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energy

Why is there oil in Val d’Agri?

About 250 million years ago, Val d’Agri was characterised by a tropical climate and temperatures never fell below 15 degrees centigrade: the climate could therefore be compared to that of the current Bahamas.

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Testimony of the seabed in the rocks of Val d’Agri at Montemurro (approx. 1000 m above sea level). Photo: Dario Colucci.

The Valley was replaced by a huge and deep basin, the “Lagonegrese Basin”. It was confined between two major tectonic platforms: the Campanian-Lucanian platform to the West and the Apulian Platform to the East, the present-day Puglia. Testifying the Miocene marine environment are numerous finds of shells, corals and marine fossils. Famous are the finds in Marsico Nuovo and especially in Latronico where, on a large stone slab, it is possible to see the fossil of a fish approx. 30 cm long, dating back to the Miocene period (approx. 25-30 million years ago).
On the bed of this basin, over 100 million years, a lot of sediment settled, both of plant as well as animal origin. A large amount of organic matter had therefore accumulated on the bottom.
During the formation of the Apennines, approx. 30 million years ago, a veritable “trap” was created that imprisoned this biological substance. As a result of tectonic movements, or to the overlapping of various units of sedimentary rock and due to their enormous weight, this organic substance sank deeper and deeper.
Ultimately, in areas of the southern Apennines, several major tectonic units emerge. In the deepest part we find the Mesozoic series, called “Lagonegresi Units”, that have siliciferous carbonate rocks (“Limestones with Chert”) at the bottom. Above these units is marl, followed by marly siliciferous sediments (“Siliceous Schist”). More on the surface we have layered Mesozoic carbonates (currently the “Apennine Platform”), generally covered by tertiary marl, while even higher up we again find the mixed Cretaceous and tertiary “flyschoid” series, often referred to as “Eocene flysch”.

 

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Geological section through the oilfields of Monte Alpi and Tempa Rossa.

By Eleonora Ippolito, Elisabetta Fortunato, Francesca Scannone, Dario Colucci

With the sponsorship of the Italian Ministry of Education, Universities and Research
 
Eni S.p.A. - P.IVA 00905811006