Dr. Wesley Parker - Sea surface cooling during the Medieval Climate Anomaly inferred from archaeological shell middens in the Canary Islands, Spain

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Dr. Wesley Parker, Geotop-McGill

Vendredi 27 novembre 2020 à 11h00 - Friday, November 27, 2020 at 11:00am
https://mcgill.zoom.us/j/86419417697?pwd=WXJZZ2E1TjJPTENjb0VTeFJsMDQydz09 Meeting ID: 864 1941 7697 Passcode: 904288
Résumé / abstract:

High-resolution sea surface temperature (SST) records can provide insight into climatic mechanisms that vary at seasonal scales, such as the North Atlantic Oscillation (NAO). However, few high-resolution SST records presently exist in the low-latitude regions of the North Atlantic Ocean, resulting in a significant gap of knowledge regarding how mechanisms like the NAO impacted regional climate in Northwest Africa during climatic perturbations of the late Holocene. To rectify this knowledge gap, the presented research integrates oxygen isotope sclerochronology and shell midden archaeology to investigate seasonal SST fluctuations in the Canary Islands, Spain, during the Medieval Climate Anomaly (MCA; 900-1300 AD). The primary objectives of this research are to 1) establish the reliability of the marine gastropods Phorcus atratus and Patella candei as paleotemperature archives, 2) to constrain the scale of time-averaging within Canarian shell middens, and 3) to utilize the oxygen isotope composition of archaeological shells to reconstruct the first seasonal-scale SST profiles for the MCA in the Canary Islands. Results indicate that SSTs were ~2°C cooler during the MCA in the Canary Islands, which is possibly explained by increased strength of NW African upwelling resultant from a persistently positive mode of the NAO. This is consistent with other low-latitude temperature/precipitation anomalies associated with a positive NAO mode, suggesting a transition to a positive NAO index during the middle and late MCA that possibly extended later into the 13th century AD.

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Sea surface cooling during the Medieval Climate Anomaly inferred from archaeological shell middens in the Canary Islands, Spain

Ajouter au calendrier 2020-11-27 11:00:00 2020-11-23 11:52:12 Dr. Wesley Parker - Sea surface cooling during the Medieval Climate Anomaly inferred from archaeological shell middens in the Canary Islands, Spain High-resolution sea surface temperature (SST) records can provide insight into climatic mechanisms that vary at seasonal scales, such as the North Atlantic Oscillation (NAO). However, few high-resolution SST records presently exist in the low-latitude regions of the North Atlantic Ocean, resulting in a significant gap of knowledge regarding how mechanisms like the NAO impacted regional climate in Northwest Africa during climatic perturbations of the late Holocene. To rectify this knowledge gap, the presented research integrates oxygen isotope sclerochronology and shell midden archaeology to investigate seasonal SST fluctuations in the Canary Islands, Spain, during the Medieval Climate Anomaly (MCA; 900-1300 AD). The primary objectives of this research are to 1) establish the reliability of the marine gastropods Phorcus atratus and Patella candei as paleotemperature archives, 2) to constrain the scale of time-averaging within Canarian shell middens, and 3) to utilize the oxygen isotope composition of archaeological shells to reconstruct the first seasonal-scale SST profiles for the MCA in the Canary Islands. Results indicate that SSTs were ~2°C cooler during the MCA in the Canary Islands, which is possibly explained by increased strength of NW African upwelling resultant from a persistently positive mode of the NAO. This is consistent with other low-latitude temperature/precipitation anomalies associated with a positive NAO mode, suggesting a transition to a positive NAO index during the middle and late MCA that possibly extended later into the 13th century AD. Geotop admin@example.com America/New_York public