2025/01/01 by Stefanie Kaboth‐Bahr, André Bahr, Patrick Blaser +7 · 1 voice · 1 citation
Earth and Planetary Sciences · Environmental Science · #Geological formations and processes #Geology and Paleoclimatology Research #Methane Hydrates and Related Phenomena
paper · doi:10.1016/j.qsa.2025.100266
openalex publication_date 2025/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/25
We present a comprehensive multi-proxy analysis spanning 550,000 years from the outer Labrador Sea region at the Integrated Ocean Drilling Program (IODP) Sites U1302/1303. We combine new benthic foraminiferal stable oxygen (δ 18 O) and carbon (δ 13 C) isotope records, with sediment elemental composition and authigenic neodymium isotope measurements, to provide insights into deep-water mass sourcing and changes of the Deep Western Boundary Current (DWBC), which exports North Atlantic Deep Water (NADW) into the wider North Atlantic as part of the lower limb of the Atlantic Meridional Overturning Circulation. We find that a prominent DWBC likely remained a persistent feature within the Labrador Sea region throughout the past 550 kyr. However, glacial peaks of marine isotope stage (MIS) 14 to MIS 2 were consistently characterized by a weaker or shallower DWBC, while all interglacial periods of MIS 13a to MIS 1, with the exception of MIS 7e, were marked by enhanced DWBC. Additionally, the dominant deep-water masses feeding into the DWBC during these glacial-interglacial periods varied from regional (K-rich sediment, unradiogenic εNd) to more distal sources from the Nordic Seas (Ti-rich sediment, radiogenic εNd). Yet, these changes in deep-water provenance did not consistently correlate with DWBC strength, suggesting that additional factors may have played a significant role in shaping the DWBC strength or core depth throughout the geological past.