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
30 citations
28 citations
27 citations
27 citations
26 citations
References
1,609 citations
884 citations
"Active surface deformation and sub-..." refers background or methods in this paper
...…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 evaluate the role of basal traction below the…...
[...]
...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 tectonic evolution of the western Mediterranean and the Alboran Sea has been dominated by the long history of Nubia-Eurasia plate convergence associated with the subduction of the Neotethys Ocean (e.g., Faccenna et al., 2004)....
[...]
...The mechanism responsible for the continental and oceanic nature of the slab (delamination or continental subduction) is still debated (Faccenna et al. 2004; Duggen et al. 2008)....
[...]
...…(1) backarc extension driven by the westward rollback of an eastward subducting slab (Royden, 1993; Lonergan and White, 1997; Gutscher et al., 2002; Faccenna et al., 2004), which passively falls in the mantle driven by its own weight (subduction without convergence, Jolivet et al. 2008) ; (2)…...
[...]
822 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)....
[...]
818 citations
"Active surface deformation and sub-..." refers background in this paper
...…interaction of plates (i.e., elastic strain and associated faulting, e.g Savage and Burford, 1973), sub-crustal processes (e.g., subduction and slab rollback, mantle delamination, Royden,1993), and/or stresses induced by gravitational potential energy differences (e.g., England and McKenzie 1982)....
[...]
710 citations