Rapid Holocene evolution and neotectonics of the Albanian Adriatic coastline

High-resolution 1986 Landsat TM images of the Adriatic coast of Albania hav e been compared with aerial photographs obtained in 1943, and published lit erature, in order to decipher the sedimentary architecture and evolution of the late-Holocene deposits of the coastal plain. This coastline is microti dal and dominated by wave action; and abundant sediment is supplied by rive rs draining the uplifted mountainous interior of this tectonically active r egion. The coastal plain has prograded up to 40 km since relative sea level rise slowed down around 6000 years BP. The inland parts of the coastal pla in are dominated by parallel storm beach ridges whilst the coastal fringe e xhibits a diversity of symmetrical to asymmetrical wave-dominated deltas an d spit-deltas encompassing cut-off lagoons. A genetic model to explain the variability of wave-dominated deltas on the Albanian coast is proposed show ing a spectrum of forms between prograding symmetrical cuspate deltas forme d by bi-directional longshore drift and highly asymmetrical spit-deltas for med by uni-directional longshore drift. Avulsive switching causes abandonme nt; the symmetrical forms become smoothed out by wave action whereas the sp it-deltas become detached barrier beaches that migrate onshore by washover, welding themselves onto the coast. The back barrier cut-off lagoons in thi s setting have a very low preservation potential. Two much larger lagoons, now partly reclaimed, at Karavasta and Narta, lie within the belt of beach ridges; both have a straight seaward margin parall el to known post-Neogene faulting. The lagoons exhibit differential subside nce which is regarded as neotectonic in origin; the presence of a 60 km lon g graben or half graben structure linking the two areas of subsidence is su ggested to explain the observed phenomena. Subsidence up to 5-10 m is indic ated within the last 1,000-2,000 years.