Long-term evolution of denudational escarpments in southeastern Brazil

Cherem, Luís Felipe Soares; Varajão, César Augusto Chicarino; Braucher, Régis; Bourlès, Didier; Salgado, André Augusto Rodrigues; Varajão, Angélica C.

doi:10.1016/j.geomorph.2012.06.002

Cited by 42 publications

(46 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…2008Cherem et al, 2012;Lal et al, 2012;Barreto et al, 2013Barreto et al, , 2014Hinderer et al, 12! 2013, Rezende et al, 2013, Brocard et al, 2014aNichols et al, 2014). Of the eight papers that 13!…”

Section: !mentioning

confidence: 99%

See 1 more Smart Citation

Long-term background denudation rates of southern and southeastern Brazilian watersheds estimated with cosmogenic 10Be

et al. 2016

View full text Add to dashboard Cite

LongNew data from 14 watersheds in the states of Santa Catarina (n = 7) and Rio de Janeiro (n = 7) show that erosion rates vary there from 13 to 90 m/My (mean = 32 m/My; median = 23 m/My) and that the difference between erosion rates of basins we sampled in the two states is not significant. Sampled basin area ranges between 3 and 14,987 km 2 , mean basin elevation between 235 and 1606 m, and mean basin slope between 11 and 29°. Basins sampled in Rio de Janeiro, including three that drain the Serra do Mar escarpment, have an average basin slope of 19°, whereas the average slope for the Santa Catarina basins is 14°. Mean basin slope (R 2 = 0.73) and annual precipitation (R 2 = 0.57) are most strongly correlated with erosion in the basins we studied. At three sites where we sampled river sand and cobbles, the 10 Be concentration in river sand was greater than in the cobbles, suggesting that these grain sizes are sourced from different parts of the landscape.Compiling all cosmogenic 10 Be-derived erosion rates previously published for southern and southeastern Brazil watersheds to date (n = 76) with our 14 sampled basins, we find that regional erosion rates (though low) are higher than those of watersheds also located on other passive margins including Namibia and the southeastern North America. Brazilian basins erode at a pace similar to escarpments in southeastern North America. Erosion rates in southern andsoutheastern Brazil are directly and positively related to mean basin slope (R 2 = 0.33) and weakly but significantly to mean annual precipitation (R 2 = 0.05). These relationships are weaker when considering all southern and southeastern Brazil samples than they are in our smaller, localized data set. We find that smaller, steeper headwater catchments (many on escarpments) erode faster than the larger, higher-order but lower slope catchments. Erosion in southern and southeastern Brazil appears to be controlled largely by mean basin slope with lesser influence by climate and lithology.

show abstract

Section: !mentioning

confidence: 99%

“…, 2008Salgado et al, 300! , 2013Cherem et al 2012;Barreto et al, 2013Barreto et al, , 2014Rezende et al, 2013; this 301! study; Table DR2).…”

Section: !unclassified

Long-term background denudation rates of southern and southeastern Brazilian watersheds estimated with cosmogenic 10Be

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Contemporary sediment yield and cosmogenically-derived erosion rates for three of the rivers we studied are similar, suggesting that human activities are not increasing sediment yield above long-term erosion rate averages in Panama. , 2006Cherem et al, 2012;Barreto et al, 2013Barreto et al, , 2014; Rezende et al, …”

mentioning

confidence: 99%

Long-term erosion rates of Panamanian drainage basins determined using in situ 10 Be

