Geophysical and petrophysical footprint of IOCG mineralization of Salobo Deposit, Carajás Mineral Province.
Geophysical Footprint, Petrophysical Footprint, Salobo Deposit.
The thesis aims to characterize the geophysical and petrophysical signatures associated with the Iron Oxide Copper Gold (IOCG) mineralizations of the Salobo deposit. Particular emphasis will be placed on the deep portions of the deposit, as the investigation draws upon of multisource and multiscale geophysical dataset and the physical properties of the rocks. Historically, qualitative petrophysical data have been employed to guide the drilling core sampling. To characterize variations in host rocks, hydrothermal alteration zones, and ore deposits, six drill holes from the Salobo project were analyzed. From the holes that segment the Deep Salobo, 84 samples have been collected for the acquisition of petrophysical, petrographic, and lithogeochemical data. Following the sample collect, new petrophysical data such as density, magnetic susceptibility, conductivity, chargeability, and resistivity was acquired, and the counter samples were sent for chemical analysis. Furthermore, 56 of the 84 samples were chosen for the preparation of polished slides for QEMSCAN analysis. Airborne and ground geophysical data, including magnetometry, gravity gradiometric, gamma-spectrometry, time-domain electromagnetometry, and induced polarization methods has been analyzed and interpreted. The processing was divided into pre-processing, processing, transformed map creation, and inversion processes. The results and interpretations were analyzed and interpreted at different scales to obtain an improved understanding and the definition of the mineralization signature, as well as to determine the benefits of each method for the characterization of Salobo Deposit. Analyses were performed on regional scales, using airborne data from the Brazilian Geological Survey (SGB), on a district scale, using Vale high-resolution airborne data, and on a deposit scale, using Vale ground geophysical data. The first chapter presents the main scope for this research, as well as the goals, materials and methods that were used. Chapter II presents the results and partial discussions of the characterization of the geophysical footprint of Salobo in the form of a scientific technical article titled "The Geophysical Signature of Salobo Deposit and its Implications for Mineral Exploration," as well as the regional geological context. The third chapter contains the following steps in this research as well as a planned timetable of activities. All of the references from Chapter I are included in Chapter IV.