Lidar-Based Detection and Interpretation of Glaciotectonic Features of the Morainic Topography of Finland

Matti V. J. Seppälä, 2016.  Lidar-Based Detection and Interpretation of Glaciotectonic Features of the Morainic Topography of Finland. Journal of Geological Research, vol. 2016, Article ID 4292806, 11 pages. doi:10.1155/2016/4292806

Abstract

In Finland’s digital elevation model, marks of glaciotectonics as an important formation process of glacial geomorphology can be seen. This is a new finding to this extent regarding central parts of the former ice sheets. Deformational processes produced fragmented till surfaces probably mostly by brittle fracture of frozen till. Good signs of deformational effect to the till surfaces are the plucked edges or steps and semilinear or fan-like quarry edges in topography, which are often oblique compared with the main direction of the flow of the glacier. Plucked fractured steps of blocks of till can be so tight that they construct horizontal-like diamond patterned surfaces. Sometimes punctate proximal endings of fan-like hollows of transported rafts can be seen. Within main ice lobes or streams the glaciated terrain is often divided into longitudinal smooth looking drumlin terrain and into rough erosional slightly lower level situated zones, where the erosion has happened firstly by glaciotectonism and then by glaciofluvial streams. The eskers and different kind of hummocky moraines are often located in same zones. Among them deformational hummocky moraines and ribbed moraines are common. The abundance of glaciotectonic and plucking related features indicates that the base of the receding ice sheet was cold based in places or from time to time.

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A thousand thanks to the Publisher, the academic editor Dr. Karoly Nemeth and the rest of the editors and reviewers.

Extracts

Landform classification: "Five types of mostly erosional glaciotectonic landforms were recognized: (1) plucked lee side, (2) hill-hole pair, (3) fanlike and transverse edges of plucked depressions, (4) sporadic plucked hollows, and (5) deformational or glaciotectonic mound or ridge."

"Glaciotectonic deformation seems quite a late

phenomenon in most places because it has there deformed

deglacial landforms,"

An additional note: The Frozen bed boundaries in Figure 2 of the paper are consistent with the source. This study suggests that the glaciotectonic landforms and at least occasional frozen bed conditions  are much more widely distributed presumably in the late local deglaciation stage. They were found for example on the south coast in Loviisa.