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Lokala miljöförändringar i samband med en plötslig havsyteförändring ca 8200 år före nutid vid Kalvöviken i centrala Blekinge

Göransson, Ammy (2006) In Examensarbeten i geologi vid Lunds universitet
Department of Geology
Abstract
A sediment transect based on ten corings were performed with a Russian peat corer in the aldercarr at
Kalvöviken on the Biskopsmåla Peninsula in central Blekinge. Three parallel sediment cores were collected at the
master coring point. These cores were subsampled and studied by means of loss of ignition (LOI), mineral magnetic
measurements, macrofossil analysis, pollen analysis and structural analysis. The chronology was obtained by radiocarbon
dating of two levels and by adopting dates from earlier studies performed at Kalvöviken in 1997-1999. The
purpose of this study was to analyse and interpret the local environmental changes that took place around 8200 cal
BP when a sudden change in sea level occurred. The stratigraphic records... (More)
A sediment transect based on ten corings were performed with a Russian peat corer in the aldercarr at
Kalvöviken on the Biskopsmåla Peninsula in central Blekinge. Three parallel sediment cores were collected at the
master coring point. These cores were subsampled and studied by means of loss of ignition (LOI), mineral magnetic
measurements, macrofossil analysis, pollen analysis and structural analysis. The chronology was obtained by radiocarbon
dating of two levels and by adopting dates from earlier studies performed at Kalvöviken in 1997-1999. The
purpose of this study was to analyse and interpret the local environmental changes that took place around 8200 cal
BP when a sudden change in sea level occurred. The stratigraphic records were compared with other similar studies
from nearby sites along the coast of Blekinge but also placed in a more regional context. The transect reveals a 15
meter long drift gyttja layer orientated in SE-NW direction. This layer was found between two layers of brackish
gyttja. The study shows that the drift gyttja layer was deposited during a period with low water level between ca
8150-8075 cal. BP. The mineral magnetic analysis confirms the assumption of a sudden transition. The plant
macrofossils indicate that Kalvöviken during this period was a shore environment with plants such as Carex,
Alisma plantago-aquatica, Equisetum fluviatile, Cyperaceae and Phragmites. Datings together with pollen concentration
values indicate a short duration of this period, 75 years or less. The drift gyttja layer in Kalvöviken is synchronous
with a short temperature anomaly found in ice cores from Greenland, the so-called “8.2 kyr event”. It
might have a meteorological explanation caused by differences in air pressure between the Azores and Island, a
phenomenon called the North Atlantic Oscillation (NAO). (Less)
Abstract (Swedish)
En sedimenttransekt bestående av tio punkter borrades med hjälp av en ryssborr i alkärret vid
Kalvöviken på Biskopsmålahalvön i centrala Blekinge. I huvudpunkten togs tre parallella 1 m långa borrkärnor.
Sedimentprov togs ur borrkärnorna och undersöktes med hjälp av glödförlust, mineralmagnetiska-, makrofossil-,
pollen- och strukturanalyser. Kronologin fastställdes genom två kol-14-dateringar kompletterade med tidigare
dateringar som utfördes i samband med undersökningarna av platsen under perioden 1997-1999. Avsikten med
studien var att analysera och tolka den lokala miljöförändringen i samband med en plötslig förändring i havsytans
nivå kring 8200 före nutid. Resultaten har jämförts med likartade undersökningar från närbelägna... (More)
En sedimenttransekt bestående av tio punkter borrades med hjälp av en ryssborr i alkärret vid
Kalvöviken på Biskopsmålahalvön i centrala Blekinge. I huvudpunkten togs tre parallella 1 m långa borrkärnor.
Sedimentprov togs ur borrkärnorna och undersöktes med hjälp av glödförlust, mineralmagnetiska-, makrofossil-,
pollen- och strukturanalyser. Kronologin fastställdes genom två kol-14-dateringar kompletterade med tidigare
dateringar som utfördes i samband med undersökningarna av platsen under perioden 1997-1999. Avsikten med
studien var att analysera och tolka den lokala miljöförändringen i samband med en plötslig förändring i havsytans
nivå kring 8200 före nutid. Resultaten har jämförts med likartade undersökningar från närbelägna platser utefter
Blekingekusten men också satts in i ett större regionalt perspektiv. Sedimentprofilen avslöjar ett lager av svämgyttja
med ca 15 meters utbredning i sydöst - nordvästlig riktning avsatt mellan två brackvattengyttjelager. Studien
visar att lagret avsattes under en period med lågt vattenstånd som inträffade mellan ca 8150-8075 år före nutid. Den
mineralmagnetiska analysen bekräftar antagandet om en plötslig övergång till perioden med lägre vattenstånd.
