The Quaternary alluvial systems tract of the Pantanal Basin, Brazil

Abstract

ABSTRACT:The Pantanal Basin is an active sedimentary basin in central-west Brazil that consists of a complex alluvial systems tract characterized by the interaction between different river systems developed in one of the largest wetlands in the world. The Paraguay River is the trunk river system that drains the water and part of the sediment load received from areas outside of the basin. Depositional styles vary considerably along the river profiles throughout the basin, with the development of entrenched meandering belts, anastomosing reaches, and floodplain ponds. Paleodrainage patterns are preserved on the surface of abandoned lobes of fluvial fans, which also exhibit many degradational channels. Here, we propose a novel classification scheme according to which the geomorphology, hydrological regime and sedimentary dynamics of these fluvial systems are determined by the geology and geomorphology of the source areas. In this way, the following systems are recognized and described: (I) the Paraguay trunk-river plains; (II) fluvial fans sourced by the tablelands catchment area; (III) fluvial fans sourced by lowlands; and (IV) fluvial interfans. We highlight the importance of considering the influences of source areas when interpreting contrasting styles of fluvial architectures in the rock record. KEYWORDS: INVITED REVIEW RESUMO: A Bacia do Pantanal é uma bacia sedimentar situada no Centro-Oeste do Brasil, caracterizada pela presença de um moderno trato deposicional aluvial e pela interação de vários tipos de sistemas desenvolvidos em uma das maiores e mais importantes áreas úmidas do planeta. O Rio Paraguai representa o rio-tronco do sistema e drena a água e parte da carga sedimentar recebida de outras áreas extrabacinais. Os rios nos diferentes sistemas apresentam mudanças de estilo fluvial em consequência de fatores alogênicos e autogênicos, com desenvolvimento de cinturões de meandros incisos, domínios distributários não confinados e mundanças de canal único para padrões multicanal (anabranching). A superfície de lobos abandonados apresenta complexa

Basin‐scale predictive models of alluvial architecture: Constraints from the Palaeocene–Eocene, Bighorn Basin, Wyoming, USA

“…fluvial fan, trunk/axial/tributary rivers and interfan areas) within modern basins include the Pantanal Basin (Brazil) (e.g. Assine et al ., ), the Okavango (Botswana) (Stanistreet & McCarthy, ) and those discussed in Weissmann et al . (, e.g.…”

Hidden in plain sight: How finding a lake in the Brazilian Pantanal improves understanding of wetland hydrogeomorphology

“…The modern depositional tract is dominantly alluvial, characterized by the interplay of fluvial megafans, fluvial interfans, piedmont alluvial fans, and a trunk fluvial plain, which drains the surrounding plateaus (Assine et al, 2015b). Based on the geology and geomorphology of the source areas, and considering the hydrological regime and sedimentary dynamics, Assine et al (2015a) proposed a classification scheme for the tract with four main categories of systems ( Figure 1A): (I) the Paraguay trunk-river plains, (II) fluvial fans sourced by tableland catchment area, (III) fluvial fans sourced by lowlands, and (IV) fluvial interfans.…”

“…meandering, distributary, and anabranching patterns) that control the interplay of the depositional systems (Assine et al, 2015a). active tectonics).…”

“…The NRIS is even distinct from other interfan systems within the Pantanal Basin (see Figure 1A). Other interfan plains such the Corixo Grande and Negro (Bolivia) do not have perennial channels and are fed only by distributary channels of neighboring megafans and by the basin flood pulse (Assine et al,2015a ). Other interfan plains such the Corixo Grande and Negro (Bolivia) do not have perennial channels and are fed only by distributary channels of neighboring megafans and by the basin flood pulse (Assine et al,2015a ).…”

Optically stimulated luminescence and isothermal thermoluminescence dating of high sensitivity and well bleached quartz from Brazilian sediments: from Late Holocene to beyond the Quaternary?

“…The modern landscape comprises a mosaic of depositional environments, which reflects heterogeneous systems within a large depositional tract dominated by alluvial sedimentation (Assine 2003, Assine et al 2015. The sediment source area originate from the upper Paraguay catchment, which comprises dissected sedimentary rocks (Paraná Basin) and metamorphic rocks (Corumbá and Cuiabá groups) (Lacerda Filho et al 2004), under tropical-savannah (Aw) climate.…”