The Eemian Baltic Sea hydrography and paleoenvironment based on foraminiferal geochemistry
(2020) GEOR02 20201Department of Geology
- Abstract (Swedish)
- I den här masteruppsatsen undersöktes geokemin i kalkskalen av bottenlevande foraminiferer från Anholt (Kattegat), Ristinge (Bälthavet) och Obrzynowo (Egentliga Östersjön), för att rekonstruera de hydrografiska förhållanden i Östersjön och paleomiljön under den senaste interglacialen (130 - 115 ka BP). De variabler som analyserades innefattade Mg/Ca, Ba/Ca och Mn/Ca samt stabila syre- och kolisotoper (δ18O och δ13C) i kombination med data från tidigare studier och modern hydrografi. Den rekonstruerade bottenvattentemperaturen beräknades med hjälp av artspecifika Mg/Ca-kalibreringar och indikerar generellt varmare bottenvattentemperaturer än modern data, däremot är resultaten motstridiga för Elphidium clavatum och Bulimina marginata och kan... (More)
- I den här masteruppsatsen undersöktes geokemin i kalkskalen av bottenlevande foraminiferer från Anholt (Kattegat), Ristinge (Bälthavet) och Obrzynowo (Egentliga Östersjön), för att rekonstruera de hydrografiska förhållanden i Östersjön och paleomiljön under den senaste interglacialen (130 - 115 ka BP). De variabler som analyserades innefattade Mg/Ca, Ba/Ca och Mn/Ca samt stabila syre- och kolisotoper (δ18O och δ13C) i kombination med data från tidigare studier och modern hydrografi. Den rekonstruerade bottenvattentemperaturen beräknades med hjälp av artspecifika Mg/Ca-kalibreringar och indikerar generellt varmare bottenvattentemperaturer än modern data, däremot är resultaten motstridiga för Elphidium clavatum och Bulimina marginata och kan vara ett resultat av att olika arter bygger sina skal under olika delar av året. Jämförelsen mellan de tre stationerna visar på en gradvis övergång från marina till mer bräckt vatten. Syreförhållanden tyder på en stark vertikal stratifiering av vattenkolumnen och relativt låga syrehalter, förutom i Ristinge där trangressionen av de Danska sunden resulterade i relativt väl ventilerade bottenvatten i motsats till de andra stationerna. Resultaten från spårelement- och isotopanalyserna från foraminiferer har visat sig kunna bidra till bestämning av absoluta temperaturer och paleo-miljörekonstruktioner som kan användas som en analog för nuvarande förändringar i miljön. (Less)
- Abstract
- In this thesis, three microfossil records from Anholt (Kattegat), Ristinge (the Danish straits) and Obrzynowo (the southern Baltic- coast) representing the last interglacial Eemian (130- 115 ka B.P) were generated. The geochemistry of benthic foraminifera was investigated to reconstruct the Eemian Baltic Sea hydrography and paleoenvironment. The paleo-environmental proxies were: the trace elements Mg/Ca, Ba/Ca, and Mn/Ca as well as stable oxygen and carbon isotopes (δ18O and δ13C), coupled with data from previous studies and modern hydrography. The reconstructed bottom water temperature was calculated with species-specific Mg/Ca calibrations and the results indicate generally warmer bottom water temperatures than modern data, albeit for... (More)
- In this thesis, three microfossil records from Anholt (Kattegat), Ristinge (the Danish straits) and Obrzynowo (the southern Baltic- coast) representing the last interglacial Eemian (130- 115 ka B.P) were generated. The geochemistry of benthic foraminifera was investigated to reconstruct the Eemian Baltic Sea hydrography and paleoenvironment. The paleo-environmental proxies were: the trace elements Mg/Ca, Ba/Ca, and Mn/Ca as well as stable oxygen and carbon isotopes (δ18O and δ13C), coupled with data from previous studies and modern hydrography. The reconstructed bottom water temperature was calculated with species-specific Mg/Ca calibrations and the results indicate generally warmer bottom water temperatures than modern data, albeit for Elphidium clavatum and Bulimina marginata the results are contradictory and could be a result of seasonal response for shell calcification and incorporation of trace elements. The comparison of the three stations (Anholt, Ristinge and Obrzynowo) show a gradient from marine to gradually more brackish environmental conditions. The oxygen conditions imply a strong stratification and relatively low oxygen levels, except in Ristinge where the transgression of the Danish Straits resulted in relatively ventilated bottom waters as opposed to the other stations. The foraminiferal geochemistry is shown to contribute to quantitative temperature and tentative paleoenvironment reconstructions that can be used as a past analogue for present changes in the environment. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9021561
- author
- Chonewicz, Julia LU
- supervisor
-
- Helena Filipsson LU
- Sha Ni LU
- organization
- alternative title
- Östersjöns hydrografi och miljö under Eem interglacialen, baserat på foraminiferers geokemi
- course
- GEOR02 20201
- year
- 2020
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- trace elements, benthic foraminifera, last interglacial, temperature reconstruction, geochemistry
- report number
- 599
- language
- English
- id
- 9021561
- date added to LUP
- 2020-06-23 15:31:32
- date last changed
- 2021-06-23 03:39:36
@misc{9021561,
abstract = {{In this thesis, three microfossil records from Anholt (Kattegat), Ristinge (the Danish straits) and Obrzynowo (the southern Baltic- coast) representing the last interglacial Eemian (130- 115 ka B.P) were generated. The geochemistry of benthic foraminifera was investigated to reconstruct the Eemian Baltic Sea hydrography and paleoenvironment. The paleo-environmental proxies were: the trace elements Mg/Ca, Ba/Ca, and Mn/Ca as well as stable oxygen and carbon isotopes (δ18O and δ13C), coupled with data from previous studies and modern hydrography. The reconstructed bottom water temperature was calculated with species-specific Mg/Ca calibrations and the results indicate generally warmer bottom water temperatures than modern data, albeit for Elphidium clavatum and Bulimina marginata the results are contradictory and could be a result of seasonal response for shell calcification and incorporation of trace elements. The comparison of the three stations (Anholt, Ristinge and Obrzynowo) show a gradient from marine to gradually more brackish environmental conditions. The oxygen conditions imply a strong stratification and relatively low oxygen levels, except in Ristinge where the transgression of the Danish Straits resulted in relatively ventilated bottom waters as opposed to the other stations. The foraminiferal geochemistry is shown to contribute to quantitative temperature and tentative paleoenvironment reconstructions that can be used as a past analogue for present changes in the environment.}},
author = {{Chonewicz, Julia}},
language = {{eng}},
note = {{Student Paper}},
title = {{The Eemian Baltic Sea hydrography and paleoenvironment based on foraminiferal geochemistry}},
year = {{2020}},
}