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Late Quaternary coastal evolution and aeolian sedimentation in the tectonically-active southern Atacama Desert, Chile

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posted on 17.11.2017 by David J. Nash, Mark D. Bateman, Joanna Bullard, Claudio Latorre
Analyses of aeolianites and associated dune, surficial carbonate and marine terrace sediments from north-central Chile (27° 54’ S) yield a record of environmental change for the coastal southern Atacama Desert spanning at least the last glacial-interglacial cycle. Optically stimulated luminescence dating indicates phases of aeolian dune construction at around 130, 111-98, 77-69 and 41-28 ka. Thin-section and stable carbon and oxygen isotope analyses suggest a predominantly marine sediment source for the three oldest dune phases. Aeolianites appear to have accumulated mainly from tectonically-uplifted interglacial marine sediments that were deflated during windier and/or stormier intervals. Bedding orientations indicate that sand-transporting winds varied in direction from S-ESE during MIS 5e and WNW-ESE during MIS 5c-5a. Winds from the southeast quadrant are unusual today in this region of the Atacama, suggesting either major shifts in atmospheric circulation or topographic airflow modification. Thin-section evidence indicates that the aeolianites were cemented by two phases of vadose carbonate, tentatively linked to wetter periods around 70 and 45 ka. Tectonic uplift in the area has proceeded at an average rate of 305-542 mm kyr-1. The study illustrates the complexity of understanding onshore-offshore sediment fluxes in the context of Late Quaternary sea-level fluctuations for an area undergoing rapid tectonic uplift.

Funding

This research was funded by the National Geographic Society (Research Grant 8493-08); by CONICYT (grant PFB-23) to the IEB; with additional support from the University of Brighton, University of Sheffield, and Loughborough University.

History

School

  • Social Sciences

Department

  • Geography and Environment

Published in

Palaeogeography, Palaeoclimatology, Palaeoecology

Citation

NASH, D.J. ...et al., 2018. Late Quaternary coastal evolution and aeolian sedimentation in the tectonically-active southern Atacama Desert, Chile. Palaeogeography, Palaeoclimatology, Palaeoecology, 490, pp. 546-562.

Publisher

© Elsevier

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

16/11/2017

Publication date

2018

Notes

This paper was published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology and the definitive published version is available at https://doi.org/10.1016/j.palaeo.2017.11.040.

ISSN

0031-0182

Language

en

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