An erosional origin for drumlins of NW Poland

Hermanowski, Piotr; Piotrowski, Jan A.; Szuman, Izabela

doi:10.1002/esp.4630

Cited by 18 publications

(44 citation statements)

References 148 publications

(249 reference statements)

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“…The results of the present study are consistent with the erosional origin hypothesis of Stargard drumlins by Hermanowski et al (). Although there is no obvious systematic relationship at the scale of the entire study area between the location of drumlins and the groundwater flow patterns and fluxes, such correlation is apparent in the south‐eastern part of the study area.…”

Section: Discussionsupporting

confidence: 94%

“…Our numerical simulation comprising a drumlin field offers a possibility to consider drumlin formation in the context of groundwater flow dynamics. In the parallel study of SDF, Hermanowski et al () documented the internal composition of several drumlins and analyzed the spatial characteristics of over 1,300 individual drumlins together with the geomorphological pattern of the entire drumlin field. Based mainly on the occurrence of diverse and from place to place different deposits (various till facies and sorted sediments) and their structural arrangements (undeformed to heavily glaciotectonized; geological contacts truncated by landform surfaces), it was concluded that the drumlin deposits mainly predate the drumlinizing event.…”

Section: Discussionmentioning

confidence: 99%

“…The eastern part of the ice lobe area hosts the most extensive drumlin field in the Central European Lowland‐the Stargard drumlin field (Figure ; Keilhack, ; Karczewski, , ; Rachlewicz, ). In this area, Hermanowski et al () documented over 1,300 drumlins and related streamlined subglacial bedforms such as megascale glacial lineations and glacial flutings. These bedforms are arranged in an arcuate pattern broadly indicating ice flow to southwest, south, and southeast toward the ice margin in accord with the general shape of the ice lobe.…”

Section: Study Area and Research Backgroundmentioning

confidence: 99%

“…The streamlined bedforms are typically 600‐800 m long, 200‐250 m wide, 3‐6 m high, and have elongation ratios mostly around 2 but in some cases as much as 15. Based on detailed geomorphological and sedimentological analysis, in particular, the lack of apparent correspondence between the drumlin deposits and drumlin shapes, Hermanowski et al () suggested that the drumlin field originated as a result of some combination of direct glacial erosion and subglacial meltwater erosion by removing older material from the interdrumlin areas and streamlining the resultant bumps.…”

Section: Study Area and Research Backgroundmentioning

confidence: 99%

“…Although the latter scenario considers that the deposits in drumlins predate the drumlinizing process, it is still consistent with fast flow of ice. Due to its location within a well‐constrained terminal part of OPIS, abundant geological and hydrogeological data, and new sedimentological information documenting the internal composition of the drumlins (Hermanowski et al, ), SDF as an example of an area of fast ice flow is well suited for numerical simulation of subglacial groundwater dynamics and its impact on landforming processes.…”

Section: Study Area and Research Backgroundmentioning

confidence: 99%

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Groundwater Flow Under a Paleo‐Ice Stream of the Scandinavian Ice Sheet and Its Implications for the Formation of Stargard Drumlin Field, NW Poland

Hermanowski

Piotrowski

2019

JGR Earth Surface

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Subglacial groundwater flow was an integral part of glaciological systems of past ice sheets, but its impact on the origin of active-ice landforms remains unexplored. Using numerical experiments, we attempt to constrain groundwater flow dynamics under a major paleo-ice stream of the southern Scandinavian Ice Sheet and its impact on the formation of the Stargard drumlin field. Flow models show a total reorganization of groundwater dynamics under the advancing ice stream to a depth of up to~200 m. A mosaic of intervening groundwater recharge and discharge areas originates, whereby the same areas may experience multiple shifts in flow directions. A prominent time-and space-transgressive pressure pump recharges groundwater in a subglacial zone up to about 20 km within the ice margin and discharges it in front of the ice sheet. The simulated groundwater flow pattern suggests that drumlins occupying a portion of the ice stream area occur preferentially where groundwater upwells and discharges at the ice/bed interface. Consistent with the geological composition, a possible drumlin-forming mechanism involves an excess of pressurized water under the ice reducing the strength of the subglacial deposits and facilitating glacial erosion, erosion by turbulent meltwater flows or both, streamlining antecedent deposits into drumlin shapes. This study emphasizes the importance of causal feedback between subglacial groundwater flow and the ice sheet dynamics and suggests an impact of the former on the formation of streamlined subglacial landforms in general.

