Palaeoceanographic and hydrodynamic variability for the last 47 kyr in the southern Gulf of Cádiz (Atlantic Moroccan margin): Sedimentary and climatic implications. (4th December 2022)

• Record Type: Journal Article
• Authors: Vandorpe, Thomas; Delivet, Stanislas; Blamart, Dominique; Wienberg, Claudia; Bassinot, Frank; Mienis, Furu; Stuut, Jan‐Berend W.; Van Rooij, David
• Is Part Of: Depositional record. Volume 9:Number 1(2023)
• Page Start: 30
• Page End: 51
• Publication Date: 2022-12-04
• Subjects: aeolian dust -- Antarctic Intermediate Water -- Azores Front -- bottom currents -- cold‐water corals -- Pen Duick drift; Sediments (Geology) -- Periodicals; Sedimentology -- Periodicals; Sedimentation and deposition -- Periodicals; 552.5
• DOI: 10.1002/dep2.212
• Languages: English
• ISSNs: 2055-4877

Abstract

Abstract: X‐ray fluorescence, grain‐size and oxygen and carbon stable isotope measurements of a 33 m long piston core, recovered from the Pen Duick drift located at the foot of the prominent Pen Duick Escarpment (Atlantic Moroccan margin), are combined to decipher past oceanographic conditions. The data indicate that, similar to the northern Gulf of Cádiz, the Azores Front exerts a major control on the palaeoclimatology of the region. Contrasting the northern Gulf of Cádiz, where Mediterranean Outflow Water is the main water mass at similar water depths, the palaeoceanography of the studied area is mostly influenced by the amount of Antarctic Intermediate Water advected from the south. The density contrast between the Antarctic Intermediate Water and the overlying North Atlantic Central Water determined the strength of the prevailing internal tides and corresponding high current speeds, which drastically impacted the sedimentary record. The most notable impact is the presence of a 7.8 kyr condensed section (30.5–22.7 ka bp ). The formation of the Pen Duick sediment drift was not just controlled by the strength of the bottom currents and the intensity of the internal tides, but also by the amount of (aeolian) sediment supplied to the region. Although variable, drift‐growth phases seem to mainly occur during colder periods of the last glacial, that is Heinrich and Dansgaard‐Oeschger events during Marine Isotope Stage 3 and late Marine Isotope Stage 2. These periods, characterised by increased aeolian dust supply and higher bottom currents, coincide with a phase of prolific cold‐water coral growth and enhanced coral mound formation as recorded in numerous cores obtained from the southern Gulf of Cádiz. This implies that both records (on and off mound cores) are pivotal to provide the complete picture of the palaeoclimatic and palaeoceanographic conditions in the region. Abstract : This paper covers the palaeoceanography and hydrodynamic variability of the southern Gulf of Cádiz, based on the study of an 18 m long sediment core from the region. The sediment core is analysed and compared to surrounding cores and studies in order to decipher the climatic and oceanographic evolution during the last 47 kyrs. The study yields insights into the changing importance of the Azores Front in the region as well as the varying sources of sediment supply to the prevailing sediment drift.