Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Mineral and isotopic (Nd, Sr) of fine-grained deglacial and Holocene sediments from the Mackenzie Trough, Arctic Canada
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.ORCID-id: 0000-0002-2023-8361
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.ORCID-id: 0000-0002-6046-1488
Vise andre og tillknytning
(engelsk)Manuskript (preprint) (Annet vitenskapelig)
HSV kategori
Forskningsprogram
maringeologi
Identifikatorer
URN: urn:nbn:se:su:diva-153903OAI: oai:DiVA.org:su-153903DiVA, id: diva2:1188394
Tilgjengelig fra: 2018-03-07 Laget: 2018-03-07 Sist oppdatert: 2022-02-28bibliografisk kontrollert
Inngår i avhandling
1. In the wake of deglaciation - sedimentary signatures of ice-sheet decay and sea-level change: Studies from south-central Sweden and the western Arctic Ocean
Åpne denne publikasjonen i ny fane eller vindu >>In the wake of deglaciation - sedimentary signatures of ice-sheet decay and sea-level change: Studies from south-central Sweden and the western Arctic Ocean
2018 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

Lacustrine and marine sedimentary archives help unravel details concerning the withdrawal of large ice sheets and resulting sea-level changes during the last deglaciation (22 -11 kyr). In a series of four manuscripts, this PhD thesis investigates the sedimentological signatures from deglacial processes at three key locations in the northern hemisphere: (i) Lake Vättern (LV) in south-central Sweden, (ii) Herald Canyon (HC) in the western Chukchi Sea, and (iii) Mackenzie Trough (MT) on the westernmost edge of the Canadian Beaufort Shelf. One lacustrine (LV) and two marine (HC and MT) sediment cores were analyzed using a broad range of methods to describe the physical, chemical, mineralogical and biological characteristics, and used to construct paleoenvironmental interpretations.

Constituting the westernmost part of the Baltic Sea during parts of the last deglaciation, LV has long been envisaged as a key region for deglacial studies in southern Scandinavia. Sediments in LV highlight four major lake development stages following the withdrawal of the Fennoscandian Ice Sheet. These include the Baltic Ice Lake, the Yoldia Sea, the Ancylus Lake and the ultimate isolated lake stage. New radiocarbon dates indicate that the lake became isolated at 9530±50 cal. yr BP. A sharp transition from a varved clay unit to a partly sulfide laminated clay unit marks the final drainage of the Baltic Ice Lake, dated to 11 650±280 cal. yr BP. However, an earlier peak in pore water chlorinity identified in the sediment provides the most compelling evidence to date for an initial drainage of the Baltic Ice Lake (~12.8 cal. kyr BP) near the onset of the Younger Dryas cold event.

Located downstream from where Pacific water flows into the Arctic, HC is a key location for understanding the details of the early Holocene (~11 cal. yr BP) flooding of the Bering Strait, and investigating sedimentological proxies for Pacific water in Arctic Ocean sediment cores. The deglacial transgression of the shelf and opening of the Bering Strait is reflected in the grain size and biogenic silica content from the HC sediment core. However, a clear Pacific water signature is not seen in the clay mineralogy which exhibits increased variability after the opening of the Bering Strait. This is interpreted as a combination of Pacific and East Siberian sources for bottom waters in HC. The absence of a clear Pacific water signature in the clay mineralogy highlights potential limitations to using this proxy in other records from the western Arctic.

Far field studies from the Arctic Ocean have argued that Mackenzie River sediments in Younger Dryas age sediments can be recognized by a unique mineral and isotopic composition, but no detailed proximal study of Mackenzie River sediments exists to support this assertion. The mineral and isotopic (Sr and Nd) studies presented in this thesis from the third of the key regions, the MT, fills this gap. The results show that the mineral assemblage and ɛNd of fine fraction material remained relatively stable during the decay of the Laurentide Ice Sheet. An exception to this exists in a transitional sedimentary unit, deposited immediately after transgression at the site, and might be related to meltwater pulses associated with the drainage of the Lake Agassiz. The results suggest that the modern mineral and isotopic signature of Mackenzie River sediments may not be a suitable proxy for deglacial meltwater events in far field sedimentary records.

sted, utgiver, år, opplag, sider
Stockholm: Department of Geological Sciences, Stockholm University, 2018. s. 40
Serie
Meddelanden från Stockholms universitets institution för geologiska vetenskaper ; 369
Emneord
paleoenvironmental changes, last deglaciation, sedimentology, Lake Vättern, western Arctic Ocean, Mackenzie Trough, Herald Canyon
HSV kategori
Forskningsprogram
maringeologi
Identifikatorer
urn:nbn:se:su:diva-153906 (URN)978-91-7797-163-4 (ISBN)978-91-7797-164-1 (ISBN)
Disputas
2018-04-27, William-Olssonsalen, Geovetenskapens hus, Svante Arrhenius väg 14, Stockholm, 13:00 (engelsk)
Opponent
Veileder
Merknad

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

Tilgjengelig fra: 2018-04-04 Laget: 2018-03-07 Sist oppdatert: 2025-01-31bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Person

Swärd, HenrikO'Regan, Matt

Søk i DiVA

Av forfatter/redaktør
Swärd, HenrikO'Regan, Matt
Av organisasjonen

Søk utenfor DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric

urn-nbn
Totalt: 136 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf