The coffee cycle represented a period of intense morphodynamic activity, proceeding by a general deforestation. On the Paraíba do Sul Middle Valley, this economic cycle lasted 100 years aproximately (1780-1880). Historical documents, radiocarbon dates and volumetric measurements of the valley fills correlated from the coffee time, have provided informations on the environmental impact, particularly associated with climatic and hidro-erosive processes both on the hillslopes and fluvial domains. Deforestation introduced a drought period up to 6 months and also to an increasing frequency of intense rainstorms, particularly in the summer. Along the Piracema river valley, sedimentation rates attained about 70.000m³km/year. Transfering this volume to the source-area on the hillslopes, it gives an estimate relief downwearing around 7,5 cm depth, resulting on the removal of the organic rich A horizon and showing so, the catastrophic effect of this economic activity, resulting in an extremely wasted degraded landscape.
High-resolution seismic reflection profiling: an aid for resolving the Pleistocene stratigraphy of a buried valley in central Illinois, USA
