6th International Drumlin Symposium

Nicholas Copernicus University, Torun, Poland
June 17-23, 2001
INQUA Commission on Glaciation

The 6th drumlin symposium sponsored by the INQUA Commission on Glaciation in northern Poland from June 17-23, was attended by 36 participants from 11 countries, and organized by Wojciech Wysota and Jan Piotrowski. The symposium began with a day of oral and poster presentations followed by a short discussion. The discussion focused on the morphological description of a drumlin, and moved to whether drumlins could be created in the lab. Ring shear devices were discussed and it was also pointed out that drumlins have been created in flumes. Additional discussion centered on preservation of the subglacial landscape and it was unanimously agreed upon that the origin of drumlins is still uncertain! Professor Piotrowski who opened the day’s session predicted that although drumlin genesis will likely remain elusive, our knowledge of subglacial processes is advancing.

The first two days of the field excursion were led by Antoni Olszewski and Wojciech Wysota of Nicholas Copernicus University to examine drumlins, which for the most part, are restricted to tunnel channels incised into the Dobrzyn Lakeland upland. The tunnel channel and drumlins terminate at either a series of end moraines composed of bedded sand and gravel with minor amounts of till and glaciolacustrine sediment, or at an extensive kame and dead ice landscape. Hummock forms and long parallel ridges, many of which are crescent shape, characterized the drumlin morphology. Drumlin sediment was variable and included tills, glaciolacustrine and glaciofluvial sediment, which in many cases was folded with the axial fold parallel to the drumlin’s length. This structural relationship which was also viewed in drumlins on the Elblag uplands in NE Poland and the Stargard drumlin field in NW Poland elicited a variety of possible origins. These ranged from glacial erosion of a glaciotectonic landscape, meltwater erosional remnants of the glaciotectonic landscape, and ice-pressing of the sediment into a large drumlin shaped cavity at the base of the ice sheet. Interestingly, the sediment within the folds was well preserved, with only minor faulting and not pervasively deformed. Low angle thrust faults indicating compression outwards from the center of a drumlin in the Obory channel, coincided with laminated sands that appear to have been drawn upwards. Because the drumlins were in most cases restricted to channels a few kilometers wide and the channels ended in large deposits of sand and gravel, a subglacial meltwater origin for the drumlins was seriously considered.

On the third day of the field trip we visited the drumlins on the Elblag glaciotectonic uplands. The one exposure we visited in these poorly studied drumlins had a similar deformed core as seen in the previous two days. From the Elblag drumlins we headed west, across the Vistula delta plain to near Gniew where we saw remarkably well exposed glaciolacustrine rhythmites in a clay pit. These sediments are spatially restricted to a small glacial lake dammed by stagnant ice in the Vistula valley. Of particular interest was a bed of ripple formsets within the clays that was explained by jökulhlaup flooding. Accommodation that night was in the Gniew castle where we were treated to a medieval feast. The well-lubricated entertainment included national songs, select choices from Dave Mickelson’s “Pleistocene songbook”, and numerous hastily written songs about Polish drumlins.

The fourth day of the field trip included some regional stratigraphy of voluminous sand and gravel deposits between tills, morphology and sedimentology of drumlins and some interesting basal till contacts with glaciofluvial sediment in NW Poland. At the drumlinoid form near Mosty, the possibility of a deformation till was discussed, where the lower part of the till contained portions of the underlying sand and laminated mud. Various aspects of deforming till mechanisms were discussed and it was agreed that the lower part of the till could be deformational in origin, but was not as obvious as a 0.2 m thick deformation till viewed previously on day two. A deformation origin for the drumlinoid was discussed but could not be substantiated with existing models.

On the final day of the field trip we visited the end moraine of the Parseta Lobe of the Pomeranian Phase (16.2 ka). The proximal edge of an outwash plain contained large boulders that appeared to have been dumped from a pulsed flow. Field trip participants described similar deposits from ice marginal areas of Skeidararjökull, Iceland and from within Rogen moraine. The outwash was then viewed from a more distal pit where the geometry of the predominantly sand bed was planar, in contrast with outwash that often contains bar and channel forms.

In summary, a good overview of the glaciation of Poland was presented throughout the trip. Many of the drumlins could be linked to specific ice-marginal systems, but the stratigraphy of northern Poland is still debated, as are the origins of the drumlins. The drumlin symposium was extremely well organized and the leaders are to be congratulated for hosting an enjoyable and scientifically interesting meeting.