The ancestors of meandering rivers

Autor(es)

de Almeida, Renato Paes ^{[1, 2]} ; Marconato, Andre ^[2] ; Freitas, Bernardo Tavares ^{[2, 3]} ; Turra, Bruno Boito ^[4]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Energia & Meio Ambiente, Ave Prof Luciano Gualberto 1289, BR-05508080 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Inst Geociencias, Rua Lago 562, Cidade Univ, BR-05508900 Sao Paulo, SP - Brazil

^[3] Univ Fed Itajuba, Inst Recursos Nat, Ave BPS 1303, BR-37500903 Itajuba, MG - Brazil

^[4] CPRM Geol Survey Brazil, Rua Costa 55, BR-01304010 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: GEOLOGY; v. 44, n. 3, p. 203-206, MAR 2016.
• Citações Web of Science: 9

Resumo

Modern alluvial plains, in contrast to their pre-Silurian counterparts, are characterized by the presence of meandering rivers in low-downstream-gradient areas, constituting efficient transport systems that maintain high bottom shear stresses in deep channels, which are made possible by bank stabilization, most commonly provided by vegetation in Earth's recent history. Here we show, through numerical modeling and field-based description of large-scale exposures in Mesoproterozoic successions, that prevegetation rivers in low-downstream-gradient areas were markedly different from both younger meandering rivers and the common prevegetation sheet-braided rivers, showing deeper braided channels and greater floodplain preservation than the latter. These systems were less frequent and had lower transport efficiency than modern meandering rivers, implying differences in global-scale Earth-surface dynamics, from the weathering of silicate minerals in floodplains to the grain size distribution in all clastic depositional systems. (AU)

• Processo FAPESP: 10/51103-6 - Sistemas de planicies de inundacao fluviais pre-vegetacao.
• Beneficiário: André Marconato
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 11/50280-4 - Arquitetura deposicional de sistemas aluviais pré-vegetação da Formação Tombador (Mesoproterozóico), Chapada Diamantina, BA
• Beneficiário: Renato Paes de Almeida
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 10/51559-0 - Evolucao tectono-sedimentar de sistemas aluviaisi pos-rift: o caso da formacao marizal (aptiano) nas sub-bacias do tucano norte e central
• Beneficiário: Bernardo Tavares Freitas
• Modalidade de apoio: Bolsas no Brasil - Doutorado