Controls of sediment dynamics on the Galician slope reconstructed from three sediment cores (GeoB11035-1, GeoB130206-1, GeoB13071-1)


Controls of sediment dynamics at the Galician continental slope (NW Iberia) during the past 30 ka were reconstructed from three new gravity cores (GeoB11035-1, 130206-1, 13071-1) based on sedimentological (e.g. sortable silt, IRD), micropalaeontological (e.g. coccoliths), geochemical (AMS 14C, XRF) and geophysical (e.g. magnetic susceptibility) diagnostics. The data are consistent with existing regional knowledge that, during marine isotope stages 3-1, variations in detrital input, marine productivity and sea level were the essential drivers of sediment availability on the slope, whereas deep-water current velocities controlled sediment deposition: (1) the period prior to 30 cal ka BP is characterized by minor but systematic variations in various proxies which can be associated with D-O cycles; (2) between 30 and 18 cal ka BP, high detrital input and steady slope-parallel currents led to constant sedimentation; (3) from the LGM until 10 cal ka BP, the shelf-transgressive sea-level rise increased the detrital particle flux; sedimentation was influenced by significantly enhanced deep-water circulation during the Bølling/Allerød, and subsequent slowing during the Younger Dryas; (4) an abrupt and lasting change to hemipelagic sedimentation at ca. 10 cal ka BP was probably due to Holocene warming and decelerated transgression; (5) after 5 cal ka BP, additional input of detrital material to the slope is plausibly linked to the evolution of fine-grained depocentres on the Galician shelf, this being the first report of this close shelf-slope sedimentary linkage off NW Iberia. Furthermore, there is novel evidence of the nowadays strong outer shelf Iberian Poleward Current becoming established at about 15.5 cal ka BP. The data also demonstrate that small-scale morphologic features and local pathways of sediment export from the neighbouring shelf play an important role for sediment distribution on the NW Iberian slope, including a hitherto unknown sediment conduit off the Ría de Arousa. By implication, the impact of local morphology on along- and down-slope sediment dynamics is more complex than commonly considered, and deserves future attention.

Supplement to: Bender, Vera Barbara; Hanebuth, Till J J; Mena, Anxo; Baumann, Karl-Heinz; Francés, Guillermo; von Dobeneck, Tilo (2012): Control of sediment supply, palaeoceanography and morphology on late Quaternary sediment dynamics at the Galician continental slope. Geo-Marine Letters, 32(4), 313-335

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Metadata Access
Creator Bender, Vera Barbara (ORCID: 0000-0002-4331-462X); Hanebuth, Till J J ORCID logo; Mena, Anxo ORCID logo; Baumann, Karl-Heinz; Francés, Guillermo; von Dobeneck, Tilo ORCID logo
Publisher PANGAEA
Publication Year 2012
Rights Creative Commons Attribution 3.0 Unported;
OpenAccess true
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 14 datasets
Discipline Earth System Research
Spatial Coverage (-9.842W, 42.172S, -9.620E, 42.808N)
Temporal Coverage Begin 2006-08-31T14:31:00Z
Temporal Coverage End 2008-06-14T15:47:00Z