Acknowledgements

Our thanks to all graduate and post-graduate students, who participated in this project for the last 20 year, specially to M. L. Santos for processing the Landsat image. We are grateful to Frank Söllner for special geochronology samples and Alexander Rocholl for discussion on the results. The following institutions directly or indirectly supported this research: CNPq, FINEP and CAPES (Brazil), the Universiy of Munich (LMU) and DAAD (Germany) and the University of Utrecht (Netherlands). We are deeply indebted to Roberto Weinberg and to an anonymous reviewer for thoughtful and careful reviews, which greatly improved the first version of this manuscript.