The Meso-Hellenic Trough (MHT) is an elongate NW-SE trending intermontane basin that developed during the Mid-Tertiary within the Hellenide fold-and-thrust belt. It formed in the late Eocene behind the deformation-front as the locus of thrusting migrated towards the foreland in the south-west. This followed collision between the Apulian and Pelagonian micro-plates and final closure of the Pindos Ocean basin (a strand of the Neotethys). The MHT basin-fill is of U. Eocene-M. Miocene age, was predominantly marine in nature and can be sub-divided into the Basin-margin and Meso-Hellenic Groups, which are separated by a basin-wide angular unconformity. The Basin-margin Group (Upper Eocene) is only preserved in small outcrops around the basin margin and the Meso-Hellenic Group (Oligocene-Middle Miocene) forms the majority of the basin-fill. The Basin-margin Group was deposited on the sub-Pelagonian thrust-sheets and is of identical age to the youngest Pindos foreland basin sediments exposed beneath the same thrust-sheets. However, large-scale folds which deform the basal thrust demonstrably do not deform the overlying Meso-Hellenic Group. The Basin-margin Group can therefore be shown to have been deposited on the thrust sheets as they overthrust the Pinodos foreland basin. Coarse ophiolitic breccia up to 600 m thick characterises the south-western margin of the Krania sub-basin (a depocentre of the Basin-margin Group) and is interpreted as having been deposited at the base of an active (?reverse) fault-scarp. In addition, there is evidence that strike-slip faults were active along the northern and southern margins of the sub-basin. Although these structures may have controlled subsidence locally, the overall setting of the Basin-margin Group is interpreted as that of a piggy-back basin, formed above the south-westward propagating thrust stack. The palaeobathymetry of the basin increased during the late Eocene, as marked by the change from shallow-marine limestone, fan delta and lagonal facies to deeper-water turbidite facies. During this period, sedimentation was tectonically controlled, for example where basement uplift along reverse faults to the north of the Krania sub-basin shed limestone-dominated mass-flow deposits southwards in Priabonian times. Further compressional folding and high-angle faulting, interpreted to have resulted from overthrusting of the Olympos seamount/micro-plate, deformed the Basin-margin Group at the end of the Eocene and eventually led to its sub-aerial erosion.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:663912 |
| Date | January 1993 |
| Creators | Wilson, Jonathan Wrigley |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14680 |
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