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B O R
0 2 4
Journal Name
Manuscript No.
B
Dispatch: 5.2.08
Author Received:
Journal: BOR
No. of pages: 8
CE: Blackwell
Te: Gayithri/Mini
Ground-penetrating radar study of Pleistocene ice scours
on a glaciolacustrine sequence boundary
NICK EYLES AND THOMAS MEULENDYK
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Eyles, N. & Meulendyk, T.: Ground-penetrating radar study of Pleistocene ice scours on a glaciolacustrine
sequence boundary. Boreas, 10.1111/j.1502-3885.2008.00024.x. ISSN 0300-9483.
Ice scouring of lake and sea-floor substrates by the keels of drifting ice masses is a common geological process in
modern northern lakes and continental shelves, and was widespread during the Pleistocene. Nonetheless, the importance of scouring as a geological process is not yet matched by many sedimentological studies of scour structures exposed in outcrop. This article presents an integrated study combining outcrop sedimentology and
subsurface ground-penetrating radar (GPR) data from a relict late Pleistocene ice-scoured glacial lake floor now
preserved below beach sediments in Ontario, Canada. Scours occur along a regressive sequence boundary where
deep-water muddy facies are abruptly overlain by shallow-water sands resulting from an abrupt drop in water
levels. This has allowed the keels of drifting ice masses to scour into muds. Three-dimensional data gained from the
GPR survey show that scours are as much as 2.5 m deep and 7 m wide; they have berms of displaced sediment and
are oriented parallel to the former shoreline. Scoured shoreface sediments that fill scours show abundant liquefaction structures, indicating substrate dewatering during repeated scouring events similar to that recently reported
in the modern Beaufort Sea in Canada’s far north. Marked changes in water depths are typical of glacially influenced lakes and seas, creating opportunities for drifting ice to scour into offshore muddy cohesive facies and be
preserved. The data presented here may aid identification in ancient successions elsewhere.
Nick Eyles (e-mail: [email protected]) and Thomas Meulendyk, Department of Physical and Environmental
Sciences, University of Toronto at Scarborough, 1265 Military Trail, Toronto, ON, Canada, M1C 1A; received 23rd
July 2007, accepted 7th December 2007.
The scouring and deformation of underwater substrates by seasonal ice, multi-year ice and/or icebergs is
a common process in northern climates, and affects
substantial portions of the floors of northern seas and
lakes (Barnes 1997; Eden & Eyles 2001 and many
references therein). So-called ‘ice keel’-turbated
sediments subject to repeated deformation, sorting and
mixing by grounding ice keels dominate Arctic and
Antarctic continental shelves and their adjacent areas
(e.g. Vorren et al. 1983; Josenhans et al. 1986; Anderson
1999). Poorly sorted, often muddy turbated sediments
containing coarse ice-rafted debris are recognized as an
important and geographically extensive stratigraphic
component of modern day glacially influenced shelf
successions (Dowdeswell et al. 1994). However, ice keel
turbates are still unknown from the geological record,
possibly as a consequence of pebbly mud facies being
misidentified as ‘tillite’ (see Eyles et al. 2005).
Scouring was an important process in Pleistocene icecontact water bodies formed in North America and
Europe during ice-sheet deglaciation (e.g. Longva &
Thoresen 1991; Winsemann et al. 2003). Exposed floors
of former glacial lakes are marked by thousands of relict scour marks (Josenhans & Zevenhuisen 1990;
Woodworth-Lynas & Dowdeswell 1994; WoodworthLynas 1995; Hequette et al. 1995). Ice-scour structures
are known from, but are rare in, Ordovician glacial
deposits (Beuf et al. 1971), and are present in PermoCarboniferous glaciomarine and glaciolacustrine
successions of the southern ‘Gondwanan’ continents
(e.g. Fairbridge 1947; Visser et al. 1984; Rocha-Campos
et al. 1994; Eyles et al. 1998). As yet, such structures are
unreported from Neoproterozoic glacial successions
(see Eden & Eyles 2001), which is at odds with recent
palaeoclimate models emphasizing the global importance of dynamic drifting ice as an oceanographic
trigger for Neoproterozoic glaciation (Lewis et al.
2003). Only a single Paleoproterozoic example of an ice
scour is known (Miall 1985). Despite the widespread
importance of scouring as a modern and Pleistocene
process, the above review indicates that relatively little
is known of the stratigraphy and geometry of ancient
ice-scoured surfaces and turbates in the rock record.
This data gap is a major avenue for continuing
research.
Modern-day scouring is of considerable economic
importance because it affects the integrity of oil and gas
pipelines, hydroelectric transmission cables and other
underwater facilities in ice-stressed waters. Much effort
has been directed toward understanding the depth of
deformation below relict scours as an aid to risk
assessment for modern sea-floor infrastructure (see
Palmer 1997; Eden & Eyles 2002 and references therein). This work has involved excavation of ancient
scours in raised marine sediments and on drained glacial lake floors (e.g. Woodworth-Lynas & Guigne
1990). Results are constrained by the small size of twodimensional excavations and by the presence of permafrost at more northern sites (see Woodworth-Lynas
et al. 1986).
