Evidence for birch forests and a highly productive environment near the margin of the Fennoscandian ice sheet in the Värriötunturit area, northeastern Finland
High-resolution records of early Holocene deposits are rare, and as a consequence reconstruction of terrestrial environments very soon after the deglaciation has often been difficult. In this study the palaeoenvironmental conditions of early Holocene (c. 10600-7500 cal. yr BP) are reconstructed in t...
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Stockholms universitet, Institutionen för naturgeografi
2019
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ftstockholmuniv:oai:DiVA.org:su-170716 2023-05-15T16:11:50+02:00 Evidence for birch forests and a highly productive environment near the margin of the Fennoscandian ice sheet in the Värriötunturit area, northeastern Finland Bogren, Fredrik 2019 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-170716 eng eng Stockholms universitet, Institutionen för naturgeografi http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-170716 info:eu-repo/semantics/openAccess Early Holocene productive ice-marginal environment subarctic birch forests plant macrofossils pollen palaeoenvironmental reconstructions palaeoclimate reconstructions Värriötunturit Kuutsjärvi northeastern Finland northern Fennoscandia Physical Geography Naturgeografi Climate Research Klimatforskning Geology Geologi Student thesis info:eu-repo/semantics/bachelorThesis text 2019 ftstockholmuniv 2023-02-23T21:40:11Z High-resolution records of early Holocene deposits are rare, and as a consequence reconstruction of terrestrial environments very soon after the deglaciation has often been difficult. In this study the palaeoenvironmental conditions of early Holocene (c. 10600-7500 cal. yr BP) are reconstructed in the Värriötunturit area of northeastern Finland, using evidence from plant macrofossils and pollen preserved in a lake sediment sequence retrieved from the small lake Kuutsjärvi. Special emphasis is put on the environment immediately following the deglaciation as the base of the sediment sequence is rich in minerogenic material interpreted to have been deposited by meltwater pulses from the retreating ice sheet. The abundance and variety of fossil remains in these early meltwater deposits provide evidence for a very productive ice-marginal environment in the area between the lake and the ice sheet, and the presence of tree-type Betula macro remains as well as high percentage values of tree-type Betula pollen suggests that a subarctic birch forest established just a few years after the deglaciation. In the following centuries the birch forest around the lake became rich in an under growth of ferns, and at c. 9400 cal. yr BP a transition into a mixed pine and birch forest took place. Due to absence of indicator plant taxa in the sediment it was not possible to reconstruct temperature conditions for any parts of the sequence in this study. However, the rapid colonisation of birch forests suggests that the climate was warm already during deglaciation, which is also in accordance with climatic conditions reconstructed for the early Holocene in the nearby Sokli area just 10 km away, as well as in other parts of Fennoscandia and Russia. Bachelor Thesis Fennoscandia Fennoscandian Ice Sheet Subarctic Stockholm University: Publications (DiVA) |
institution |
Open Polar |
collection |
Stockholm University: Publications (DiVA) |
op_collection_id |
ftstockholmuniv |
language |
English |
topic |
Early Holocene productive ice-marginal environment subarctic birch forests plant macrofossils pollen palaeoenvironmental reconstructions palaeoclimate reconstructions Värriötunturit Kuutsjärvi northeastern Finland northern Fennoscandia Physical Geography Naturgeografi Climate Research Klimatforskning Geology Geologi |
spellingShingle |
Early Holocene productive ice-marginal environment subarctic birch forests plant macrofossils pollen palaeoenvironmental reconstructions palaeoclimate reconstructions Värriötunturit Kuutsjärvi northeastern Finland northern Fennoscandia Physical Geography Naturgeografi Climate Research Klimatforskning Geology Geologi Bogren, Fredrik Evidence for birch forests and a highly productive environment near the margin of the Fennoscandian ice sheet in the Värriötunturit area, northeastern Finland |
topic_facet |
Early Holocene productive ice-marginal environment subarctic birch forests plant macrofossils pollen palaeoenvironmental reconstructions palaeoclimate reconstructions Värriötunturit Kuutsjärvi northeastern Finland northern Fennoscandia Physical Geography Naturgeografi Climate Research Klimatforskning Geology Geologi |
description |
High-resolution records of early Holocene deposits are rare, and as a consequence reconstruction of terrestrial environments very soon after the deglaciation has often been difficult. In this study the palaeoenvironmental conditions of early Holocene (c. 10600-7500 cal. yr BP) are reconstructed in the Värriötunturit area of northeastern Finland, using evidence from plant macrofossils and pollen preserved in a lake sediment sequence retrieved from the small lake Kuutsjärvi. Special emphasis is put on the environment immediately following the deglaciation as the base of the sediment sequence is rich in minerogenic material interpreted to have been deposited by meltwater pulses from the retreating ice sheet. The abundance and variety of fossil remains in these early meltwater deposits provide evidence for a very productive ice-marginal environment in the area between the lake and the ice sheet, and the presence of tree-type Betula macro remains as well as high percentage values of tree-type Betula pollen suggests that a subarctic birch forest established just a few years after the deglaciation. In the following centuries the birch forest around the lake became rich in an under growth of ferns, and at c. 9400 cal. yr BP a transition into a mixed pine and birch forest took place. Due to absence of indicator plant taxa in the sediment it was not possible to reconstruct temperature conditions for any parts of the sequence in this study. However, the rapid colonisation of birch forests suggests that the climate was warm already during deglaciation, which is also in accordance with climatic conditions reconstructed for the early Holocene in the nearby Sokli area just 10 km away, as well as in other parts of Fennoscandia and Russia. |
format |
Bachelor Thesis |
author |
Bogren, Fredrik |
author_facet |
Bogren, Fredrik |
author_sort |
Bogren, Fredrik |
title |
Evidence for birch forests and a highly productive environment near the margin of the Fennoscandian ice sheet in the Värriötunturit area, northeastern Finland |
title_short |
Evidence for birch forests and a highly productive environment near the margin of the Fennoscandian ice sheet in the Värriötunturit area, northeastern Finland |
title_full |
Evidence for birch forests and a highly productive environment near the margin of the Fennoscandian ice sheet in the Värriötunturit area, northeastern Finland |
title_fullStr |
Evidence for birch forests and a highly productive environment near the margin of the Fennoscandian ice sheet in the Värriötunturit area, northeastern Finland |
title_full_unstemmed |
Evidence for birch forests and a highly productive environment near the margin of the Fennoscandian ice sheet in the Värriötunturit area, northeastern Finland |
title_sort |
evidence for birch forests and a highly productive environment near the margin of the fennoscandian ice sheet in the värriötunturit area, northeastern finland |
publisher |
Stockholms universitet, Institutionen för naturgeografi |
publishDate |
2019 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-170716 |
genre |
Fennoscandia Fennoscandian Ice Sheet Subarctic |
genre_facet |
Fennoscandia Fennoscandian Ice Sheet Subarctic |
op_relation |
http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-170716 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1765997030286557184 |