Geomorphology on geologic timescales: evolution of the late Cenozoic Pacific paleosurface in Northern Chile and Southern Peru

Evenstar, L.A., Mather, A.E., Hartley, A.J., Stuart, F.M. , Sparks, R.S.J. and Cooper, F.J. (2017) Geomorphology on geologic timescales: evolution of the late Cenozoic Pacific paleosurface in Northern Chile and Southern Peru. Earth Science Reviews, 171, pp. 1-27. (doi:10.1016/j.earscirev.2017.04.004)

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Abstract

The Atacama Desert on the western margin of the Central Andes is one of the driest and oldest deserts in the world. It is defined by a distinct and ancient surface, known as the Pacific Paleosurface (PPS) or Atacama Paleosurface. The age of this surface is determined as the time at which sediment deposition ceased, and the surface was effectively abandoned. Early studies suggested that this abandonment took place between 14 and 10 Ma, and was related to both the uplift of the Andes and the onset of hyperaridity in the region. Here we provide a regional re-examination of the PPS, compiling existing work on the underlying geology, sedimentology, surface exposure dating, and seismic profiling. We also present new multispectral satellite maps of the PPS and 45 new cosmogenic 3He and 21Ne surface exposure ages in order to constrain the formation age, and the preservation and incision history of the paleosurface. We conclude that the PPS is not a single paleosurface, but instead is a mosaic of smaller surfaces that were formed by aggradational and degradational processes over 19 million years (or more) and should be termed collectively as the Pacific Paleosurfaces. The time at which individual paleosurfaces formed is related to regional climate, where the location of each is controlled by regional tectonic activity. Cosmogenic surface exposure ages suggest that the surfaces are a record of regional scale climate events.

Item Type:Articles
Additional Information:This study was funded by BHP Billiton.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Stuart, Professor Finlay
Authors: Evenstar, L.A., Mather, A.E., Hartley, A.J., Stuart, F.M., Sparks, R.S.J., and Cooper, F.J.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Earth Science Reviews
Publisher:Elsevier
ISSN:0012-8252
ISSN (Online):1872-6828
Published Online:08 April 2017
Copyright Holders:Copyright © 2017 Elsevier B.V.
First Published:First published in Earth Science Reviews 171:1-27
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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