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An architectural element analysis of a large-scale thrust complex, Kanin Peninsula, NW Russia : interaction between the Barents and Kara Sea ice sheets

Håkansson, Lena (2003) In Dissertations in Geology at Lund University
Department of Geology
Abstract (Swedish)
Den Eurasiska shelfen var under Weichsel istiden täckt av inlandsisar centrerade i Barents och Kara Havet. Kanin Halvön i nordvästra Ryssland upptar en nyckelposition för att registrera de shelfbaserade isarnas passage över till fastlandet. De vidsträckta kvartära blottningarna längs dess nordkust erbjuder en unik möjlighet att studera istäckens fluktuationer och dynamiska beteende.

Denna artikel syftar till att, med hjälp av architektur element analys, undersöka den kvartära lagerföljden längs Kanin Halvöns nordkust. Kustprofilens architektur och sedimentologi är beskriven med tungvikt lagd på de diamikta avlagringarna, vilket har lett till att fyra diamikt element (DE1-4) och tre interbeds (I1-3) har identifierats. Dessa är tolkade... (More)
Den Eurasiska shelfen var under Weichsel istiden täckt av inlandsisar centrerade i Barents och Kara Havet. Kanin Halvön i nordvästra Ryssland upptar en nyckelposition för att registrera de shelfbaserade isarnas passage över till fastlandet. De vidsträckta kvartära blottningarna längs dess nordkust erbjuder en unik möjlighet att studera istäckens fluktuationer och dynamiska beteende.

Denna artikel syftar till att, med hjälp av architektur element analys, undersöka den kvartära lagerföljden längs Kanin Halvöns nordkust. Kustprofilens architektur och sedimentologi är beskriven med tungvikt lagd på de diamikta avlagringarna, vilket har lett till att fyra diamikt element (DE1-4) och tre interbeds (I1-3) har identifierats. Dessa är tolkade som subglacialt bildad morän, avsatt i samband med ett deformations lager och som grundhavs/sjösediment.

Det är föreslaget att den enklaste tolkningen för lagerföljden av morän och sorterade sediment är en repetition av samma moränenhet och dess sorterade underlag, orsakad av glacialtektonik. Det resulterande uppskjutningskomplexet består av stora flak som har rubbats och förflyttats åtminstone 14 km längs med vågräta förkastningsplan. Storleksordningen på dessa förflyttningar är oöverträffad i litteraturen. Modellen för utvecklingen av det beskrivna uppskjutningskomplexet innefattar tre deformationsfaser, varav den första är sammanknippad med avlagringen av moränen som utgör DE1-3, medan den andra och den tredje innefattar uppskjutningsfaser från nordväst respektive nordöst.

Uppskjutningskomplexets architektur tyder på en spröd tektonisk stil, vilket innebär att den mesta av deformationen varit koncentrerad till förkastningsplanen. De nordvästliga deformations riktningarna har blivit relaterade till ett Barents Havs- och de nordöstliga till ett Kara Havs istäcke. Det stratigrafiska bevismaterialet från Kanins nordkust, tillsammans med de nuvarande glaciation modellerna för området, visar på ett dynamiskt samspel mellan enskilda Barents och Kara Havs istäcken under Mellan Weichsel. (Less)
Abstract
During the Weichselian glaciation, ice sheets centred in the Barents and Kara Seas occupied the Eurasian shelf, although their nature and extent have been debated. In NW Russia the Kanin Peninsula occupies a key position for recording the passage of shelf based ice sheets onto the mainland. The extensive Quaternary exposures along its northern coast offer a unique possibility to study ice sheet fluctuations and their dynamic behaviour.

The objective of the present work is to investigate the Quaternary succession at the northern coast of the Kanin Peninsula, using the principles of architectural element analyses. The coastal profile is described regarding to the architecture and sedimentology with emphasis on the diamict sediments,... (More)
During the Weichselian glaciation, ice sheets centred in the Barents and Kara Seas occupied the Eurasian shelf, although their nature and extent have been debated. In NW Russia the Kanin Peninsula occupies a key position for recording the passage of shelf based ice sheets onto the mainland. The extensive Quaternary exposures along its northern coast offer a unique possibility to study ice sheet fluctuations and their dynamic behaviour.

