Expedition 381 Scientific Prospectus: Corinth Active Rift Development

Abstract

Continental rifting is fundamental for the formation of ocean basins, and active rift zones are dynamic regions of high geohazard potential. However, much of what we know from the fault to plate scale is poorly constrained and is not resolved at any level of spatial or temporal detail over a complete rift system. For International Ocean Discovery Program Expedition 381, we propose drilling within the active Corinth rift, Greece, where deformation rates are high, the synrift succession is preserved and accessible, and a dense, seismic database provides high-resolution imaging, with limited chronology, of the fault network and of seismic stratigraphy for the recent rift history. In Corinth, we can therefore achieve an unprecedented precision of timing and spatial complexity of rift-fault system development and rift-controlled drainage system evolution in the first 1-2 My of rift history. We propose to determine at a high temporal and spatial resolution how faults evolve, how strain is distributed, and how the landscape responds within the first few million years in a nonvolcanic continental rift, as modulated by Quaternary changes in sea level and climate. High horizontal spatial resolution (1-3 km) is provided by a dense grid of seismic profiles offshore that have been recently fully integrated and are complemented by extensive outcrops onshore. High temporal resolution (~20-50 ky) will be provided by seismic stratigraphy tied to new core and log data from three carefully located boreholes to sample the recent synrift sequence.Two primary themes are addressed by the proposed drilling integrated with the seismic database and onshore data. First, we will examine fault and rift evolutionary history (including fault growth, strain localization, and rift propagation) and deformation rates. The spatial scales and relative timing can already be determined within the seismic data offshore, and dating of drill core will provide the absolute timing offshore, the temporal correlation to the onshore data, and the ability to quantify strain rates. Second, we will study the response of drainage evolution and sediment supply to rift and fault evolution. Core data will define lithologies, depositional systems and paleoenvironment (including catchment paleoclimate), basin paleobathymetry, and relative sea level. Integrated with seismic data, onshore stratigraphy, and catchment data, we will investigate the relative roles and feedbacks between tectonics, climate, and eustasy in sediment flux and basin evolution. A multidisciplinary approach to core sampling integrated with log and seismic data will generate a Quaternary chronology for the synrift stratigraphy down to orbital timescale resolutions and will resolve the paleoenvironmental history of the basin in order to address our objectives.

A New Data‐Driven Bayesian Inversion of Fluvial Topography Clarifies the Tectonic History of the Corinth Rift and Reveals a Channel Steepness Threshold

“…Our research indicates the CFS initiated at ∼0.6 Ma in the eastern portion of the rift. This time of fault initiation aligns with a growing body of literature pinning down the onset of the rapid and localized Middle Pleistocene rifting in Corinth (e.g., de Gelder et al., 2019; McNeill et al., 2019; Nixon et al., 2016). Still, further research and new data sets are needed to provide additional constraints in westward portions of the rift margin.…”

“…(1996) also recovered a rigid layer thickness of ∼10 km, which translates into a T e between 2.0 and 2.5 km, in line with our determination (Table 3). The offshore sedimentary record in the hanging wall, both from cores and geophysics, suggests similarly rapid slip rates and flexural wavelengths (de Gelder et al., 2019; McNeill et al., 2019).…”

Pliocene–Pleistocene sedimentary development of the syntectonic Polis graben, NW Cyprus: evidence from facies analysis, nannofossil biochronology and strontium isotope dating

“…Similar extensional processes and related sedimentary deposits characterize other complex multi-plate regions such as the Caribbean (Driscoll & Diebold, 1999; Escalona & Mann, 2011) and Indonesia, for example Kalimantan Basins, Borneo (Van de Weerd & Armin, 1992; Hall, 2002). Acquiring additional information on the deep sedimentary fill of marine extensional basins requires deep-sea drilling, as recently achieved for the Gulf of Corinth (Greece) (McNeill, Shillington & Carter, 2017) during October–December 2017, together with ongoing onshore studies (January 2018 onwards).…”

A Relative Paleointensity (RPI)-Calibrated Age Model for the Corinth Syn-rift Sequence at IODP Hole M0079A (Gulf of Corinth, Greece)

“…From October to December 2017 International Ocean Discovery Program (IODP) Expedition 381 drilled the uppermost (~800 m) part of the offshore syn-rift sedimentary sequence of the Corinth rift basin at four holes from the central and eastern part of the Gulf of Corinth (McNeill et al, 2019b) (Figure 1), providing a unique continuous and intact sedimentary archive to study the evolution of this young rift basin in high detail. The study of these cores, presented by (McNeill et al 2019a;2019b) revealed that the initial connection of the Corinth basin to the global oceans was preceded by several marine incursions controlled by eustatic sea level fluctuation during glacial-interglacial cycles. This caused a cyclic shift in basin paleoenvironment from marine to lacustrine, which in turn affected sediment supply (i.e., higher sedimentation rates during lacustrine/lowstand periods, and lower sedimentation rates during marine/highstand periods), and lithology (McNeill et al 2019a;2019b).…”

“…The study of these cores, presented by (McNeill et al 2019a;2019b) revealed that the initial connection of the Corinth basin to the global oceans was preceded by several marine incursions controlled by eustatic sea level fluctuation during glacial-interglacial cycles. This caused a cyclic shift in basin paleoenvironment from marine to lacustrine, which in turn affected sediment supply (i.e., higher sedimentation rates during lacustrine/lowstand periods, and lower sedimentation rates during marine/highstand periods), and lithology (McNeill et al 2019a;2019b). Higher sediment supply during glacials has also been documented from the onshore syn-rift sequence at the southern margin of the Corinth basin by Cullen et al (2021).…”