THE ROLE OF PLEISTOCENE STRIKE-SLIP TECTONICS IN THE NEOGENE-QUATERNARY EVOLUTION OF THE SOUTHERN APENNINE OROGENIC BELT: IMPLICATIONS FOR OIL TRAP DEVELOPMENT

C. Monaco*+, L. Tortorici*, S. Catalano*, W. Paltrinieri** and N. Steel**

* Dipartimento di Scienze Geologiche, UniversitÓ di Catania, Corso Italia 55, 95129 Catania, Italy.

** British Gas Rimi, Piazza Cavour 2, 20121 Milan, Italy.

+ author for correspondence: cmonaco@mbox.unict.it

The Southern Apennine orogenic belt is composed of allochthonous continental units derived from the African and European palaeo-margins of NeoTethys (the Adria and Corsica-Sardinia Blocks, respectively), together with oceanic units derived from the intervening NeoTethyan domain. The frontal part of the belt has been thrust over a foredeep-foreland system consisting of the Bradano Trough and Apulian Platform. The belt can be divided into two structural levels which are separated by a major detachment surface. The upper level consists of a multilayer complex made up of allochthonous NeoTethyan nappes; these were deformed during oceanic subduction, and are now emplaced on the Adria Block as a consequence of continent-continent collision. The lower structural level is characterised by large-scale duplexes involving the Mesozoic-Cenozoic sedimentary cover of the Adria Block which in recent years has formed an important target for oil exploration. On top of these allochthonous terranes, a series of small Plio-Pleistocene basins developed during the final phases of the thrust belt’s migration into the foreland. During the last stages of orogenesis, thrust migration became locked as a result of collisional thickening of the continental crust, and deformation in the southern Apennines was taken up by strike-slip faults which now cut across the fold and thrust belt.

In this paper, we describe the major Pleistocene strike-slip structures in the southern Apennines between the Pollino Mountains in the south and the Potenza region in the north, and investigate the role of wrench tectonics in the belt’s Neogene-Quaternary evolution. The study combines field mapping with analyses of satellite images and aerial photographs. Sinistral WNW-ESE trending strike-slip faults are accommodated by thrusts and folds which cross-cut the pre-existing tectonic layering, giving rise to an interference pattern in which culminations may act as structural traps suitable for oil and gas exploration.

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