The giant Mauritanian cold-water coral mound province: oxygen control on coral mound formation
Wienberg, C.; Titschack, J.; Freiwald, A.; Frank, N.; Lundälv, T.; Taviani, M.; Beuck, L.; Schröder-Ritzrau, A.; Krengel, T.; Hebbeln, D. (2018). The giant Mauritanian cold-water coral mound province: oxygen control on coral mound formation. Quat. Sci. Rev. 185: 135-152. https://dx.doi.org/10.1016/j.quascirev.2018.02.012
In: Quaternary Science Reviews. Pergamon Press: Oxford; New York. ISSN 0277-3791; e-ISSN 1873-457X, more
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| Keywords |
Desmophyllum pertusum (Linnaeus, 1758) [WoRMS]
Marine/Coastal |
| Author keywords |
Lophelia pertusa; Coral mound; Submarine canyon; Uranium-series dating; Mound aggradation rate; Last glacial; Dissolved oxygen concentration; South Atlantic Central Water; Mauritanian margin |
| Authors | | Top |
- Wienberg, C.
- Titschack, J.
- Freiwald, A., more
- Frank, N.
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- Lundälv, T.
- Taviani, M.
- Beuck, L.
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- Schröder-Ritzrau, A.
- Krengel, T.
- Hebbeln, D.
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| Abstract |
The largest coherent cold-water coral (CWC) mound province in the Atlantic Ocean exists along the Mauritanian margin, where up to 100 m high mounds extend over a distance of ∼400 km, arranged in two slope-parallel chains in 400–550 m water depth. Additionally, CWCs are present in the numerous submarine canyons with isolated coral mounds being developed on some canyon flanks. Seventy-seven Uranium-series coral ages were assessed to elucidate the timing of CWC colonisation and coral mound development along the Mauritanian margin for the last ∼120,000 years. Our results show that CWCs were present on the mounds during the Last Interglacial, though in low numbers corresponding to coral mound aggradation rates of 16 cm kyr−1. Most prolific periods for CWC growth are identified for the last glacial and deglaciation, resulting in enhanced mound aggradation (>1000 cm kyr−1), before mound formation stagnated along the entire margin with the onset of the Holocene. Until today, the Mauritanian mounds are in a dormant state with only scarce CWC growth. In the canyons, live CWCs are abundant since the Late Holocene at least. Thus, the canyons may serve as a refuge to CWCs potentially enabling the observed modest re-colonisation pulse on the mounds along the open slope. The timing and rate of the pre-Holocene coral mound aggradation, and the cessation of mound formation varied between the individual mounds, which was likely the consequence of vertical/lateral changes in water mass structure that placed the mounds near or out of oxygen-depleted waters, respectively. |
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