High-resolution palaeoenvironmental reconstructions of the Late Holocene using ombrotrophic mires from western Britain
The aim of this thesis has been to reconstruct proxy-climatic conditions from three ombrotrophic mires across the western side of Britain (Bolton Fell Moss, Langlands Moss, Mynydd Llangatwg). Detailed investigations of core material has incorporated the application of a range of palaeoecological techniques including colorimetric humification, plant macrofossil and testate amoebae analyses at high-resolution intervals. Results from the humfication analyses indicate significant fluctuations in mire surface conditions which, in the case of Bolton Fell Moss, appear to be replicatable. Plant macrofossil datasets also record variations in surface conditions, indicated by changes in species composition, although, in contrast to the humification datasets, records obtained from Bolton Fell Moss have been found to differ markedly. Statistical modelling of these raw macrofossil datasets using multivariate techniques has enabled the transformation of the data into indices of relative mire surface conditions, thereby generating proxy-climatic curves which are directly comparable with the humification records. Having identified a number of correlating shifts in relative surface conditions, interpolated timescales were developed for each of the sites investigated using a combination of wiggle-matched AMS dating, lead-210 and spheroidal carbonaceous particle (SCP) analyses. Comparison of the proxy-climate records has led to the identification of correlating shifts in mire surface conditions. A number of these shifts have been found to be associated with established shifts in regional climatic conditions, such as the coldest stages of the Little Ice Age, the Medieval Warm Period, the AD 540 tree-ring event and the Sub-boreal/Sub-atlantic transition.