Fossil megafans evidenced by remote sensing in the Amazonian wetlands

Autor(es)

Rossetti, Dilce F. ^[1] ; Zani, Hiran ^[1] ; Cremon, Edipo H. ^[1]

Afiliação do(s) autor(es)

^[1] Brazilian Natl Inst Space Res, Div Remote Sensing, BR-12245970 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ZEITSCHRIFT FUR GEOMORPHOLOGIE; v. 58, n. 2, p. 145-161, JUN 2014.
• Citações Web of Science: 14

Resumo

In the present work, remote sensing data are analyzed for investigating if a set of Late Quaternary triangular, fan-shaped morphologies from a large wetland in northern Brazilian Amazonia corresponds to residual megafan deposits. The results revealed main characteristics suggestive of megafans, which include: fan shape; distribution on a low-lyirig wetland; wide individual areas of several tens or hundreds of km(2) in surface; concave-up and convex-up longitudinal and transverse profiles, respectively; very low gradient; axes pointing toward basement rocks and smooth slopes converging into the basin center; and surfaces with distributary drainage networks. The recognition of megafan systems with distributary drainage in this region is an interesting finding, as these megafans record a past landscape that differs from the modern fluvial tributary drainage of the Amazon basin. Characterizing these palaeomorphologies is of high relevance for reconstructing changes in the Amazonian landscape during the Late Quaternary. (AU)

• Processo FAPESP: 10/09484-2 - Megaleques quaternários no estado de Roraima, norte da Amazônia: implicações sedimentológicas, climáticas e tectônicas
• Beneficiário: Dilce de Fátima Rossetti
• Modalidade de apoio: Auxílio à Pesquisa - Regular