Tracking Holocene climate change using peat bog stable isotopes

• Main Author: Daley, Timothy James
• Format: Thesis
• Language: English
• Published: University of Southampton 2007
• Subjects: Newfoundland; North Atlantic
• Online Access: https://eprints.soton.ac.uk/466356/; https://eprints.soton.ac.uk/466356/1/1123767.pdf

Stable isotopic analyses of Sphagnum cellulose from four raised peat bog cores in the North Atlantic region are used to reconstruct past variation in the isotopic composition of precipitation. These records are then calibrated using modern relationships for each site between the isotopic composition of precipitation and temperature to derive palaeotemperature estimates through the mid- to late Holocene in Europe and during the widespread cold event ~8200 BP in Newfoundland. The data indicate that through the mid- to late Holocene in Europe, regional scale precipitation-isotopic gradients were generally similar to the present day, although during periods of climatic instability, the amplitude of change increased with distance from the Atlantic Ocean. During the ~8200 BP event in Newfoundland, it is estimated that surface air temperatures decreased by 8.9 ± 3.5 o C between ~8450 and 8360 BP. It is demonstrated that the link between the isotopic composition of precipitation and the signal recorded in Sphagnum moss involves limited isotopic fractionation. The link to palaeotemperature is made difficult for sites in Europe by uncertainty in the relationship between the isotopic composition of precipitation and temperature in the modern day. Variation in Bog Surface Wetness records is highly correlated with variation in the isotopic signal from Sphagnum cellulose, suggesting a common primary driver.