Geochemistry of organic matter by multi-proxy analyses and temperature sensitivity of methanogenesis in clearwater Amazonian lake sediments

Pereira, Vinícius B.; Lopes, Alexander A.; Sasso, Marco Aurélio Dal; Amora-Nogueira, Leonardo; Fonseca, Thairiny; Marotta, Humberto; Cordeiro, Renato Campello; Azevedo, Débora de Almeida

doi:10.1016/j.apgeochem.2022.105467

Cited by 2 publications

(1 citation statement)

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“…Together with palynological analyses, C and N isotopes were very important to elucidate factors related to floristic composition, history of plant communities and sources of organic matter in Carajás lakes (Guimarães et al 2023a). A detailed characterization of the organic matter components is a challenge, since it presents multiple sources, representing dynamic components of the sediments (Pereira et al 2022). Facies analysis identifies the nature and scale of the physical processes that act in each sedimentary environment, with greater robustness in the interpretation of paleoenvironmental changes and in the distribution of vegetation in tropical forests during the Pleistocene-Holocene (Reis et al 2017, Guimarães et al 2021.…”

Section: Introductionmentioning

confidence: 99%

Late Quaternary hydroclimate and vegetation changes in an upland lake in southeastern Amazonia

SILVA,

LOPES,

ALVES

et al. 2023

An. Acad. Bras. Ciênc.

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An integrated approach considering facies, isotopic, and palynological analyses of lake sediments from the Serra Norte de Carajás, southeastern Amazonia, is presented in this work to refine paleoclimate and paleohydrological changes based on upland lake sediments during the late Quaternary. The sediments have a fining-upward deposition cycle typical of upland swamps/lakes. The origin of organic matter is autochthonous mainly related to C 3 terrestrial plants, macrophytes and algae. The pollen records of Hedyosmum during the Early Pleistocene suggest lower temperatures than those observed along Holocene. In the transitional period between the Pleistocene and the Holocene, rainfall decreased, causing the retraction of the flooded area, favoring the development of marshy conditions. The Late and Middle Holocene were marked by higher temperatures and lower humidity. Afterward, the increased pollen concentration from canga and forest vegetation, macrophytes, palms, and algae suggested increased humidity in the Early Holocene. The relative contribution of forest pollen along the records indicated that drier conditions were not strong enough for an extensive expansion of canga over forested areas.

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Section: Introductionmentioning

confidence: 99%