This paper investigates the sedimentological response of the Tertiary Pindos and Mesohellenic Basins to localized tectonic and eustatic sea-level changes in a submarine setting dominated by turbidite deposition. Five composite stratigraphic cross-sections were compiled from field data, three in the Pindos Basin and two in the Mesohellenic Basin; 45 samples were dated by means of nannofossil biostratigraphy. On the basis of these field studies, we relate observed changes in depositional environment to eustatic sea-level changes and to activity on local thrusts. Between the early Eocene and the late Miocene, tectonically-driven subsidence in both basins was generally more significant than eustatic variations in controlling depositional patterns. However, depositional conditions can be related to eustatic changes at four specific times:

(i) late Eocene submarine fans and deltaic or fan-delta deposits in the Mesohellenic Basin can be related to a sea-level rise (NP17) and subsequent fall (NP18-19), respectively;
(ii) the development of submarine fans in both basins during the early to middle Oligocene (NP22-23) can be related to a sea-level rise;
(iii) a late Oligocene (NP24-25) sea-level fall can be related to more restricted depositional conditions, accompanied by intra-basinal thrusting in the Pindos Basin and the presence of two indentors in the Mesohellenic Basin;
(iv) a change from deep-water (submarine fan) to shallow-marine deposition during the late Miocene in the Mesohellenic Basin can be related to a eustatic fall in sea-level.

    Standard organic geochemical analyses were carried out on 93 samples from both basins, including Rock-Eval pyrolysis and column and gas chromatography. Preliminary results indicate that the sedimentary sequences in both the Pindos and Mesohellenic Basins may have the potential to generate natural gas.