ICG2022-61
https://doi.org/10.5194/icg2022-61
10th International Conference on Geomorphology
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Megadunes and their sedimentary successions on the proximal part of the Augustów Sandur, NE Poland

Piotr Weckwerth1, Wojciech Wysota2, Jan Piotrowski3,2, Arkadiusz Krawiec2, Marek Chabowski4, Edyta Kalińska1, and Aleksander Adamczyk2,5
Piotr Weckwerth et al.
  • 1Nicolaus Copernicus University in Toruń, Faculty of Earth Sciences and Spatial Management, Department of Geomorphology and Quaternary Paleogeography, Poland (pweck@umk.pl)
  • 2Nicolaus Copernicus University in Toruń, Faculty of Earth Sciences and Spatial Management, Department of Geology and Hydrogeology, Poland
  • 3Aarhus University, Department of Geoscience, Aarhus C, Denmark
  • 4Nicolaus Copernicus University in Toruń, Faculty of Earth Sciences and Spatial Management, Poland
  • 5State Water Holding, Polish Waters Regional Water Management Authority in Bydgoszcz, Poland

Extreme geological processes include cataclysmic glacial floods often contribute to glacial landscape evolution. Based on the geomorphological research the unique glacial megaflood landforms were discovered on the proximal part of the Augustów Sandur, NE Poland (Weckwerth et al., 2019). First-order and second-order megaflood-related landforms were distinguished. The latter includes straight-crested (two-dimensional) megadunes located south of Suwałki. The megadunes have mean heights on stoss slopes between 2.3 and 3.9 m and mean heights on lee slopes between 2.5 and to 4.5 m, while the maximum recorded megadune height is 8.5 m, and the maximum length is 420 m. Characteristic features of the 2D megadunes south of Suwałki are elongated depressions occurring along megadune crests. Megadunes located in the vicinity of Wigry Lake originated from depositional processes related to the reduction in flow energy and competence in the area of the broad outwash plain. The width of this plain rapidly increases and thus creates an accommodation space (unconfined outwash plain) for the aggradation of mega-scale, superimposed bedforms (Weckwerth et al. 2020b). Their three-stage evolution was recognised as a result of sedimentological and geophysical investigations. The first stage represents foreset deposition on the lee side of the megadunes, while the second was deposition from 2D and 3D superimposed bedforms and longitudinal gravelly bars climbing downstream on a megadune stoss slope, which were locally separated by gravelly pavement and scour infills. During the third stage, the crestal depressions evolved as a result of the development of both north- and south-dipping normal faults oriented parallel to the megadune crest, representing syn- and meta-sedimentary deformations (Weckwerth et al., 2020a, b).

This study was carried out as part of the scientific project financed by the National Science Centre (NCN) in Poland, project no. 2018/31/B/ST10/00976 and Danish Council for Independent Research (FNU) grant DFF-7014-00156.

References

Weckwerth P., Piotrowski J.A., Wysota W., Krawiec A., Adamczyk A., Kalińska E., Chabowski M., 2020a. Mature and immature megadunes : insights from morphology and sedimentary successions of mega-scale bedforms south of Wigry Lake (NE Poland). [In:] Weckwerth P., Wysota W., Kalińska E. (eds), Glacial megaflood landforms and sediments in North-Eastern Poland. Wydawnictwo Naukowe Uniwersytetu Mikołaja Kopernika, Toruń: 99-107.

Weckwerth P., Wysota W., Chabowski M., Krawiec A., Kalińska E., Adamczyk A., 2020b. Morphology, geological structure and development of two-dimensional megadunes formed on an outwash plain in NE Poland. [In:] Weckwerth P., Wysota W., Kalińska E. (eds), Glacial megaflood landforms and sediments in North-Eastern Poland. Wydawnictwo Naukowe Uniwersytetu Mikołaja Kopernika, Toruń: 89-97.

Weckwerth, P., Wysota, W., Piotrowski, J. A., Adamczyk, A., Krawiec, A., Dąbrowski, M., 2019. Late Weichselian glacier outburst floods in North-Eastern Poland: Landform evidence and palaeohydraulic significance. Earth-Science Reviews, 194: 216–233.

How to cite: Weckwerth, P., Wysota, W., Piotrowski, J., Krawiec, A., Chabowski, M., Kalińska, E., and Adamczyk, A.: Megadunes and their sedimentary successions on the proximal part of the Augustów Sandur, NE Poland, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-61, https://doi.org/10.5194/icg2022-61, 2022.