High-resolution LiDAR mapping of glacial landforms and ice stream lobes in Finland

Abstract

Newly available high resolution airborne LiDAR (Light Detection And Ranging) technology is generating unprecedented next-generation imagery of Earth surface features. LiDAR datasets are being employed by the Geological Survey of Finland (GTK) as part of a new national geological initiative (Glacier Dynamic database: GDdatabase) to rapidly and cost-effectively map glacial landforms and sediments left by the last (Late Weichselian) Fennoscandian Ice Sheet (FIS). There is a high demand for such data in hydrogeological, geoengineering and mineral exploration projects and also for the identification of glacial landforms that provide key information regarding ice sheet rheology, growth and decay. An important step forward with this new technique is the recognition of paleoice stream corridors with fast flowing ice (> 3 km yr -1 based on modern ice sheets), surrounded by stagnant or sluggish-flowing ice. Precise geomorphic criteria are now available for recognition of paleo-ice streams, based on the elongation of subglacial streamlined bedforms and the presence of megascale glacial lineations. Flow sets of drumlins and megascale glacial lineations can now be mapped in high resolution using LiDAR and are now seen as genetically related forms in a continuum that records increasing ice flow velocity and the creation of a low friction bed. This paper briefly outlines the nature of the GDdatabase and the methodology behind its construction and provides examples of principal bedform types that record the dynamic interplay of paleo-ice stream lobes in the Finnish sector of the last FIS.

Evolution of the eastern part of the Kuusamo Ice Lobe, based on geomorphological interpretation of high-resolution LiDAR data

“…Figure 2 shows the interpreted ice flow directions over the LiDAR-based digital elevation model. About 9000 different types of lineations were mapped and classified into one of five categories based on the GTK's Glacier Dynamic database (see Putkinen et al, 2017 in this volume). These were: drumlins, megascale glacial lineations (MSGLs), rock drumlins, pre-crags and flutings.…”

Reply to the comment by H.A.J. Russell on “Converging ice streams: a new paradigm for reconstructions of the Laurentide Ice Sheet in southern Ontario and deposition of the Oak Ridges Moraine”

“…A wealth of work at the margins of modern ice sheets in Antarctica, Greenland, and Spitsbergen has shown that MSGLs are the geomorphic fingerprint of dynamic fast-flowing ice streams (King et al 2009;Stokes 2011;Livingstone et al 2012;Dowdeswell et al 2016;Fernandez et al 2018). They are now widely identified on the beds of Pleistocene and pre-Pleistocene ice sheets, indicating that they too were similarly structured (Le Heron 2017; Putkinen et al 2017;Stokes et al 2016;Margold et al 2014Margold et al , 2015Margold et al , 2018Stokes 2018). Today, almost 200 ice streams are currently recognized in the last Cordilleran and Laurentide ice sheets (Clark 1993;Patterson 1997;Dyke 2008;Kleman 2005, 2007;Evans et al 2006Evans et al , 2008Evans et al , 2014Ross et al 2006Ross et al , 2009Ross et al , 2011Ó Cofaigh et al 2010aÓ Cofaigh et al , 2013MacLean et al 2010MacLean et al , 2015MacLean et al , 2017Occhietti et al 2011;Paulen et al 2017;McMartin 2017;McMartin et al 2018;Veillette et al 2017;Shaw and Longva 2017;Margold et al 2018;Eyles et al 2018a).…”

Factors affecting the dynamics of the North Karelian/Oulu Ice Lobe, Central Finland, during the last deglaciation – a LiDAR and DEM interpretation of subglacial lineation patterns

“…The glacial lineations studied were mapped manually using ESRI's (Environmental Systems Research Institute) ArcMap 10.3 software and the GTK's database classification for landforms (Putkinen et al, 2017, Supplementary file 2; this volume). The lineation data in ArcMap-format is saved in the GTK's personal geodatabase.…”