Multiproxy evidence of `Little Ice Age' palaeoenvironmental changes in a peat bog from northern Poland

Abstract

`Little Ice Age' (LIA) climatic deteriorations have been abundantly documented in various archives such as ice, lake sediments and peat bog deposits. Palaeoecological analyses of peat samples have identified these climatic deteriorations using a range of techniques, for example palynology, plant macrofossils, testate amoebae or carbon isotopic analyses. The use of inorganic geochemistry and the reconstruction of dust fluxes has remained a challenge in tracing the nature of LIA climatic changes. Although the idea of enhanced erosion conditions and storminess is commonly discussed, the conditions for dust deposition in peatlands over Europe during the LIA are rarely favourable, because the natural forest cover over Europe was much more important than nowadays, preventing dust deposition. This intense forest canopy masks the deposition of dust in peatlands. In northern Poland, near the Baltic shore, the Słowińskie Błota area was deforested around AD 1100, ie, just before the LIA, and therefore constitutes a key area for the reconstruction of LIA climatic change. With the support of a well-constrained chronology, climatic fluctuations are recorded in an ombrotrophic bog using inorganic geochemistry, plant macrofossils and carbon isotopic analyses. The reconstruction of LIA climatic changes is in good agreement with other records from Poland and NE Europe. However, a c. 50-year discrepancy can be observed between various records. This discrepancy is possibly due to progressive time-dependent cooling gradient from north to south Europe.

Development and refinement of proxy-climate indicators from peats

“…The Scandinavian records were not acquired through geochemistry, but rather through the counting of mineral particles in the peat records; while in Poland, a highresolution geochemical study of an ombrotrophic mire allowed for the reconstruction of ASD using titanium as a conservative element. Both records were recently compared in De Vleeschouwer et al (2009) and de Jong et al (2010) and gave promising results, showing similarities in signals, in particular during the Little Ice Age (LIA) where enhanced ASD was recorded, suggesting increased erosion and wind storminess. However, considerable effort has to be devoted to assess enhanced ASD accurately during cold phases, especially because coastal areas are rich in easily erodible sand and finer material.…”

“…4), mainly originating from the hydrosphere or the geosphere. Bromine and chlorine have been found in high amounts in oceanic mires De Vleeschouwer et al, 2009); however, these elements, which are highly enriched in sea salt sprays, are generally poorly retained by peat , although Biester et al (2004) demonstrated a close relationship between organohalogen concentrations and peat decomposition, a process strongly influenced by climate. Martínez-Cortizas et al (2007) showed a similar pattern with other major and trace elements.…”

“…However, even now, only a few ASD curves have been generated from mires at highresolution, because (i) ASD peaks generally occur during shortterm intervals (at least in Northern Europe), in which very few samples are analysed; (ii) many radiocarbon dates are needed for precise and accurate dating; and (iii) ASD is still an indirect parameter that needs to be cross-checked with the direct quantification of mineral matter in the peat. Recent work has focused on high-resolution reconstruction of dust content in the late Holocene, on the South Swedish (de Jong et al, 2007) and North Polish coasts (De Vleeschouwer et al, 2009). The Scandinavian records were not acquired through geochemistry, but rather through the counting of mineral particles in the peat records; while in Poland, a highresolution geochemical study of an ombrotrophic mire allowed for the reconstruction of ASD using titanium as a conservative element.…”

Deciphering human–climate interactions in an ombrotrophic peat record: REE, Nd and Pb isotope signatures of dust supplies over the last 2500years (Misten bog, Belgium)

“…See text for explanation. the upper 1 m of several Misten peat cores emphasize the last millennium changes in vegetation, organic and/or inorganic geochemistry mainly recorded human perturbations (De Vleeschouwer et al, 2009, Allan et al, 2013a.…”

“…Previous work has used peat cores as dust archives (Shotyk et al, 1998Bjö rck and Clemmensen, 2004;Martini and Martinez-Cortizas, 2006;Sapkota et al, 2007;De Vleeschouwer et al, 2009;Le Roux et al, 2012;Kylander et al, 2013). For instance Shotyk et al (1998) used the geochemical signature of peat to reconstruct the atmospheric particulate flux for the entire Holocene in a 6 m bog in the Swiss Jura.…”