acceptable limits marked for the method, there are differences between granites and metamorphic rocks. According to the interpretation presented here, such variations could be related to the type of rock, grade of metamorphism and tectonic deformation associated