A Preliminary Study of Periodicities in Percentage Curves Dated by Pollen Density

Abstract

SUMMARY The refined dating technique based on both pollen density and radio‐carbon dating proposed by Middeldorp (1982) was applied to five curves of a pollen‐ and macro‐remain diagram from a peat section from the Engbertsdijksveen (Vriezeveen, The Netherlands). Percentages curves of Alnus, Quercus, Corylus, alkaline soluble humic acids and coarse fraction of peat were then subjected to time series analysis by means of Periodic Regression (Briskin et al. 1980). In this way periodicities of approximately 1450, 1000, 800, 600, 500, 350, 200, 145, 85, 40 and possible 22 years could be established with reasonable confidence. Several of these periods seem to correspond to known sunspot cycles (22, 40, 80, 150, 200 and possibly 1000 years).

Mid‐ and late‐Holocene climatic changes: a test of periodicity and solar forcing in proxy‐climate data from blanket peat bogs

“…This data set was based principally on peat humification and on the frequencies of selected testate amoebae. The figures were not replicated by Wijmstra et al, (1984), who showed evidence for a wide variety of periodic elements in their data, with those at ca. 210 yr the most persistent, shown by a number of different variables.…”

“…Chambers et al (1997) demonstrated a periodicity estimated at ca. 208 yr, which matched approximately the main one shown by Wijmstra et al (1984). However, studies of Sphagnum species changes by Barber et al (1994) and pollen data by Oliver et al (1997) showed a longer-wavelength oscillation of PERIODICITY AND SOLAR FORCING SIGNALS IN HOLOCENE BLANKET PEAT Apparent, but not statistically significant.…”

“…Mire data provide an integrated record of climate change, and so can be expected to be less affected by single-year events (except in the extreme cases of bog bursts) than are proxy-climate data derived from tree-rings or ice cores. Several studies of peat-based palaeoclimatic proxy records have identified a periodic component in the data set, and a range of century-or millennial-scale periodicities has been claimed by researchers (Aaby, 1976;Wijmstra et al, 1984;Barber et al, 1994;Oliver et al, 1997;Chambers et al, 1997;Hong et al, 2000). The periodicities suggested by these studies are shown in Table 2.…”

“…Both Oliver et al (1997) and Wijmstra et al (1984) showed apparent cycles of ca. 360 yr, not detected in other studies.…”

Solar forcing of climatic change during the mid-Holocene: indications from raised bogs in The Netherlands

“…Temporal links between archives of climate change and changes in solar activity have been reported before (e.g., Wijmstra et al, 1984;Blackford and Chambers, 1995;Hong et al, 2000;Bond et al, 2001;Chambers and Blackford, 2001;Magny, 2004), but the chronologies used in these studies often were rather imprecise. With our approach of 14 C wiggle-match dating, peat chronologies become far more precise.…”