Sediment transport processes in the Rockall Through (North Atlantic) with special emphasis on submarine mass wasting
Zusammenfassung der Projektergebnisse
The Rockall Trough is an NE trending depression on the northeast Atlantic margin, west of Ireland. The Rockall Bank Mass Flow (RBMF) is located in the southern part of the trough. Several headwall scarps related to this mass flow complex have been found along the eastern margin of the Rockall Bank. During the Celtic Explorer Cruise CE11011, new reflection seismic data have been collected in the central part of the Rockall Trough. The quality of the raw data is poor due to bad weather conditions during data collection. Hence careful data processing was needed in order to optimize the data quality. A sophisticated static correction was an essential step during processing in order to correct for significant static shifts as result of bad weather conditions. The data processing resulted in seismic sections of significantly increased signal to noise ratio. Analyzing the processed data allowed the identification of at least 4 major mass transport deposits. The oldest mass transport deposit destroyed a sediment wave field in the southern part of the RBMF area. In the following, at least three additional failures occurred; the corresponding deposits overlay the older slide deposits in the south and destroyed additional sediment waves in the north. Wavy reflectors underneath the slide deposits suggest that a previously existing large and continuous sediment wave field is disrupted by the individual events of the RBMF. We consider the occurrence of sediment waves in the survey area as most important preconditioning factor for sediment failures because sediment waves are well known to be potentially unstable especially as good grain-size sorting makes them weaker than poorly sorted sediments and excess pore pressure may develop within units that are sandwiched between impermeable horizons. The new data shows that the RBMF was not one very large event but consists of several failures. The determination of landslide parameters such as length, width, and volume proofs that each individual slide is still large in comparison to other failures in the north Atlantic. The combination of failed volumes and failure depth suggest a high probability for tsunami generation. The recurrence rate, however, is low; hence the risk for landslide generated tsunamis in the Rockall Trough is considered to be low.
Projektbezogene Publikationen (Auswahl)
- Deepwater sedimentary processes and deposits. Geoscience, Dublin, 3 - 4 November 2010
Georgiopoulou, A., Benetti, S., Krastel, S., Sacchetti, F., Shannon, P., Haughton, P.
- (2012) RV Celtic Explorer CE11011 cruise report, 7th - 21st September 2011 (Hamburg to Galway via Killybegs): Seismic investigation of the geology and oceanography of the Northern Rockall Trough, NE Atlantic. Cruise-Report. 40 pp.
Georgiopoulou, A., Krastel, S.
- Quaternary sedimentary facies distribution in the Rockall Trough, NE Atlantic. 55th Irish Geological Research Meeting, Cork, 17 – 19 February 2012
Borrego Olalla D., Georgiopoulou A., Shannon, P.M., Haughton P.D.W., Benetti S., Turner J.N., Krastel S.
- Reflexionsseismische Messung zur Untersuchung des Ablagerungsraumes des Rockall Bank Mass Flows (Nord Atlantik). 73. Jahrestagung der DGG, Leipzig, 4. – 7. März, 2013
Trappe, K., Krastel, S., Georgiopoulou, A., Quer, L.
