Insights into glacial processes from micromorphology of silt-sized sediment
Meltwater plume deposits (MPDs) from marine sediment cores have elucidated clearly connected, yet difficult to constrain, relationships between ice-marginal landform construction, grounding-zone retreat patterns, and subglacial hydrology for several glacial systems in both hemispheres. Few attempts...
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fttexasamucorpus:oai:tamucc-ir.tdl.org:1969.6/98052 2024-05-12T08:11:58+00:00 Insights into glacial processes from micromorphology of silt-sized sediment Lepp, Allison P. Miller, Lauren E. Anderson, John B. O'Regan, Matt Winsborrow, Monica C.M. Smith, James A. Hillenbrand, Claus-Dieter Wellner, Julia S. Prothro, Lindsay O. Podolskiy, Evgeny A. 2023-06-20 application/pdf https://hdl.handle.net/1969.6/98052 https://doi.org/10.5194/tc-2023-70 en_US eng Lepp, A. P., Miller, L. E., Anderson, J. B., O'Regan, M., Winsborrow, M. C. M., Smith, J. A., Hillenbrand, C.-D., Wellner, J. S., Prothro, L. O., and Podolskiy, E. A.: Insights into glacial processes from micromorphology of silt-sized sediment, The Cryosphere Discuss. [preprint], https://doi.org/10.5194/tc-2023-70, in review, 2023. https://hdl.handle.net/1969.6/98052 https://doi.org/10.5194/tc-2023-70 CC BY 4.0 DEED Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ sediment meltwater plume deposits (MPDs) micromorphology Article 2023 fttexasamucorpus https://doi.org/10.5194/tc-2023-70 2024-04-14T23:49:23Z Meltwater plume deposits (MPDs) from marine sediment cores have elucidated clearly connected, yet difficult to constrain, relationships between ice-marginal landform construction, grounding-zone retreat patterns, and subglacial hydrology for several glacial systems in both hemispheres. Few attempts have been made, however, to infer coveted details of subglacial hydrology, such as flow regime, drainage style, and mode(s) of sediment transport through time from grain-scale characteristics of MPDs. Using MPD, till, and ice-proximal diamicton samples collected offshore of six modern and relict glacial systems in both hemispheres, we examine whether grain-shape distributions and microtexture assemblages (collectively, grain micromorphology) of the silt fraction are the result of subglacial meltwater action, or are indistinguishable from glacial proximal and subglacial sediments from the same region. We find that of all grains imaged (n=9,400), three-quarters can be described by one-quarter of the full range of measured shape morphometrics, indicating widespread and efficient abrasive processes in subglacial environments. Microtexture analysis reveals that while grains comprising MPDs show evidence of edge rounding more often than tills, fluvial microtextures occur in modest amounts on grain surfaces. Furthermore, MPDs retain many mechanical (i.e., glacial) textures in comparable abundances to tills. Significant alteration of MPDs from till sources is observed for systems (1) for which intensive, potentially catastrophic, meltwater drainage events in the Holocene are inferred from marine geologic records, and (2) with comparatively less mature till grains and a contribution of supraglacial melt to the bed, indicating that quantifiable grain-shape alteration of MPDs may reflect a combination of young till, high-energy flow of subglacial meltwater, persistent sediment entrainment, and/or long sediment transport distances. We encourage future works to integrate grain micromorphology into site-specific marine sediment ... Article in Journal/Newspaper The Cryosphere Texas A&M University - Corpus Christi: DSpace Repository |
institution |
Open Polar |
collection |
Texas A&M University - Corpus Christi: DSpace Repository |
op_collection_id |
fttexasamucorpus |
language |
English |
topic |
sediment meltwater plume deposits (MPDs) micromorphology |
spellingShingle |
