Interpretation of deep boreholes G1 (CORSEIS) and AIG 10 (DGLab-3F) (Corinth Gulf, Central Greece)

F Lemeille, M Makanou, Chapoutis, Fourmelis, Rettenmaier, Unkel, Moretti, Micharelli, Guernet, Bourdillon, Muller, Keraudren

Worshop Corinth Rift Laboratory, Aigion, Grèce, 03 au 08 juin 2003

  Two deep boreholes (205 and 1001 m), performed in the footwall of the Aigion Fault, bring new data on the Holocene and Pleistocene deposits in the western Gulf of Corinth. 14C dating carried out in the Upper part of the borehole Gl, environmental data inferred from microorganisms analyses in borehole G1 and nannoplancton analyses in the lower part of the borehole AIG 10, are not enough to interpret the whole borehole in term of age and of paleogeography.

Based on assumed subsidence rates (slow and fast respectively), two extreme interpretations are proposed. In the first case study (slow subsidence rates), the borehole AIG10 crossed Holocene to old lacustrine deposits (related to Corinth lake before MIS 11 i.e. <405 ka). In the second interpretation, the borehole AIG 10 crossed Holocene to interglacial lacustrine MIS 6e sediments.

The two case studies are discussed with respect to uplift rate in the footwall (since MIS 9a), to constraints from relation between uplift rates and subsidence rates inferred from fault modelling, to Vertical Seismic Profile data (Naville et al., 2003) performed around the borehole AIG 10, to regional paleogeography and to the precise geometry of Aigion Fault.