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Title: The role of abrupt climate change in the formation of an open vegetation enclave in northern Amazonia during the late Quaternary
Authors: Zular, André
Sawakuchi, André Oliveira
Chiessi, Cristiano Mazur
D'Horta, Fernando Mendonça
Cruz, Francisco W.
Dematt?, José Alexandre Melo
Ribas, Camila Cherem
Hartmann, Gelvam A.
Giannini, Paulo César Fonseca
Soares, Emílio Alberto Amaral
Keywords: Deposition
Glacial Geology
Magnetic Susceptibility
Abrupt Climate Change
Amazon Forests
Heinrich Stadial 1
Intertropical Convergence Zone
Last Glacial Maximum
Optically Stimulated Luminescence
Reflectance Analysis
Vegetation Environments
Climate Change
Climate Change
Climate Effect
Depositional Environment
Endemic Species
Heinrich Event
Intertropical Convergence Zone
Landscape Ecology
Last Glacial Maximum
Radiocarbon Dating
Southern Hemisphere
Vegetation Cover
Issue Date: 2019
metadata.dc.publisher.journal: Global and Planetary Change
metadata.dc.relation.ispartof: Volume 172, Pags. 140-149
Abstract: The effects of climate changes on biotic expansion or divergence is a widely debated topic. This discussion is particularly relevant for northern Amazonia where patches of open vegetation environments that harbor high endemic and specialized species are present in a matrix of tall closed canopy forest. This paper presents the depositional chronology and evolution of an 8.7-m thick stabilized fluvial and eolian sediment profile in a sandy plain substrate that underpins the largest open vegetation enclave in northern Amazonia. Three depositional units were identified using optically stimulated luminescence and radiocarbon ages coupled with grain size, magnetic susceptibility, and reflectance analyses. A lower unit of coarse fluvial silt deposited between 53 and 28 ka is overlain unconformably by a 5-m thick middle unit of fine eolian sand deposited at high accumulation rates between the Last Glacial Maximum (23–19 ka) and Heinrich Stadial 1 (HS1; 18.1–14.7 ka) when persistent and long-lasting shifts of the Intertropical Convergence Zone (ITCZ) to the Southern Hemisphere promoted dry and windy conditions in northern South America. An upper ~2-m thick unit was deposited when the climate became wetter after HS1, promoting the formation of soils that support open vegetation habitats. This study indicates that abrupt millennial-scale climate events can induce significant changes in the Amazonian landscape, which in turn play an essential role in the distribution and diversification of specialized biota. © 2018 Elsevier B.V.
metadata.dc.identifier.doi: 10.1016/j.gloplacha.2018.09.006
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