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

Abstract

The Corinth basin (Greece) is a young continental rift that recorded cyclic basin paleoenvironment variations (i.e., marine to lacustrine) caused by glacio-eustatic sea level fluctuations during its initial connection to the global oceans. The Corinth syn-rift sequence offers therefore a unique opportunity to determine the timing and modality of connection of young rifts to the global oceans, and investigate how sediment supply change during this extremely dynamic stage of their evolution. Here we use magnetostratigraphic and relative paleointensity (RPI) constraints from 885 discrete samples from International Ocean Discovery Program (IODP) Hole M0079A to generate an unprecedented high-resolution (∼15kyr) age model for the youngest part of the Corinth’s offshore syn-rift sequence. Our RPI-calibrated age model spans the last ∼850 kyr and reveals that initial connection of the Corinth basin to the Mediterranean Sea occurred at ∼530 ky, more recently than previously thought and after a short-lived marine incursion at ∼740 kyr. Accumulation rates calculated from our age model indicate two significant changes in sediment supply at 530 (from 74 to 156 cm/kyr on average) and 70 ka (from 156 to 258 cm/kyr on average), interpreted as due to increased local fault activity in the southern margin of the Corinth basin. Sedimentation rates also display a short-term variation indicating a lower sediment supply (98 cm/kyr on average) during interglacial periods and a higher input (156 cm/kyr on average) during glacial periods. We conclude that long-term variations of sediment supply in young rifts connecting to the global oceans are predominantly controlled by local tectonics (i.e., new depocenters formation), while short-term variations may be driven by global climate (i.e., increased erosion aided by fewer vegetation during glacial periods). Grain size of the Corinth syn-rift sequence shows a weak correlation with glacial cycles too (i.e., coarser sediments during interglacials), but we suggest this to be controlled by the hydrodynamics of the basin (i.e., stronger bottom currents when the basin was connected to the Mediterranean Sea during interglacial periods).

Late Quaternary mud‐dominated, basin‐floor sedimentation of the Gulf of Corinth, Greece: Implications for deep‐water depositional processes and controls on syn‐rift sedimentation

“…Our age model is based on published age determinations based on sedimentation rates (e.g. McNeill, Shillington, Carter, & Expedition 381 Participants, 2019; McNeill, Shillington, Carter, Everest, et al, 2019), magnetostratigraphy and relative palaeointensity data (Maffione & Herrero‐Bervera, 2022) and our new Th/U isotopic analysis of aragonite within thin white laminated packages (Table 1 and Figure 12). Based on integration of these datasets there is a good correlation between the occurrence of the bioturbated packages and the major interglacial sea‐level highstands of Marine Isotope Stages (MISs) 1, 5, 7, 9 and 11 (T, U, V, W and X respectively on Figure 12).…”

Vegetation Composition in a Typical Mediterranean Setting (Gulf of Corinth, Greece) during Successive Quaternary Climatic Cycles

“…The Brunhes/Matuyama boundary (MBB, 773 ka [27]) of M0078 ha orded at the depth of 386 mbsf, close to the boundary between LU1 and LU addition, the proposed occurrence of the Jaramillo Subchron (1000-1080 k 519.32 and 574.72 mbsf provides further independent chronostratigraphic poin ther age control points using coccolithophore assemblages are limited only to (interglacial) intervals when the basin was connected to the Mediterranean Sea fore, the last occurrence of Pseudoemiliania lacunosa recorded at 298.6 mbsf is not the true last appearance (LAD) at 430 ka [28] as it is recorded during the low 12, when the Gulf of Corinth was isolated from the Mediterranean Sea [23]. age constraints are obtained through stratigraphic correlation with the neigh M0079, while the age-depth model is based on magnetostratigraphy and pala data [29], as well as several Th/U absolute datings [26]. Gawthorpe et al [26] three types of stratal packages (bioturbated, laminated and bedded), which allo detailed stratigraphic subdivision of lithostratigraphic unit 1, leading to a new lution correlation of stratal packages between sites M0078 and M0079, both from the central of the Gulf of Corinth, from MIS 1-13 (Figure 2).…”

“…Therefore, the last occurrence of Pseudoemiliania lacunosa recorded at 298.6 mbsf is most likely not the true last appearance (LAD) at 430 ka [28] as it is recorded during the lowstand MIS 12, when the Gulf of Corinth was isolated from the Mediterranean Sea [23]. Additional age constraints are obtained through stratigraphic correlation with the neighboring site M0079, while the age-depth model is based on magnetostratigraphy and palaeointensity data [29], as well as several Th/U absolute datings [26]. Gawthorpe et al [26] recognized three types of stratal packages (bioturbated, laminated and bedded), which allowed a new detailed stratigraphic subdivision of lithostratigraphic unit 1, leading to a new high-resolution correlation of stratal packages between sites M0078 and M0079, both originating from the central of the Gulf of Corinth, from MIS 1-13 (Figure 2).…”

Timing of Tectonic and Magmatic Events in the Philippine Sea Plate Since 50 Ma From High‐Resolution Magnetostratigraphy of IODP Site U1438

“…Our magnetostratigraphy-based age model allowed precise determination of sedimentation rates throughout the entire sedimentary sequence. To take into account the effect of compaction on the sedimentation rates, we computed the decompacted thickness of the sediments using their porosity, following the method of Van Hinte (1978) and recalculated corrected sedimentation rates using the decompacted thicknesses of each interval following the approach used by McNeill et al (2019) and subsequently Maffione and Herrero-Bervera (2022). Van Hinte (1978) proposed that the initial thickness of a sedimentary unit at the time of deposition and any time thereafter is controlled by the change in porosity of the sediment during burial; in fact, during burial-induced compaction, the volume of the pore space decreases, while that of the grains remains fixed.…”