--> Deepwater Syn-Rift Sedimentation: Tectonic Geomorphology and Sedimentology From the Modern and Plio-Pleistocene of the Corinth Rift, Greece

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Deepwater Syn-Rift Sedimentation: Tectonic Geomorphology and Sedimentology From the Modern and Plio-Pleistocene of the Corinth Rift, Greece

Abstract

Deep-water reservoirs are common reservoir targets in syn-rift successions of rift basins, often present in complex, down-faulted stratigraphic and combination traps adjacent to major tilted fault blocks. However, the location and architecture of these reservoirs is often difficult to image and predict, and better understanding of the controls on reservoir volume, geometry and heterogeneity is needed in order to reduce risk and improve success. We focus on the modern Gulf of Corinth, Greece and the uplifted and now exposed, Pliocene to Middle Pleistocene, abandoned portion of the Corinth Rift, in order to investigate the geomorphology and sedimentology of deep-water syn-rift deposits. Fault geometry, sea-level and regional climate variations are well constrained, and drainage catchments are still preserved giving information on sediment sources. These geological constraints make the Corinth Rift one of the best active rifts for attempting to disentangle the structural and environmental controls on deep-water, syn-rift sedimentation and tectonics. The Gulf of Corinth, Greece, is an ESE–WNW-trending rift basin up to 800 m deep and containing up to 2.5 km of syn-rift sediment. The morphology of the modern west-central Gulf of Corinth is dominated by fault-controlled, hangingwall fan-deltas with slope canyon systems that feed an axial submarine canyon/channel, transporting sediment to the basin floor in the central-east part of the gulf. Steep, fault-controlled basin margins with narrow shelves are dominated by mass wasting. Although local structures control the location of major sediment transport pathways, timing of basin floor sedimentation is largely driven by climate-driven changes in sediment supply. Exposed, Pliocene to Middle Pleistocene deep-water deposits display a similar source-to-sink system. They were sourced from rift shoulder drainages to the southwest, via a series of major fan deltas (the Kilini, Mavro, Evrostini and Illias deltas). A wide range of depositional environments can be recognized, including mass transport deposits, major channel complexes, channelized lobes and background sedimentation consisting of low-density sandy turbidites and hemi-pelagic mudstones. Sediment transport pathways involving bypass of the delta front and axial flow in the hangingwall of active normal faults are indicated. Both the modern and Plio-Pleistocene systems indicate the importance of axial deep-water sediment transport.