Pleistocene-Holocene sedimentary deposits of the Solimões-Amazonas fluvial system, Western Amazonia

Passos, Marcel Silva; Soares, Emílio Alberto Amaral; Tatumi, Sônia Hatsue; Yee, Márcio; Mittani, Juan Carlos Ramírez; Hayakawa, Ericson Hideki; Salazar, Carlos Alejandro

doi:10.1016/j.jsames.2019.102455

Cited by 15 publications

(23 citation statements)

References 61 publications

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“…7 ). Although above flood limits today, the site is at an elevation known to have been inundated in the early Holocene and possibly into the middle Holocene 49 . We do not expect a significant contribution from the modern river water or water table because Sr and Nd are mainly found in the mineral phase.…”

Section: Resultsmentioning

confidence: 99%

A new hypothesis for the origin of Amazonian Dark Earths

et al. 2021

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Amazonian Dark Earths (ADEs) are unusually fertile soils characterised by elevated concentrations of microscopic charcoal particles, which confer their distinctive colouration. Frequent occurrences of pre-Columbian artefacts at ADE sites led to their ubiquitous classification as Anthrosols (soils of anthropic origin). However, it remains unclear how indigenous peoples created areas of high fertility in one of the most nutrient-impoverished environments on Earth. Here, we report new data from a well-studied ADE site in the Brazilian Amazon, which compel us to reconsider its anthropic origin. The amounts of phosphorus and calcium—two of the least abundant macronutrients in the region—are orders of magnitude higher in ADE profiles than in the surrounding soil. The elevated levels of phosphorus and calcium, which are often interpreted as evidence of human activity at other sites, correlate spatially with trace elements that indicate exogenous mineral sources rather than in situ deposition. Stable isotope ratios of neodymium, strontium, and radiocarbon activity of microcharcoal particles also indicate exogenous inputs from alluvial deposition of carbon and mineral elements to ADE profiles, beginning several thousands of years before the earliest evidence of soil management for plant cultivation in the region. Our data suggest that indigenous peoples harnessed natural processes of landscape formation, which led to the unique properties of ADEs, but were not responsible for their genesis. If corroborated elsewhere, this hypothesis would transform our understanding of human influence in Amazonia, opening new frontiers for the sustainable use of tropical landscapes going forward.

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Section: Resultsmentioning

confidence: 99%

A new hypothesis for the origin of Amazonian Dark Earths

et al. 2021

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“…The detailed characterization of the fluvial systems in the Amazon is still a hard task due to the large extension of the area and ubiquitous forest vegetation cover, but the remote sensing data has allowed to improve the knowledge on the alluvial deposits (e.g. Hayakawa et al, 2010;Passos et al, 2020). Currently, easy access to emerging remote sensing methods and tools such as high-resolution spatial data such as aerial and satellite imagery or digital elevation models provides enormous opportunities to produce more accurate and detailed geomorphological maps (Bangen et al, 2014;Jones et al, 2007;Williams et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Geomorphology of fluvial deposits in the middle Tocantins River, eastern Amazon

et al. 2020

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This paper presents the geomorphological mapping at a 1:100,000 scale of fluvial deposits in the middle Tocantins River. The region preserves an important sedimentary archive of environmental changes of the Amazon and Cerrado biomes. Yet, the region is under influence of diverse anthropogenic activities, including planned or operational hydropower plants, and detailed geomorphological mapping is lacking. The mapping combined interpretation of surface geomorphic features, morphometric analysis, and field surveys. Three main geomorphic units were defined: (i) fluvial plain, (ii) fluvial terraces, and (iii) paleo-alluvial fans. The detailed mapping survey allowed a hierarchical organization of geomorphological units as well as their relative chronology of formation. Our results improve the understanding on the complex geomorphological processes which shape the current fluvial landscape. Specifically, improving the understanding of the Tocantins River floodplains is crucial to support conservation of flooded forests, sustainable use of natural resources and minimize socioeconomic losses and damages.

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“…Additionally, the graben margin faults are not coincident with the valley margins (as interpreted in many previous works, e.g. Latrubesse & Franzinelli, 2002, Rossetti et al 2014, Passos et al 2020, and are not visible at all, as the incipient escarpments are constantly being eroded and covered by the intense alluvial dynamics.…”

Section: Topography Due To Tectonismmentioning

confidence: 75%

“…Rossetti et al, 2014) and distribution of altitudes, orientation and width of in-valley alluvial plains (e.g. Latrubesse & Franzinelli, 2002, Rossetti et al 2014, Passos et al 2020 in Amazonia.…”

Section: Topography Due To Tectonismmentioning

confidence: 99%

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Numerical model of alluvial terrace and valley evolution applied to the Quaternary of Central Amazonia

Prado¹

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Gostaria de agradecer primeiramente ao meu orientador Prof. Dr. Renato Paes de Almeida, que participou de minha formação desde a graduação em Geofísica, onde me orientou na Iniciação Científica. Agradeço pela intensa participação na proposta e desenvolvimento deste trabalho e pelo apoio em momentos de dificuldade. Agradeço aos integrantes do grupo de pesquisa Mocó, Carlos Eduardo Manjon Maz oca, Geovana Leite Geraldo, Larissa Natsumi Tamura, Liliane Janikian e Lucas Corrêa D'Almeida qu e participaram de momentos chave no desenvolvimento deste trabalho. E principalmente agradeço ao companheiro de trabalho Cristiano Padalino Galeazzi que participou de discussões cruciais para o desenvolvimento deste trabalho e se disponibilizou a revisar detalhadamente toda a dissertação. Agradeço à Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP-Proc. 2018/02197-0) pela concessão da bolsa de mestrado e pelo apoio financeiro para a realização desta pesquisa. Também agradeço a Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) pelo apoio. Aos professores, funcionários e alunos do IGc-USP pela amizade e pela ajuda em diferentes necessidades durante o mestrado. Agradeço à minha companheira Beatriz pelo seu apoio, carinho e paciência durante todo o desenvolvimento deste trabalho. Ao meu pai Antônio e à minha mãe Heloísa por sua confiança e apoio desde a minha infância. E a todos os amigos que de forma indireta me ajudaram durante todo esse percurso.

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Pleistocene-Holocene sedimentary deposits of the Solimões-Amazonas fluvial system, Western Amazonia

Cited by 15 publications

References 61 publications

A new hypothesis for the origin of Amazonian Dark Earths

A new hypothesis for the origin of Amazonian Dark Earths

Geomorphology of fluvial deposits in the middle Tocantins River, eastern Amazon

Numerical model of alluvial terrace and valley evolution applied to the Quaternary of Central Amazonia

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