Subduction and Slab Detachment in the Mediterranean-Carpathian Region

Abstract

Seismic tomography models of the three-dimensional upper mantle velocity structure of the Mediterranean-Carpathian region provide a better understanding of the lithospheric processes governing its geodynamical evolution. Slab detachment, in particular lateral migration of this process along the plate boundary, is a key element in the lithospheric dynamics of the region during the last 20 to 30 million years. It strongly affects arc and trench migration, and causes along-strike variations in vertical motions, stress fields, and magmatism. In a terminal-stage subduction zone, involving collision and suturing, slab detachment is the natural last stage in the gravitational settling of subducted lithosphere.

Kinematic reconstructions and magmatic evolution illuminating crustal and mantle dynamics of the eastern Mediterranean region since the late Cretaceous

“…The width of this continuously subducting lithosphere was then probably reduced by several episodes of slab tearing, leading to an increase of its retreating rate. Since the middle Miocene, large-scale block rotations ( figure 3) and evolution of magmatism in the Cyclades and western Anatolia (see details in Section 5.5) support the existence of a slab tear below western Anatolia, as suggested by several tomographic models [de Boorder et al, 1998;Wortel and Spakman, 2000;Piromallo and Morelli, 2003;Jolivet et al, 2009Jolivet et al, , 2013Brun and Sokoutis, 2010;Salaün et al, 2012]. The reduced width of the slab thus could have induced its fast retreat and the fast rotation of the Hellenic trench from 15 to 8…”

“…km-long slab in the Rhodope-Aegean-west Anatolian region, suggesting continuous subduction since the late Cretaceous without any slab break-off [Wortel and Spakman, 2000; A C C E P T E D M A N U S C R I P T…”

A map-view restoration of the Alpine-Carpathian-Dinaridic system for the Early Miocene

“…between 40 and 35 Ma, in the transition area between Western and Eastern Alps (von blanckenburg & Davis 1995) but took place at around 20 Ma in the Eastern Alps and the area of the carpathian embayment. Whether or not this break-off was a continuous process, systematically migrating eastward (spakman & Wortel 2000), is not yet fully understood. the carpathian embayment was formerly underlain, according to most authors (e.g.…”

“…Deep reflection seismic profiling and seismic tomography have since shown that the western and central segments of the Alps are underlain by a south-dipping lithospheric slab, attributed to subducted European lower lithosphere (schmid et al 1996, 2004aschmid & Kissling 2000), whereas the Dinarides and Hellenides are underlain by a northeast-dipping lithospheric s274 K. Ustaszewski et al slab (e.g. Wortel & spakman 2000;Piromallo & Morelli 2003) south of 44° N.…”

Abrupt tectonics and rapid slab detachment with grain damage

“…7 and 8). Such detachment has been invoked to explain seismicity gaps and pinched tomographic features in slab structures (9,10). However, slab detachment also has significant geodynamic consequences and may help account for precipitous tectonic events that are not readily explained by mantle convective motions (11).…”