sediment meltwater plume deposits (MPDs) micromorphology Lepp, Allison P. Miller, Lauren E. Anderson, John B. O'Regan, Matt Winsborrow, Monica C.M. Smith, James A. Hillenbrand, Claus-Dieter Wellner, Julia S. Prothro, Lindsay O. Podolskiy, Evgeny A. Insights into glacial processes from micromorphology of silt-sized sediment |
topic_facet |
sediment meltwater plume deposits (MPDs) micromorphology |
description |
Meltwater plume deposits (MPDs) from marine sediment cores have elucidated clearly connected, yet difficult to constrain, relationships between ice-marginal landform construction, grounding-zone retreat patterns, and subglacial hydrology for several glacial systems in both hemispheres. Few attempts have been made, however, to infer coveted details of subglacial hydrology, such as flow regime, drainage style, and mode(s) of sediment transport through time from grain-scale characteristics of MPDs. Using MPD, till, and ice-proximal diamicton samples collected offshore of six modern and relict glacial systems in both hemispheres, we examine whether grain-shape distributions and microtexture assemblages (collectively, grain micromorphology) of the silt fraction are the result of subglacial meltwater action, or are indistinguishable from glacial proximal and subglacial sediments from the same region. We find that of all grains imaged (n=9,400), three-quarters can be described by one-quarter of the full range of measured shape morphometrics, indicating widespread and efficient abrasive processes in subglacial environments. Microtexture analysis reveals that while grains comprising MPDs show evidence of edge rounding more often than tills, fluvial microtextures occur in modest amounts on grain surfaces. Furthermore, MPDs retain many mechanical (i.e., glacial) textures in comparable abundances to tills. Significant alteration of MPDs from till sources is observed for systems (1) for which intensive, potentially catastrophic, meltwater drainage events in the Holocene are inferred from marine geologic records, and (2) with comparatively less mature till grains and a contribution of supraglacial melt to the bed, indicating that quantifiable grain-shape alteration of MPDs may reflect a combination of young till, high-energy flow of subglacial meltwater, persistent sediment entrainment, and/or long sediment transport distances. We encourage future works to integrate grain micromorphology into site-specific marine sediment ... |
format |
Article in Journal/Newspaper |
author |
Lepp, Allison P. Miller, Lauren E. Anderson, John B. O'Regan, Matt Winsborrow, Monica C.M. Smith, James A. Hillenbrand, Claus-Dieter Wellner, Julia S. Prothro, Lindsay O. Podolskiy, Evgeny A. |
author_facet |
Lepp, Allison P. Miller, Lauren E. Anderson, John B. O'Regan, Matt Winsborrow, Monica C.M. Smith, James A. Hillenbrand, Claus-Dieter Wellner, Julia S. Prothro, Lindsay O. Podolskiy, Evgeny A. |
author_sort |
Lepp, Allison P. |
title |
Insights into glacial processes from micromorphology of silt-sized sediment |
title_short |
Insights into glacial processes from micromorphology of silt-sized sediment |
title_full |
Insights into glacial processes from micromorphology of silt-sized sediment |
title_fullStr |
Insights into glacial processes from micromorphology of silt-sized sediment |
title_full_unstemmed |
Insights into glacial processes from micromorphology of silt-sized sediment |
title_sort |
insights into glacial processes from micromorphology of silt-sized sediment |
publishDate |
2023 |
url |
https://hdl.handle.net/1969.6/98052 https://doi.org/10.5194/tc-2023-70 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_relation |
Lepp, A. P., Miller, L. E., Anderson, J. B., O'Regan, M., Winsborrow, M. C. M., Smith, J. A., Hillenbrand, C.-D., Wellner, J. S., Prothro, L. O., and Podolskiy, E. A.: Insights into glacial processes from micromorphology of silt-sized sediment, The Cryosphere Discuss. [preprint], https://doi.org/10.5194/tc-2023-70, in review, 2023. https://hdl.handle.net/1969.6/98052 https://doi.org/10.5194/tc-2023-70 |
op_rights |
CC BY 4.0 DEED Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.5194/tc-2023-70 |
_version_ |
1798834212199989248 |