Late quaternary landscape evolution in the Atlantic Plateau (Brazilian highlands): Tectonic and climatic implications of fluvial archives

Transient hillslope erosion in slow evolution landscapes

“…For example, precipitation has been shown to be strongly modulated by orbital fluctuations (Cruz et al, 2009; Wang et al, 2007), with some speleothem records suggesting a wetter climate starting at 70 ka (Cruz et al, 2009), a timing comparable to the transition time inferred from our inversion results. Early and Middle Quaternary geomorphological markers, such as river terraces, are often poorly preserved in the area, but display strong climatic control on cycles of erosion and deposition (Barros & Magalhões Junior, 2020). The hypothesis that climatic fluctuations are the main driver of the increase in denudation rates is reinforced by the fact that there was a reduction in intraplate tectonic activity beginning in the Middle Quaternary or earlier in the southeastern highlands of Brazil (Salgado et al, 2016).…”

“…Nowadays, the climate of the Serra do Cipó Range is mesothermal, with mean annual temperature between 18°C and 19°C and mean annual precipitation ranging from 1250 to 1550 mm, with dry winters and wet summers. However, there are lines of evidence, from pedological and geomorphological records, that the region underwent many climatic changes during the Holocene and late Pleistocene, with occurrences of periods that were wetter and dryer than present‐day conditions (Barros & Magalhões Junior, 2020; Chueng et al, 2019; Silva et al, 2020).…”

“…Solid and dashed brown curves correspond to expectations for steady-state erosion and a constantly exposed surface, respectively. Production rates are calculated for the average conditions at the sampled sites in the Serra do Cip o (Figure 3), using a time-independent scaling scheme (Stone, 2000) [Color figure can be viewed at wileyonlinelibrary.com] Pleistocene, with occurrences of periods that were wetter and dryer than present-day conditions (Barros & Magalhões Junior, 2020;Chueng et al, 2019;Silva et al, 2020).…”

“…Gray lines are predictions for different timeconstant sediment transport coefficient scenarios. Blue and red curves correspond to the predictions associated with sets of parameters from the filled circles in panel A. Dark-green curve corresponds to the predictions with a sediment transport coefficient evolution mapped on the δ 18 O curve, ranging from 10 À5 to 3 Â 10 À4 m 2 /a [Color figure can be viewed at wileyonlinelibrary.com] deposition(Barros & Magalhões Junior, 2020). The hypothesis that climatic fluctuations are the main driver of the increase in denudation rates is reinforced by the fact that there was a reduction in intraplate tectonic activity beginning in the Middle Quaternary or earlier in the southeastern highlands of Brazil(Salgado et al, 2016).…”

The endorheic – Exorheic transition and later stage of fluvial incision in a wet tropical margin setting: The Atlantic draining Paraíba do Sul River basin (Brazil)

“…The present-day climate favours the development of a dense tropical forest -the Atlantic Forest; however, since the 19th century much of the natural vegetation has been cleared along the Paraíba do Sul River valley to make way for cultivated and grazing land. It is worth noting that Brazil's south-eastern plateau experienced several climate changes throughout the Quaternary, with drier and colder periods, interspersed with hotter and more humid periods (Barros and Magalães, 2020).…”