Glacial geomorphology of the south Swedish uplands – focus on the spatial distribution of hummock tracts

Abstract

We present the first comprehensive glacial-landform map of the south Swedish uplands (SSU), deglaciated 15-13 ka ago, using one consistent method and dataset; a Light Detection and Ranging-derived digital elevation model. In particular, this map focuses on the spatial distribution of hummock tracts. The distribution of hummock tracts reinforces previous thinking of a broad lobate east-west zone of hummocks across the southern part of the SSU. But this map also reveals a pattern of hummock tracts confined in what we call hummock corridors that have a radial pattern sub-parallel to the overall ice-flow direction. Hummocks occur in a wide variety of morphologies, but we also show the distribution of two distinct forms: V-shaped hummocks and 'ribbed moraine'. Cross-cutting relationships between hummocks and glacial lineations indicate a more complex chronology than previously suggested. In places, lineations are overlain by hummocks and in other places hummocks are overlain by lineations. Additionally, directional variation of glacial lineations together with a complex end-moraine pattern suggests a dynamic ice sheet with multiple small lobes. Finally, mapped end moraines help to better correlate the deglacial timescales of western and eastern Sweden.

Hummock corridors in the south‐central sector of the Fennoscandian ice sheet, morphometry and pattern

“…Recent mapping of the glacial geomorphology of the SSU using detailed light detection and ranging (LiDAR) based elevation models shows a more detailed picture of the glacial landscape than earlier mapping efforts and also reveals landforms not recognized previously in this area (Peterson et al ., ). In addition to drumlins, crag and tails, eskers, and end moraines, there are abundant hummocks.…”

“…Right, glacial geomorphology map: moraines, eskers, hummock tracts and corridors in a small‐scale version of the map by Peterson et al . (). [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…In addition to drumlins, crag and tails, eskers, and end moraines, there are abundant hummocks. Many of the hummocks are found within elongated zones that together form a radial pattern over the SSU (Peterson et al ., ; Figure ).…”

“…Individual hummock shapes differ markedly within the hummock tracts in the study area. The majority of the hummocks vary broadly in their shape, spacing and relief (Peterson et al ., ). However, within the hummock tracts, we have identified two distinct forms that occur in various places in the SSU.…”

Editorial: LiDAR – rapid developments in remote sensing of geological features

“…These include research on issues such as ribbed (Rogen) and hummock moraines and their tracks and corridors (Möller and Dowling, 2015;Peterson et al, 2017), ice streaming (Greenwood et al, 2015), De Geer moraines (Bouvier et al, 2015;Ojala et al, 2015;Ojala 2016), subglacial meltwater systems , beach ridges, cliffs and shore terraces (Ojala et al, 2013), fluvial terraces, floods plains and lateral meltwater channels (Eilertsen et al, 2015), postglacial fault scarps and landslides (e.g. Mikko et al, 2015;Palmu et al, 2015;Ojala et al, 2017aOjala et al, , 2017b, as well as bedrock lineaments, fracture sets, and fissures (Scheiber et al, 2015;Skyttä et al, 2015).…”