A 7500-year peat-based palaeoclimatic reconstruction and evidence for an 1100-year cyclicity in bog surface wetness from Temple Hill Moss, Pentland Hills, southeast Scotland

Abstract

Analyses of plant macrofossils, peat humification and testate amoebae were used to reconstruct a proxy climate record spanning the last 7500 years from an ombrotrophic bog, Temple Hill Moss, in southeast Scotland. The plant macrofossil data were subjected to detrended correspondence analysis (DCA) which modelled effectively the significant wet shifts within the record. A mean water table depth transfer function was applied to the testate amoebae data to provide quantifiable changes. The three proxy records show coherent phase changes which are interpreted as variability in past effective precipitation. Two tephra horizons (Glen Garry and Lairg A) were used in conjunction with radiocarbon dates to construct an age/depth model, producing a robust geochronology from which a time series was calculated. The palaeoclimatic reconstruction identified major wet shifts throughout the Holocene, with specific events occurring around cal. 6650, 5850, 5300, 4500, 3850, 3400, 2800–2450, 1450–1350 and 250–150 BP. Spectral analysis of the plant macrofossil DCA and colorimetric humification data produced a millennial scale periodicity of 1100 years. The same periodicity has also been found in a palaeoclimatic reconstruction from a site in Cumbria (Walton Moss), and may be linked with millennial scale periodicities found in oceanic palaeoclimatic records.