Change search
ReferencesLink to record
Permanent link

Direct link
Late Holocene coastal hydrographic and climate changes in the eastern North Sea
Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
Show others and affiliations
2006 (English)In: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 16, no 7, 987-1001 p.Article in journal (Refereed) Published
Abstract [en]

We present a high-resolution palaeoenvironmental reconstruction covering the late Holocene from the Skagerrak and other sites in the North Sea area. The data, which are based on the analyses of marine sediment cores, reveal a marked environmental shift that took place between AD 700 and AD 1100, with the most pronounced changes occurring at AD 900. Both surface and bottom waters in the Skagerrak were subject to major circulation and productivity changes at this time due to an enhanced advection of Atlantic waters to the North Sea marking the beginning of the 'Mediaeval Warm Period' (MWP). The observed increase in bottom current strength is especially remarkable as there is hardly any comparable signal in the older part of the record going back to 1000 BC. At the transition to the 'Little Ice Age' (LIA) the bottom current strength remains at a high level, now probably forced by atmospheric circulation. Thus, despite opposite temperature forcing, these two consecutive climate scenarios are apparently able to generate distinctly stronger bottom currents in the Skagerrak than observed in the preceding 2000 years, and demonstrate the significance of climatic forcing in shaping the marine environment. Indeed, both the MWP and the LIA are reported as strong climatic signals in northwest Europe, being the warmest (except the late twentieth century) and coldest periods, respectively, during at least the last 2000 years.

Place, publisher, year, edition, pages
2006. Vol. 16, no 7, 987-1001 p.
Keyword [en]
*CLIMATIC changes *GEOLOGY, Stratigraphic -- Holocene *OCEAN bottom *MARINE sediments *SEDIMENTATION & deposition *SUBMARINE geology *ATMOSPHERIC circulation *OCEAN currents
National Category
Earth and Related Environmental Sciences
URN: urn:nbn:se:su:diva-23630DOI: 10.1177/0959683606hl989rpOAI: diva2:193570
Part of urn:nbn:se:su:diva-413Available from: 2005-03-23 Created: 2005-03-23 Last updated: 2010-09-10Bibliographically approved
In thesis
1. Holocene and Latest Glacial Paleoceanography in the North-Eastern Skagerrak
Open this publication in new window or tab >>Holocene and Latest Glacial Paleoceanography in the North-Eastern Skagerrak
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Detailed information on past oceanographic and climatic changes is crucial for our understanding of natural climate variability and for the assessment of future climate variations. Sediments strongly influenced by the North Atlantic Current accumulate at high rates in the northeastern Skagerrak, forming a potential highresolution archive for information on past climatic and oceanographic processes and events. Through a highresolution, multi-proxy study of the 32 meter long core MD99-2286 from the north-eastern Skagerrak, and interpretation of chirp sonar profiles from the coring area, this thesis provides new and detailed insights about the paleoceanographic development of the eastern North Sea region since the deglaciation.

The chronostratigraphic control of core MD99-2286 relies on 27 radiocarbon dates. Ages are presented in calibrated thousand years before present (abbreviated “kyr”). Core MD99-2286 was correlated to chirp sonar profiles using measured physical properties. This correlation demonstrates that a strong regional acoustic reflector, previously assumed to represent the Pleistocene/Holocene boundary, was formed as a result of rapid ice retreat during the latest Pleistocene. Based on the distribution of ice rafted debris in the core, ice berg calving in the Skagerrak ended at 10.7 kyr. Detailed grain-size analyses of the core were interpreted using a novel 3D-visualization technique. Between 11.3 and 10.3 kyr, clay-rich distal glacial marine sediments were deposited in the northeastern Skagerrak, derived from Baltic melt-water outflow across south-central Sweden through the Otteid-Stenselva strait. As a result of differential isostatic uplift, the route of the major outflow and the associated sediment deposition moved southwards along the Swedish west coast. After 10.3 kyr, sediment deposition in the north-eastern Skagerrak gradually adopted to a fully interglacial normal marine sedimentation dominated by Atlantic inflow and the North Jutland Current.

The establishment of the modern circulation system in the eastern North Sea is marked by abrupt coarsening of the sediments in core MD99-2286 at 8.5 kyr. This was a result of increased Atlantic inflow, opening of the English Channel and the Danish straits, and formation of the South Jutland Current. Mineral magnetic properties of the core show a distinct relationship reflecting general sediment source variability. After 8.5 kyr, sediments in the northeastern Skagerrak were derived predominantly from the Atlantic Ocean and the North Sea, with varying contributions from the South Jutland Current, the Baltic Current, and the currents along the coasts of western Sweden and southern Norway. Between 6.3 and 3.8 kyr, the eastern North Sea was further developed towards the modern situation by an increase of the South Jutland Current flow. The Skagerrak bottom currents were probably forced by strong Atlantic water inflow between 0.9 and 0.5 kyr, and after that by increased wind stress. The influence of regional climate on the eastern North Sea circulation has increased since the middle of the Holocene.

Place, publisher, year, edition, pages
Stockholm: Institutionen för geologi och geokemi, 2005. 30 p.
Meddelanden från Stockholms universitets institution för geologi och geokemi, ISSN 1101-1599 ; 322
Skagerrak, Holocene, sediment, chirp sonar, grain size, mineral magnetic properties
National Category
Earth and Related Environmental Sciences
urn:nbn:se:su:diva-413 (URN)91-7155-038-0 (ISBN)
Public defence
2005-04-15, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 8 C, Stockholm, 10:00
Available from: 2005-03-23 Created: 2005-03-23Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Gyllencreutz, RichardBackman, Jan
By organisation
Department of Geology and Geochemistry
In the same journal
The Holocene
Earth and Related Environmental Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 35 hits
ReferencesLink to record
Permanent link

Direct link