Evolution of the West Andean Escarpment at 18 degrees S (N. Chile) during the last 25 Ma: uplift, erosion and collapse through time
2002 | journal article. A publication with affiliation to the University of Göttingen.
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Evolution of the West Andean Escarpment at 18 degrees S (N. Chile) during the last 25 Ma: uplift, erosion and collapse through time
Worner, G. ; Uhlig, D.; Kohler, I. & Seyfried, H. (2002)
Tectonophysics, 345(1-4) art. PII S0040-1951(01)00212-8. DOI: https://doi.org/10.1016/S0040-1951(01)00212-8
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- Authors
- Worner, G. ; Uhlig, D.; Kohler, I.; Seyfried, H.
- Abstract
- The geological record of the Western Andean Escarpment (WARP) reveals episodes of uplift, erosion, volcanism and sedimentation. The lithological sequence at 18degreesS comprises a thick pile of Azapa Conglomerates (25-19 Ma), an overlying series of widespread rhyodacitic Oxaya Ignimbrites (up to 900 m thick, ca. 19 Ma), which are in turn covered by a series of mafic andesite shield volcanoes. Between 19 and 12 Ma, the surface of the Oxaya Ignimbrites evolved into a large monocline on the western slope of the Andes. A giant antithetically rotated block (Oxaya Block, 80 kmx20 km) formed on this slope at about 10-12 Ma and resulted in an easterly dip and a reversed drainage on the block's surface. Morphology, topography and stratigraphic observations argue for a gravitational cause of this rotation. A "secondary" gravitational collapse (50 km(3)), extending 25 kin to the west occurred on the steep western front of the Oxaya Block. Alluvial and fluvial sediments (11-2.7 Ma) accumulated in a half graben to the east of the tilted block and were later thrust over by the rocks of the escarpment wall, indicating further shortening between 8 and 6 Ma. Flatlying Upper Miocene sediments (<5.5 Ma) and the 2.7 Ma Lauca-Perez Ignimbrite have not been significantly shortened since 6 Ma, suggesting that recent uplift is at least partly caused by regional tilting of the Western Andean slope. (C) 2002 Elsevier Science B.V. All rights reserved.
- Issue Date
- 2002
- Status
- published
- Publisher
- Elsevier Science Bv
- Journal
- Tectonophysics
- Organization
- Fakultät für Geowissenschaften und Geographie
- ISSN
- 0040-1951