Structural and Stratigraphic Architecture of the Corinth Rift (Greece): An Integrated Onshore to Offshore Basin-Scale Synthesis

Abstract

The overall rifting history of the Corinth basin in Greece is still debated due to (1) the lack of deep wells to constrain the offshore domain, (2) sparse dating available onshore and (3) the only few integrated basin-scale studies covering both offshore and onshore data providing an homogeneous overview of its stratigraphic architecture. This paper provides an update to the structural and stratigraphic architecture of the Corinth rift through the results of field mapping, geological and structural map synthesis, outcrop stratigraphic characterization and seismic sequence stratigraphic correlations. A comparison with the surrounding basins to extrapolate ages and a correlation between onshore stratigraphic architecture and offshore seismic stratigraphy in the Corinth rift are proposed to establish time lines of the key stages during the rift evolution, and its relationship with the previous Hellenic compressive phase and the Aegean back-arc opening eastward. The rift history can be subdivided into two major syn-rift phases. A Syn-rift 1 including (a) the rift initiation at around 5.3 Ma with continental to lacustrine sediments deposited in km-scale isolated depocenters. (b) The rift widening (ca. 5.3–3.0 Ma) combined with a rift propagation from east to west. First marine incursions were recorded along the Corinth Isthmus. At that time, the rift was still subdivided into numerous 2–10 km-wide depocenters controlled by active faults where continental to lacustrine deposits occurred. The depocenters progressively grew and became linked. (c) The Syn-rift 1 “climax” (ca. 3.0–2.6 Ma) with 15–25 km-long fault segments subdivided the rift into 5–10 km wide fault blocks. Sedimentation was characterized by thick alluvial fans and large Gilbert-type deltas along the active fault segments and a starved basin along the basin axis. Marine connection with the Mediterranean Sea was dominantly established thought the Corinth Isthmus. (d) The Syn-rift 1 phase ended with a basinward fault migration phase (ca. 2.6–0.8 Ma) characterized by a progressive demise of the rift border fault and a rapid forced regressive trend recorded by the large Gilbert-type deltas. Bathymetry continued to increase along the basin axis. An additional phase of rifting (Syn-rift 2) ensued, and was characterized by the Peloponnesus margin uplift combined with an increase of both tectonic and total subsidences in the basin axis (ca. 0.8 Ma to present day). The depositional profile was shorter than during the previous stages, the rift progressively narrowed and the sedimentation rate strongly increased in the depocenter. The short lived duration of each phase and the peculiarity of the present phase are discussed in relation to the inherited structures and relative influence of the far field stress changes within the global context of the Hellenic subduction.