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This work presents the evolution of geological history of the Alkalic Mass of Poços de Caldas, based on a lineament study. The lineaments are correlated to ruptil fractures on the ground. For this purpose, the fractal geometry of lineaments was used to explain the results.The lineaments were obtained from Landsat-TM and Radar images. Graphics were generated such as the cumulative frequency of direction, histograms of structural lineaments direction per cumulative length and a plot of direction by lineament length. A map of fractal dimension of these lineaments was generated too.The correspondence between the plans of processed data, the structural context and the location of mineralizations allowed to conclude: (1) the uranium mineralizations are associated to fractures oriented preferentially NW and NE and (2) the zirconium mineralizations are oriented preferentially NS and EW.

Ion-beam-assisted phase transformation in the Fe-N system has been studied in Fe samples implanted with N. By bombarding with Ar ions at temperatures in the 140°C < T < 420°C range, the &-Fe2N -+ e-Fe2+,N + e-Fen2N and e-Fe3,2N + y'-Fe4N phase transformations were induced. The ion-assisted phase transformations were studied as a function of firstly the temperature of the substrate, secondly the initial N concentration and thirdly the irradiation time.The results of the experiments show that the concomitant use of ion bombardment and temperature induces a given phase transformation at a temperature that is typically 40-50°C lower than that required for thermal annealing alone.