Characteristic of till formation during the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania
Studies of the till structure and composition of the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania has enabled recognition of a multilayered till structure. This can be seen visually (colour, bed structure, interlayers, insertions of different composition and so on)...
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Polish Geological Institute-National Research Institute
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ftjgq:oai:geojournals.pgi.gov.pl:article/7387 2024-09-15T18:12:34+00:00 Characteristic of till formation during the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania Baltrūnas, Valentinas Karmaza, Bronislavas Dundulis, Kastytis Gadeikis, Saulius Račkauskas, Vytautas Šinkūnas, Petras 2010-03-27 application/pdf https://gq.pgi.gov.pl/article/view/7387 eng eng Polish Geological Institute-National Research Institute https://gq.pgi.gov.pl/article/view/7387/6037 10.7306/gq.v49i4.7387.g6037 https://gq.pgi.gov.pl/article/view/7387 Geological Quarterly; Vol. 49 No. 4 (2005); 417-428 Geological Quarterly; Tom 49 Nr 4 (2005); 417-428 1641-7291 10.7306/gq.v49i4 Lithuania Last Glaciation Nemunas Glaciation Baltija till sedimentology physical properties info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2010 ftjgq https://doi.org/10.7306/gq.v49i4 2024-07-30T03:29:08Z Studies of the till structure and composition of the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania has enabled recognition of a multilayered till structure. This can be seen visually (colour, bed structure, interlayers, insertions of different composition and so on) and established from features determined by analytical and statistical methods (physical and mechanical properties, material composition, orientation and dip of longer axes of pebbles). Borehole log data from boreholes drilled during geological mapping showed heterogeneity within the subglacial till of the Baltija Stage and provided a preliminary picture of variations of its multilayered structure from S to N. This showed that two layers predominate in the subglacial till in the area of the South Lithuanian Phase while three layers are present in the area of the Middle Lithuanian Phase farther north. The petrographic composition of the gravel fraction as well as the orientation and dip of the long axes of pebbles measured in till beds in natural exposures and quarries further demonstrated the multilayered structure of the Baltija till. Research at key sections in areas of the subsurface extent of till of the East, South and Middle Lithuanian phases of the Baltija glacial recession confirmed the increase in the number of till layers from S to N. The physical and mechanical properties of the till also reflect its multilayered structure. Relative entropy values calculated for the grain-size frequency distribution of the Baltija till enabled evaluation of a change in its sorting along the direction of glacial ice advance from N to S. There is a correlation between the higher values of entropy of grain-size distribution and the rate of development of preferred orientation of longer axes of pebbles throughout the till section vertically. The formation of the multilayered structure of the Baltija till is ascribed to cyclic dynamics of the subglacial processes associated with the receding ice sheet; consequently, the number ... Article in Journal/Newspaper Ice Sheet Geological Quarterly |
institution |
Open Polar |
collection |
Geological Quarterly |
op_collection_id |
ftjgq |
language |
English |
topic |
Lithuania Last Glaciation Nemunas Glaciation Baltija till sedimentology physical properties |
spellingShingle |
Lithuania Last Glaciation Nemunas Glaciation Baltija till sedimentology physical properties Baltrūnas, Valentinas Karmaza, Bronislavas Dundulis, Kastytis Gadeikis, Saulius Račkauskas, Vytautas Šinkūnas, Petras Characteristic of till formation during the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania |
topic_facet |
Lithuania Last Glaciation Nemunas Glaciation Baltija till sedimentology physical properties |
description |
Studies of the till structure and composition of the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania has enabled recognition of a multilayered till structure. This can be seen visually (colour, bed structure, interlayers, insertions of different composition and so on) and established from features determined by analytical and statistical methods (physical and mechanical properties, material composition, orientation and dip of longer axes of pebbles). Borehole log data from boreholes drilled during geological mapping showed heterogeneity within the subglacial till of the Baltija Stage and provided a preliminary picture of variations of its multilayered structure from S to N. This showed that two layers predominate in the subglacial till in the area of the South Lithuanian Phase while three layers are present in the area of the Middle Lithuanian Phase farther north. The petrographic composition of the gravel fraction as well as the orientation and dip of the long axes of pebbles measured in till beds in natural exposures and quarries further demonstrated the multilayered structure of the Baltija till. Research at key sections in areas of the subsurface extent of till of the East, South and Middle Lithuanian phases of the Baltija glacial recession confirmed the increase in the number of till layers from S to N. The physical and mechanical properties of the till also reflect its multilayered structure. Relative entropy values calculated for the grain-size frequency distribution of the Baltija till enabled evaluation of a change in its sorting along the direction of glacial ice advance from N to S. There is a correlation between the higher values of entropy of grain-size distribution and the rate of development of preferred orientation of longer axes of pebbles throughout the till section vertically. The formation of the multilayered structure of the Baltija till is ascribed to cyclic dynamics of the subglacial processes associated with the receding ice sheet; consequently, the number ... |
format |
Article in Journal/Newspaper |
author |
Baltrūnas, Valentinas Karmaza, Bronislavas Dundulis, Kastytis Gadeikis, Saulius Račkauskas, Vytautas Šinkūnas, Petras |
author_facet |
Baltrūnas, Valentinas Karmaza, Bronislavas Dundulis, Kastytis Gadeikis, Saulius Račkauskas, Vytautas Šinkūnas, Petras |
author_sort |
Baltrūnas, Valentinas |
title |
Characteristic of till formation during the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania |
title_short |
Characteristic of till formation during the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania |
title_full |
Characteristic of till formation during the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania |
title_fullStr |
Characteristic of till formation during the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania |
title_full_unstemmed |
Characteristic of till formation during the Baltija (Pomeranian) Stage of the Nemunas (Weichselian) Glaciation in Lithuania |
title_sort |
characteristic of till formation during the baltija (pomeranian) stage of the nemunas (weichselian) glaciation in lithuania |
publisher |
Polish Geological Institute-National Research Institute |
publishDate |
2010 |
url |
https://gq.pgi.gov.pl/article/view/7387 |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
Geological Quarterly; Vol. 49 No. 4 (2005); 417-428 Geological Quarterly; Tom 49 Nr 4 (2005); 417-428 1641-7291 10.7306/gq.v49i4 |
op_relation |
https://gq.pgi.gov.pl/article/view/7387/6037 10.7306/gq.v49i4.7387.g6037 https://gq.pgi.gov.pl/article/view/7387 |
op_doi |
https://doi.org/10.7306/gq.v49i4 |
_version_ |
1810450157555154944 |