High resolution sequence stratigraphic architecture of beach-shoreface deposits on a rift basin interbasinal high, Corinth Isthmus, Greece

Active rift basins preserve highly complex sedimentary records shaped by the interplay of tectonic deformation, eustatic sea-level change, and autogenic depositional processes. The Gulf of Corinth, one of Earth’s most tectonically active continental rifts, provides an exceptional natural laboratory for investigating these interactions due to its high subsidence rates, detailed Quaternary stratigraphic record, and world-class exposures at the Corinth Canal that arise from uplift of the Corinth Isthmus, an interbainsal high. Despite extensive research, significant uncertainties remain regarding: (1) the influence of accommodation zones and relay structures on shallow-marine stratigraphic architecture; (2) the relative contributions of tectonic subsidence/uplift versus glacio-eustatic forcing in controlling three-dimensional sequence architecture; and (3) the formation mechanisms and diagnostic criteria of stepped transgressive wave-ravinement surfaces (WRS) in rift settings.
This thesis employs integrated sedimentological logging, facies analysis, drone-based photogrammetry, LiDAR-derived digital outcrop models, and chronostratigraphic tools to develop a high-resolution tectono-stratigraphic framework within a new age model for the Chibanian (late Quaternary) succession of the Corinth Canal. Three analytical chapters address the core research questions through detailed facies characterization, mapping of stratal surfaces, structural analysis, and correlation of key surfaces with global sea-level curves. Results demonstrate transfer-zone-related variations in sedimentary accommodation exert controls on facies distributions, beach to shoreface clinoform geometries, and stacking patterns, producing stratigraphic architectures that deviate from classical sequence models at fifth order sequence resolution. Quantitative comparison of tectonic and global mean sea level signals reveals that rates of normal fault block-controlled subsidence or uplift are significantly exceeded by rates of sea-level change at millennial timescales, with implications for predicting stratigraphic heterogeneity in active rifts. New evidence for the origin of stepped WRS morphologies indicates that both global deglacial sea-level rises driven by meltwater-pulses and a lesser component of tectonically driven tilting and uplift associated with the transfer zone contribute to WRS formation.
Collectively, this research provides a unified tectono-stratigraphic model for shallow-marine systems developed on interbasinal accommodation highs in active rift systems, advancing theoretical understanding of accommodation zone dynamics and informing predictive models for subsurface reservoir characterisation. The findings offer broader relevance for extensional basins globally, particularly as analogues for hydrocarbon, geothermal, and carbon-storage reservoir systems. Analysis of the Marine Isotope Stage MIS 10-9 WRS also provides novel geological evidence for pauses or reversals in sea-level rise at millennial timescales within that interval. This suggests that analysis of other WRS around the world may offer an archive of geological evidence for millennial-scale sea-level fluctuations within this and other Chibanian (Middle Pleistocene) deglacial transgressions.