Imaging the western mediterranean margins: a key target to understand the interaction between deep and shallow processes

Duration: 01.03.2005 - 15.08.2010

Sponsored by: DFG in the frame of the EUROMARGIN Programs

Participating institutes: Universitat de Barcelona, Spain; Instituto di Geoscienze e Georisorse, Padova, Italy; Universita di Roma TRE, Roma, Italy; Faculteit Aard-Vrije Universiteit, Amsterdam, Netherlands; Université de Bretagne Occidentale, Brest, France; University of Utrecht, Netherlands; Université Pierre et Marie Curie, Paris, France; ICTJA-CSIC, Barcelona, Spain; IACT-CSIC, Granada, Spain;

Continental breakup – Deep seismic investigations of the passive continental margins in the western Mediterranean

The Western Mediterranean is a natural laboratory to study the processes of continental extension and rifting in a convergent setting. Gravitational collapse due to tectonic thickening of continental lithosphere and the rollback of an oceanic slab during the latest phases of consumption of the Tethys oceanic lithosphere have led to rapid Neogene extension in an area characterized by a constant convergence of the African and European Plates since Cretaceous time. The current setting displays a complex array of tectonic units that may be characteristic of the stage previous to a large scale continent-continent collision and that may include the lithospheric terranes that will eventually be emplaced along an orogenic belt. However, little is known about the crustal and upper mantle structure of much of the area and about the mechanisms of extension that have controlled the formation of the continental margins. Scientists believe, though, that the Ligurian Sea and the deep sea basin to the south of the Balearic Islands (Algerian Basin) is either floored by Neogene oceanic crust or perhaps by exhumed continental mantle, while the Alboran Sea and the transition from the south-Balearic margin into the basins are suggested to be characterized by streched continental crust. The understanding of the formation mechanisms and the evolution of the continental margins of the Western Mediterranean has been hampered by the lack of modern geophysical data. During M69/2 two seismic refraction and wide-angle profiles were acquired between Spain and Morocco to study the structure of the Alboran Sea and the transition from the Alboran Sea into the adjacent eastern basin of unknown nature. Three additional lines while run from the Spanish coast and from the Balearic Islands into the Algerian Basin. Shots from four of the five lines were received not only on seismic receivers deployed on the seafloor but also on seismic landstations.

• Meteor M69/1, 08.08.2006-28.08.2006, Las Palmas (Spain) - Cartagena (Spain), chief scientist: Dr. Christian Hübscher
• Meteor M69/2, 29.08.2006-20.09.2006, Cartagena (Spain) - La Valetta (Malta), chief scientist: Dr. Ingo Grevemeyer

More information you will find in the expedition brochure.

1.Grevemeyer, I., E.R. Flueh, C. Reichert, J. Bialas, D. Kläschen, C. Kopp, Crustal architecture and deep structure of the Ninetyeast Ridge hotspot trail from active-source ocean bottom seismology, Geophys. J. Int., 144, 414-413, 2001

2. Grevemeyer, I., H. Villinger, Gas hydrate stability and the assessment of heat flow through continental margins, Geophys. J. Int., 145,, 647-660, 2001

3. Kopf, A., D. Kläschen, W. Weinrebe, E.R. Flueh, I. Grevemeyer, Geophysical evidence for late stage magmatism at the central Ninetyeast Ridge, Eastern Indian Ocean, Mar. Geophys. Res., 22, 225-234, 2001

4. Grevemeyer, I., W. Weigel, S. Schüssler, F. Avedik, Crustal and upper mantle seismic structure and lithospheric flexure along the Society Island hotspot chain, Geophys. J. Int., 137, 123-140, 2001

5. Fisher, A.T., H. Villinger, M. Pfender, M. Müller, I. Grevemeyer, N. Kaul, R.N. Harris, R.P. von Herzen, C.G. Wheat, Comment on “Deep-penetration heat flow probes raise questions about interpretations from shorter probes“, EOS 83(18), 196, 2002

6. Grevemeyer, I., B. Schramm, C.W. Devey, D.S. Wilson, B. Jochum, J. Hauschild, K. Aric, H. Villinger, W. Weigel, A multibeam-sonar, magnetic and geochemical flow-line survey at 14°14‘S on the southern East Pacific Rise – insights into the fourth dimension of ridge crest segmentation, Earth Planet. Sci. Lett., 199, 359-372, 2002

7. Reston, T.J., W. Weinrebe, I. Grevemeyer, E.R. Flueh, N.C. Mitchell, L. Kristein, C. Kopp, H. Kopp, participants of Meteor 47/2, A rifted inside corner massif on the Mid-Atlantic Ridge at 5°S, Earth Planet. Sci. Lett., 200, 255-269,2002

8. Villinger, H., I. Grevemeyer, N. Kaul, J. Hauschild, M. Pfender, Hydrothermal heat flux through aged oceanic crust: where does the heat escape?, Earth Planet. Sci. Lett., 2002, 159-170, 2002

9. Schlindwein, V., C. Bönnemann, C. Reichert, I. Grevemeyer, E.R. Flueh, Three-dimensional seismic tomography of the crustal structure at the ION site on the Ninetyeast Ridge, Indian Ocean, Geophys. J. Int., 152, 171-184, 2003

10. Hauschild, J., I. Grevemeyer, N. Kaul, H. Villinger, Asymmetric sedimentation on young ocean floor at the East Pacific Rise, 15°S, Mar. Geol., 193, 49-59, 2003

11. Grevemeyer, I., J.L. Diaz-Naveas, C.R. Ranero, H.W. Villinger, Ocean Drilling Program Leg 202 Scientific Party, Heat flow over the descending Nazca plate in Central Chile, 32°S to 41°S: evidence from ODP Leg 202 and the occurrance of natural gas hydrates, Earth Planet. Sci. Lett., 213, 285-298, 2003

12. Essen, H.-H., F. Krüger, T. Dahm, I. Grevemeyer, On the generation of microseisms observed in north and central Europe, J. Geophys. Res., 108, doi:10.1029/2002JB002338, 2003

13. Grevemeyer, I., A. Bartetzko, Hydrothermal ageing of oceanic crust: inferences from seismic refraction and borehole studies, in Hydrogeology of Oceanic Lithosphere, eds. E.E. Davis & H. Elderfield, Cambridge University Press, p. 128-150, 2004

14. Grevemeyer^, I., A.J. Kopf, N. Fekete, N. Kaul, M. Heesemann, H.-H. Gennerich, M. Müller, V. Spieß, K. Wallmann, W. Weinrebe, Fluid flow through active mud dome Mound Culebra offshore Nicoya Peninsula, Costa Rica: evidence from heat flow surveying, Mar Geol., 207, 145-157, 2004

15. Schmidt, M., C. Hensen, T. Mörz, C. Müller, I. Grevemeyer, K. Wallmann, S. Mau, N. Kaul, Methane hydrate accumulation in „Mound 11“ mud volcano, Costa Rica forearc, Marine Geol., 216, 77-94, 2005.

16. Grevemeyer, I., N. Kaul, J.L. Diaz-Naveas, H. Villinger, C.R. Ranero, C. Reichert, Heat flow and bending-related faulting at subduction trenches: case studies offshore of Nicaragua and Central Chile, Earth Planet. Sci. Lett., 236, 238-248, 2005

17. Grevemeyer, I., N. Kaul, J.L. Diaz-Naveas, Geothermal evidence for fluid flow through the gas hydrate stability field off Central Chile – transient flow related to large subduction zone earthquakes?, Geophys. J. Int.,