skip to primary navigationskip to content
 

C433 Impact of Fleuve Manche Megafloods on North Atlantic Climate and Overturning Circulation (Lead Supervisor: David Hodell, Earth Sciences)

Supervisor: David Hodell (Earth Sciences)  

Importance of the area of research:

Prior to the opening of the Dover Strait by the breaching of the Chalk Ridge, Britain was connected to Europe even during sea-level highstands (Gupta et al. 2007, 2017). On the basis of bathymetric and geomorphologic information from the floor of the English Channel, the opening of the Dover Strait is postulated to have been related to an outburst flood, known as the Fleuve Manche Megaflood, that occurred 450,000 years ago in Marine Isotope Stage 12 (Elsterian–Anglian glaciation). This initial and subsequent megaflood events are suggested to have had wider paleoceanographic significance although direct evidence remains elusive. Icebergs and sediments from the Fleuve Manche megafloods are transported down the English Channel into the Bay of Biscay where they are recorded by increases in terrigenous sedimentation and ice rafted detritus (Toucanne et al., 2009). The megafloods were large enough to have affected the Portuguese Margin off Lisbon where continuously high sedimentation rates provide the opportunity for recognition of these events, and placing them into a robust stratigraphic and paleoceanographic context.

Project summary:

This project will utilize sediment from IODP Site U1385 (“Shackleton site”) drilled on the Iberian Margin to identify the occurrence of Fleuve Manche outburst floods and other events related to European ice sheet dynamics. Sources of ice-rafted detritus (IRD) will be identified along with associated changes in surface water temperature and salinity. Importantly, the events will be compared with changes in deep-water circulation, as monitored by benthic d13C, to evaluate the broader paleoceanographic implications of these events. The history will be integrated with the glacial geology of Britain and Europe.

What the student will do:

The student will produce high-resolution proxy records of climate variability including counts of IRD, foraminifera (N. pachyderma), stable isotopes and trace metals in foraminifer shells. Geochemical and petrologic methods will be used to identify the source of IRD grains. The results will be integrated with existing core scanning XRF, alkenone SST, and geochemical data from Site U1385. There will be ample opportunity to collaborate directly with other IODP scientists working on complementary proxies from Site U1385.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.

References:

Gupta, S., Collier, J. S., Palmer-Felgate, A. & Potter, G. 2007. Catastrophic flooding origin of shelf valley systems in the English Channel, Nature, vol.448, pp. 342–345.

Gupta, S. et al. 2017. Two-stage opening of the Dover Strait and the origin of island Britain, Nature Communications, vol. 8, pp. 15101, DOI: 10.1038/ncomms15101

Toucanne, S. et al. 2009. Timing of massive ‘Fleuve Manche’ discharges over the last 350 kyr: insights into the European ice-sheet oscillations and the European drainage network from MIS 10 to 2. Quat. Sci. Rev., vol. 28, pp. 1238–1256.

Follow this link to find out about applying for this project.

Other projects available from the Lead Supervisor can be viewed here.

Filed under: