Tertiary geodynamic evolution of the Southern Adria microplate

Abstract

The southern Adria microplate is the common foreland for the Hellenide and Southern Apennine thrust belts. The Apulian Platform dominates the microplate; outcrop, well and seismic data allow us to trace the carbonate platform edge, whilst structural analysis, geophysical and palaeomagnetic data provide important clues to the geodynamic evolution of the region. The present structural fabric of Apulia is dominated by several E‐W lineaments that divide the region into different blocks (Rospo Plateau, Gargano Promontory, Murge Ridge, Salento Peninsula, Apulian Plateau). One such lineament (the Pescara Dubrovnik ‘Line’, a prominent feature traversing the Adriatic Sea between central Italy and southern Croatia) has been active since the early Mesozoic, when it acted as a major transform fault controlling sedimentation along the northern margin of Southern Adria. During the Cenozoic the Pescara‐Dubrovnik underwent predominantly vertical and oblique movement due to a differential flexural response of the platform and the adjacent pelagic sequences to the thrust belt loading. In Tertiary time the Southern Adria microplate was partly involved in HeIlenide collision. The Apulian platform can be considered as an area of thicker crust more resistant to underthrusting than the surrounding basins. During the orogenic events it acted as a passive rigid indentor, causing local distortion of the most external Hellenide structures. The dextral transpressive activity recorded along the south‐east margin of this indentor (Kephallinia line) can be interpreted as the result of the oblique collision between the margin of the thick Apulian Platform (in this zone NNE‐SSW striking) and the NW‐SE striking Hellenic thrust belt. Horizontal stress generated during the collision was partly transmitted to the rigid foreland re‐activating palaeo E‐W faults within the south Adria microplate in a dextral strike‐slip sense. The clockwise rotation recorded in the Salento Peninsula can be explained by the rotation of several NW‐SE striking faulted blocks. The rotation was accompanied by the opening of small transtensional basins between blocks. This block rotation was caused by the dextral shear that is expressed along the North and the South Salento Fault Zones.

Sinkhole evolution in the Apulian Karst of Southern Italy: a case study, with some considerations on Sinkhole Hazards

“…These faults were active during the Pliocene and Pleistocene and show high-angle planes, with opposite dip directions, along which a maximum extensional offset of about 200 m can be estimated. However, according to Tozzi (1993) and Gambini and Tozzi (1996), a transcurrent component characterizes their kinematics as well. The activity of the faults would be responsible for the formation of open to gentle folds, especially in the Cretaceous and EoMiocenic units (Martinis, 1962;Tozzi, 1993;Fig.…”

The environmental effects of the 1743 Salento earthquake (Apulia, southern Italy): a contribution to seismic hazard assessment of the Salento Peninsula

“…According to Ambrosetti et al (1986), Bigi et al (1983) and Gambini and Tozzi (1996), the major structural lineaments cutting the Apulian foreland and to be considered as significant probable seismogenic sources are ( Fig. 1): the Pescara-Dubrovnik Fault Zone (PDFZ); the Nord-Gargano Fault Zone (NGFZ); the Mattinata-Gondola Fault Zone (MGFZ); the North-Salento Fault Zone (NSFZ) and the North-Kerkira Fault Zone (NKFZ).…”

The influence of Late Cretaceous synsedimentary deformation on the Cenozoic structuration of the middle Adriatic, Croatia

“…These data are complemented by interpretations of seismic sections [44,45]. The results of geophysical data integration bring forward two main conclusions [46][47][48][49][50][51]: (1) the deep seismic horizons (Moho discontinuity) show that structures in the central off-shore part of the Adriatic plunge beneath the Dinaric structures exposed on land, and (2) deformations of the Moho discontinuity in the coastal region mark the zones of pronounced tectonic activity. Such relationships indicate the presence of reversethrust compressional structures.…”