Sequence of Multiple Slope Failures in the Headwall Area of the Giant Sahara Slide Complex at the NW African Continental Margin
Abstract Submarine mega‐slides involving hundreds of cubic kilometers of slope material pose a major threat due to their potential to destroy offshore infrastructure and trigger devastating tsunamis. The Sahara Slide Complex affected about 50,000 km2 of the northwestern (NW) African continental marg...
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| Format: | Article |
| Language: | English |
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Wiley
2022-07-01
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| Series: | Geochemistry, Geophysics, Geosystems |
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| Online Access: | https://doi.org/10.1029/2021GC010283 |
| _version_ | 1797638112755580928 |
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| author | Q. Tang J. Geersen A. Düring D. Unverricht J. Schneider von Deimling K.‐F. Lenz W. Li S. Krastel |
| author_facet | Q. Tang J. Geersen A. Düring D. Unverricht J. Schneider von Deimling K.‐F. Lenz W. Li S. Krastel |
| author_sort | Q. Tang |
| collection | DOAJ |
| description | Abstract Submarine mega‐slides involving hundreds of cubic kilometers of slope material pose a major threat due to their potential to destroy offshore infrastructure and trigger devastating tsunamis. The Sahara Slide Complex affected about 50,000 km2 of the northwestern (NW) African continental margin. Previous studies focused either on its distal depositional zone or the uppermost headwall area, but failed in reconstructing the succession of individual slide events within the entire headwall area. New hydroacoustic data reveal a complex slide morphology including three main acoustic facies, large scale slide blocks, linear troughs, multiple glide planes and three major headwall scarps (the upper, southern and lower headwall). The evacuated slide scar hosts chaotic slide deposits that cover stratified sediments in the upper and southern headwall area, but are vertically stacked onto older slide deposits in the lower headwall area. Based on these observations, and dating of recently collected sediment samples, we reconstructed the history of slope failures that led to the formation of the structurally and morphologically complex headwall area of the Sahara Slide. Slope instability initiated when the lower headwall failed at ∼60 kyr, followed by the failure of the northeastern upper headwall at ∼14 kyr. Around 6 kyr, a major slide within the upper headwall area took place, followed by a series of smaller events within the southern and most‐proximal upper headwall area. The youngest of these slides occurred around 2 kyr. This scenario suggests a long‐lasting history of successive slope failures for the Sahara Slide Complex along the NW African continental slope. |
| first_indexed | 2024-03-11T12:57:55Z |
| format | Article |
| id | doaj.art-d2beddb531e047d89e649f63969e027c |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:57:55Z |
| publishDate | 2022-07-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-d2beddb531e047d89e649f63969e027c2023-11-03T16:56:11ZengWileyGeochemistry, Geophysics, Geosystems1525-20272022-07-01237n/an/a10.1029/2021GC010283Sequence of Multiple Slope Failures in the Headwall Area of the Giant Sahara Slide Complex at the NW African Continental MarginQ. Tang0J. Geersen1A. Düring2D. Unverricht3J. Schneider von Deimling4K.‐F. Lenz5W. Li6S. Krastel7Institute of Geosciences Kiel University Kiel GermanyInstitute of Geosciences Kiel University Kiel GermanyInstitute of Geosciences Kiel University Kiel GermanyInstitute of Geosciences Kiel University Kiel GermanyInstitute of Geosciences Kiel University Kiel GermanyInstitute of Geosciences Kiel University Kiel GermanySouth China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou ChinaInstitute of Geosciences Kiel University Kiel GermanyAbstract Submarine mega‐slides involving hundreds of cubic kilometers of slope material pose a major threat due to their potential to destroy offshore infrastructure and trigger devastating tsunamis. The Sahara Slide Complex affected about 50,000 km2 of the northwestern (NW) African continental margin. Previous studies focused either on its distal depositional zone or the uppermost headwall area, but failed in reconstructing the succession of individual slide events within the entire headwall area. New hydroacoustic data reveal a complex slide morphology including three main acoustic facies, large scale slide blocks, linear troughs, multiple glide planes and three major headwall scarps (the upper, southern and lower headwall). The evacuated slide scar hosts chaotic slide deposits that cover stratified sediments in the upper and southern headwall area, but are vertically stacked onto older slide deposits in the lower headwall area. Based on these observations, and dating of recently collected sediment samples, we reconstructed the history of slope failures that led to the formation of the structurally and morphologically complex headwall area of the Sahara Slide. Slope instability initiated when the lower headwall failed at ∼60 kyr, followed by the failure of the northeastern upper headwall at ∼14 kyr. Around 6 kyr, a major slide within the upper headwall area took place, followed by a series of smaller events within the southern and most‐proximal upper headwall area. The youngest of these slides occurred around 2 kyr. This scenario suggests a long‐lasting history of successive slope failures for the Sahara Slide Complex along the NW African continental slope.https://doi.org/10.1029/2021GC010283northwest African continental marginmultiple slope failuresheadwall areasubmarine landslide evolutionslope instability |
| spellingShingle | Q. Tang J. Geersen A. Düring D. Unverricht J. Schneider von Deimling K.‐F. Lenz W. Li S. Krastel Sequence of Multiple Slope Failures in the Headwall Area of the Giant Sahara Slide Complex at the NW African Continental Margin Geochemistry, Geophysics, Geosystems northwest African continental margin multiple slope failures headwall area submarine landslide evolution slope instability |
| title | Sequence of Multiple Slope Failures in the Headwall Area of the Giant Sahara Slide Complex at the NW African Continental Margin |
| title_full | Sequence of Multiple Slope Failures in the Headwall Area of the Giant Sahara Slide Complex at the NW African Continental Margin |
| title_fullStr | Sequence of Multiple Slope Failures in the Headwall Area of the Giant Sahara Slide Complex at the NW African Continental Margin |
| title_full_unstemmed | Sequence of Multiple Slope Failures in the Headwall Area of the Giant Sahara Slide Complex at the NW African Continental Margin |
| title_short | Sequence of Multiple Slope Failures in the Headwall Area of the Giant Sahara Slide Complex at the NW African Continental Margin |
| title_sort | sequence of multiple slope failures in the headwall area of the giant sahara slide complex at the nw african continental margin |
| topic | northwest African continental margin multiple slope failures headwall area submarine landslide evolution slope instability |
| url | https://doi.org/10.1029/2021GC010283 |
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