SIMULATION OF COLLISION ZONE SEGMENTATION IN THE CENTRAL MEDITERRANEAN

Collision processes between the African and European plates in the Ion ian Sea offshore Calabria and in Sicily take place in several ways. To the east, normal subduction of oceanic crust (underlying the Ionian S ea) occurs underneath the Calabrian are, whereas to the west, continen tal collision between the Pelagian block and the Calabrian are (which extends from Calabria to the northeastern tip of Sicily and offshore o f the island to the north) gives rise to the Maghrebian thrust belt on mainland Sicily. This belt consists mostly of stacked basinal and pla tform carbonates of Mesozoic-early Tertiary age deposited along the Af rica passive margin. No clear subduction characterizes the area north of the Hyblean-Malta plateau where it collides with the Maghrebian cha in. The origin of the Hyblean-Malta plateau is unclear. Geophysical da ta indicate, however, that its crustal structure is different from tha t of the surrounding Pelagian foreland. Crustal structure variations a t the edge of the subducted African plate may thus cause the observed segmentation of the collisional are system. A computer model of the re gion was created to learn about the deformation and faulting processes in the region. The simulation starts prior to the collision of the Pe lagian block with the Calabrian are. With time the Hyblean-Malta plate au collides with the northern crustal block and, as a result, a new si mulated topography, a new distribution of velocities and, most importa nt, a new distribution of fracture zones are created. A shear fracture zone is formed east of the Hyblean-Malta plateau (Malta escarpment) e xtending to the subduction zone at the Calabrian are. A less active st rike-slip fracture zone is created west of the Hyblean-Malta plateau. An additional E-W trending active fracture zone is creating in the sou thern part of the simulated area. This feature may correspond to a fau lt zone which runs from the Strait of Sicily to the Ionian Sea.