Late Pleistocene glacial forest of Humaitá—Western Amazonia

Glacial-aged vegetation dynamics of the Humaitá—Western Brazilian Amazonia were studied by pollen, sedimentary facies, 14C dating, δ13Corg and C/Nmolar. Two sediment cores were taken to a depth of 10 and 8m from areas covered by grassland and dense/open forest, respectively. The deposits represent a...

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Bibliographic Details
Published in:Palaeogeography, palaeoclimatology, palaeoecology palaeoclimatology, palaeoecology, 2014-12, Vol.415, p.37-47
Main Authors: Cohen, M.C.L., Rossetti, D.F., Pessenda, L.C.R., Friaes, Y.S., Oliveira, P.E.
Format: Article
Language:English
Subjects:
Alnus
Brazilian Amazonia
C isotope
Ilex
Last Glacial Maximum
Palynology
Podocarpus
Sedimentary facies
Weinmannia
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Summary:Glacial-aged vegetation dynamics of the Humaitá—Western Brazilian Amazonia were studied by pollen, sedimentary facies, 14C dating, δ13Corg and C/Nmolar. Two sediment cores were taken to a depth of 10 and 8m from areas covered by grassland and dense/open forest, respectively. The deposits represent a succession of sediment accumulation in active channel (>42,600cal yr B.P.), abandoned channel/floodplain (>42,600 to ~39,000cal yr B.P.), and oxbow lake sedimentary environments (~39,000cal yr B.P. to modern). The predominance of mud sediments, depletion of δ13Corg and decrease in C/Nmolar values identify the lake establishment. In these settings, low energy subaqueous conditions were developed, locally favoring preservation of a pollen assemblage representing herbaceous vegetation, some modern taxa from Amazonia and cold-adapted plants from the Andes represented by Alnus (2–11%), Hedyosmum (2–17%), Weinmannia (0–18%), Podocarpus (0–4%), Ilex (0–4%) and Drymis (0–1%), at least between >42,600 and
ISSN:0031-0182
1872-616X
DOI:10.1016/j.palaeo.2013.12.025