New evidence for a major late Quaternary submarine landslide on the external western levee of Laurentian Fan
The Laurentian Fan is one of the largest submarine fans on the western margin of the North Atlantic. Recently acquired high-resolution multibeam bathymetric data (60 m horizontal resolution) reveal a major mass transport deposit (MTD) on the Western Levee of Western Valley (WLWV), covering >1...
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2018
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crescholarship:10.31223/osf.io/c7a4x 2024-09-15T18:22:49+00:00 New evidence for a major late Quaternary submarine landslide on the external western levee of Laurentian Fan Normandeau, Alexandre Campbell, D. Piper, David Jenner, Kimberley 2018 http://dx.doi.org/10.31223/osf.io/c7a4x unknown California Digital Library (CDL) http://opensource.org/licenses/AFL-3.0 posted-content 2018 crescholarship https://doi.org/10.31223/osf.io/c7a4x 2024-07-25T04:24:15Z The Laurentian Fan is one of the largest submarine fans on the western margin of the North Atlantic. Recently acquired high-resolution multibeam bathymetric data (60 m horizontal resolution) reveal a major mass transport deposit (MTD) on the Western Levee of Western Valley (WLWV), covering >14 000 km2 in water depths from 3900 m to >5000 m. Typical submarine landslide features are observed such as headscarps that in places reach the crest of the levee, crown cracks, extensional ridges, blocky debris and flow lineations. Multiple headwalls are observed on 3.5 kHz sub-bottom profiles indicating that the landslide retrogressed upslope. While the upper parts of the MTD consist of intact blocks that were displaced downslope as ridges and troughs, the lower parts exhibit a ~30 m thick incoherent to transparent acoustic facies typical of debris flows. Landslide geomorphology thus suggests that it was generated as a retrogressive spread and that slide blocks disintegrated downslope to become a blocky landslide with a surficial debris flow. The blocky landslide/debris flow extends downslope ~90 km and partially fills a submarine channel. The superposition of the MTD filling the channel and its location at the top of the stratigraphic succession in the levee suggests that it is late Quaternary in age, possibly Holocene. Deeper seismic reflection data also show that this is a rare event during the Quaternary; it is the largest MTD observed in the upper ~375 m of the levee succession and among the largest and deepest in the Western North Atlantic. Other/Unknown Material North Atlantic eScholarship Repository (University of California) |
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The Laurentian Fan is one of the largest submarine fans on the western margin of the North Atlantic. Recently acquired high-resolution multibeam bathymetric data (60 m horizontal resolution) reveal a major mass transport deposit (MTD) on the Western Levee of Western Valley (WLWV), covering >14 000 km2 in water depths from 3900 m to >5000 m. Typical submarine landslide features are observed such as headscarps that in places reach the crest of the levee, crown cracks, extensional ridges, blocky debris and flow lineations. Multiple headwalls are observed on 3.5 kHz sub-bottom profiles indicating that the landslide retrogressed upslope. While the upper parts of the MTD consist of intact blocks that were displaced downslope as ridges and troughs, the lower parts exhibit a ~30 m thick incoherent to transparent acoustic facies typical of debris flows. Landslide geomorphology thus suggests that it was generated as a retrogressive spread and that slide blocks disintegrated downslope to become a blocky landslide with a surficial debris flow. The blocky landslide/debris flow extends downslope ~90 km and partially fills a submarine channel. The superposition of the MTD filling the channel and its location at the top of the stratigraphic succession in the levee suggests that it is late Quaternary in age, possibly Holocene. Deeper seismic reflection data also show that this is a rare event during the Quaternary; it is the largest MTD observed in the upper ~375 m of the levee succession and among the largest and deepest in the Western North Atlantic. |
format |
Other/Unknown Material |
author |
Normandeau, Alexandre Campbell, D. Piper, David Jenner, Kimberley |
spellingShingle |
Normandeau, Alexandre Campbell, D. Piper, David Jenner, Kimberley New evidence for a major late Quaternary submarine landslide on the external western levee of Laurentian Fan |
author_facet |
Normandeau, Alexandre Campbell, D. Piper, David Jenner, Kimberley |
author_sort |
Normandeau, Alexandre |
title |
New evidence for a major late Quaternary submarine landslide on the external western levee of Laurentian Fan |
title_short |
New evidence for a major late Quaternary submarine landslide on the external western levee of Laurentian Fan |
title_full |
New evidence for a major late Quaternary submarine landslide on the external western levee of Laurentian Fan |
title_fullStr |
New evidence for a major late Quaternary submarine landslide on the external western levee of Laurentian Fan |
title_full_unstemmed |
New evidence for a major late Quaternary submarine landslide on the external western levee of Laurentian Fan |
title_sort |
new evidence for a major late quaternary submarine landslide on the external western levee of laurentian fan |
publisher |
California Digital Library (CDL) |
publishDate |
2018 |
url |
http://dx.doi.org/10.31223/osf.io/c7a4x |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_rights |
http://opensource.org/licenses/AFL-3.0 |
op_doi |
https://doi.org/10.31223/osf.io/c7a4x |
_version_ |
1810462826084433920 |