Age through tandem correlation of Quaternary relative paleointensity (RPI) and oxygen isotope data at IODP Site U1306 (Eirik Drift, SW Greenland)

Abstract

Planktic oxygen isotope (δ18O) and relative paleointensity (RPI) data are used in tandem to generate an age model for the last 1 Myr from Integrated Ocean Drilling Program (IODP) Site U1306 drilled on the crest of the Eirik Drift (SW Greenland) in 2272 m water depth. For the 1–1.5 Ma interval, the age model is based on RPI alone due to insufficient foraminifera for isotope analyses. Utilizing RPI and δ18O in tandem allows recognition of low-δ18O “events” prior to glacial Terminations I, III, IV, V, VII, VIII, IX and X, that are independently supported by radiocarbon dates through the last deglaciation, and are attributed to local or regional surface-water effects. At Site U1306, Quaternary sedimentation rates (mean ∼15 cm/ka) are elevated during peak glacials and glacial onsets, and are reduced during interglacials, in contrast to the pattern at Site U1305 in 3460 m water depth at the distal toe of the drift, 191 km SW of Site U1306. The contrasting sedimentation-rate pattern appears to hold for the entire ∼1.5 Myr record. The slackening and/or shoaling (due to lowered salinity) of the Deep Western Boundary Current (DWBC) during glacial intervals coincided with greater sediment supply to Site U1306 whereas the deepening, and possibly increased vigor, of the DWBC during interglacial intervals boosted sediment supply to Site U1305.