--> --> Abstract: Fault Development and Syn-rift Basin Structure Within the Corinth Rift, Greece, by Rebecca Bell, Lisa McNeill, Jon Bull, and Tim Henstock; #90124 (2011)

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Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA

Fault Development and Syn-rift Basin Structure Within the Corinth Rift, Greece

Rebecca Bell1; Lisa McNeill2; Jon Bull2; Tim Henstock2

(1) Imperial College London, London, United Kingdom.

(2) National Oceanography Centre, Southampton, Southampton, United Kingdom.

Early syn-rift basin structure is often obscured by post-rift sediments in mature hydrocarbon bearing basins. Even with the aid of three-dimensional seismic reflection datasets, the geometry and facies of rift initiation deposits are still poorly understood due to their limited thickness, highly variable lateral extent and limited well penetrations. Examining fault development and syn-rift basin geometry at currently active rift zones could be key to the successful exploitation of syn-rift plays. The Corinth Rift in central Greece is an active continental rift zone, opening at a rate of up to ~15mm/yr, with an extension history of < 5 myr. The Corinth Rift’s relatively simple N-S extensional regime is yet to be overprinted by later tectonics and a fluctuation between marine and lacustrine conditions results in the syn-rift infill being clearly imaged seismically, revealing details of fault development and syn-rift basin geometry.

We synthesise seismic reflection data throughout the active offshore Gulf of Corinth basin to investigate fault activity history and the spatio-temporal evolution of the basin, producing for the first time basement depth and syn-rift isochron maps throughout the offshore rift. A major basin-wide unconformity surface with an age estimated from sea-level cycles at ca. 0.4 Ma separates distinct seismic stratigraphic units, and highlights major structural changes in the orientation of dominant faults even over the Gulf of Corinth’s short 1-2myr history.

The Gulf of Corinth initiated as two separated depocentres with opposing polarity, each 20-50 km long. Since ca. 0.4 Ma the two originally isolated depocentres have coalesced, due to linkage of faults with a dominant dip direction. This has created a single 80 km long depocentre in the central Gulf of Corinth, with maximum subsidence focused between the two older depocentres. These results show that individual fault segments can persist for timescales ca.1Ma and form major isolated syn-rift half-graben before becoming linked. This style of syn-rift basin evolution is similar to observations from other young rifts (eg. the East African Rift) and numerical and laboratory models. The Corinth rift is a convenient analogue to investigate the likely geometry and facies distribution of syn-rift half-graben, providing a greater understanding of the location and scale of poorly-imaged, early syn-rift reservoirs in hydrocarbon-bearing basins.