Thick- and Thin-Skinned Thrusting in the Development of the Southern Apennine Thrustbelt: A Case Study from the Val D'Agri

Peter R. Shiner¹, Stefano Mazzoli², and Giuseppe Cello^3
1 Shell Italia E&P, Roma, Italy
² Università di Urbino,
³ Università di Camerino,

The S Apennine orogen has generally been interpreted as a classic thin-skinned thrustbelt. However, recent studies in the Val d'Agri area, based on the integration of surface geological data with subsurface data derived from appraisal of the several significant hydrocarbon discoveries in the area, suggest that structural geometries result from complex interactions between thin and thick-skinned compressional tectonics. The deep hydrocarbon-bearing Apulian platform structures are overlain by an allochthon consisting of Mesozoic units – including both peritidal carbonates (Apenninic platform) and pelagic (Lagonegro basin) assemblages – initially deposited on the Adriatic passive margin, and of Miocene ‘flysch' units, deposited within the evolving thrustbelt. Early compressional structures include buckle folds and thrusts developed within Mesozoic basinal units, the development of which are interpreted to have been controlled by Mesozoic normal faults and can thus be considered ‘thick-skinned'. This early phase was followed by several phases of thin-skinned thrusting: firstly within the Lagonegro basin sequence and then subsequently the Apenninic platform was emplaced onto the Lagonegro thrust pile. A final phase of thin-skinned tectonics resulted in emplacement of the Lagonegro-Apenninic platform thrust-pile onto the Apulian platform. The last phase of compressional activity is related to the development of the trap-forming deep Apulian platform structures. These developed in the hanging wall of deep moderate-high angle convex-up reverse faults that probably result from the inversion of Permo-Triassic extensional faults. The S Apennine orogen is thus the result of both thick and thin-skinned compressional tectonics resulting in complex geometries that are not easily explained by simple models.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005