Interactions Between Tectonic Activity and Eustatic Sea‐level Changes in the Pindosand Mesohellenic Basins, Nw Greece: Basin Evolution and Hydrocarbon Potential

Abstract

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 bio stratigraphy. 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: 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; the development of submarine fans in both basins during the early to middle Oligocene (NP22‐23) can be related to a sea‐level rise; 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; 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.

Maturity of dispersed organic matter in bituminous formations of the Ionian Zone (Epirus region, NW Greece)

“…Figure 6 displays some abundant types of organic matter contained in the studied samples. Avramidis et al (2002) the submarine fans have the potential to yield hydrocarbons. This is in agreement with the high vitrinite content of the Dragopsa sample, typical for kerogen type III being gas-prone.…”

“…IGRS-IFP, 1966;BP, 1971;Jenkins, 1972;Karakitsios and Rigakis, 1996;2007;Rigakis and Karakitsios, 1998;Avramidis and Zelilidis, 2001;Avramidis et al, 2002;Karakitsios, 2003;Zelilidis et al, 2003;Kokkinou et al, 2005).…”

The Auriferous Submarine Fans Sandstones of the Ionian Zone (Epirus, Greece)

“…The proximal clastics of the internal areas are thicker and coarser than the distal ones of the middle or even external parts. Accordingly, submarine fans sedimentation, mainly clays and sandstones with conglomeratic beds, started earlier in the east than in the west (Bizon, 1967), and earlier in the north than in the south (Avramidis et al, 2002). The western border of the Ionian trough is the slope of the Apulian Platform, known as the Pre-Apulian Zone, and was not covered by submarine fan deposits.…”

“…According to Richter (1974Richter ( , 1976) the internal, middle and external parts of the Ionian Basin are separated by intrabasinal highs. This arrangement of the sea-floor was the main factor that controlled the flow direction and the extension of the clastic terrigenous turbidity currents (Avramidis & Zelilidis, 2001;Avramidis et al, 2002). This long year's research work has created many views on the distribution of submarine fan deposits in the three sub-basins, as well on the lithostratigraphic nomenclature reflected in the geological maps of Western Greece.…”

Peri-equatorial paleolatitudes for Jurassic radiolarian cherts of Greece

“…Regional metamorphic events (e.g., HP/LT of the south Aegean core complex; Jolivet et al, 1996) accompanied the latter orogenic phase, as did formation of the Meso-Hellenic basin since the Late Eocene ( Fig. 1; Avramidis et al, 2002). Following the "Meso-Hellenic" orogenesis, western Greece was subjected to two main pulses of late orogenic exhumation and extension in the early Miocene (Jolivet et al, 1996;Jolivet et al, 2003;van Hinsbergen et al, 2005c), with detachment faulting and exhumation of the south Aegean core complex on the Peloponnesus and Crete (Ring et al, 2001), and in late Miocene to early Pliocene time by collision of northern Greece with the Apulian platform and continued subduction of oceanic lithosphere in the Ionian basin beneath southern Greece (van Hinsbergen et al, 2006).…”