Modelado fractal en prospección geoquímica de las subcuencas de Alto Camaná y Hornillos Alto - Arequipa

Abstract

This thesis performs the processing of geochemical data in stream sediment and lithogeochemistry, using the fractal models Concentration - Area (CA) and Number - Size (NS), in order to determine new exploration targets of economically important minerals. Fractal models efficiently face several difficulties that come from the application of the traditional method (means and standard deviation). The most notorious ones are the elimination of the outliers and the logarithmic transformation of the dataset so that a normal or log-normal distribution is established. Both processes alter the dataset, which is not convenient. With the fractal models, the previous process is not necessary, all the data are used without exception and we work with any type of distribution. The first chapter describes the research environment, emphasizing on the problems of the traditional method to delineate geochemical anomalies. The specific general objectives of this thesis are presented, as well as describing the scope of the study. In the second chapter the description of the geology of the study area is made, touching on the topics of structural geology, geotectonics and economic geology. In the third chapter the concept of fractal geometry, its presence in nature, its applications in geology and fractal models for geochemical exploration have been extended. It also deals briefly with the hyperbolic method, which is used for the validation of chemical analyzes of large quantities of samples. In the fourth chapter we proceed with the application of the fractal model, both in stream sediment and lithogeochemical data, of the elements As, Cu, Cr, Hg, Mo, Ni, Pb and Zn. The different geochemical populations (background and anomalies) are determined and the maps of geochemical anomalies of each element are generated. In the fifth chapter, the use of different layers of information for the validation of the anomalous zones delimited by the fractal models is explained. These layers are mineral deposits and geological faults. Finally, the conclusions respond to the objectives set out at the beginning of this thesis; and the recommendations of new exploration targets are enunciated.