Cluster analysis in pollen data of Holocene vegetation in northern Ireland: 12.000 to 1.000 years B.P. - I. Numerical method

Abstract

Palynological data from 9 spectra developed from peat cores taken in Northern Irish raised bogs are an ideal data set for the evaluation of cluster analysis applied to pollen data sets. The cores are from a geographically restricted area; samples from each core are taken at intervals of 20+40 mm; 9 radiocarbon dates are on average available for each core; analyses were carried out by 4 palynoiogists operating within the same laboratory. Data subjected to clustering have been corrected using Andersen's (1970) correction factors in order to allow equal representability of all identified woody species on the basis of individual pollen productivity. Identified vegetational units are placed along the radiocarbon time scale and mapped to highlight the simultaneous distribution of different vegetation types.