Silvio Hiruma

... O mapa de isovalores de Dd foi gerado pelo programa de sistema de informação geográfica (SIG) desenvolvido pelo INPE/ENGESPAÇO. Nas áreas de represas, onde a coleta de dados não foi possível, a inter-paIação foi feita a partir das celas vizinhas. ...

According to the autocorrelation, spectral Fourier and lag plot analyses, rainfall data don't show visible periodicities, the signal appears fairly random. The same analysis applied to the water level in the springs indicates the presence of an autoregressive model, there is high ...

The Bocaina Plateau, which is situated on the eastern flank of the continental rift of southeastern Brazil, is the highest part of the Serra do Mar. Topographic relief in this area is suggested to be closely related to its complex tectono-magmatic evolution since the breakup of Western Gondwana and opening of the South Atlantic Ocean. Apatite fission track ages and track length distributions from 27 basement outcrops were determined to assess these hypotheses and reconstruct the denudation history of the Bocaina Plateau. The ages range between 303 ± 32 and 46 ± 5 Ma, and are significantly younger than the stratigraphic ages. Mean track lengths vary from 13.44 ± 1.51 to 11.1 ± 1.48 μm, with standard deviations between 1.16 and 1.83 μm. Contrasting ages within a single plateau and similar ages at different altitudes indicate a complex regional tectonothermal evolution. The thermal histories inferred from these data imply three periods of accelerated cooling related to the Early Cretaceous continental breakup, Early Cretaceous alkaline magmatism, and the Paleogene evolution of the continental rift of southeastern Brazil. The oldest fission track ages (> 200 Ma) were obtained in the Serra do Mar region, suggesting that these areas were a long-lived source of sediments for the Paraná, Bauru, and Santos basins.