Micromorphology of modern tills in southwestern Spitsbergen – insights into depositional and post-depositional processes
Textural properties and microstructures are commonly used properties in the analysis of Pleistocene and older glacial deposits. However, contemporary glacial deposits are seldom studied, particularly in the context of post-depositional changes. This paper presents the results of a micromorphological...
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Polish Academy of Sciences
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ftdoajarticles:oai:doaj.org/article:27eaf5854dd04d1f9616940281721464 2023-05-15T15:12:06+02:00 Micromorphology of modern tills in southwestern Spitsbergen – insights into depositional and post-depositional processes Skolasińska Katarzyna Rachlewicz Grzegorz Szczuciński Witold 2016-12-01T00:00:00Z https://doi.org/10.1515/popore-2016-0023 https://doaj.org/article/27eaf5854dd04d1f9616940281721464 EN eng Polish Academy of Sciences http://www.degruyter.com/view/j/popore.2016.37.issue-4/popore-2016-0023/popore-2016-0023.xml?format=INT https://doaj.org/toc/2081-8262 2081-8262 doi:10.1515/popore-2016-0023 https://doaj.org/article/27eaf5854dd04d1f9616940281721464 Polish Polar Research, Vol 37, Iss 4, Pp 435-456 (2016) Arctic Svalbard subglacial till supraglacial till microstructures postdepositional changes Geology QE1-996.5 article 2016 ftdoajarticles https://doi.org/10.1515/popore-2016-0023 2022-12-31T09:35:55Z Textural properties and microstructures are commonly used properties in the analysis of Pleistocene and older glacial deposits. However, contemporary glacial deposits are seldom studied, particularly in the context of post-depositional changes. This paper presents the results of a micromorphological study of recently deposited tills in the marginal zones of Hansbreen and Torellbreen, glaciers in southwestern Spitsbergen. The main objectives of this study were to compare modern tills deposited in subglacial and supraglacial conditions, as well as tills that were freshly released from ice with those laid down several decades ago. The investigated tills are primarily composed of large clasts of metamorphic rocks and represent coarse-grained, matrix-supported diamictons. The tills reveal several characteristic features for ductile (e.g. turbate structures) and brittle (e.g. lineations, microshears) deformations, which have been considered to be indicative of subglacial conditions. In supraglacial tills, the same structures are common as in the subglacial deposits, which points to the preservation of the primary features, though the sediment was transferred up to the glacier surface due to basal ice layer deformation and redeposited as slumps, or to formation of similar structures due to short-distance sediment re-deposition by mass flows. This study revealed that it might not be possible to distinguish subglacial and supraglacial tills on the basis of micromorphology if the latter are derived from a subglacial position. The only noted difference was the presence of iron oxide cementation zones and carbonate dissolution features in supraglacial tills. These features were found in tills that were deposited at least a few years ago and are interpreted to be induced by early post-depositional processes involving porewater/sediment interactions. Article in Journal/Newspaper Arctic glacier Polar Research Svalbard Spitsbergen Directory of Open Access Journals: DOAJ Articles Arctic Svalbard Hansbreen ENVELOPE(15.650,15.650,77.075,77.075) Torellbreen ENVELOPE(14.863,14.863,77.179,77.179) Polish Polar Research 37 4 435 456 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Arctic Svalbard subglacial till supraglacial till microstructures postdepositional changes Geology QE1-996.5 |
spellingShingle |
Arctic Svalbard subglacial till supraglacial till microstructures postdepositional changes Geology QE1-996.5 Skolasińska Katarzyna Rachlewicz Grzegorz Szczuciński Witold Micromorphology of modern tills in southwestern Spitsbergen – insights into depositional and post-depositional processes |
topic_facet |
Arctic Svalbard subglacial till supraglacial till microstructures postdepositional changes Geology QE1-996.5 |
description |
Textural properties and microstructures are commonly used properties in the analysis of Pleistocene and older glacial deposits. However, contemporary glacial deposits are seldom studied, particularly in the context of post-depositional changes. This paper presents the results of a micromorphological study of recently deposited tills in the marginal zones of Hansbreen and Torellbreen, glaciers in southwestern Spitsbergen. The main objectives of this study were to compare modern tills deposited in subglacial and supraglacial conditions, as well as tills that were freshly released from ice with those laid down several decades ago. The investigated tills are primarily composed of large clasts of metamorphic rocks and represent coarse-grained, matrix-supported diamictons. The tills reveal several characteristic features for ductile (e.g. turbate structures) and brittle (e.g. lineations, microshears) deformations, which have been considered to be indicative of subglacial conditions. In supraglacial tills, the same structures are common as in the subglacial deposits, which points to the preservation of the primary features, though the sediment was transferred up to the glacier surface due to basal ice layer deformation and redeposited as slumps, or to formation of similar structures due to short-distance sediment re-deposition by mass flows. This study revealed that it might not be possible to distinguish subglacial and supraglacial tills on the basis of micromorphology if the latter are derived from a subglacial position. The only noted difference was the presence of iron oxide cementation zones and carbonate dissolution features in supraglacial tills. These features were found in tills that were deposited at least a few years ago and are interpreted to be induced by early post-depositional processes involving porewater/sediment interactions. |
format |
Article in Journal/Newspaper |
author |
Skolasińska Katarzyna Rachlewicz Grzegorz Szczuciński Witold |
author_facet |
Skolasińska Katarzyna Rachlewicz Grzegorz Szczuciński Witold |
author_sort |
Skolasińska Katarzyna |
title |
Micromorphology of modern tills in southwestern Spitsbergen – insights into depositional and post-depositional processes |
title_short |
Micromorphology of modern tills in southwestern Spitsbergen – insights into depositional and post-depositional processes |
title_full |
Micromorphology of modern tills in southwestern Spitsbergen – insights into depositional and post-depositional processes |
title_fullStr |
Micromorphology of modern tills in southwestern Spitsbergen – insights into depositional and post-depositional processes |
title_full_unstemmed |
Micromorphology of modern tills in southwestern Spitsbergen – insights into depositional and post-depositional processes |
title_sort |
micromorphology of modern tills in southwestern spitsbergen – insights into depositional and post-depositional processes |
publisher |
Polish Academy of Sciences |
publishDate |
2016 |
url |
https://doi.org/10.1515/popore-2016-0023 https://doaj.org/article/27eaf5854dd04d1f9616940281721464 |
long_lat |
ENVELOPE(15.650,15.650,77.075,77.075) ENVELOPE(14.863,14.863,77.179,77.179) |
geographic |
Arctic Svalbard Hansbreen Torellbreen |
geographic_facet |
Arctic Svalbard Hansbreen Torellbreen |
genre |
Arctic glacier Polar Research Svalbard Spitsbergen |
genre_facet |
Arctic glacier Polar Research Svalbard Spitsbergen |
op_source |
Polish Polar Research, Vol 37, Iss 4, Pp 435-456 (2016) |
op_relation |
http://www.degruyter.com/view/j/popore.2016.37.issue-4/popore-2016-0023/popore-2016-0023.xml?format=INT https://doaj.org/toc/2081-8262 2081-8262 doi:10.1515/popore-2016-0023 https://doaj.org/article/27eaf5854dd04d1f9616940281721464 |
op_doi |
https://doi.org/10.1515/popore-2016-0023 |
container_title |
Polish Polar Research |
container_volume |
37 |
container_issue |
4 |
container_start_page |
435 |
op_container_end_page |
456 |
_version_ |
1766342841039060992 |