Middle-late pleistocene evolution of the adriatic coastline of southern apulia (Italy) in response to relative sea-level changes

Abstract

The Adriatic coastal area stretching from Monopoli to Brindisi in Apulia is characterised by landforms and marine/coastal deposits of Mid- dle-Upper Pleistocene age. An E-W striking fault system, roughly corre- sponding to the geographic “Soglia Messapica”, is also present. This area shows the effects of different phases of coastal evolution. During the Middle Pleistocene, north of the Soglia Messapica, thin coastal deposits accumulated and abrasion surfaces were cut whereas, to the south, ma- rine sediments were deposited. During the last interglacial period, two thin transgressive beach deposits formed along with a dune belt and backdune deposits. From the geodynamic point of view, facies and elevation of marine and coastal deposits suggest that before 125 ka the region north of the Soglia Messapica was uplifting with a higher rate than the southern one. Afterwards, both areas north and south of the Soglia Messapica showed a similar tectonic behaviour, characterised by stability or, locally, by low subsidence rates. Mesostructural analysis on extensional joints indicates that at least three separate deformational events occurred during the Middle and Late Quaternary. If matched against the uplift rate changes, this structural evolution may be interpreted as due to the shift toward the SE of the peripheral bulge related to the Ionian slab subduction process and to the set up of a different tectonic event in the Late Pleistocene. In the study area such event is essentially characterised by widespread sta- bility, accompanied by the development of joint sets which suggest a doming-like deformation mechanism.