THE ALBANIAN OROGEN: CONVERGENCE ZONE BETWEEN EURASIA AND THE ADRIA MICROPLATE

Abstract

In Albania and Greece, along the southern convergent margin of the Eurasia Plate, we distinguish a northern segment of the margin, belonging to the Adriatic continental collision, and a southern one, belonging to the Aegean (Hellenic) Arc related to active oceanic subduction. The boundary between the Aegean Arc and the Adriatic collision is the Cephalonia Transform Fault. The Albanian orogen and surroundings are divided into two active tectonic domains: an external compressional domain, constituting the Adriatic collision zone, and an internal extensional domain. In Albania, Adria collides with Eurasia along a series of thrusts. The Albanian orogenic front is thrusting over the Adria microplate, partly over Apulian platform and partly over Albanian Basin (southern Adriatic basin). The Albanian orogenic thrust front is cut and displaced by the Othoni Island-Dhermi, the north Sazani Island, and the Gjiri i Drinit-Lezha strike-slip faults, which divide the orogen into separate segments with diachronous development: The NW-trending Lefkas-Corfu offshore segment, where the Ionian zone consists of the orogenic front; The NW-trending Karaburuni-Sazani Island offshore segment, where the Sazani Zone comprises the orogenic front; The ~N-trending Frakulla-Durresi mainly onshore segment, where Ionian zone makes up this orogenic front, and The W-NW-trending Lezha-Ulqini segment, where the orogenic front is composed of Kruja Zone. The Adriatic collision zone is the most seismically active region in Albania and makes up the Ionian-Adriatic coastal earthquake belt at the eastern margin of the Adria microplate.