Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from Hornitos, Northern Chile
In this study we question the former interpretation of a shallow marine backwash tsunami origin of a conspicuous Pliocene coarse clastic unit at Hornitos, northern Chile, and instead argue for a debris flow origin for this unit. We exclude a relation to a tsunami in general and to the Eltanin impact...
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Online Access: | https://edoc.unibas.ch/63482/ https://doi.org/10.1016/j.sedgeo.2014.03.003 |
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ftunivbasel:oai:edoc.unibas.ch:63482 2023-05-15T18:25:49+02:00 Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from Hornitos, Northern Chile Spiske, Michaela Bahlburg, Heinrich Weiss, Robert 2014 https://edoc.unibas.ch/63482/ https://doi.org/10.1016/j.sedgeo.2014.03.003 unknown Elsevier Spiske, Michaela and Bahlburg, Heinrich and Weiss, Robert. (2014) Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from Hornitos, Northern Chile. Sedimentary Geology, 305. pp. 69-82. doi:10.1016/j.sedgeo.2014.03.003 info:isi/000336891600005 urn:ISSN:0037-0738 info:eu-repo/semantics/closedAccess Article PeerReviewed 2014 ftunivbasel https://doi.org/10.1016/j.sedgeo.2014.03.003 2023-03-05T07:18:46Z In this study we question the former interpretation of a shallow marine backwash tsunami origin of a conspicuous Pliocene coarse clastic unit at Hornitos, northern Chile, and instead argue for a debris flow origin for this unit. We exclude a relation to a tsunami in general and to the Eltanin impact in particular. The observed deposit at Hornitos was not generated either directly (impact-triggered tsunami) or indirectly (submarine mass flow caused by seismic shaking) by an impact. Re-calculation of the alleged impact tsunami including consideration of the Van Dorn effect shows that an impact in the Southern Ocean did not cause a significant tsunami at Hornitos. Impact-related seismic shaking was not able to trigger slides several thousands of kilometers away because the Eltanin event was a deep sea-impact that did not create a crater. Additionally, the biostratigraphic age of 5.1–2.8 Ma of the associated La Portada Formation is not concurrent with the newly established age of 2.511 ± 0.07 Ma for the Eltanin impact. Instead, we argue for an origin of the conspicuous unit at Hornitos as a debris flow deposit caused by an earthquake in the Andean subduction zone in northern Chile. Our re-interpretation considers the local synsedimentary tectonic background, a comparison to recent submarine tsunami sediments, and recent examples of mass wasting deposits along the Chilean margin. The increased uplift during the Pliocene caused oversteepening of the coastal scarp and entailed a contemporaneous higher frequency of seismic events that triggered slope failures and cliff collapses. The coarse clastic unit at Hornitos represents an extraordinary, potentially tsunami-generating mass wasting event that is intercalated with mass wasting deposits on a smaller scale. Article in Journal/Newspaper Southern Ocean University of Basel: edoc Southern Ocean Sedimentary Geology 305 69 82 |
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University of Basel: edoc |
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ftunivbasel |
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unknown |
description |
In this study we question the former interpretation of a shallow marine backwash tsunami origin of a conspicuous Pliocene coarse clastic unit at Hornitos, northern Chile, and instead argue for a debris flow origin for this unit. We exclude a relation to a tsunami in general and to the Eltanin impact in particular. The observed deposit at Hornitos was not generated either directly (impact-triggered tsunami) or indirectly (submarine mass flow caused by seismic shaking) by an impact. Re-calculation of the alleged impact tsunami including consideration of the Van Dorn effect shows that an impact in the Southern Ocean did not cause a significant tsunami at Hornitos. Impact-related seismic shaking was not able to trigger slides several thousands of kilometers away because the Eltanin event was a deep sea-impact that did not create a crater. Additionally, the biostratigraphic age of 5.1–2.8 Ma of the associated La Portada Formation is not concurrent with the newly established age of 2.511 ± 0.07 Ma for the Eltanin impact. Instead, we argue for an origin of the conspicuous unit at Hornitos as a debris flow deposit caused by an earthquake in the Andean subduction zone in northern Chile. Our re-interpretation considers the local synsedimentary tectonic background, a comparison to recent submarine tsunami sediments, and recent examples of mass wasting deposits along the Chilean margin. The increased uplift during the Pliocene caused oversteepening of the coastal scarp and entailed a contemporaneous higher frequency of seismic events that triggered slope failures and cliff collapses. The coarse clastic unit at Hornitos represents an extraordinary, potentially tsunami-generating mass wasting event that is intercalated with mass wasting deposits on a smaller scale. |
format |
Article in Journal/Newspaper |
author |
Spiske, Michaela Bahlburg, Heinrich Weiss, Robert |
spellingShingle |
Spiske, Michaela Bahlburg, Heinrich Weiss, Robert Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from Hornitos, Northern Chile |
author_facet |
Spiske, Michaela Bahlburg, Heinrich Weiss, Robert |
author_sort |
Spiske, Michaela |
title |
Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from Hornitos, Northern Chile |
title_short |
Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from Hornitos, Northern Chile |
title_full |
Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from Hornitos, Northern Chile |
title_fullStr |
Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from Hornitos, Northern Chile |
title_full_unstemmed |
Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from Hornitos, Northern Chile |
title_sort |
pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from hornitos, northern chile |
publisher |
Elsevier |
publishDate |
2014 |
url |
https://edoc.unibas.ch/63482/ https://doi.org/10.1016/j.sedgeo.2014.03.003 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
Spiske, Michaela and Bahlburg, Heinrich and Weiss, Robert. (2014) Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments – an example from Hornitos, Northern Chile. Sedimentary Geology, 305. pp. 69-82. doi:10.1016/j.sedgeo.2014.03.003 info:isi/000336891600005 urn:ISSN:0037-0738 |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.1016/j.sedgeo.2014.03.003 |
container_title |
Sedimentary Geology |
container_volume |
305 |
container_start_page |
69 |
op_container_end_page |
82 |
_version_ |
1766207494795821056 |