Determining the provenance, recurrence, magnitudes and failure mechanisms of submarine landslides from the Moroccan margin and Canary Islands using distal turbidite records

Abstract

The Moroccan continental margin and Canary Islands have been subjected to repeat submarine mass wasting. This thesis aims to investigate the sediment gravity flow deposits associated with these submarine landslides. The Agadir Basin represents a deepwater depocentre and conduit for turbidity currents sourced from the Agadir Canyon and Western Canary Islands. A previous basin stratigraphy is re-analysed and extended to cover the last 600 ka. This stratigraphy is validated by using down-core geophysics and chemostratigraphy. ITRAX mudcap geochemistry has been used to assess turbidite provenance. Siliciclastic turbidites in this record have been shown to occur predominantly at transitions from glacial to interglacial periods.

The latest landslides identified from the Western Canary Islands, the El Golfo and Icod landslides, have been proposed to be multistage. This is based on the presence of multiple fining-upwards sequences, known as subunits, within the associated sediment gravity flow deposits. Grain-size data, core petrophysics, bulk geochemistry and volcanic glass geochemistry has shown that the subunits within the Icod deposit originate from a multistage collapse. The Late Quaternary volcaniclastic turbidites in the Madeira Abyssal Plain in the last 1.5 Ma are also investigated, and found to potentially represent the El Golfo, Icod, Cumbre Nueva, Orotava, El Julán, Güímar, Tinor and Rogues de García landslides from the Western Canary Islands. These deposits also represent multistage landslides, which show that this failure mechanism is more common and has major implications for tsunamigenesis. Furthermore, analysis of ODP volcaniclastic turbidites (0- 17 Ma) shows that deposits are coincidental in age and provenance with periods of voluminous and explosive volcanism on specific islands.

More information

Identifiers

ORCID for Damon A.H. Teagle: orcid.org/0000-0002-4416-8409

Catalogue record

Export record