FROM ALLUVIAL FAN TO DISTAL TURBIDITIC SYSTEMS:PRELIMINARY RESULTS ON DEEP-WATER BYPASS PROCESSES BASED ONGILBERT-TYPE FAN DELTA OUTCROPS OF THE CORINTH RIFT (GREECE)

International audience; Source-to-sink (S2S) can be seen as the integration with other earth science disciplines;from geomorphology, sedimentary geology to basin geodynamic analysis. A major limitationto go further is the access to the entire basin geometry (proximal to distal setting, “closed” box,deep crustal and lithospheric geometries) as well as age constrains.We present the preliminary results of a sedimentological and sequence stratigraphyanalysis of outcropping Gilbert-type deltas from the Corinth rift (Plio-Pleistocene). Drone acquisitionhas also been carried out to propagate the correlations in 3D along steep cliffs. Thestudy case provides an unique opportunity to describe the sedimentary facies and correlatedthem though space and time from the proximal to the most distal setting, in a very wellconstrained basin geometry and timing. In this communication, we will mainly focus on deepwatersediment bypass in terms of flow processes and associated stratigraphic expression, as itis a key issue to address sedimentary budget analysis in a S2S perspective.A new bottomset typology has been established including 4 end-members: (1) Gravelybottomset, (2) Major erosion – by pass, (3) Fine-grained starved bottomset, and (4) Deep WaterMassive Sand (DWMS) bottomset. The relationship between the bottomset end-members andtheir associated turbiditic system has also been characterized. (1) During Gravely bottomsetdeposition, unconfined to low relief channel-levee complex occurs at the very end of the bottomset.(2) The major erosion in bottomset occurs when the foresets present a maximal progradationrate, the bottomset is eroded and bypassed. Coarse- to fine-grained sediments areexported in the turbiditic system to form large channel-levee complex. (3) During Fine-grainedstarved bottomset deposition, limited amount of sediment feed the turbiditic system from thedelta. Indeed, the major part of the sediments is stored in topset and foreset areas. (4) Deepwater massive sand bottomset forms coarse-grained slope apron geometry on the delta toe.Coarse-grained material is massively stored in the bottomset, and only fine-grained sedimentsare exported to the turbiditic system to form lobe complex. Superimposed onto this dynamic,evidences of contouritic events have also been identified.