Active surface deformation and sub-lithospheric processes in the western Mediterranean constrained by numerical models
Summary (1 min read)
INTRODUCTION
- The authors modeling studies demonstrate the need for sub-crustal or sub-lithospheric, southwestward-directed forcing to account for observed southwestward motion of the Rif and Betic domains.
- The authors then discuss the implications of these model results in light of previous geodynamic models of the plate boundary zone.
TECTONIC SETTING OF THE WESTERN MEDITERRANEAN
- In the western Mediterranean, the Alboran Sea is a thinned continental domain (15 km thickness; Lonergan and White 1997) surrounded by the Internal Rif and Internal Betics , which are the westernmost limit of the Alpine mountain belt (Fig. 1).
- Three factors are likely to infl uence the spatial distribution of the interseismic strain 1) lateral plate driving forces due to long term Nubia-Eurasia oblique convergence, 2) low rigidity of the diffuse plate boundary zone, and 3) deep traction beneath the plate boundary due to upper mantle drag or slab traction.
- The RMSs for the entire zone and for the Rif-Betics region are summarized in Table 1.
- Depending on the thermal regime, the effective elastic thickness of continental plates varies from 3 to 80 km (Watts and Burov, 2003).
DISCUSSION AND GEODYNAMIC IMPLICATIONS
- The authors modeling experiments include no a priori information on sub-lithospheric geometry and are designed to determine whether sublithospheric processes are needed to account for observed deformation of the western Mediterranean region.
- Geodynamic models of the zone involving still active westward rollback of the western Mediterra- nean narrow slab (Gutscher et al., 2002) cannot generate such a small coupling zone confi ned to the External Rif. Spakman and Wortel (2004) suggested that the western Mediterranean slab is detached under the Betics.
- The authors further suggest that the horizontal traction patch could represent the remaining coupling zone between the slab and the overlying continental lithosphere.
- According to their delamination model (Fig. 3) the traction zone is expected to move to the south-southwest following propagation of the delamination front.
- During the Pliocene-Quaternary, eastward subduction has died out, as suggested by the accretionary wedge sealed by undeformed sediments (Zitellini et al., 2009).
ACKNOWLEDGMENTS
- The authors thank G. Bokelmann, S. Lallemand and J.L. Bodinier for their fruitful discussions, and to C. Faccenna and fi ve anonymous reviewers for their constructive comments on this manuscript.
- Reilinger benefi ted from a Visiting Researcher Fellowship from the Observatoire de Recherche Méditerranéen en Environnement of Montpellier while engaged in this study.
Did you find this useful? Give us your feedback
Citations
365 citations
356 citations
281 citations
Cites background from "Active surface deformation and sub-..."
...There are GPS and paleomagnetic evidences of active radial motion of the Betic and Riff nappes (Cifelli et al., 2008; Pérouse et al., 2010) and the tomography would also suggest an E-ward dipping slab (Gutscher et al., 2002; Spakman and Wortel, 2004)....
[...]
...There are GPS and paleomagnetic evidences of active radial motion of the Betic and Riff nappes (Cifelli et al., 2008; Pérouse et al., 2010) and the tomography would also suggest an E-ward dipping slab (Gutscher et al....
[...]
279 citations
169 citations
References
437 citations
"Active surface deformation and sub-..." refers background or methods in this paper
...This slab seems to be detached under the Betics (Spakman and Wortel 2004)....
[...]
...This southsouthwest motion of the Rif (5.4 ± 1.5 mm/yr) in a Nubia fi xed reference frame, and to a lesser extent the southern velocity component for sites in the Betics with respect to Eurasia, depict more complicated dynamics than can be ascribed to simple crustal block interactions; or to stresses induced by gravitational potential energy differences, since the Rif motion is not consistent with the highest topographic gradient north of the Rif....
[...]
...Tomographic studies (Calvert et al. 2000; Gutscher et al., 2002; Faccenna et al., 2004; Spakman and Wortel, 2004) reveal a narrow east dipping slab (100–200 km wide) located in the Gibraltar Arc....
[...]
...The GPS velocities show signifi cant motions in the Rif and Betics relative to Nubia and Eurasia respectively (black arrows, Fig....
[...]
...In the western Mediterranean, the Alboran Sea is a thinned continental domain (15 km thickness; Lonergan and White 1997) surrounded by the Internal Rif (Morocco) and Internal Betics (Spain), which are the westernmost limit of the Alpine mountain belt (Fig....
[...]
383 citations
"Active surface deformation and sub-..." refers background in this paper
...…1993); (3) crustal extrusion due to forces transmitted across the Eurasia-Africa plate boundary (Rebai et al., 1992); and (4) delamination and convective removal of the lithospheric mantle root beneath the collisional orogen (Platt and Vissers, 1989; Seber et al., 1996; Calvert et al., 2000)....
[...]
356 citations
"Active surface deformation and sub-..." refers background in this paper
...Depending on the thermal regime, the effective elastic thickness of continental plates varies from 3 to 80 km (Watts and Burov, 2003)....
[...]
317 citations
"Active surface deformation and sub-..." refers background or methods in this paper
...Tomographic studies (Calvert et al. 2000; Gutscher et al., 2002; Faccenna et al., 2004; Spakman and Wortel, 2004) reveal a narrow east dipping slab (100–200 km wide) located in the Gibraltar Arc....
[...]
...…the confi guration of the Nubian-Eurasian plate boundary in the western Mediterranean and the geometry of the subducted plate are still debated (Calvert et al., 2000; Gutscher et al., 2002; Faccenna et al., 2004; Spakman and Wortel, 2004), we use an elastic plate model approach in order to…...
[...]
...…1993); (3) crustal extrusion due to forces transmitted across the Eurasia-Africa plate boundary (Rebai et al., 1992); and (4) delamination and convective removal of the lithospheric mantle root beneath the collisional orogen (Platt and Vissers, 1989; Seber et al., 1996; Calvert et al., 2000)....
[...]
288 citations