Odensjön - A new varved lake sediment record from southern Sweden
(2021) In Dissertations in Geology at Lund University GEOR02 20201Department of Geology
- Abstract
- Annually laminated (varved) sediments provide opportunities to reconstruct climate change and human impact on the environment with high temporal resolution. Depending on the character of the varves, such sediments can provide insight into the delivery of both autochthonous and allochthonous material from the lake and its catch- ment and answer questions regarding both regional and local responses to climate- and land-use changes. This the- sis examines a new sediment record from the small Lake Odensjön in southern Sweden. The aim of the study is to describe the sedimentary sequence, determine the type of laminations and establish if these are annual, and to date the sediment sequence using radiometric methods together with varve counts.... (More)
- Annually laminated (varved) sediments provide opportunities to reconstruct climate change and human impact on the environment with high temporal resolution. Depending on the character of the varves, such sediments can provide insight into the delivery of both autochthonous and allochthonous material from the lake and its catch- ment and answer questions regarding both regional and local responses to climate- and land-use changes. This the- sis examines a new sediment record from the small Lake Odensjön in southern Sweden. The aim of the study is to describe the sedimentary sequence, determine the type of laminations and establish if these are annual, and to date the sediment sequence using radiometric methods together with varve counts. The uppermost 910 mm of the sedi- ment sequence was collected with a freeze-corer at 20 m water depth in the deepest part of the lake. Dating with 210Pb and 137Cs in combination with identification of the distinctive and well-documented pollution Pb peak associ- ated with the use of leaded petrol in the mid 1970’s confirms that the sediments partly consist of laminations repre- senting annual varves. Radiocarbon dating of the lower part of the record demonstrates its extension to around 450 years before present. The sediments are characterized by X-ray fluorescence, biogenic silica content, total carbon and nitrogen content and microscopic analyses are showing high contents of biogenic silica and organic matter, abundant diatoms and low minerogenic content, demonstrating that the varves are of biogenic origin and annual. The varve counting was limited by thin and indistinct layers in part of the core. The conditions for varve formation have changed through time and substantial variations in the content of macroscopic plant remains give evidence of pronounced changes in catchment land-use. In the late 19th century the catchment most likely was completely de- forested, while rapid colonization by beech, Fagus sylvatica, occurred during the following century as demonstrat- ed by abundant well-preserved leaves. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9050993
- author
- Hertzman, Hanna LU
- supervisor
-
- Karl Ljung LU
- Dan Hammarlund LU
- organization
- course
- GEOR02 20201
- year
- 2021
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Varved lake sediment, late Holocene, organic sediments, diatoms, land-use history, southern Sweden, palaeolimnology
- publication/series
- Dissertations in Geology at Lund University
- report number
- 611
- language
- English
- id
- 9050993
- date added to LUP
- 2021-06-09 14:37:30
- date last changed
- 2022-07-13 15:28:15
@misc{9050993,
abstract = {{Annually laminated (varved) sediments provide opportunities to reconstruct climate change and human impact on the environment with high temporal resolution. Depending on the character of the varves, such sediments can provide insight into the delivery of both autochthonous and allochthonous material from the lake and its catch- ment and answer questions regarding both regional and local responses to climate- and land-use changes. This the- sis examines a new sediment record from the small Lake Odensjön in southern Sweden. The aim of the study is to describe the sedimentary sequence, determine the type of laminations and establish if these are annual, and to date the sediment sequence using radiometric methods together with varve counts. The uppermost 910 mm of the sedi- ment sequence was collected with a freeze-corer at 20 m water depth in the deepest part of the lake. Dating with 210Pb and 137Cs in combination with identification of the distinctive and well-documented pollution Pb peak associ- ated with the use of leaded petrol in the mid 1970’s confirms that the sediments partly consist of laminations repre- senting annual varves. Radiocarbon dating of the lower part of the record demonstrates its extension to around 450 years before present. The sediments are characterized by X-ray fluorescence, biogenic silica content, total carbon and nitrogen content and microscopic analyses are showing high contents of biogenic silica and organic matter, abundant diatoms and low minerogenic content, demonstrating that the varves are of biogenic origin and annual. The varve counting was limited by thin and indistinct layers in part of the core. The conditions for varve formation have changed through time and substantial variations in the content of macroscopic plant remains give evidence of pronounced changes in catchment land-use. In the late 19th century the catchment most likely was completely de- forested, while rapid colonization by beech, Fagus sylvatica, occurred during the following century as demonstrat- ed by abundant well-preserved leaves.}},
author = {{Hertzman, Hanna}},
language = {{eng}},
note = {{Student Paper}},
series = {{Dissertations in Geology at Lund University}},
title = {{Odensjön - A new varved lake sediment record from southern Sweden}},
year = {{2021}},
}