The objective of the present work is to investigate the Quaternary succession at the northern coast of the Kanin Peninsula, using the principles of architectural element analyses. The coastal profile is described regarding to the architecture and sedimentology with emphasis on the diamict sediments, leading to the identification of four Diamict elements (DE1-4) and three interbeds (I1-3) in superposition. These are interpreted as basal tills deposited in association with a deforming bed and as shallow marine/lacustrine sediments.

It is suggested that the simplest interpretation of the succession of till and interbeds is a glaciotectonically induced repetition of the same till unit and its sorted substratum. The resulting thrust complex is constituted by large nappes, which have been dislocated at least 14 km along subhorizontal thrust planes, indicating a scale of glaciotectonism that is unprecedented in the literature. The sequential model for the tectonic development includes three deformation events. The first one is associated with the deposition of the till constituting DE1-3 and the second and the third with thrusting events from NW and NE respectively. The architecture of the thrust complex indicates a brittle tectonic style implying that most of the deformation was concentrated along major thrust planes. It is suggested that the fine grained till constituting DE1-3 allowed build-up of high water pressures at its base reducing the friction along the décollment horizon. The NW directions are related to a Barents- and the NE to a Kara Sea ice sheet. Substantiated by current glaciation models, the stratigraphic evidence from the present study indicates a major glaciotectonic event revealing a dynamic interaction between individual Barents and Kara Sea ice sheets probably during the Middle Weichselian. (Less)
Please use this url to cite or link to this publication:
author
Håkansson, Lena
supervisor
organization
alternative title
En architektur element analys av ett storskaligt uppskjutningskomplex, Kanin halvön, nordvästra Ryssland : samspel mellan Barents- och Kara havs istäcken
year
type
H1 - Master's Degree (One Year)
subject
keywords
glaciotectonism, architectural element analyses, large-scale thrust complexes, basal tills, NW Russia
publication/series
Dissertations in Geology at Lund University
report number
162
funder
Crafoord Foundation
funder
The Swedish Polar Secretariat
funder
Lund university
funder
Danish Natural Science Research Council
language
English
id
2342797
date added to LUP
2012-12-06 11:34:47
date last changed
2012-12-06 11:37:33
@misc{2342797,
  abstract     = {During the Weichselian glaciation, ice sheets centred in the Barents and Kara Seas occupied the Eurasian shelf, although their nature and extent have been debated. In NW Russia the Kanin Peninsula occupies a key position for recording the passage of shelf based ice sheets onto the mainland. The extensive Quaternary exposures along its northern coast offer a unique possibility to study ice sheet fluctuations and their dynamic behaviour.

The objective of the present work is to investigate the Quaternary succession at the northern coast of the Kanin Peninsula, using the principles of architectural element analyses. The coastal profile is described regarding to the architecture and sedimentology with emphasis on the diamict sediments, leading to the identification of four Diamict elements (DE1-4) and three interbeds (I1-3) in superposition. These are interpreted as basal tills deposited in association with a deforming bed and as shallow marine/lacustrine sediments. 

It is suggested that the simplest interpretation of the succession of till and interbeds is a glaciotectonically induced repetition of the same till unit and its sorted substratum. The resulting thrust complex is constituted by large nappes, which have been dislocated at least 14 km along subhorizontal thrust planes, indicating a scale of glaciotectonism that is unprecedented in the literature. The sequential model for the tectonic development includes three deformation events. The first one is associated with the deposition of the till constituting DE1-3 and the second and the third with thrusting events from NW and NE respectively. The architecture of the thrust complex indicates a brittle tectonic style implying that most of the deformation was concentrated along major thrust planes. It is suggested that the fine grained till constituting DE1-3 allowed build-up of high water pressures at its base reducing the friction along the décollment horizon. The NW directions are related to a Barents- and the NE to a Kara Sea ice sheet. Substantiated by current glaciation models, the stratigraphic evidence from the present study indicates a major glaciotectonic event revealing a dynamic interaction between individual Barents and Kara Sea ice sheets probably during the Middle Weichselian.},
  author       = {Håkansson, Lena},
  keyword      = {glaciotectonism,architectural element analyses,large-scale thrust complexes,basal tills,NW Russia},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {An architectural element analysis of a large-scale thrust complex, Kanin Peninsula, NW Russia : interaction between the Barents and Kara Sea ice sheets},
  year         = {2003},
}