The Tell-Rif orogenic system (Morocco, Algeria, Tunisia) and the structural heritage of the southern Tethys margin

Abstract

-The Tell-Rif (Tell in Algeria and Tunisia; Rif in Morocco) is the orogenic system fringing to the south the West Mediterranean basins. This system comprises three major tectonic-palaeogeographic zones from north to south: (1) the internal zones (AlKaPeCa for Alboran, Kabylies, Peloritan, Calabria) originating from the former northern European margin of the Maghrebian Tethys, (2) the "Flyschs zone" regarded as the former cover of the oceanic domain and (3) the external zones, forming the former southern Maghrebian Tethys margin more or less inverted. The Tell-Rif is interpreted as the direct result of the progressive closure of the Maghrebian Tethys until the collision between AlKaPeCa and Africa and, subsequently, the propagation of the deformation within Africa. This gives a consistent explanation for the offshore Neogene geodynamics and most authors share this simple scenario. Nevertheless, the current geodynamic models do not completely integrate the Tell-Rif geology. Based on the analysis of surface and sub-surface data, we propose a reappraisal of its present-day geometry in terms of geodynamic evolution. We highlight its non-cylindrical nature resulting from both the Mesozoic inheritance and the conditions of the tectonic inversion. During the Early Jurassic, we emphasize the development of NE-SW basins preceding the establishment of an E-W transform corridor connecting the Central Atlantic Ocean with the Ligurian Tethys. The Maghrebian Tethys developed just after, as the result of the Late Jurassic-Early Cretaceous left-lateral spreading between Africa and Iberia. By the Late Cretaceous, the occurrence of several tectonic events is related to the progressive convergence convergence between the two continents. A major pre-Oligocene (pre-35 Ma) compressional event is recorded in the Tell-Rif system. The existence of HP-LT metamorphic rocks associated with fragments of mantle in the External Metamorphic Massifs of the Eastern Rif and Western Tell shows that, at that time, the western part of the North-African margin was involved in a subduction below a deep basin belonging to the Maghrebian Tethys. At the same time, the closure of the West Ligurian Tethys through east-verging subduction led to a shift of the subduction, which jumped to the other side of AlKaPeCa involving both East Ligurian and Maghrebian Tethys. Slab rollback led to the development of the Oligo-Miocene back-arc basins of the West-Mediterranean, reworking the previous West Ligurian Tethys suture. The docking of AlKaPeCa against Africa occurred during the Late Burdigalian (17 Ma). Subsequently, the slab tearing triggered westward and eastward lateral movements that are responsible for the formation of the Gibraltar and Tyrrhenian Arcs respectively. The exhumation of the External Metamorphic Massifs occurred through tectonic underplating during the westward translation of the Alboran Domain. It resulted in the formation of both foredeep and wedge-top basins younger and younger westward. The lack of these elements in the eastern part ...

Geology of the Ionian Basin and Margins: A Key to the East Mediterranean Geodynamics

“…The black arrow represents the movement of Africa relative to fixed Europe during Middle Jurassic time. Modified after Frizon de Lamotte et al (), Guiraud et al (), and Leprêtre et al ().…”

Active Faulting Geometry and Stress Pattern Near Complex Strike‐Slip Systems Along the Maghreb Region: Constraints on Active Convergence in the Western Mediterranean

“…The Maghrebides were considered as the Alpine chain of North Africa resulting from the closure of the Tethyan oceanic Basin (Auzende et al, ; Durand‐Delga & Fontobé, ). It consists a Neogene pile of thrust sheets trending E‐W with a significant curvature in the Rif, which swings from E‐W in the its eastern part to N‐S in the western part (Frizon de Lamotte et al, ; Rémi Leprêtre et al, ; Roure et al, ). During the lower Oligocene‐Burdigalian, northward subduction and slab retreat of African oceanic lithosphere allowed the deposition of the Numidian flysch at the front of the Kabylides nappes (e.g., Essid et al, ; Frizon de Lamotte et al, ; Roure et al, ).…”

“…During the lower Oligocene‐Burdigalian, northward subduction and slab retreat of African oceanic lithosphere allowed the deposition of the Numidian flysch at the front of the Kabylides nappes (e.g., Essid et al, ; Frizon de Lamotte et al, ; Roure et al, ). The collision between AlKaPeCa and Africa occurred during the Langhian (e.g., Frizon de Lamotte et al, ; Jolivet & Faccenna, ; Rémi Leprêtre et al, ; Roure et al, ). During the Tortonian, the subducting slab break off accelerated the continental collision and occurred the uplift of the Tellian domain (e.g., Benaouali‐Mebarek et al, ; Faccenna et al, ; Frizon de Lamotte et al, ; Roure et al, ; Soumaya et al, ).…”

“…Simplified tectonic map showing the main geological and structural features of the Maghreb region. This map was established using Medaouri et al (), Meghraoui et al (), Leprêtre et al (), Vially et al (), Ben Ayed (), Domzig et al (2009), Mauffret (), Martínez‐García et al (), Rabaute and Chamot‐Rooke (), Yelles et al (), and Medina (). Abbreviations are as follows: WAB: Western Alboran Basin, EAB: Eastern Alboran Basin, SAB: Southern Alboran Basin, CF:Chott fault, COF: Canstantine fault, THF: Thenia fault, TF: Ténes fault, AF: Arzew fault, ASF: Al Asnam fault, YF: Yusuf fault, CF: Carboneras fault zone, GF: Gafsa fault.…”

“…Simplified tectonic map showing the main geological and structural features of the Maghreb region. This map was established using Medaouri et al (2014), , Leprêtre et al (2018), Vially et al (1994), Ben Ayed (1993), Domzig et al (2009), Mauffret (2007), Martínez-García et al (2011), Rabaute and Chamot-Rooke (2014), Yelles et al (2009), and Medina (1995). 1980, and references therein).…”