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Climatically Influenced Progradation of a Deep-Water Turbidite Fan, Late Pliocene Syn-Rift Succession, Corinth Rift, Greece

Abstract

Climatically Influenced Progradation of a Deep-Water Turbidite Fan,

Late Pliocene Syn-Rift Succession, Corinth Rift, Greece

The structural, sedimentary and climatic evolution of a rift basin and its associated catchment area is reflected in its deposits, but deconvolving primary controls on stratigraphic evolution is often problematic. Here we present results from an integrated sedimentological, palaeoenvironmental and structural study of the Corinth Rift to investigate the role of basin tectonics and climatic variations on deep-water depositional processes in a highly active rift setting.

Northward migration of active faulting in the Corinth Rift during Early Pleistocene times resulted in uplift of early syn-rift deposits on the northern Peloponnese peninsula. We focus on the Late Pliocene to earliest Pleistocene deep-water deposits of the Rethi-Dendro Formation (RDF) that are spectacularly exposed in the central part of the rift. In general, the RDF consists of coarse grained siliciclastic sediments emplaced as mass transport deposits, channel complexes and channelised lobes, and fine grained intervals consisting of thinly bedded turbidites and hemipelagic mudstones.

Sedimentology and sequence stratigraphy of the RDF has been analysed using traditional field methods tied to terrestrial LiDAR and AUV photogrammetry, together with continuously cored shallow research boreholes. This integrated dataset allows for sedimentary observations at a variety of scales, from mm-scale sedimentary structures to seismic-scale geobodies. To supplement our sedimentological observations, detailed palynological analysis has been undertaken to identify changes in hinterland vegetation as a result of climate change. Focus has been placed on a 80 m interval that is characterised by an abrupt change in depositional style from a thick unit of dominantly hemipelagic mudstones sharply overlain by laterally extensive, amalgamated and channelised sandstone and conglomerate bodies that are consecutively replaced by hemipelagic mudstones. The change in depositional style is contemporaneous to changes in the pollen and spore assemblage suggesting that a shift to drier and colder conditions aids to the delivery of coarse grained sediment into the deeper parts of the basin. This study highlights how climate change in the hinterland can have a major impact on the timing of deep-water reservoir development, even in highly active basins.