Ice-Sheet Dynamics Of Warta Glaciation (SAALE) In The Marginal Zone Of Knyszewicze Area, Northeastern Poland

• Published in: Studia Quaternaria
• Main Authors: Rychel, Joanna, Woronko, Barbara, Karasiewicz, Mirosław T., Szymczuk, Paweł, Morawski, Marcin
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Walter de Gruyter GmbH 2015
• Subjects: Earth-Surface Processes; Geology; Ice; Ice Sheet; permafrost
• Online Access: http://dx.doi.org/10.1515/squa-2015-0007; http://content.sciendo.com/view/journals/squa/32/2/article-p79.xml

Abstract The paper presents a research on a marginal zone near Knyszewicze in the southern part of Sokółka Hills (northeastern Poland). Terminal moraine hills are arranged amphitheatrically in a lobal pattern. Dynamics of the Knyszewicze frontal ice-sheet lobe during the Saale Glaciation and successive stages of the marginal zone near the village of Knyszewicze were reconstructed based on sedimentary and geomorphological analysis, using a digital elevation model and morpholineaments. Three main phases of the Knyszewicze glacial-lobe activity were identified including accumulation of glaciofluvial deposits, advances of the ice margin and ice-lobe retreat. Moraine hills developed at a stable ice-lobe terminus, initially as short end-moraine fans with the following sequence of lithofacies Gh ⇒ SGh ⇒ Sh or Gm ⇒ Gh ⇒ Sh . Such a sequence indicates cyclic sheet-floods. During a small but dynamic advance of the ice sheet terminus, these deposits were moved forward and monoclinally folded, then furrowed with sloping faults due to horizontal pressure. Typical thrust-block push moraines developed in this way. Ice sheet advance took place when permafrost was present in the substratum and very high water pressure occurred at glacial terminus. Inside a lobal configuration of moraines, there is a rich inventory of glacial forms with a classic terminal depression in the central part. Based on this landform pattern, their shape, rhythm and glaciotectonic disturbances, the land relief may be referred to as a hill-hole pair. The structure of Horczaki Knoll, deposited on the sub-Quaternary tectonic structure, significantly contributed to a development of this marginal zone.