Λεπτομερής μελέτη των κλαστικών αποθέσεων στα νησιά του Ιονίου Πελάγους, η σχέση τους με την Ιόνια λεκάνη προχώρας και την λεκάνη προχώρας της Πίνδου. Η συνεισφορά τους στην ανάπτυξη πεδίων υδρογονανθράκων στην Απούλια πλατφόρμα

The goal of the present study is the detailed investigation of the depositional environments that were formed (or transformed) due to the activity of the Ionian Thrust in the broad region of the External Hellenides in Western Greece (Early Miocene to Middle Pliocene). The study aims to include new insights in the paleogeographic model of the region and also provide new data in respect of oil and gas plays, established or under investigation, in the Ionian Sea. The investigation was focused on the Ionian Islands, with special emphasis in basins and sub-basins that were, up to this date, either partially or not studied. From the preliminary stage approx.. 15 sections of interest where defined, corresponding to four islands (Corfu, Cephalonia, Lefkas, Zakynthos) two major chronostratigraphic units: One of the Middle to Late Miocene and one of the Early to Middle Pliocene. Those sections were studied in detail, in respect of their sedimentary structure and stratigraphy, and were sampled in detail for further laboratory analysis in University of Patras and Technical University of Crete. More than 350 samples were collected for further sedimentological and geochemical analysis. Sedimentological investigation through grain analysis and statistical evaluation took place in the Laboratory of Sedimentology in the Geology Dpt. of University of Patras. Measurements of calcium carbonate and preliminary evaluation of TOC% content also took place, leading to the selection of most promising samples for further study. One third of the samples where further analyzed with Rock Eval IV pyrolysis in the Laboratory of Geochemistry in Crete. Samples from Corfu and Zakynthos where selected for biomarker analysis with the use of gas chromatography-mass spectrometry (GC-MS). The RE IV results from samples of Lefkas and Cephalonia were studied with applied statistical methods (Cluster analysis and principal component factor analysis) with a simultaneous aim to assess interpretational capabilities of the aforementioned tools regarding source rock evaluation. Results of the above investigations, integrated with previous studies in the broad region of various disciplines, where utilized for a holistic approach in the paleogeographic evolution of the area during all phases of the Ionian Thrust activity. The geological and geotectonic framework is introduced in Chapter 1, with emphasis on the External Hellenides and each individual study area. A brief scientific, social and historical overview in hydrocarbon exploration in Western Greece is presented in Chapter 2, along with up-to-date Oil Geology models for proven and estimated plays. The studied basins, their characteristics and structures and their stratigraphy are thoroughly presented in Chapter 3, along with representative photos and illustrations. The grain size analysis results and their statistical interpretations are presented and illustrated in Chapter 4. The detail geochemical investigation is presented in Chapter 4, along with the methodology used and the framework of organic matter and biomarker occurrence in sediments. Presented results are utilized in source rock assessments for all sediments and also for paleodepositional conditions insights. The synthesis of the results is presented in Chapter 6, with the region’s paleogeography, basin evolution and sedimentation history and the presentation of new insights in hydrocarbon exploration. Conclusions in English and Greek are presented in Chapter 7 and in Chapter 8 there is a brief presentation of at the time of writing of this thesis published results in journals and conferences. In Chapter 9 is the full reference list and Chapter 10 contains acknowledgments and authors addendum.