Human impact signals from peat bogs – a combined palynological and geochemical approach

Abstract

This research compares palynological evidence for changes in land use histories with a geochemical method for reconstructing past soil erosion. Changes in land use have significant effects on soil erosion. It has been shown elsewhere that silicon (Si) and titanium (Ti) are good proxies for soil erosion. Ombrotrophic peat bogs are useful archives in which to measure Si and Ti depositions as they only receive inorganic erosional inputs through atmospheric deposition and they contain very low background levels of mineral matter. The correlation between geochemical and pollen analytical reconstructions of past human activity from three raised bog sites in Great Britain and Ireland is discussed here, with reference to examples from four particular time periods: the mid-to-late Bronze Age/Iron Age, the late Iron Age/Roman period, the Middle Ages/Tudor period and the more recent past. The results generally indicate a close correlation between the palynological and geochemical proxies, with the combination of both methods allowing a more comprehensive interpretation of the palaeoenvironmental record. Plantago lanceolata and Poaceae pollen frequencies appear to correlate particularly well with the geochemical proxies. A multi-proxy approach such as this may be particularly useful for identifying and interpreting low-level prehistoric human impact.