Modeling the Stratigraphic Architecture of the Southern Margin of the Corinth Rift (Greece)

Sebastien Rohais¹, Mary Ford², Rémi Eschard³, François Guillocheau⁴, and I. Moretti^5
1Institut Français du Pétrole, 92852 Rueil Malmaison Cedex, France
²ENSG-CRPG, Nancy, France
³IFP, Rueil Malmaison, France
⁴Rennes University, Rennes, France
⁵Institut Français du Pétrole, Rueil Malmaison, France

Plio-Pleistocene stratigraphic architecture of the southern margin of the Corinth Rift has been characterized using an integrated approach based on field observations and analyses, and numerical modeling. Detailed sedimentologic, structural and biostratigraphic studies provide a tectono-stratigraphic model within a well-constrained climatic and eustatic setting. Using DIONISOS software, stratigraphic simulations test this model and better define the relative role of controlling factors on stratigraphic architecture.
In the Akrata-Derveni region, syn-rift stratigraphy comprises three groups, with a maximum total thickness of ca. 2800 m. The Lower Group (> 1.8 Ma to <1.4 Ma) records early rifting. Continental to lacustrine environments pass progressively upward to brackish environments, with occasional marine incursions, in response to fault growth. Transition to rift climax is recorded by the transition from the Lower Group to Middle Group (~1.4 Ma), characterised by a rapid increase in accommodation space. The Middle Group (around 1.4 Ma to 0.7 Ma), characterized by large fan deltas, records sediment supply being firstly outpaced by subsidence but then catching up with, and exceeding subsidence, probably in relation with the Mid-Pleistocene Revolution climatic change. Progressive tilting and uplift of the southern rift margin began between 0.7 and 0.4 Ma and is still active today. A forced regression therefore took place during Upper Group deposition with a >5 km northward shift of the depocentre (now in the present Gulf) and a 600 m relative sea-level drop.
This stratigraphic architecture is consistent with many non-marine rift settings and is primarily controlled by tectonic evolution, as suggested by the DIONISOS simulations. Sediment supply increase induced by climate variations can be inferred as a secondary controlling parameter.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece