Variação Secular No Brasil De 1900 A 2000: Uma Comparação Com O Modelo Elemag

Values of the geomagnetic total field (F) obtained at<br>repeat stations in Brazil for the period 1900 to 2000<br>were analyzed. These data were compared with that<br>obtained through the theoretical model ELEMAG,<br>prepared at the Observatório Nacional. The<br>comparison indicates that the model provides a good<br>fit to geomagnetic variation at repeat stations,<br>important to the study of the secular variation. In<br>some stations the discrepancy between the real and<br>the theoretical data is higher than the average<br>deviation. These stations were analyzed taking into<br>account their geological characteristics and this has<br>allowed the identification of the presence of crustal<br>anomalies. For the anomaly stations on South and<br>Southeast Brazil it has been possible to identify<br>relationships with the Mesozoic flood volcanism of<br>the Paraná Basin.