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Titre du document / Document title

Inherited landforms and glacial impact of different palaeosurfaces in Southwest Sweden

Auteur(s) / Author(s)

JOHANSSON Magnus (1) ; OLVMO Mats (2) ; LIDMAR-BERGSTRÖM Karna (3) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Department of Earth Science and Geography, Karlstad University, Karlstad, SUEDE
(2) Department of Physical Geography, Göteborg University, Göteborg, SUEDE
(3) Department of Physical Geography, Stockholm University, Stockholm, SUEDE

Résumé / Abstract

Landforms are used as analytical tools to separate inherited features from the glacial impact on Precambrian basement rocks in southwest Sweden. The study covers three different palaeosurfaces, the sub-Cambrian peneplain (relative relief (r.r.) 0-20 m) with the character of a pediplain, an uplifted and dissected part of the sub-Cambrian peneplain (r.r. 5-40 m) and an etch-surface (r.r. 20-135 m), presumably sub-Mesozoic. The surfaces were recently re-exposed, probably due to a Neogene upheaval with some pre-glacial reshaping. Strong structural control and no alignment with glacial erosional directions other than those coinciding with structures, are arguments for etch processes as a most important agent for relief differentiation. This is strengthened by the occurrence of saprolite residues and etchforms in protected positions. The glacial reshaping of the sub-Cambrian flat bedrock surfaces is negligible. The glacial impact becomes more evident in the uplifted and dissected parts of the peneplain and within the hilly sub-Mesozoic surface. The higher the initial relief the more effect of glacial erosion on individual hills, both on the abrading side, with formation of roches moutonnées, and on the plucking side. Detailed etchforms are preserved in protected positions in spite of erosion by a clearly wet-based ice. The magnitude of the Pleistocene glacial erosion is considerably less than the amplitude of the palaeorelief in the entire area. Landscapes of areal glacial scouring have been described as comprising irregular depressions with intervening bosses scraped by ice and labelled 'knock and lochan' topography, but we suggest that an etched bedrock surface is a prerequisite for this type of landscape to develop.

Revue / Journal Title

Geografiska annaler. Series A. Physical geography    ISSN  0435-3676   CODEN GAPGAP 

Source / Source

2001, vol. 83, no1-2, pp. 67-89 (1 p.1/2)

Langue / Language

Anglais

Editeur / Publisher

Svenska sällskapet för antropologi och geografi, Stockholm, SUEDE  (1965) (Revue)

Mots-clés anglais / English Keywords

igneous rocks

;

plutonic rocks

;

Phanerozoic

;

Cenozoic

;

Europe

;

Scandinavia

;

granites

;

peneplains

;

topographic maps

;

ice movement

;

basement

;

Pleistocene

;

glacial erosion

;

Quaternary

;

environment impact

;

glacial periods

;

landform evolution

;

landforms

;

Sweden

;

Mots-clés français / French Keywords

Roche ignée

;

Roche plutonique

;

Phanérozoïque

;

Cénozoïque

;

Europe

;

Scandinavie

;

Granite

;

Pénéplaine

;

Carte topographique

;

Mouvement glace

;

Socle

;

Pléistocène

;

Erosion glaciaire

;

Quaternaire

;

Impact environnement

;

Période glaciaire

;

Morphodynamique

;

Forme relief

;

Suède

;

Mots-clés espagnols / Spanish Keywords

Roca ignea

;

Roca granuda

;

Fanerozoico

;

Cenozoico

;

Europa

;

Granito

;

Penillanura

;

Plano topográfico

;

Movimiento hielo

;

Basamento

;

Erosión glaciar

;

Cuaternario

;

Período glaciario

;

Morfodinámica

;

Suecia

;

Localisation / Location

INIST-CNRS, Cote INIST : 2704 A, 35400009845570.0060

Nº notice refdoc (ud4) : 14156275



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