Dust historical record in ombrotrophic peat: The case study of a NW European bog

Poster (2013, May 16)

Ombrotrophic peatlands are unique environmental archives of natural and anthropogenic atmospheric dust deposition because their surface layers are exclusively fed by atmospheric inputs. Lead (Pb) isotopes ... [more ▼]

Ombrotrophic peatlands are unique environmental archives of natural and anthropogenic atmospheric dust deposition because their surface layers are exclusively fed by atmospheric inputs. Lead (Pb) isotopes have been often used to evidence any anthropogenic influence in peat, but they only record trace metal pollution. Another radiogenic isotope, the Neodymium (Nd), could be also use to discriminate the sources of dust in peat bogs. Dust fluxes were investigated over the last 2500 years in the Misten peat bog in Eastern Belgium. Our aims were to use Nd isotope signature to decipher between local and distal dust supplies, the Pb isotopes to trace the antropogenic influences. To address these aims we analyzed REE and lithogenic element analyses, as well as the Nd and Pb isotopes, using HR-ICP-MS and MC-ICP-MS, respectively in peat layers dated by 210Pb and 14C. Changes in REE concentration variations in peat samples are correlated with Ti, Al, and Zr that are lithogenic conservative elements, suggesting that REE are immobile in the studied peat bogs and can be used as tracers of dust deposition. Dust fluxes show pronounced increase at BC300, AD600, 1000AD, 1200AD and from 1700AD, recording either influence of human activities (regional erosion due to forest clearing and soil cultivation activities) or local and regional climate changes. Lead enrichments reveal strong human impact over the last 300 years. Lead isotope signatures are consistent with local and regional contamination by coal combustion and smelting activities. Neodymium isotopes allow to identify three periods characterised by dominant-distal sources (at 320AD, 1000 AD and 1700AD). Those periods are consistent with local wetter intervals as indicated by lower humification degree. Local erosion prevails durier drier (higher humification) intervals (-100AD, 600AD). On a global scale more distal supplies are driven during colder periods, in particular Oort and Maunder minima, confirming the hypothesis that cold climate conditions favor distal supplies. Combining geochemical elementary content and isotope data in ombrotrophic peat allows to decipher between dust flux changes related to human and climate forcing. [less ▲]

Identifying early Earth microfossils in unsilicified sediments

in Geophysical Research Abstracts (2013), 15

Anthropogenic impacts in North Poland over the last 1300 years -- A record of Pb, Zn, Cu, Ni and S in an ombrotrophic peat bog

in Science of the Total Environment (2009)

Lead pollution history over Northern Poland was reconstructed for the last ca. 1300 years using the elemental and Pb isotope geochemistry of a dated Polish peat bog. The data show that Polish Pb–Zn ores ... [more ▼]

Lead pollution history over Northern Poland was reconstructed for the last ca. 1300 years using the elemental and Pb isotope geochemistry of a dated Polish peat bog. The data show that Polish Pb–Zn ores and coal were the main sources of Pb, other heavy metals and S over Northern Poland up until the industrial revolution. After review of the potential mobility of each element, most of the historical interpretation was based on Pb and Pb isotopes, the other chemical elements (Zn, Cu, Ni, S) being considered secondary indicators of pollution. During the last century, leaded gasoline also contributed to anthropogenic Pb pollution over Poland. Coal and Pb–Zn ores, however, remained important sources of pollution in Eastern European countries during the last 50 years, as demonstrated by a high 206Pb/207Pb ratio (1.153)relative to that of Western Europe (ca. 1.10). The Pb data for the last century were also in good agreement with modelled Pb inventories over Poland and the Baltic region. [less ▲]

Roman road pollution assessed by elemental and lead isotope geochemistry in East Belgium

in Applied Geochemistry (2008), 23(12), 3253-3266

The ability of inorganic geochemistry to record environmental change and especially human impact has been evidenced by several studies across Europe, especially in peat, where it is possible to record the ... [more ▼]

The ability of inorganic geochemistry to record environmental change and especially human impact has been evidenced by several studies across Europe, especially in peat, where it is possible to record the impact of agriculture, mining and other industries. However, despite the numerous investigations on the impact of ancient human activities such as ore mining and smelting, little attention has been paid to geochemistry as a tool to solve problems of palaeopollution in the surroundings of archaeological sites. This paper presents geochemical evidence of the impact of a possible early Roman road built in SE Belgian peatland. Increased Zn and Pb concentrations suggest that Pb-Zn ores were transported on the road, Lead isotope analyses suggest that these ores are locally derived, being compatible with those found in the nearby Pb-Zn ore deposits from East Belgium. Present results provide direct evidence that East Belgian Pb-Zn ores were already being mined during Roman times, i.e. earlier than previously suspected (i.e. 14th century) and that Zn appears to be relatively immobile here. On a broader scale, it also demonstrates that such an early road already had an impact on the environment in terms of metal pollution. This paper enlarges on the range of possibilities offered by geochemistry in the field of geoarchaeology. (C) 2008 Elsevier Ltd. All rights reserved. [less ▲]