Blanket mires and climatic change: a palaeoecological study based on peat humification and microfossil analyses

Blackford, Jeff

Abstract

The aim of this thesis is to evaluate the role of blanket peats as a source of proxy data by examining various properties of the peat and comparing the results with climatic changes known or inferred from other sources. Blanket mires from the North York Moors, England, Connemara, Western Ireland and Snowdonia, North Wales, were chosen to cover a range of current climatic conditions. The humification degree of peat was measured by a revised version of a previously used colorimetric technique. The method was reviewed and tested, showing that optical transmission values were indicative of, and proportional to, but not an exact measure of, the degree of humification. Pollen and non-pollen microfossils, including previously unrecorded fungal, algal and unidentified remains, were counted and compared with the humification data. Horizons showing evidence of a change to wetter conditions were radiocarbon dated. Detailed palaeoecological analysis across inferred wet-shifts demonstrate the nature of the changes and, in some cases, possible causes. In some examples the palaeoecology of blanket mires appears to have been dominated by the impact of man. However, synchronous increases in peat-surface humidity are recorded from all the areas studied, although not from every profile. Some microfossils show a different ecological preference from that found in previous studies. An attempt is made to model the response of blanket mire systems to different changing variables, and hydrological implications are discussed. Coincident wet-shifts are inferred for the period around 1500 BC, between 1000 and 750 BC, between 400 and 200 BC, and around AD 650. Further periods of increased miresurface wetness are recorded at AD 1150-1200, AD 1520-1600 and AD 1730-1800. Blanket mires appear to have some of the properties required of a source of proxy climatic data.

Citation

Blackford, J. (1990). Blanket mires and climatic change: a palaeoecological study based on peat humification and microfossil analyses. (Thesis). Keele University. Retrieved from https://keele-repository.worktribe.com/output/830854

• Thesis Type: Thesis
• Deposit Date: May 21, 2024
• Publicly Available Date: May 21, 2024
• Public URL: https://keele-repository.worktribe.com/output/830854
• Award Date: 1990