Pindos Zone Sub-Marine Fans in Greece Related to the Remnant Pindos Ocean Closure in a Trench during Paleocene and Later in a Rift during Miocene Time

By

 George Ananiadis¹, A. Zelilidis¹

(1) University of Patras, Patras, Greece

 The early Tertiary renewed crustal compression initiated eastward subduction of the remnant Pindos ocean basin, where submarine fans were accumulated, from Paleocene to early Eocene. Palaeocurrent data show mainly a south direction that indicates a longitudinal transportation, along trench, that typifies trench sedimentation. Submarine fans are characterized mostly by inner fan deposits. The absence of outer fans could be attributed either to a confinement of sediments within the trench or preferential subduction of outer fan sequences. The presence of high-energy lithofacies, conglomerates and thick coarse-grained sandstones with lithic fragments at their base, are typical of a trench environment due to the steep gradient of the slope. The presence of thick muddy sequences record deposition from large muddy turbidity currents induced by ponding and interaction of the flow with the topographical confinements of the trench (elongate depressions formed by normal faulting along the outer trench wall). Finally, these deposit deformed into close synclines and anticlines that are typical features of an accretionary prism. Dating of the studied deposits show a stratigraphic gap from early Eocene to late Oligocene, that could be related to the closure of the Pindos ocean and the continent to continent collision, with the development of the Pindos foreland. On the other hand, the presence of Miocene deposits could be related with the development of a rift in the Pindos zone, where submarine fans were accumulated due to the migration of the foreland bulge, both westwards in the Pindos foreland and eastwards in the Mesohellenic basin.