A high-resolution record of early rift development and tectonic, sedimentary and environmental conditions in an active rift basin: IODP MSP drilling in the Corinth Rift, Greece (Expedition 381)

Abstract

The Corinth Rift in Greece is very active, with high rates of extension, sedimentation and environmental change. International Ocean Discovery Program (IODP) Expedition 381 drilled three sites sampling syn-rift sediments, complementing previous fault and stratigraphic interpretations and providing the longest high-resolution stratigraphic record for an early phase rift. Sedimentation in the Gulf of Corinth started ~2.0–2.5 Ma as an isolated basin, with the most recent rift phase starting at ~0.75 Ma, marking a shift to increasingly orbitally-controlled marine incursions. A wide range of paleoenvironmental conditions have been generated, reflected in the diverse microfossil assemblages and sedimentary lithologies. Drilling results highlight a recent acceleration of strain rate and fault activity connected to rapid strain Localization, with linkage of the border fault system over 10s–100s kyr timescales. Over long timescales (100 s kyr), these variations in fault slip rate control sediment accumulation. On shorter time scales (10s kyr), changes in accumulation rate and type of sediment are primarily controlled by glacial-interglacial climate change, with accumulation rates in glacial periods at least double that of interglacial periods, accompanied by enhanced basin stratification and dominance of non-marine faunal assemblages. The mud-dominated sediments have three stratal package types (bioturbated, bedded, laminated) that record distinct hydrological conditions linked to climate and sea level which influence the landscape and basin conditions. Results from the Corinth Rift are compared with other active basins and rift systems for a better understanding of the tectonic and climatic processes shaping these environments.