<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Fast moving palaeo-ice masses within the European Alpine Ice Cap (EAIC) during the Last Glacial Maximum within the large valleys of the European Alps are likely comparable in terms of their subglacial conditions to ice streams that drained the larger Quaternary Ice Sheets in Europe and North America. Unlike these continental-style ice sheets, the ice inundating the European Alps, like the Cordilleran Ice Sheet in North America, flowed through confined bedrock valleys that, at close to the glacial maximum, acted in a similar manner to ice streams. Little mention exists as to the extent of soft sediment basal deformation in these deep valleys although increasingly such conditions are known from several parts of the EAIC. The Drau (Drava) ice stream during the Alpine Last Glacial Maximum (= Würmian Pleniglacial, ~ 29 – ~20 ka) as well as small tributary glacier during the early Lateglacial phase of ice decay (~20 – 19 ka) appears as a temperate, fast-moving ice mass that would likely be underlain by soft deforming sediment. It is the underlying microsedimentology of parts of the Drau Valley catchment in the Lienz area of Austria that is the focus of this paper. The tills in the Isel Valley at Ainet reveal a detailed depiction of soft sediment deformation processes throughout the basal zones of this ice stream illustrative of temperate basal ice conditions and comparable to those tills of northern Austria under the Inn Ice Stream. The tills exhibit the characteristics of ongoing active soft-sediment deformation. The evidence from Ainet supports the contention that most likely subglacial processes beneath ice streams in the palaeo-EAIC were comparable to those today in Antarctica and in the Quaternary ice streams of the Cordilleran, Laurentide and North European Ice Sheets.</p></abstract>

Fast moving palaeo-ice masses within the European Alpine Ice Cap (EAIC) during the Last Glacial Maximum within the large valleys of the European Alps are likely comparable in terms of their subglacial conditions to ice streams that drained the larger Quaternary Ice Sheets in Europe and North America. Unlike these continental-style ice sheets, the ice inundating the European Alps, like the Cordilleran Ice Sheet in North America, flowed through confined bedrock valleys that, at close to the glacial maximum, acted in a similar manner to ice streams. Little mention exists as to the extent of soft sediment basal deformation in these deep valleys although increasingly such conditions are known from several parts of the EAIC. The Drau (Drava) ice stream during the Alpine Last Glacial Maximum (= Würmian Pleniglacial, ~ 29 – ~20 ka) as well as small tributary glacier during the early Lateglacial phase of ice decay (~20 – 19 ka) appears as a temperate, fast-moving ice mass that would likely be underlain by soft deforming sediment. It is the underlying microsedimentology of parts of the Drau Valley catchment in the Lienz area of Austria that is the focus of this paper. The tills in the Isel Valley at Ainet reveal a detailed depiction of soft sediment deformation processes throughout the basal zones of this ice stream illustrative of temperate basal ice conditions and comparable to those tills of northern Austria under the Inn Ice Stream. The tills exhibit the characteristics of ongoing active soft-sediment deformation. The evidence from Ainet supports the contention that most likely subglacial processes beneath ice streams in the palaeo-EAIC were comparable to those today in Antarctica and in the Quaternary ice streams of the Cordilleran, Laurentide and North European Ice Sheets.

Microsedimentology of tills near Ainet, Austria - were palaeo-ice streams in the European Alps underlain by soft deforming bed zones?

Austrian Journal of Earth Sciences

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fast moving palaeo-ice masses within the European Alpine Ice Cap (EAIC) during the Last Glacial Maximum within the large valleys of the European Alps are...

Microsedimentology of tills near Ainet, Austria - were palaeo-ice streams in the European Alps underlain by soft deforming bed zones?

Published Online: Jul 13, 2020

Page range: 71 - 86

Received: Dec 18, 2019

Accepted: Mar 26, 2020

DOI: https://doi.org/10.17738/ajes.2020.0005

Keywords
Glacial sedimentology, deformable bed, paleogeography, Last Glacial Maximum, Alpine Lateglacial, Eastern Alps

© 2020 Jürgen M. Reitner et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Microsedimentology of tills near Ainet, Austria - were palaeo-ice streams in the European Alps underlain by soft deforming bed zones?

Published Online: Jul 13, 2020

Page range: 71 - 86

Received: Dec 18, 2019

Accepted: Mar 26, 2020

DOI: https://doi.org/10.17738/ajes.2020.0005

KeywordsGlacial sedimentology, deformable bed, paleogeography, Last Glacial Maximum, Alpine Lateglacial, Eastern Alps

© 2020 Jürgen M. Reitner et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Glacial sedimentology, deformable bed, paleogeography, Last Glacial Maximum, Alpine Lateglacial, Eastern Alps