Tectono‐sedimentary evolution of the Plio‐Pleistocene Corinth rift, Greece

Abstract

The onshore central Corinth rift contains a syn-rift succession >3 km thick deposited in 5-15 kmwide tilt blocks, all now inactive, uplifted and deeply incised. This part of the rift records upward deepening from fluviatile to lake-margin conditions and finally to sub-lacustrine turbidite channel and lobe complexes, and deep-water lacustrine conditions (Lake Corinth) were established over most of the rift by 3.6 Ma. This succession represents the first of two phases of rift development -Rift 1 from 5.0-3.6 to 2.2-1.8 Ma and Rift 2 from 2.2-1.8 Ma to present. Rift 1 developed as a 30 kmwide zone of distributed normal faulting. The lake was fed by four major N-to NE-flowing antecedent drainages along the southern rift flank. These sourced an axial fluvial system, Gilbert fan deltas and deep lacustrine turbidite channel and lobe complexes. The onset of Rift 2 and abandonment of Rift 1 involved a 30 km northward shift in the locus of rifting. In the west, giant Gilbert deltas built into a deepening lake depocentre in the hanging wall of the newly developing southern border fault system. Footwall and regional uplift progressively destroyed Lake Corinth in the central and eastern parts of the rift, producing a staircase of deltaic and, following drainage reversal, shallow marine terraces descending from >1000 m to present-day sea level. The growth, linkage and death of normal faults during the two phases of rifting are interpreted to reflect self-organization and strain localization along co-linear border faults. In the west, interaction with the Patras rift occurred along the major Patras dextral strike-slip fault. This led to enhanced migration of fault activity, uplift and incision of some early Rift 2 fan deltas, and opening of the Rion Straits at ca. 400-600 ka. The landscape and stratigraphic evolution of the rift was strongly influenced by regional palaeotopographic variations and local antecedent drainage, both inherited from the Hellenide fold and thrust belt.

Syn‐rift delta interfan successions: Archives of sedimentation and basin evolution

“…Siliciclastic sediments sourced from the Hellenide fold and thrust belt (eroded Mesozoic carbonates, radiolarites and Cenozoic turbidites) were transported northwards and deposited syn-kinematically during Rift phases 1 and 2 (Degnan and Robertson, 1998;Ford et al, 2013;Gawthorpe et al, 2017a). The related stratigraphy is split into three groups in the study area; the Lower, Middle and Upper groups (Ford et al, 2007(Ford et al, , 2013(Ford et al, , 2016Rohais et al, 2007a).…”

“…The locus of faulting on the southern coast of the present gulf has migrated northwards over time (Goldsworthy and Jackson, 2001;Leeder et al, 2008;Ford et al, 2013Ford et al, , 2016Nixon et al, 2016), recording two major rifting phases (Rohais and Moretti, 2017;Gawthorpe et al, 2017a). In the west, activity was focussed upon the Kalavrita Fault in Northern Peloponnesos, before activity migrated basinwards onto the P-M Fault (study area, Figure 2) at ~1.8 Ma (Ford et al, 2016;Gawthorpe et al, 2017a). In the west, activity was focussed upon the Kalavrita Fault in Northern Peloponnesos, before activity migrated basinwards onto the P-M Fault (study area, Figure 2) at ~1.8 Ma (Ford et al, 2016;Gawthorpe et al, 2017a).…”

“…Rift Phase 2 commenced, and the Kerinitis and Selinous fan deltas formed, before activity migrated from the P-M Fault onto the Helike Fault system around ~0.8 Ma (Ford et al, 2013). This occurred as the Gulf of Corinth opened during interglacial highstands to the Ionian and Aegean seas and into its modern configuration (Freyberg, 1973;Collier, 1990;Collier and Thompson, 1991;Moretti et al, 2004;Rohais et al, 2007b;Ford et al, 2016;Nixon et al, 2016;Rohais and Moretti, 2017;Gawthorpe et al, 2017a). Lacustrine conditions prevailed during Rift 1, with a transition from episodic marine incursions to periodically fully marine conditions during Rift 2 (~0.6 Ma).…”

“…The P-M Fault hangingwall deltas constitute the Middle Group, deposited during early Rift 2 (Gawthorpe et al, 2017a). The age of these deltas is constrained to ~1.8 to 0.7 Ma based on pollen analysis at the Vouraikos fan delta (Ford et al, 2007).…”

“…The southern shore of the Gulf of Corinth ( Figure 2) offers an ideal field laboratory for exploring interfan architectures, as there are a series of modern fan deltas along the coast, Late Pleistocene lowstand fan deltas that are submerged and imaged in bathymetry data, and a number of exhumed syn-rift fan deltas that formed along normal faults since ~1.8 Ma (Ford et al, 2016;Gawthorpe et al, 2017a). A number of studies focus upon the stratigraphic architecture of the Early-Middle Pleistocene Gilbert-type fan deltas in the Gulf of Corinth: Evrostini/Ilias (Zelilidis and Kontopoulos, 1996;Zelilidis, 2003;Rohais et al, 2007aRohais et al, , 2008Gobo et al, 2014Gobo et al, , 2015, Kryoneri (Gawthorpe et al, 2017b), Vouraikos (Ford et al, 2007), Kerinitis (Ori et al, 1991;Poulimenos et al, 1993;Dart et al, 1994;Gawthorpe et al, 1994;Backert et al, 2010;Gawthorpe et al, 2017b) and Selinous fan deltas (Poulimenos et al, 1993;Barrett et al, 2019).…”