Remote sensing analysis of depositional landforms in alluvial settings: Method development and application to the Taquari megafan, Pantanal (Brazil)

Autor(es)

Zani, Hiran ^[1] ; Assine, Mario Luis ^[2] ; McGlue, Michael Matthew ^[3]

Afiliação do(s) autor(es)

^[1] Inst Nacl Pesquisas Espaciais, Div Sensoriamento Remoto, BR-12227010 Sao Jose Dos Campos - Brazil

^[2] Univ Estadual Paulista, Dept Geol Aplicada, BR-13506900 Rio Claro, SP - Brazil

^[3] Univ Arizona, Dept Geosci, Tucson, AZ 85721 - USA

• Tipo de documento: Artigo Científico
• Fonte: Geomorphology; v. 161, p. 82-92, AUG 1 2012.
• Citações Web of Science: 35

Resumo

Traditional Shuttle Radar Topography Mission (SRTM) topographic datasets hold limited value in the geomorphic analysis of low-relief terrains. To address this shortcoming, this paper presents a series of techniques designed to enhance digital elevation models (DEMs) of environments dominated by low-amplitude landforms, such as a fluvial megafan system. These techniques were validated through the study of a wide depositional tract composed of several megafans located within the Brazilian Pantanal. The Taquari megafan is the most remarkable of these features, covering an area of approximately 49,000 km(2). To enhance the SRTM-DEM, the megafan global topography was calculated and found to be accurately represented by a second order polynomial. Simple subtraction of the global topography from altitude produced a new DEM product, which greatly enhanced low amplitude landforms within the Taquari megafan. A field campaign and optical satellite images were used to ground-truth features on the enhanced DEM, which consisted of both depositional (constructional) and erosional features. The results demonstrate that depositional lobes are the dominant landforms on the megafan. A model linking baselevel change, avulsion, clastic sedimentation, and erosion is proposed to explain the microtopographic features on the Taquari megafan surface. The study confirms the potential promise of enhanced DEMs for geomorphological research in alluvial settings. (c) 2012 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 07/55987-3 - Sistemas deposicionais do quaternário (Pleistoceno tardio/holoceno) da Bacia do Pantanal Mato-Grossense, centro-oeste do Brasil
• Beneficiário: Mario Luis Assine
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 06/02381-8 - Construção e abandono de lobos deposicionais na evolução sedimentar do megaleque do Rio Taquari, Pantanal Mato-Grossense
• Beneficiário: Hiran Zani
• Modalidade de apoio: Bolsas no Brasil - Mestrado