Português

Abstract

The Chapada Diamantina is one of the few places in Brazil, where one can find drylands with a backswamp containing hundreds of dead deciduous trees in the floodplain. During the 18th century, the region was globally important due to the exploration of mineral resources. We obtained calibrated radiocarbon dates in the 18th century by analyzing four samples from the same tree’s bark and core. A simple sequence model was built, revealing a high probability that the tree lived until approximately 1720 AD. The death of trees was caused by silting in the main river, leading to the impoundment of the tributary river, where the axis of the fluvial course was permanently flooded. There are two possibilities to evaluate the 300-year-old Marimbus wetland: (i) insufficient time for the deposition of the alluvial fans, demonstrating the anthropogenic origin
of sediments concentrated where mining activities at the Chapada Diamantina were also concentrated;
and (ii) the exploration and use of mineral resources existed since the 18th century in the
Sincorá mountain range and has not been historically documented.