Late Eocene to Early Miocene depositional environments of the Mesohellenic Basin, North-Central Greece: Implications for hydrocarbon potential

Abstract

Late Eocene to Early Miocene Mesohellenic Basin deposits accumulated in a tectonically controlled basin with irregular and narrow shelves. The boundaries between the Eocene-Oligocene Krania-Eptachori Formations and the Oligocene-Miocene Eptachori-Pentalophos Formations record the global sea-level falling during the corresponding time intervals. The sediments of the Mesohellenic Basin have characteristics of lowstand fan deposits without coastal onlap. It is suggested that the concept of the hydrocarbon habitat is applicable to the Mesohellenic Basin due to the following characteristics of the studied deposits: (a) The outer fan sandstones lobes, classified in this work as suprafan lobes, are characterized by stacked channel sand bodies with good lateral and vertical communications. These features constitute excellent reservoir facies. (b) The fme-grained, lobe-fringe and basin-plain deposits of the studied marine turbidites may have operated as either fertile source rocks or topseals. (c) The geometry ofthe lobes (stacked channel sand bodies) and the internal unconformities (between the four formations) present excellent stratigraphic traps. (d) The synchronous evolution of these deposits assures the timely relationship among all factors listed above. Since the studied sediments correspond mostly to the western margin deposits it is very possible that basinwards, in the direction of the progradation, the interchannel deposits must laterally pass into, the outer fan sandstone lobe, lobe fringe and basin plain deposits. Therefore, sediments of the basin interior not presently exposed are very likely to support favourable conditions for petroleum play.