TECTONICS AND SEDIMENTATION WITHIN A MESSINTAN FOREDEEP IN THE CENTRAL APENNINES, ITALY

The Mtirche-Abruzzi thrust system is part of the Central Apennine fold- and-thrust belt of mainland Italy. Our study area covers the SE portion of the Umbria-Marche-Abruzzi region and the northern part of the Gran Sasso Mountains. A thick pile of turhidites is exposed in this area: they were deposited within a Messinian foredeep in front of the evolving fold-and-thrust belt. We have. used regional structural interpretations together with unpublished well-log and seismic data to construct a cross-section across the external portion of the thrust system. Our work suggests that: (i) deformation of the sediments in the Messinian foredeep began shortly after their deposition, and continued until the late Pliocene; (ii) the. restored(pre-deformation) width of the basin was approximately twice that of the presentday basin, and the depocentre migrated eastwards at a rate of about 4 cm/yr: (iii) the geometry and physiography of the Messinian foredeep were controlled by a number of longitudinal and transverse structural features which may he related to foreland ramp activity or to differential flexuring of the Apulian lithosphere, respectively.