Tertiary Sedimentary and Tectonic Evolution of Apulian Platform in the Val d’Agri Subsurface Area (Southern Italy)

Pugliese, Alfredo ²; Ghielmi, Manlio ¹; Barbacini, Giulia ³; Carubelli, Paolo ²; Magistroni, Corrado ⁴; Miraglia, Salvatore ²; Renna, Luca A.¹; Scola, Valeria A.¹
(1)ESEI, Eni S.p.A. Exploration & Production Division, San Donato Milanese, Italy. (2) SPES, Eni S.p.A. Exploration & Production Division, San Donato Milanese, Italy. (3) GICA, Eni S.p.A. Exploration & Production Division, San Donato Milanese, Italy. (4) GEBA, Eni S.p.A. Exploration & Production Division, San Donato Milanese, Italy.

The Apulian Platform (AP), consisting of Mesozoic-Tertiary shallow-water carbonates up to 7000m thick, is the main HC exploration target in Southern Apennines (SA). Large sectors of AP were involved in the SA eastward migration during Tertiary. Large volumes of subsurface data of the Val d’Agri Field (VAF) provided the opportunity to reconstruct a detailed geological model of the area.

In the VAF area pelagic sediments (mainly mud-supported limestone) were deposited above a submarine paleo-high during M. Paleocene-M. Eocene. An intense tectonic activity affected the area in the M. Eocene upper part, as indicated by intercalations of carbonate breccias and volcanic layers. At the end of M. Eocene, an important compressive event, related to the last Ligurian phase of SA, interested this sector of the Mediterranean area causing the AP emersion (from U. Eocene to Miocene) as confirmed by continental “red beds” associated to widespread karst.

During Neogene large sectors of AP were progressively involved in the regional eastward migration of SA. While the AP western-central sectors were deeply deformed, the eastern part remained substantially undeformed and partially cropping out in the Gargano-Salento areas. From M.-U. Miocene the AP western margin was interested by active subsidence due to the Adria Plate subduction and the tectonic overburden of the forming SA. In VAF area a tectonic-controlled relative sea-level rise caused the return to marine condition with the sedimentation of a thin overall transgressive succession (up to 40m thick with shallow-water bioclastic limestones passing upward to moderately deeper phosphatic packestone and wackestone). These deposits are unconformably overlaid by a regressive Messinian succession made up of pre-evaporitic coastal bioclastic limestones, syn-evaporitic anhydrites of hyperhaline lagoons and post-evaporitic calcareous breccias. L. Pliocene succession mainly consists of sandstones and shales, up to 600m thick, representing the turbiditic infill of the westernmost and oldest Plio-Pleistocene Bradanic Foredeep depocenter. A severe deformation phase during the upper part of L. Pliocene (Intra-Zanclean Phase) is responsible for the rapid overthrusting of the Allochthonous Complex on the L. Pliocene Val d’Agri foredeep. A major transpressional event (Gelasian Phase) interested VAF with the reactivation as high-angle reverse faults of AP normal faults resulting in the uplift of a NW-SE-oriented large-scale pop-up.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.