Fra Lovisa - Academia.edu (original) (raw)
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Papers by Fra Lovisa
Holocene, 2002
Mineral magnetic, organic carbon and pollen studies of two varved Holocene lake-sediment sequence... more Mineral magnetic, organic carbon and pollen studies of two varved Holocene lake-sediment sequences in the boreal forest of northern Sweden indicate that signi cant environmenta l changes took place between c. 6000 and 5700 bc. This interval is characterized by an increase in mineral-matter accumulation , which is a proxy for winter-snow accumulation , and a statistically signi cant decrease in total pollen in ux (predominantly Pinus, Betula and Alnus), which may re ect lower spring and summer temperatures and increased frost frequency. Notable increases in the in ux of deciduous tree species (including Quercus and Corylus) suggest a rapid change to warmer conditions between 5700 and 5600 bc. Given dating errors associated with the varve chronologie s and the Greenland ice-core timescales, the cold interval can be considered to re ect a regional (possibly global) climatic cooling, which is often referred to as the '8.2 kyr BP cooling event'. However, the younger age of the cold event in northern Sweden does not support the hypothesis of forcing by the sudden drainage of Laurentide glacial lakes into the North Atlantic, unless a minimal 300-year delay in ocean-atmospheri c coupling is accepted. The data contribute to a complex picture of early-Holocene environmenta l change, in response to deglaciation of the Northern Hemisphere.
Holocene, 2002
Mineral magnetic, organic carbon and pollen studies of two varved Holocene lake-sediment sequence... more Mineral magnetic, organic carbon and pollen studies of two varved Holocene lake-sediment sequences in the boreal forest of northern Sweden indicate that signi cant environmenta l changes took place between c. 6000 and 5700 bc. This interval is characterized by an increase in mineral-matter accumulation , which is a proxy for winter-snow accumulation , and a statistically signi cant decrease in total pollen in ux (predominantly Pinus, Betula and Alnus), which may re ect lower spring and summer temperatures and increased frost frequency. Notable increases in the in ux of deciduous tree species (including Quercus and Corylus) suggest a rapid change to warmer conditions between 5700 and 5600 bc. Given dating errors associated with the varve chronologie s and the Greenland ice-core timescales, the cold interval can be considered to re ect a regional (possibly global) climatic cooling, which is often referred to as the '8.2 kyr BP cooling event'. However, the younger age of the cold event in northern Sweden does not support the hypothesis of forcing by the sudden drainage of Laurentide glacial lakes into the North Atlantic, unless a minimal 300-year delay in ocean-atmospheri c coupling is accepted. The data contribute to a complex picture of early-Holocene environmenta l change, in response to deglaciation of the Northern Hemisphere.