<abstract xmlns="http://www.w3.org/1999/xhtml"><p>The 14-m-thick sandy succession at Ujście in western Poland formed during the Odranian stadial of the Saalian glaciation, is exceptional in being very well sorted, almost mono-fractional (fine-grained sands) and mono-mineral (mainly quartz grains) and in lacking Scandinavian erratics. The lower sequence (5 metres in thickness) consists of three stacked packages of clinoforms (inclined cross-stratified sands) and is interpreted as having been deposited on a subaqueous fan in a shallow lake during two phases of rising water levels. The upper sand (9 metres in thickness) with (sub) horizontal stratification was redeposited on a subaerial alluvial fan. Distinctive distributary channels that occur in the uppermost part of the subaqueous fan and in the lowermost portion of the alluvial fan may indicate a change in sedimentation style from subaqueous to subaerial. Moreover, the subaerial position of the fan supports the presence of ice-wedge casts that developed under periglacial conditions in the upper part of alluvial fan. The results of granulo-metric analysis, rounding and frosting of grains and mineral analysis indicate that the sands are derived from Gorzów Formation of Early Miocene age. The only feasible explanation is that the 14-m-thick unit must have been redeposited during the Saalian glaciation.</p></abstract>

The 14-m-thick sandy succession at Ujście in western Poland formed during the Odranian stadial of the Saalian glaciation, is exceptional in being very well sorted, almost mono-fractional (fine-grained sands) and mono-mineral (mainly quartz grains) and in lacking Scandinavian erratics. The lower sequence (5 metres in thickness) consists of three stacked packages of clinoforms (inclined cross-stratified sands) and is interpreted as having been deposited on a subaqueous fan in a shallow lake during two phases of rising water levels. The upper sand (9 metres in thickness) with (sub) horizontal stratification was redeposited on a subaerial alluvial fan. Distinctive distributary channels that occur in the uppermost part of the subaqueous fan and in the lowermost portion of the alluvial fan may indicate a change in sedimentation style from subaqueous to subaerial. Moreover, the subaerial position of the fan supports the presence of ice-wedge casts that developed under periglacial conditions in the upper part of alluvial fan. The results of granulo-metric analysis, rounding and frosting of grains and mineral analysis indicate that the sands are derived from Gorzów Formation of Early Miocene age. The only feasible explanation is that the 14-m-thick unit must have been redeposited during the Saalian glaciation.

Miocene quartz sands redeposited on subaqueous and alluvial fans during the Saalian: Interpretation of the depositional scenario at Ujście, western Poland

Geologos

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

The 14-m-thick sandy succession at Ujście in western Poland formed during the Odranian stadial of the Saalian glaciation, is exceptional in being very well...

Miocene quartz sands redeposited on subaqueous and alluvial fans during the Saalian: Interpretation of the depositional scenario at Ujście, western Poland

Pubblicato online: 13 set 2019

Pagine: 125 - 137

Ricevuto: 18 apr 2019

Accettato: 10 lug 2019

DOI: https://doi.org/10.2478/logos-2019-0012

Parole chiave
proglacial lake, distributary channels, sandy clinothems, Odranian stadial

© 2019 Mateusz Mleczak et al., published by Sciendo

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

Miocene quartz sands redeposited on subaqueous and alluvial fans during the Saalian: Interpretation of the depositional scenario at Ujście, western Poland

Pubblicato online: 13 set 2019

Pagine: 125 - 137

Ricevuto: 18 apr 2019

Accettato: 10 lug 2019

DOI: https://doi.org/10.2478/logos-2019-0012

Parole chiaveproglacial lake, distributary channels, sandy clinothems, Odranian stadial

© 2019 Mateusz Mleczak et al., published by Sciendo

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

Parole chiave
proglacial lake, distributary channels, sandy clinothems, Odranian stadial