Oceanic cooling recorded in shells spanning the Medieval Climate Anomaly in the subtropical eastern North Atlantic Ocean ...

• Main Authors: Surge, D., Yanes, Y., Hernández, E.M., Parker, W.G.
• Format: Text
• Language: English
• Published: The University of North Carolina at Chapel Hill University Libraries 2020
• Subjects: North Atlantic; North Atlantic oscillation
• Online Access: https://dx.doi.org/10.17615/q25x-cz56; https://cdr.lib.unc.edu/concern/articles/0c483t916

The Medieval Climate Anomaly (MCA; 900–1300 AD) was the most recent period of pre-industrial climatic warming in the northern hemisphere, and thus estimations of MCA signals can illuminate possible impacts of anthropogenic climate change. Current high-resolution MCA climate signals are restricted to mid- and high-latitude regions, which confounds inferences of how the MCA impacted some global/hemispheric climate mechanisms (e.g. North Atlantic Oscillation; NAO). To address this knowledge gap, we estimate seasonally-resolved sea surface temperatures (SSTs) from the oxygen isotope composition (δ18O) of serially sampled Phorcus atratus shells from archaeological sites spanning the MCA in the Canary Islands. Twelve archaeological and six modern P. atratus shells were analyzed, and archaeological shells were dated using carbonate-target radiocarbon dating. SSTs were estimated using the published aragonite-water equilibrium fractionation equation. Modern shells showed a mean SST of 20.0 ± 1.5 °C, with a seasonal ...