SGU Research Paper C 838 Research Paper C 838 Plains, steps, hilly relief and valleys in northern Sweden – review, interpretations and implications for conclusions on Phanerozoic tectonics Karna Lidmar-Bergström & Mats Olvmo Plains, steps, hilly relief and valleys in northern Sweden interpretations – review, and implications for implications and conclusions on conclusions Phanerozoic tectonics Phanerozoic C 838 Plains, steps, hilly relief and valleys in northern Sweden – review, interpretations and implications for conclusions on Phanerozoic tectonics Karna Lidmar-Bergström & Mats Olvmo Sveriges geologiska undersökning 2015 ISSN 1103-3371 ISBN 978-91-7403-308-3 Cover: Hilly relief, west of Borlänge, surrounding the confluence of Västerdalälven and Österdalälven. Map construction: Mats Olvmo. Data sources: GSD-Elevation data, Grid 2+ and GSD-Terrängkartan from Lantmäteriet. © Sveriges geologiska undersökning Layout: Jeanette Bergman Weihed, SGU Tryck: Elanders Sverige AB, 2015 Innehåll Abstract .............................................................................................................................................................. 5 Introduction ..................................................................................................................................................... 6 Bedrock and glaciation ................................................................................................................................. 7 Overview of relief types .............................................................................................................................. 8 Discovery, mapping and interpretation of relief types ................................................................... 8 Sten De Geer 1926 ........................................................................................................................................... 8 Sten Rudberg 1960 and 1970 ......................................................................................................................... 9 Christian Elvhage & Karna Lidmar-Bergström 1987 ............................................................................. 10 S. Rudberg 1988 ............................................................................................................................................... 12 The relation landform – rock type (1) .................................................................................................. 12 Rock structure and landscape (2) .......................................................................................................... 12 Erosion surfaces (4) .................................................................................................................................... 12 Climatic geomorphology (5) ................................................................................................................... 12 Glacial erosion (6) ...................................................................................................................................... 12 K. Lidmar-Bergström 1994, 1995 and 1996 ............................................................................................... 13 The sub-Cambrian peneplain and further relief classification ...................................................... 13 The importance of former covers in preserving relief ...................................................................... 13 Origin of “plains with residual hills” .................................................................................................... 15 K. Lidmar-Bergström 1999 ............................................................................................................................ 17 Relief differentiation, causes and implications ................................................................................... 17 The differential uplift of the Scandinavian mountains ................................................................... 18 Karin Ebert, Adrian M. Hall & Clas Hättestrand 2012a: Shaping of inselbergs ........................... 18 Stepped peneplains ....................................................................................................................................... 18 Observations and ideas on stepped peneplains in the classical international discussion .............. 18 Stepped peneplains and valleys in northern Sweden – a review .......................................................... 19 Walter Wråk 1908 ..................................................................................................................................... 19 John Frödin 1914 ........................................................................................................................................ 20 Gustav Braun 1935 ..................................................................................................................................... 20 Hans W. Ahlmann, Erik Laurell & Carl Mannerfeldt 1942 .......................................................... 20 S. Rudberg 1954 .......................................................................................................................................... 20 S. Rudberg 1970 .......................................................................................................................................... 21 K. Lidmar-Bergström 1994, 1996 ........................................................................................................... 21 K. Lidmar-Bergström, Jens-Ove Näslund, K. Ebert, Truls Neubeck & Johan M. Bonow 2007 ........................................................................................... 21 K. Ebert, C. Hättestrand, A. Hall & Göran Alm 2011 .................................................................... 22 Fluvial valleys and their implications ..................................................................................................... 22 Sven Norlindh 1924 ......................................................................................................................................... 22 S. Rudberg 1988 ................................................................................................................................................ 22 K. Lidmar-Bergström 1996 ............................................................................................................................ 25 Valley patterns ............................................................................................................................................. 25 Suggested river deflections ...................................................................................................................... 26 Relief and the effect of glacial erosion .................................................................................................. 27 Peneplains and glacial erosion ....................................................................................................................... 27 Valleys and glacial erosion .............................................................................................................................. 27 Glacial erosion in general ............................................................................................................................... 28 Discussion .......................................................................................................................................................... 31 Relief development in relation to weathering in different climates and structure .......................... 31 Deep weathering – an important factor in relief formation even in a formerly glaciated area ........................................................................................ 31 Undulating hilly relief ............................................................................................................................. 31 Plains with residual hills (inselberg plains) ......................................................................................... 31 Relief preservation below remnant covers and its tectonic implications ........................................... 32 Significance and correlation of peneplains (stepped and re-exposed) ............................................... 33 Major peneplains: summary .................................................................................................................... 33 The faulted sub-Cambrian peneplain .................................................................................................. 33 Correlations of stepped peneplains in northern Lapland ................................................................ 33 Inclined or horizontal peneplain steps ................................................................................................ 34 Differential tectonic uplift and correlation of stepped peneplains ............................................... 34 Crosscutting relationships ....................................................................................................................... 35 Implications of valleys for conclusions on tectonics and glacial erosion ............................................ 35 Valleys and water gaps along the Bothnian coast in relation to tectonics constrained by the sub-Cambrian peneplain .......................................... 35 Influence of the glaciations on some water gaps ...............................................................................