Late Quaternary evolution of the Madeira Abyssal Plain, Canary Basin, NE Atlantic

Abstract

The deepest part of the Canary Basin, the Madeira Abyssal Plain, receives allochthonous sediments derived from a large drainage basin which, if its subaerial continuation is included, covers an area of 3.36 x lo6 km2. An international research effort over the last 10 years has recovered over 160 sediment cores from the plain, and the development of a high-resolution stratigraphy has enabled individual turbidites to be correlated layer by layer. Sedimentation on the Madeira Abyssal Plain during the late Quaternary is dominated by thick turbidite muds separated by thin pelagic intervals. The core density has allowed the mapping of each sedimentary unit throughout the abyssal plain, thus building up a layer by layer picture of sediment accumulation. Over the last 300 kyr, 600 km3 of turbidites compared to 60 km3 of pelagic sediments have been deposited on the plain. Sedimentary structures developed in the coarse basal facies of the larger turbidites are more complex than simple models predict due to surging flows, fluctuating flow velocities and reflection from adjacent high ground. Over the last 300 kyr, there has been a switching of entry points for turbidity currents entering the abyssal plain. From 300 ka to 200 ka, organic-rich turbidites were emplaced predominantly from the south but around 200 ka this source switched off and subsequent organic-and volcanic-rich turbidites, which included units deposited by giant, possibly hyperconcentrated flows, were emplaced from northern or eastern sources. Although restricted to the late Quaternary, the data presented provides a detailed case study of the evolution of an oceanic basin fill.

Construction of volcanic records from marine sediment cores: A review and case study (Montserrat, West Indies)

“…As well as forming debris avalanche or debris flow deposits, such events can evolve into poorly-sorted, mud-rich debris flows, or turbidity currents via flow dilution (c.f. Mulder & Cochonat 1996;Ilstad et al, 2004;Bryn et al, 2005), and may appear in marine sediments as thick (up to several metres; Rothwell et al, 1992), coarsegrained and far-reaching turbidites (>1000 km; Rothwell et al, 1992;Piper et al, 1999;Fine et al, 2005), with significant basal erosion (Garcia 1996;Wynn and Masson 2003;Masson et al, 2006;Hunt et al, 2011). Although widespread, the distribution of these deposits is ultimately subject to topographic controls, in contrast to tephra fallout deposits.…”

Flank stability and processes off the western Canary Islands: a review from El Hierro and La Palma

“…6). For example, volcaniclastic turbidites derived from the flanks of the Canary Islands are found in the MAP more than 1,000 km from source (Pearce and Jarvis., 1992;Rothwell et al, 1992;Weaver et al, 1992;Masson, 1996;Alibés et al, 1999).…”

Identification, Correlation and Origin of Multistage Landslide Events in Volcaniclastic Turbidites in the Moroccan Turbidite System

“…Siliciclastic turbidity currents sourced from the Moroccan slope are fed into the northwest of the basin via Agadir Canyon (Ercilla et al 1998;Wynn et al 2002). The Western Canary Islands are the source of the large-volume volcaniclastic turbidites in the MTS (Weaver and Rothwell 1987;Jarvis 1992, 1995;Weaver et al 1992;Rothwell et al 1992;Wynn et al 2002;Hunt et al 2013c). …”

“…In both continental margin and volcanic island settings, submarine landslides have been associated with generation of sediment gravity flows (Weaver and Rothwell 1987;Weaver et al 1992;Rothwell et al 1992;Wynn et al 2002;Masson et al 2006, and references therein; Hunt et al 2011). These turbidity currents (typically > 1 km 3 ) are either instigated by action of the landslide on the sea floor or from disaggregation of landslide materials into more dilute sediment suspensions.…”