SciELO - Scientific Electronic Library Online

 
vol.91 suppl.2Distributional patterns of Aptian-Albian paleoichthyofauna of Brazil and Africa based on Track AnalysisA new saurolophine hadrosaurid (Dinosauria: Ornithopoda) from the Upper Cretaceous of Shandong, China author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand

Journal

Article

Indicators

Related links

Share


Anais da Academia Brasileira de Ciências

Print version ISSN 0001-3765On-line version ISSN 1678-2690

Abstract

GUIMARAES, JOSÉ T.F. et al. Holocene history of a lake filling and vegetation dynamics of the Serra Sul dos Carajás, southeast Amazonia. An. Acad. Bras. Ciênc. [online]. 2019, vol.91, suppl.2, e20160916.  Epub July 24, 2017. ISSN 1678-2690.  https://doi.org/10.1590/0001-3765201720160916.

Down-core changes in sedimentary facies, elemental geochemistry, pollen, spore, δ13C, δ15N and radiocarbon records from a filled lake, named R4, of the Serra Sul dos Carajás were used to study the relationship between the paleomorphological and paleoecological processes and their significance for Holocene paleoclimatology of the southeast Amazonia. The sediment deposition of the R4 lake started around 9500 cal yr BP. Increase of detrital components from 9500 to 7000 cal yr BP suggests high weathering of surrounding catchment rocks and soils, and deposition into the lake basin under mudflows. At that time, montane savanna and forest formation were already established suggesting predominance of wet climate. However, from 7000 to 3000 cal yr BP, a decline of detrital input occurred. Also, forest formation and pteridophytes were declined, while palms and macrophytes were remained relatively stable, indicating that water levels of the lake is likely dropped allowing the development of plants adapted to subaerial condition under drier climate conditions. After 3000 cal yr BP, eutrophication and low accommodation space lead to high lake productivity and the final stage of the lake filling respectively, and forest formation may has acquired its current structure, which suggests return of wetter climate conditions.

Keywords : Amazon Forest; canga vegetation; palynology; carbon and nitrogen isotopes; geochemistry.

        · text in English     · English ( pdf )