et al. 2016

View full text Add to dashboard Cite

Erosion rates of tropical landscapes are poorly known. Using measurements of in situproduced 10 Be in quartz extracted from river and landslide sediment samples, we calculate longterm erosion rates for many physiographic regions of Panama. We collected river sediment samples from a wide variety of watersheds (n = 35), and then quantified 24 landscape-scale variables (physiographic, climatic, seismic, geologic, and land-use proxies) for each watershed before determining the relationship between these variables and long-term erosion rates using linear regression, multiple regression, and analysis of variance (ANOVA). We also used grainsize-specific 10 Be analysis to infer the effect of landslides on the concentration of 10 Be in fluvial sediment and thus on erosion rates. The strongest and most significant relationship in the dataset was between erosion rate and silicate weathering rate, the mass of material leaving the basin in solution. None of the topographic variables showed a significant relationship with erosion rate at the 95% significance level; we observed weak but significant correlation between erosion rates and several climatic variables related to precipitation and temperature. On average, erosion rates in Panama are higher than other cosmogenically-derived erosion rates in tropical climates including those from Puerto Rico, Madagascar, Australia and Sri Lanka, likely the result of Panama's active tectonic setting and thus high rates of seismicity and uplift. Contemporary sediment yield and cosmogenically-derived erosion rates for three of the rivers we studied are similar, suggesting that human activities are not increasing sediment yield above long-term erosion rate averages in Panama.3 10 Be concentration is inversely proportional to grain size in landslide and fluvial samples from Panama; finer grain sizes from landslide material have lower 10 Be concentration than finegrained fluvial sediment. Large grains from both landslide and stream sediments have similarly low 10 Be concentrations. These data suggest that fluvial gravel is delivered to the channel by landslides whereas sand is preferentially delivered by soil creep and bank collapse. Furthermore, the difference in 10 Be concentration in sand-sized material delivers by soil creep and that delivered by landsliding suggests that the frequency and intensity of landslides influences basin scale erosion rates.

show abstract

“…Estudos sobre áreas de grandes divisores são comuns na região Sudeste do Brasil (VALADÃO, 1998;CHEREM et al,2012; Porém, apesar da importância que os grandes divisores hidrográfi cos possuem para a elucidação e compreensão da evolução do relevo, poucos foram os estudos que, mesmo tangencialmente, se dedicaram a esse tema na região sul do Brasil. Tal lacuna é ainda mais evidente no interior do Planalto de Santa Catarina (Figura 1).…”

Section: Introductionunclassified

Evolução Do Relevo Em Áreas De Tríplice Divisor De Águas Regional - O Caso Do Planalto De Santa Catarina: Análise Da Rede Hidrográfica

Sordi

Salgado

Paisani

2015

Rev. Bras. Geomorfol.

View full text Add to dashboard Cite

Resumo:No Planalto interior de Santa Catarina se localiza o divisor hidrográfi co entre três das principais bacias hidrográfi cas da região sul do Brasil: Uruguai, Paraná (Iguaçu) e Itajaí-Açu-Açu. Considerando-se que a evolução do relevo em áreas de tríplice divisor regional está intimamente relacionada à dinâmica erosiva dos cursos fl uviais, o presente trabalho investiga a importância dos processos de dissecação do relevo e de capturas fl uviais para a confi guração do modelado dessa região. Para isso, foram aplicadas técnicas de análise morfométricas e morfológicas. Os resultados permitiram estabelecer uma hierarquização do grau de dissecação: (i) áreas pertencentes à bacia do rio Itajaí-Açu são as mais dissecadas, com maior amplitude altimétrica, maior densidade de drenagem e nível de base regional mais baixo; os perfi s são mais íngremes e os valores de RDE são elevados; (ii) áreas menos dissecadas, de baixa amplitude altimétrica e densidade drenagem e nível de base regional mais elevado pertencem bacia do rio Paraná (Iguaçu); os perfi s topográfi cos são mais suaves e os valores de RDE mais baixos e (iii) áreas pertencentes à bacia do rio Uruguai, apresentam níveis de dissecação, amplitude altimétrica, densidade de drenagem e nível de base regional intermediários, assim como seus perfi s e os valores de RDE. Deste modo, Informações sobre o Artigo

show abstract

Long-term evolution of denudational escarpments in southeastern Brazil

Cited by 42 publications

References 57 publications

Long-term background denudation rates of southern and southeastern Brazilian watersheds estimated with cosmogenic 10Be

Long-term background denudation rates of southern and southeastern Brazilian watersheds estimated with cosmogenic 10Be

Long-term erosion rates of Panamanian drainage basins determined using in situ 10 Be

Evolução Do Relevo Em Áreas De Tríplice Divisor De Águas Regional - O Caso Do Planalto De Santa Catarina: Análise Da Rede Hidrográfica

Contact Info

Product

Resources

About