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Equifinality in glacial geomorphology: instability theory examined via ribbed moraine and drumlins in Sweden

Möller, Per LU and Dowling, Thomas LU (2018) In GFF 140(2). p.106-135
Abstract
A contemporary trend in glacial geomorphology is the quest for a unifying theory of drumlin and ribbed moraine formation. Three Swedish example areas of each are here newly mapped, using high-resolution Light Detecting and Ranging (LiDAR) data. From previous ribbed moraine studies in these areas, we know that they formed differently, one by melt-out of stagnant debris-zonated ice, another by remoulding of pre-existing landforms and the third by active subglacial stacking and folding of sediment into proto ridges, contemporaneously with lee-side cavity sediment infill. Through previous work on streamlined terrain in Sweden we know that rock-cored drumlins dominate, while soft-cored drumlins are much less common. The morphology of both... (More)
A contemporary trend in glacial geomorphology is the quest for a unifying theory of drumlin and ribbed moraine formation. Three Swedish example areas of each are here newly mapped, using high-resolution Light Detecting and Ranging (LiDAR) data. From previous ribbed moraine studies in these areas, we know that they formed differently, one by melt-out of stagnant debris-zonated ice, another by remoulding of pre-existing landforms and the third by active subglacial stacking and folding of sediment into proto ridges, contemporaneously with lee-side cavity sediment infill. Through previous work on streamlined terrain in Sweden we know that rock-cored drumlins dominate, while soft-cored drumlins are much less common. The morphology of both types varies along a continuum, whereas their processes of formation differ. Our field examples from ribbed moraine tracts and streamlined terrain suggest that the subglacial environment contains a suite of different ice-sediment physics that, irrespective of this, leads to an equifinality of shape of some subglacial landforms (ribbed moraine and streamlined terrain) despite the differences in the detail of their process of formation. We thus argue that different processes, on their own or in combination, lead to a similar form of morphometric expression, that is, equifinality, and the quest for a unifying process of formation is a misleading one. Furthermore, we argue that large morphological data sets of subglacial landforms can only be used to classify features as part of a formation continuum – or not – when they are used in conjunction with the sedimentology of said landforms.
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author
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organization
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type
Contribution to journal
publication status
published
subject
in
GFF
volume
140
issue
2
pages
31 pages
publisher
Taylor & Francis
external identifiers
  • scopus:85047141658
ISSN
2000-0863
DOI
10.1080/11035897.2018.1441903
project
Sub-till sediments on the Småland peneplain - their age and implication for glacial stratigraphy and glacial dynamics in South Sweden
Drumlin formation in south Sweden
language
English
LU publication?
yes
id
504cb21b-7b62-481b-9280-086690a9c826
date added to LUP
2017-11-30 16:57:06
date last changed
2020-10-07 05:37:13
@article{504cb21b-7b62-481b-9280-086690a9c826,
  abstract     = {A contemporary trend in glacial geomorphology is the quest for a unifying theory of drumlin and ribbed moraine formation.  Three Swedish example areas of each are here newly mapped, using high-resolution Light Detecting and Ranging (LiDAR) data. From previous ribbed moraine studies in these areas, we know that they  formed differently, one by melt-out of stagnant debris-zonated ice, another by remoulding of pre-existing landforms and the third by active subglacial stacking and folding of sediment into proto ridges, contemporaneously with lee-side cavity sediment infill. Through previous work on streamlined terrain in Sweden we know that rock-cored drumlins dominate, while soft-cored drumlins are much less common. The morphology of both types varies along a continuum, whereas their processes of formation differ. Our field examples from ribbed moraine tracts and streamlined terrain suggest that the subglacial environment contains a suite of different ice-sediment physics that, irrespective of this, leads to an equifinality of shape of some subglacial landforms (ribbed moraine and streamlined terrain) despite the differences in the detail of their process of formation. We thus argue that different processes, on their own or in combination, lead to a similar form of morphometric expression, that is, equifinality, and  the quest for a unifying process of formation is a misleading one. Furthermore, we argue that large morphological data sets of subglacial landforms can only be used to classify features as part of a formation continuum – or not – when they are used in conjunction with the sedimentology of said landforms.<br/>},
  author       = {Möller, Per and Dowling, Thomas},
  issn         = {2000-0863},
  language     = {eng},
  month        = {05},
  number       = {2},
  pages        = {106--135},
  publisher    = {Taylor & Francis},
  series       = {GFF},
  title        = {Equifinality in glacial geomorphology: instability theory examined via ribbed moraine and drumlins in Sweden},
  url          = {http://dx.doi.org/10.1080/11035897.2018.1441903},
  doi          = {10.1080/11035897.2018.1441903},
  volume       = {140},
  year         = {2018},
}