Late Oligocene‐Miocene syn‐/‐late‐orogenic successions in Western and Central Mediterranean Chains from the Betic Cordillera to the Southern Apennines*

TLDR

During the Late Jurassic–Early Cretaceous a microplate bounded by the Piemontese and Maghrebian oceans was positioned between the European and African plates, and its margins were structured from the Late Cretaceous to the Eocene to form the Eo‑alpine Chain, while the southern margin was deformed in the Aquitanian producing syn‑orogenic flysch. The study identifies syn‑ and late‑orogenic flysch deposits from the Betic Cordillera to the Southern Apennines to reconstruct the tectonic‑sedimentary evolution of the perimediterranean chains. Metamorphism (25–22 Ma) and nappe emplacement created the AlKaPeCa orogenic belt, which was later fragmented and thrust onto the Flysch Basin and adjacent margins during a Burdigalian late‑orogenic cycle, followed by folding, back‑thrusting, Langhian suturing, and final thrusting of the entire orogen onto the foredeep in the Middle–Late Miocene.

Abstract

The identification of syn‐ and late‐orogenic flysch deposits, extending from the Betic Cordillera to the Southern Apennines, assists in the reconstruction of the tectonic‐sedimentary evolution of the perimediterranean chains. A microplate was located between the European and African Plates during the Late Jurassic–Early Cretaceous, bordered northwards by the Piemontese Ocean and southwards by another (North Africa ‘Flysch’ Basin or Maghrebian) Ocean. The Piemontese Ocean and the northern margin of the microplate were structured from the Late Cretaceous to the Eocene to create an Eo‐alpine Chain. The southern margin of the microplate was deformed in the Aquitanian, when the internal areas of the Maghrebian Ocean were characterized by syn‐orogenic flysch deposits. This episode culminated with metamorphism (25–22 Ma) and nappe emplacement, which destroyed the former palaeogeography and created an orogenic belt (AlKaPeCa). Afterwards, a lower Burdigalian late‐orogenic cycle started in the deformed area, which as a result of the opening of the Algero‐Provençal Basin, caused the fragmentation of the AlKaPeCa, its thrusting on the ‘Flysch’ Basin and the collision with the North Africa and South Iberia Margins. These latter were folded and thrusted, the ‘Flysch’ Units pushed over the External Domain and also back‐thrusted. Langhian late‐orogenic deposits suture the new tectonic features. Finally, the whole orogen was thrust onto the foredeep during the Middle–Late Miocene.