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Vegetation changes in the Neotropical Gran Sabana (Venezuela) around the Younger Dryas chron

Montoya, Encarnacion; Rull, Valenti; Stansell, Nathan D.; Bird, Broxton W.; Nogué, Sandra; Vegas-vilarrúbia, Teresa; Abbott, Mark B. and Díaz, Wilmer A. (2011). Vegetation changes in the Neotropical Gran Sabana (Venezuela) around the Younger Dryas chron. Journal of Quaternary Science, 26(2) pp. 207–218.

DOI (Digital Object Identifier) Link: https://doi.org/10.1002/jqs.1445
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Abstract

The occurrence of the Younger Dryas cold reversal in northern South America midlands and lowlands remains controversial. We present a palaeoecological analysis of a Late Glacial lacustrine section from a midland lake (Lake Chonita, 4.6501 °N, 61.0157 °W, 884 m elevation) located in the Venezuelan Gran Sabana, based on physical and biological proxies. The sediments were mostly barren from ∼15.3 to 12.7 k cal a BP, probably due to poor preservation. A ligneous community with no clear modern analogues was dominant from 12.7 to 11.7 k cal a BP (Younger Dryas chronozone). At present, similar shrublands are situated around 200 m elevation above the lake, suggesting a cooling-driven downward shift in vegetation during that period. The interval from 11.7 to 10.6 k cal a BP is marked by a dramatic replacement of the shrubland by savannas and a conspicuous increase in fire incidence. The intensification of local and regional fires at this interval could have played a role in the vegetation shift. A change to wetter, and probably warmer, conditions is deduced after 11.7 k cal a BP, coinciding with the early Holocene warming. These results support the hypothesis of a mixed origin (climate and fire) of the Gran Sabana savannas, and highlight the climatic instability of the Neotropics during the Late Glacial.

Item Type: Journal Item
Copyright Holders: 2011 John Wiley & Sons
ISSN: 0267-8179
Keywords: fire; Late Glacial; Neotropics; vegetation change; Younger Dryas
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 35714
Depositing User: Encarnacion Montoya Romo
Date Deposited: 11 Dec 2012 09:07
Last Modified: 07 Dec 2018 10:11
URI: http://oro.open.ac.uk/id/eprint/35714
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