Structural and Time Constraints of Long-Lived, Crustal-Scale Structures in the Foreland Domains of the Apennine-Maghrebian Chain (Southern Italy): Implications for Background Deformation
Cilona, Antonino 1; Tondi, Emanuele 1;
Agosta, Fabrizio 2; Spina, Vincenzo 3
(1)Division,
School of Science and Technology, University of Camerino, Camerino, Italy. (2)
Department of Geology, University of Basilicata, Potenza, Italy. (3) Geoscience
Division, Total Italia E&P, Roma, Italy.
In southern Italy, oil and thermogenic gas accumulated in Mesozoic
carbonate rocks belonging to the Apulian platform. At this location, petroleum
plays are related to the main phases of Tethyan crustal stretching. These
carbonate reservoir rocks crop out in the Puglia Region (Gargano Promontory,
Murge Plateau) and in SE Sicily (Hyblean Plateau); they are crosscut by 2
regional structures: The Mattinata (MFZ) and The Scicli-Ragusa (SRFZ) Fault
Zones respectively. Both are crustal-scale fault zones characterized by
predominant strike-slip motion, they recorded different tectonic phases and
played a important role in the structural arrangement of the foreland domains
of the Apennine-Maghrebian Chain. Thus they are key areas in order to gather a
new knoledge on the fracturing state of the Mesozoic carbonate reservoirs.
In this work, we focus on the kinematic and evolutionary histories
of these fault zones by mean of detailed geo-structural and morphological
analyses.
The MFZ is a E-W oriented structure and crosscuts the Gargano
Promontory that is part of an about 3km-thick Jurassic-Cretaceous carbonate
succession consisting, of shallow-water carbonates passing into slope and
basinal deposits. In agreement with other authors, our data suggest two
kinematic episodes associated to the MFZ: 1sta left-lateral motion (L. Mioc.-E.
Pleist.), then a right-lateral motion (since Middle-Late Pleist. up to
present).
The SRFZ is NNE-SSW oriented structure which crosscuts the Hyblean
Plateau. This Plateau is made up by Mesozoic-to-Tertiary carbonate rocks
belonging to platform-to-ramp environments. Our data are consistent with the
SRFZ being developed as a dextral strike-slip fault, since Up. Mioc.. Then,
some SRFZ-related fault segments have been reactivated since the L. Pleistocene
with a left-lateral kinematics.
According to the our results, both fault zones nucleated and
developed, since Late Mioc., under a stress field characterized by horizontal
NE-oriented and NW-oriented σ1 and σ3 axes, respectively. A second
kinematic episode, associated to the two FZ, started in the Middle-Late
Pleistocene, driven by a new stress field with horizontal σ1 and σ3
axes oriented NW-SE and NE-SW, respectively.
Our results suggest that the foreland domains of the Apennine-Maghrebian Chain were subjected to two different stress fields that, away from the main fault zones, were responsible of a background deformation which strongly affects the fluid flow properties of the carbonates.
AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.