Print this pageLate Cenozoic Fault Kinematics and Basin Development, Calabrian Arc, Italy
Steven D. Knott, Eugenio Turco
Current views for explaining the present structure of the Calabrian arc emphasize bending or buckling of an initially straight zone by rigid indentation. Although bending has played an important role, bending itself cannot explain all structural features now seen in the arc for the following reasons: (1) across-arc extension is inconsistent with buckling, (2) north-south compression predicted by a bending mechanism to occur in the internal part of a curved mountain belt is not present in the Calabrian arc, and (3) lateral shear occurs throughout the arc, not just along the northern and southern boundaries.
The 
model
presented here is based on lateral bending of mantle and lower
crust (demonstrated by variation in extension in the Tyrrhenian basin) and
semibrittle faulting and block rotation in the upper crust. These two styles of
deformation are confined to the upper plate of the Calabrian subduction system.
This deformation is considered to have been active from the beginning of
extension in the Tyrrhenian basin (late Tortonian) and is still active today
(based on Holocene seismicity).
Block rotations are a consequence of lateral heterogeneous shear during
extension. Therefore, some of the observed rotation of paleomagnetic
declinations may have occurred in areas undergoing extension and not just during
thrusting. Inversion of sedimentary basins by block rotation is predicted by the
model. The model
will be a useful aid in interpreting reflection seismic data
and exploring and developing offshore and onshore sedimentary basins in southern
Italy.
AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.