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

Research output: Contribution to journalReview article

Original languageEnglish
Pages (from-to)1-27
Number of pages27
JournalEarth-Science Reviews
Volume171
Early online date8 Apr 2017
DOIs
DateAccepted/In press - 7 Apr 2017
DateE-pub ahead of print - 8 Apr 2017
DatePublished (current) - 1 Aug 2017

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.

    Research areas

  • Andes, Pediment, Paleosurface, Cosmogenic surface exposure dating, Atacama, Desert pavement, Landscape evolution, Climate, Tectonics, Remote sensing

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    Rights statement: This is the author accepted manuscript (AAM). The final published version (version of record) is available online via Elsevier at http://www.sciencedirect.com/science/article/pii/S0012825216302057. Please refer to any applicable terms of use of the publisher.

    Accepted author manuscript, 3 MB, PDF-document

    Licence: CC BY-NC-ND

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