Reconstructing environmental variability at Leynavatn, Faroe Islands

A new continuous environmental reconstruction has been established based on a 390 cm long lake core from Leynavatn Streymoy (southeast Faroes Islands), containing sediments spanning from the last 550 CE (Common Era). To acquire further understanding, the lake core is compared to other proxy records...

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Main Author: Langnæs, Melissa Marie
Format: Master Thesis
Language:English
Published: The University of Bergen 2020
Subjects:
Online Access:https://hdl.handle.net/1956/20438
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spelling ftunivbergen:oai:bora.uib.no:1956/20438 2023-05-15T16:10:59+02:00 Reconstructing environmental variability at Leynavatn, Faroe Islands Langnæs, Melissa Marie 2020-06-03 application/pdf https://hdl.handle.net/1956/20438 eng eng The University of Bergen https://hdl.handle.net/1956/20438 Copyright the Author. All rights reserved 756199 Master thesis 2020 ftunivbergen 2023-03-14T17:40:46Z A new continuous environmental reconstruction has been established based on a 390 cm long lake core from Leynavatn Streymoy (southeast Faroes Islands), containing sediments spanning from the last 550 CE (Common Era). To acquire further understanding, the lake core is compared to other proxy records from the North Atlantic region to examine the amplitude and timing of regional climate variability. A firm chronology is generated by radiocarbon dating from the sediments. In addition, magnetic susceptibility, loss-on-ignition, XRF-core scanning and X-ray CT-scanning were used to unravel different catchment activities. A simplified Quaternary geological map is proposed to explore the present activity and define different catchment processes. Leynavatn sediment record suggest that the concentration of geochemical elements Ti, Ca and K, together with dry bulk density and magnetic susceptibility reflect changes in amount of inorganic delivery to the lake. In contrary, the geochemical ratio Incoh/Coh scattering and loss-on-ignition reflect variations in the organic input. These proxies are associated to landscape changes, which are sensitive to late Holocene climate variability and the human expansion at the Faroes. The results from Leynavatn sediments indicate that all climatic induced phenomena including precipitation, atmosphere and sea surface temperatures, underwent an evident change at the transition from Medieval Warm Period to the Little Ice Age. The geochemical and geophysical changes in the lake sediments are associated with enhanced weathering and increased erosion around 1200-1400 CE, referring to the Medieval Warm Period. After 1400 CE a prolonged decrease in inorganic delivery propose a climatic cooling, where increasing frequency of cold summers and cold winters reflect the onset of the Little Ice Age. Masteroppgave i geovitenskap GEOV399 MAMN-GEOV Master Thesis Faroe Islands Faroes North Atlantic Streymoy University of Bergen: Bergen Open Research Archive (BORA-UiB) Faroe Islands Leynavatn ENVELOPE(-7.023,-7.023,62.128,62.128) Streymoy ENVELOPE(-7.000,-7.000,62.133,62.133)
institution Open Polar
collection University of Bergen: Bergen Open Research Archive (BORA-UiB)
op_collection_id ftunivbergen
language English
topic 756199
spellingShingle 756199
Langnæs, Melissa Marie
Reconstructing environmental variability at Leynavatn, Faroe Islands
topic_facet 756199
description A new continuous environmental reconstruction has been established based on a 390 cm long lake core from Leynavatn Streymoy (southeast Faroes Islands), containing sediments spanning from the last 550 CE (Common Era). To acquire further understanding, the lake core is compared to other proxy records from the North Atlantic region to examine the amplitude and timing of regional climate variability. A firm chronology is generated by radiocarbon dating from the sediments. In addition, magnetic susceptibility, loss-on-ignition, XRF-core scanning and X-ray CT-scanning were used to unravel different catchment activities. A simplified Quaternary geological map is proposed to explore the present activity and define different catchment processes. Leynavatn sediment record suggest that the concentration of geochemical elements Ti, Ca and K, together with dry bulk density and magnetic susceptibility reflect changes in amount of inorganic delivery to the lake. In contrary, the geochemical ratio Incoh/Coh scattering and loss-on-ignition reflect variations in the organic input. These proxies are associated to landscape changes, which are sensitive to late Holocene climate variability and the human expansion at the Faroes. The results from Leynavatn sediments indicate that all climatic induced phenomena including precipitation, atmosphere and sea surface temperatures, underwent an evident change at the transition from Medieval Warm Period to the Little Ice Age. The geochemical and geophysical changes in the lake sediments are associated with enhanced weathering and increased erosion around 1200-1400 CE, referring to the Medieval Warm Period. After 1400 CE a prolonged decrease in inorganic delivery propose a climatic cooling, where increasing frequency of cold summers and cold winters reflect the onset of the Little Ice Age. Masteroppgave i geovitenskap GEOV399 MAMN-GEOV
format Master Thesis
author Langnæs, Melissa Marie
author_facet Langnæs, Melissa Marie
author_sort Langnæs, Melissa Marie
title Reconstructing environmental variability at Leynavatn, Faroe Islands
title_short Reconstructing environmental variability at Leynavatn, Faroe Islands
title_full Reconstructing environmental variability at Leynavatn, Faroe Islands
title_fullStr Reconstructing environmental variability at Leynavatn, Faroe Islands
title_full_unstemmed Reconstructing environmental variability at Leynavatn, Faroe Islands
title_sort reconstructing environmental variability at leynavatn, faroe islands
publisher The University of Bergen
publishDate 2020
url https://hdl.handle.net/1956/20438
long_lat ENVELOPE(-7.023,-7.023,62.128,62.128)
ENVELOPE(-7.000,-7.000,62.133,62.133)
geographic Faroe Islands
Leynavatn
Streymoy
geographic_facet Faroe Islands
Leynavatn
Streymoy
genre Faroe Islands
Faroes
North Atlantic
Streymoy
genre_facet Faroe Islands
Faroes
North Atlantic
Streymoy
op_relation https://hdl.handle.net/1956/20438
op_rights Copyright the Author. All rights reserved
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