Late Cenozoic Evolution and Present Tectonic Setting of the Aegean–Hellenic Arc

Enzo Mantovani,Marcello Viti,Caterina Tamburelli,Daniele Babbucci

doi:10.3390/geosciences12030104

Abstract

The Aegean–Hellenic arc is a deformed sector of a long heterogeneous orogenic system (Tethyan belt), constituted by an inner old metamorphic crystalline core flanked by younger chains of European and African affinity, running from the Anatolian to the Pelagonian zones. Due to the convergence between the Arabian promontory and the Eurasian continental domain, the Anatolian sector of that belt has undergone a westward extrusion, accommodated by oroclinal bending, at the expense of the surrounding low buoyancy domains. Since the late Miocene, when the Aegean Tethyan belt collided with the Adriatic continental promontory, the southward bowing of the Aegean–Hellenic sector accelerated, leading to the consumption of the Levantine and Ionian oceanic domains and to the formation of the Mediterranean Ridge accretionary complex. The peculiar distribution of extensional and compressional deformation in the Aegean zone has mainly been influenced by the different rheological behaviours of the mainly ductile inner core (Cyclades arc) and of the mainly brittle outer belt (Hellenic arc). The bowing of the inner belt developed without involving any major fragmentation, whereas the outer brittle belt underwent a major break in its most curved sector, which led to the separation of the eastern (Crete–Rhodes) and western (Peloponnesus) Hellenic sectors. After separation, these structures underwent different shortening patterns, respectively driven by the convergence between southwestern Anatolia and the Libyan continental promontory (Crete–Rhodes) and by the convergence between the Cycladic Arc and the Adriatic continental domain (Peloponnesus). A discussion is given about the compatibility of the observed deformation pattern with the main alternative geodynamic interpretations and with the Nubia–Eurasia relative motions so far proposed.

Highlights

The Aegean–Hellenic system is the most seismic zone of the Mediterranean area (Figure 1)
This was because the second kind of data may relate to the transient displacement and strain fields triggered by the strong earthquake sequence that has developed along the entire North Anatolian Fault system (NAF) since 1939 [17,18,19]
Transtensional tectonics has occurred in the northern Aegean zone since the late Miocene–early Pliocene [26,27,28], while extension and subsidence have developed in the southern Ae4goef a28n zone since the early Pliocene in the western Cretan basin, and since the Pleistocene in the eastern Cretan basin and Karpathos trough

Summary

Introduction

The Aegean–Hellenic system is the most seismic zone of the Mediterranean area (Figure 1). We separated the evidence relating to long-term deformation (Figure 2), mainly derived by geological or geophysical investigations, from the short-term deformations (Figure 3), inferred from geodetic and seismicity data This was because the second kind of data may relate to the transient displacement and strain fields triggered (as postseismic relaxation) by the strong earthquake sequence that has developed along the entire North Anatolian Fault system (NAF) since 1939 [17,18,19]. Transtensional tectonics has occurred in the northern Aegean zone since the late Miocene–early Pliocene [26,27,28], while extension and subsidence have developed in the southern Ae4goef a28n zone since the early Pliocene in the western Cretan basin, and since the Pleistocene in the eastern Cretan basin and Karpathos trough VHM—Victor–Hensen Medina fault system. (B) Tentative reconstruction of the Oligocene–early Miocene configuration of the Tethyan belt and surroundings

Late Cenozoic Evolution

Alternative Geodynamic Interpretations

Slab-Pull Model

Gravitational Spreading

Nubia–Eurasia Relative Motion

Conclusions