Aeolian activity in northern Amazonia:optical dating of Late Pleistocene and Holocene palaeodunes
Date
2004
Authors
Teeuw, Richard
Rhodes, Edward
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley-VCH Verlag GMBH
Abstract
Palaeodunes were examined on the eastern margin of the Rio Branco-Rupununi savanna, northeast Amazonia. Optical dating suggests that the onset of aeolian activity was between 17 000 and 15 000 yr ago, just after the Last Glacial Maximum. Both the palaeodune axes and modern dominant wind directions have northeast to east-northeast directions, implying no significant shift in atmospheric circulation patterns over northeast Amazonia during the Late Pleistocene to Holocene. Major regional climate change events, such as the Younger Dryas, do not appear to have had any effect on the rates of aeolian deposition at the study site. Aeolian activity appears to have continued to the present day, showing a remarkably constant deposition rate of around 0.13 m kyr-1 initially, increasing smoothly to the present. Until more palaeodunes in northern Amazonia are dated, it is impossible to determine if this record of gradual aeolian deposition is a reliable regional palaeoclimate indicator, rather than being the result of local bioclimatic and geomorphological effects.
Description
Keywords
Keywords: chronology; dune field; eolian deposit; Holocene; luminescence; paleoenvironment; Pleistocene; sedimentation; Amazonia; South America Aeolian activity; Amazonia; Optical dating; Optically stimulated luminescence (OSL); Palaeodunes; Pleistocene-Holocene
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Source
Journal of Quaternary Science
Type
Journal article