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Glacial Processes and Landforms

Evans, D.J.A.; Evans, I.S.

Authors

I.S. Evans



Contributors

T.P. Burt
Editor

A.S. Goudie
Editor

H.A. Viles
Editor

Abstract

From 1965 to 2000 glacial geomorphology became increasingly specialized and developed significantly due to technological improvements, particularly in remote sensing, surveying and field-based glaciological process studies. The better understanding of basal thermal regimes in ice sheets and glaciers led to the development of concepts such as spatial and temporal migration of ice divides in dynamic ice sheets that could overprint subglacial landform assemblages, debris entrainment processes related to polythermal glacier systems, and glacier and ice sheet beds composed of cold and warm based mosaics. Process observations at the ice–bed interface led to the discovery of the third glacier flow mechanism, substrate deformation, which provided the impetus to reconstruct the genesis of subglacial bedforms such as drumlins and to evaluate the origins and potential flow law for till. Numerical evaluations of glacial erosion led to a better understanding of abrasion and quarrying as well as the erection of genetic models and erosion rates for larger-scale features such as U-shaped valleys and cirques. Linkages were made between debris transport pathways and moraine construction in supraglacial environments, with the role of glacier structure being linked to specific landforms, such as medial, lateral, hummocky and ice-cored moraines as well as rock glaciers. Our appreciation of the erosional and depositional impacts of glacifluvial systems was enhanced significantly with the advent of process observations on the hydrology of modern glaciers as well as the final vindication of J.H. Bretz and his proposed jökulhlaup origins of the Channelled Scablands and the Missoula Floods. In addition to the increasing numbers of studies at modern glacier snouts, the embracing of sedimentology by glacial geomorphologists was to result in significant developments in understanding the process-form regimes of subglacial, marginal and proglacial landforms, particularly the recognition of landform continua and hybrids. Advances resulting from this included the recognition of different modes of moraine and glacitectonic thrust mass development, lithofacies models of the varied glacifluvial depositional environments, and the initial expansion of work on the sediments and depocentres of glacimarine settings, the latter being the result of glacial research taking to submersibles and ice-strengthened ships for the first time. A similarly new frontier was the expansion of research on the increasingly higher resolution images returning from Mars, where extraterrestrial glaciations were recognized based on comparisons with Earth analogues. Holistic appreciations of glaciation signatures using landform assemblages were developed, initially as processform models and later as glacial landsystems, providing an ever-expanding set of templates for reconstructing palaeoglaciology in the wide variety of topographic and environmental settings, which also acknowledge spatial and temporal change in glacier and ice sheet systems.

Citation

Evans, D., & Evans, I. (2022). Glacial Processes and Landforms. In T. Burt, A. Goudie, & H. Viles (Eds.), The History of the Study of Landforms or the Development of Geomorphology. Volume 5: Geomorphology in the Second Half of the Twentieth Century (333-377). The Geological Society. https://doi.org/10.1144/m58-2021-17

Publication Date Oct 20, 2022
Deposit Date Feb 18, 2022
Publisher The Geological Society
Pages 333-377
Series Title GSL Memoirs
Series Number 58
Book Title The History of the Study of Landforms or the Development of Geomorphology. Volume 5: Geomorphology in the Second Half of the Twentieth Century
DOI https://doi.org/10.1144/m58-2021-17
Publisher URL https://www.geolsoc.org.uk/M0058
Additional Information Co-published with British Society for Geomorphology Url of publication in Lyell Collection https://doi.org.10.1144/M58-2021-17