A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Effects of land use and climate change on erosion intensity and sediment geochemistry at Lake Lehmilampi, Finland
Tekijät: Anna Augustsson, Marie-José Gaillard, Pasi Peltola, Florence Mazier, Bo Bergbäck, Timo Saarinen
Julkaisuvuosi: 2013
Journal: Holocene
Numero sarjassa: 9
Vuosikerta: 23
Numero: 9
Aloitussivu: 1247
Lopetussivu: 1259
Sivujen määrä: 13
ISSN: 0959-6836
DOI: https://doi.org/10.1177/0959683613484615
Tiivistelmä
This paper aims to evaluate the possible relationships between erosion intensity and changes in climate and land use during the past 5.5 cal. k years at
Lake Lehmilampi, eastern Finland. In this study we compare a detailed geochemical sediment record with (1) forest and land use history inferred from
the first pollen and charcoal records from Lake Lehmilampi, and (2) existing archaeological surveys and independent proxy-records of climate change in
the study region. The physical and geochemical sediment parameters examined include grain size analysis data and 23 chemical elements, determined with
four selective extractions and ICP-MS. There are indications of possible human impact in the lake catchment as early as the Neolithic period, c. 3000–2550
bc, but the first undisputable signs are dated to 1800–100 bc. Cereal pollen reappears at c. ad 1700 and increases rapidly until c. ad 1950. The Holocene
Thermal Maximum, its end c. 2000 bc, and the ‘Medieval Climate Anomaly’ were major climate events that had a prominent effect on erosion intensity, while
human impact was a more significant factor during the period 3000 bc–ad 800 and from ad 1500 onwards. Although signs of changes in erosion intensity
found in the sediment were small in this small catchment, they were significant enough to have a clear impact on the fraction of potentially mobile element
species. This fraction increases with decreasing erosion intensity, which is probably related to a higher degree of chemical weathering and leaching during
periods of decreased erosion.
This paper aims to evaluate the possible relationships between erosion intensity and changes in climate and land use during the past 5.5 cal. k years at
Lake Lehmilampi, eastern Finland. In this study we compare a detailed geochemical sediment record with (1) forest and land use history inferred from
the first pollen and charcoal records from Lake Lehmilampi, and (2) existing archaeological surveys and independent proxy-records of climate change in
the study region. The physical and geochemical sediment parameters examined include grain size analysis data and 23 chemical elements, determined with
four selective extractions and ICP-MS. There are indications of possible human impact in the lake catchment as early as the Neolithic period, c. 3000–2550
bc, but the first undisputable signs are dated to 1800–100 bc. Cereal pollen reappears at c. ad 1700 and increases rapidly until c. ad 1950. The Holocene
Thermal Maximum, its end c. 2000 bc, and the ‘Medieval Climate Anomaly’ were major climate events that had a prominent effect on erosion intensity, while
human impact was a more significant factor during the period 3000 bc–ad 800 and from ad 1500 onwards. Although signs of changes in erosion intensity
found in the sediment were small in this small catchment, they were significant enough to have a clear impact on the fraction of potentially mobile element
species. This fraction increases with decreasing erosion intensity, which is probably related to a higher degree of chemical weathering and leaching during
periods of decreased erosion.
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