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Section: Discussionsupporting

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Section: Study Area and Research Backgroundmentioning

confidence: 99%

Section: Study Area and Research Backgroundmentioning

confidence: 99%

Section: Study Area and Research Backgroundmentioning

confidence: 99%

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Groundwater Flow Under a Paleo‐Ice Stream of the Scandinavian Ice Sheet and Its Implications for the Formation of Stargard Drumlin Field, NW Poland

Hermanowski

Piotrowski

2019

JGR Earth Surface

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Origin of glacial curvilineations by subglacial meltwater erosion: Evidence from the Stargard drumlin field, Poland

Hermanowski

Piotrowski

2022

Earth Surf Processes Landf

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Deciphering the origin of subglacial landforms is crucial for understanding processes operating under ice sheets. Due to the inaccessibility of the ice/bed interface limiting real-time observations, the origin of these landforms is typically interpreted from the morphological and sedimentological record exposed after ice retreat, which makes the conclusions conjectural. Here, we focus on a recently discovered new type of subglacial landform called glacial curvilineations (GCLs), whose formation generates some controversy. We use LiDAR imagery and geological data to constrain the origin of GCLs found in a tunnel valley in the Stargard drumlin field, Poland. The tunnel valley is about 3800 m long, 520 m wide, and it occupies about 2 km 2 . A total of 61 individual GCLs have been mapped there; they are up to 550 m long and typically 0.5-1.5 m high, but some reach a height of up to 5 m. The GCLs are composed of mostly massive till represented by either a single or several diamicton units occasionally separated by thin layers of meltwater sand. Till macrofabrics in the GCLs and in the nearby till plain are distinctly consistent, and have high and uniform clustering strengths. At all locations, the dominant till fabric direction broadly corresponds with the ice movement direction given by the drumlin orientations, but it is oblique to the orientation of the tunnel valley and independent of the orientations of the individual GCLs. The lack of correspondence between the orientation of the GCLs and the till fabrics in them suggests that the GCLs consist of an antecedent till deposited during the drumlinizing ice advance and subsequently carved by subglacial meltwater erosion in the tunnel valley. These results substantiate the hypothesis that GCLs are erosional features postdating the material constituting them, and emphasize the role of subglacial meltwater flows as a landforming agent.

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LiDAR‐based semi‐automated mapping of drumlins and mega‐scale glacial lineations of the Green Bay Lobe, Wisconsin, USA: Ice sheet beds as glaciotribological systems

Eyles

Bukhari

Sookhan

et al. 2022

Earth Surf Processes Landf

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A machine learning methodology for processing and visualizing high-resolution LiDAR digital data is used to map drumlins and mega-scale glacial lineations (MSGLs) on the bed of the Late Wisconsin Green Bay Lobe in Wisconsin, USA, which exhibited surge-like behaviour during deglaciation. Previous work has shown that streamlined bedforms are the product of erosional streamlining of pre-existing sediment. Analysis of bedform height and elongation ratio using curvature-based relief separation (CBRS) and K-means clustering of 32,003 bedforms reveals a continuum of six morphotypes ranging from drumlins, through "channeled" more elongated multi-crested drumlins, to MSGLs. Further statistical analysis shows that morphotypes cluster into six types of streamlined surfaces (S1-S6) recording progressive elimination of an antecedent overridden topography to produce a smoother bed. Initial, relatively high-relief drumlinized surfaces (S1, S2) occur around the slowerflowing lateral flanks of the lobe, where a pre-existing hummocky morainal topography was only partially modified by subglacial erosion. More streamlined surfaces (S3, S4) dominated by multi-crested more elongate drumlins of reduced relief amplitude are transitional to flow sets of MSGL-dominated surfaces (S5, S6) indicative of much faster-flowing ice streaming along the lobe's axis. Estimates of basal drag based on roughness calculations for each surface type identify a 61% reduction in frictional retardation from poorly streamlined surfaces S1 and S2 to MSGL-dominated surfaces S5 and S6, with a step-like reduction between drumlins and channeled drumlins (S3, S4) possibly recording the rapid onset of fast flow. Subglacial streamlining is argued to be accomplished by a thin (<1 m) "third layer" of deforming subglacial debris between ice and its bed which functioned as an erodent layer. A thin (<3 m) till cap, formed by aggradation of deforming debris, rests unconformably on heterogeneous core sediments. Streamlined subglacial surfaces are comparable to the "functional" surfaces resulting from erosion by a "third layer" of wear debris in engineering tribological systems, and also by gouge on faults. Pleistocene ice sheets expanded over pre-existing landsystems, pointing to the broader relevance of the methodology and findings reported here.

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An erosional origin for drumlins of NW Poland

Cited by 18 publications

References 148 publications

Groundwater Flow Under a Paleo‐Ice Stream of the Scandinavian Ice Sheet and Its Implications for the Formation of Stargard Drumlin Field, NW Poland

Groundwater Flow Under a Paleo‐Ice Stream of the Scandinavian Ice Sheet and Its Implications for the Formation of Stargard Drumlin Field, NW Poland

Origin of glacial curvilineations by subglacial meltwater erosion: Evidence from the Stargard drumlin field, Poland

LiDAR‐based semi‐automated mapping of drumlins and mega‐scale glacial lineations of the Green Bay Lobe, Wisconsin, USA: Ice sheet beds as glaciotribological systems

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