Buried cold-water coral mound provinces and contourite drifts along the eastern Atlantic margin; controls, interactions and connectivity

Author(s): van Rooij, David; Vandorpe, Thomas; Delivet, Stanislas; Hebbeln, D.; Wienberg, C.; Martins, I.
Author Affiliation(s): Primary:
Ghent University, Geology & Soil Science, Ghent, Belgium
Other:
University of Bremen, Germany
Portuguese Hydrographic Institute, Portugal
Volume Title: AGU 2014 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2014; American Geophysical Union 2014 fall meeting, San Francisco, CA, Dec. 15-19, 2014. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The association between cold-water coral mounds and contourite drift deposits has been demonstrated in the Belgica mound province, off Ireland. On that location, IODP expedition 307 was able to drill through the base of a mound, dating mound initiation at 2.65 Ma. However, the Belgica mounds are just one of the many expressions of mound growth. More enigmatic is the buried Magellan mound province, located in the northern part of the Porcupine Basin, featuring over 1000 relatively closely spaced buried mounds, which are all rooted on a common reflector. This indicates a common start-up event, but the true driving forces behind their initial settling, growth and demise are still unknown. The influence of bottom currents cannot be ruled out, since clear obstacle marks are present surrounding the mounds. In 2013, some 3000 km south of the Magellan mounds, a new province of buried mounds was discovered along the Moroccan Atlantic Margin, which may shed new light on the "life" cycle of mounds. Here, we report the preliminary results and propose a first view on the controls, interactions and connectivity between these 2 provinces, assisted by a series of studies of contourite drifts along the Eastern Atlantic Margin. The newly discovered buried mounds can be associated to a vast province of several clusters of seabed mounds. They occur in water depths between 500 and 1000 m, buried under up to 50 m of sediment. With respect to the Magellan mounds, they are smaller, but more importantly, they do not root on one single stratigraphic level. At least 4 different initiation levels were identified. The off-mound reflectors indicate a slight influence of bottom currents, since the mounds are located in a large sediment drift. Moreover, the link between the two buried mound provinces may be found in connecting the evolution of the associated contourite drift systems, respectively in Porcupine Seabight and the Gulf of Cadiz. Intermediate sites on Goban Spur and near Le Danois Bank have enabled to correlate stratigraphic events over such large distances, mainly driven by changes in the Mediterranean Outflow Water. However, the influence of the Antarctic Intermediate Water on the Moroccan Margin may not be underestimated, suggesting a linkage between the dynamics of both water masses in the southern Gulf of Cadiz.
Year of Publication: 2014
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Atlantic Ocean; Contourite; Cores; Expedition 307; Integrated Ocean Drilling Program; Marine sediments; North Atlantic; Northeast Atlantic; Porcupine Seabight; Sediments
Coordinates: N512200 N512700 W0113300 W0114400
Record ID: 2015092833
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