Makrofossilanalysen indikerar att Kalvöviken vid denna period var en strandmiljö med växter såsom starr (Carex),
svalting (Alisma plantago-aquatica), sjöfräken (Equisetum fluviatile), halvgräs (Cyperaceae) och vass
(Phragmites). Dateringar tillsammans med pollenkoncentrationsvärden antyder att varaktigheten troligen var
mycket kort, 75 år eller kortare. Svämgyttjelagret är samtida med den korta temperaturanomali som identifierats i
grönländska iskärnor, s.k. 8.2 kyr event. Det kan ha en meteorologisk bakgrund som beror på skillnader i lufttryck
mellan Azorerna och Island, ett fenomen som benämns den Nordatlantiska oscillationen (North Atlantic Oscillation
- NAO). (Less)
Please use this url to cite or link to this publication:
author
Göransson, Ammy
supervisor
organization
alternative title
Local environmental changes 8200 cal BP as a result of a sudden change in sea level at Kalvöviken in central Blekinge
year
type
H1 - Master's Degree (One Year)
subject
keywords
LOI, mineral magnetism, pollen analysis, macrofossil analysis, sea level change, 8.2 kyr event, glödförlust, mineralmagnetism, pollenanalys, havsyteförändring, makrofossilanalys, Blekinge
publication/series
Examensarbeten i geologi vid Lunds universitet
report number
197
language
Swedish
id
2338790
date added to LUP
2012-02-06 10:39:29
date last changed
2012-02-06 10:39:29
@misc{2338790,
  abstract     = {A sediment transect based on ten corings were performed with a Russian peat corer in the aldercarr at
Kalvöviken on the Biskopsmåla Peninsula in central Blekinge. Three parallel sediment cores were collected at the
master coring point. These cores were subsampled and studied by means of loss of ignition (LOI), mineral magnetic
measurements, macrofossil analysis, pollen analysis and structural analysis. The chronology was obtained by radiocarbon
dating of two levels and by adopting dates from earlier studies performed at Kalvöviken in 1997-1999. The
purpose of this study was to analyse and interpret the local environmental changes that took place around 8200 cal
BP when a sudden change in sea level occurred. The stratigraphic records were compared with other similar studies
from nearby sites along the coast of Blekinge but also placed in a more regional context. The transect reveals a 15
meter long drift gyttja layer orientated in SE-NW direction. This layer was found between two layers of brackish
gyttja. The study shows that the drift gyttja layer was deposited during a period with low water level between ca
8150-8075 cal. BP. The mineral magnetic analysis confirms the assumption of a sudden transition. The plant
macrofossils indicate that Kalvöviken during this period was a shore environment with plants such as Carex,
Alisma plantago-aquatica, Equisetum fluviatile, Cyperaceae and Phragmites. Datings together with pollen concentration
values indicate a short duration of this period, 75 years or less. The drift gyttja layer in Kalvöviken is synchronous
with a short temperature anomaly found in ice cores from Greenland, the so-called “8.2 kyr event”. It
might have a meteorological explanation caused by differences in air pressure between the Azores and Island, a
phenomenon called the North Atlantic Oscillation (NAO).},
  author       = {Göransson, Ammy},
  keyword      = {LOI,mineral magnetism,pollen analysis,macrofossil analysis,sea level change,8.2 kyr event,glödförlust,mineralmagnetism,pollenanalys,havsyteförändring,makrofossilanalys,Blekinge},
  language     = {swe},
  note         = {Student Paper},
  series       = {Examensarbeten i geologi vid Lunds universitet},
  title        = {Lokala miljöförändringar i samband med en plötslig havsyteförändring ca 8200 år före nutid vid Kalvöviken i centrala Blekinge},
  year         = {2006},
}