DOI 10.1111/j.1502-3885.2008.00024.x r 2008 The Authors, Journal compilation r 2008 The Boreas Collegium
024
2
This article furthers our understanding of ancient icescour structures by reporting the results of a GPR study
of Pleistocene scours preserved below a cover of
younger sediment near Toronto, Canada. Whereas
GPR has been used widely in exploring the substrates
of a wide range of sedimentary settings (e.g. Gawthorpe
et al. 1993; Vandenberghe & Van Overmeeren 1999;
Heinz & Aigner 2003; Woodward et al. 2003; Neal
2004; Zeng et al. 2004), including glacial environments
(Bennett et al. 2004), this is the first application of this
geophysical tool to the study of ancient ice scours. Our
study is additionally significant because outcrop sedimentological data are available to supplement geophysical data.
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Nick Eyles and Thomas Meulendyk
Physical setting, age and origin of studied
sediments
Long, high cliffs along the northern shore of Lake Ontario just east of Toronto, Ontario, Canada, expose a
lengthy sediment record of the last glaciation (Wisconsin/
Weichselian) that is unique in eastern North America
(Fig. 1). Cliffs expose sediments belonging to the early
part of that glaciation and that were deposited in an
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ancestral ice-dammed Lake Ontario more than 100 m
deeper than the present water body. Glaciolacustrine
sediments (Scarborough Formation to Upper Thorncliffe Formation; Fig. 1C) began to accumulate during
the earliest incursion of the Laurentide Ice Sheet into
the Great Lakes basin some time around 60 000 years
ago. Glaciolacustrine conditions prevailed until the
Laurentide Ice Sheet overran the entire basin after
23 000 yr BP. This event is recorded by an uppermost
till cap (Halton Till; Fig. 1C).
In its entirety, the succession from the Scarborough
Formation to the Upper Thorncliffe Formation
(Fig. 1C) records changing water depths in a long-lived
ice-dammed lake of regional extent. Pebbly mud ‘rainout’ facies (Sunnybrook, Seminary, Meadowcliffe diamicts; Fig. 1C) were deposited by the combined actions
of ice-rafting of coarser debris and deposition of mud
from suspension (Eyles et al. 2005). These facies contain deep-water ostracod faunas and alternate with
shallower-water sediments (Thorncliffe Formation)
consisting of shoreface sands that show storm deposits,
such as hummocky and swaley cross stratification
(Eyles & Clark 1986, 1988). Alternations of deep-water
and shallow-water facies record abrupt changes in
water depth in the basin (typical of ice-dammed lakes);
Fig. 1. A, B. Sylvan Park study area near Toronto, Canada. C. Stratigraphy of glacial sediments exposed along north shore of Lake Ontario at
Scarborough Bluffs.
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Pleistocene ice scours
3
Fig. 2. A. Vertical air photograph of study area (X–Y)
along Scarborough Bluffs
showing flat terrace top to
modern bluffs and inland bluff
of Glacial Lake Iroquois. B.
Oblique air shot of same area
showing Iroquois terrace cut
across Bluffs stratigraphy and
location of study area (X–Y)
and cliff top outcrops of ice
scours in modern cliffs.
the abrupt contacts that occur between these facies are
‘sequence boundaries’ (Brookfield & Martini 1999).
The deep-water and shallow-water sedimentary facies
exposed at Scarborough and the palaeoenvironmental
interpretations drawn from them have been described
in numerous publications (see Eyles et al. 2005) and the
reader is referred to these for sedimentological details.
Of particular interest here is the regressive sequence
boundary marking the contact between shallow-water
024
shoreface sediments of the lower Thorncliffe Formation and underlying muddy facies (Sunnybrook diamict) that was extensively deformed by floating ice
(Eyles et al. 2005). Existing description of these scours
has been limited to two-dimensional outcrops. The
purpose here is to integrate outcrop data with a geophysical study of planform characteristics to create a
three-dimensional picture of the relict ice-scoured lake
floor.
4
Study area
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Nick Eyles and Thomas Meulendyk
The study area at Sylvan Park (Fig. 2A, B) comprises a
terrace bounded on its lakeward margin by actively
eroding cliffs, and inland by a former cliff cut during a
highstand of an ancestral Lake Ontario 12 250 years
ago (Glacial Lake Iroquois). Thin (o2 m) Iroquois
beach gravels rest unconformably on Wisconsin shoreface sands (Lower Thorncliffe Formation) that display
hummocky and swaley cross-stratification (Fig. 3).
Such facies record a storm-influenced, shallow-water
setting where fine sand was reworked by powerful oscillatory currents. Shoreface sediments rest on the undulating surface of an underlying mud with ice-rafted
clasts (Sunnybrook Diamict; Fig. 3). As related above,
the mud/sand contact is a regressive sequence boundary
recording a rapid reduction in water depths, prograda-
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tion of shoreface sediments over deep-water muds and
scouring by floating ice (Eyles et al. 2005). Thorncliffe
Formation shoreface sands are ice keel turbated and
were pushed down into the underlying mud with corresponding upward penetrating mud diapirs. Sands show
large ice-rafted boulders and extensive soft sediment
deformations indicating widespread liquefaction of the
substrate during scouring. Deformed horizons are
truncated by beds of hummocky and swaley crossstratified facies suggesting multiple episodes of scouring
and storm activity in an energetic, ice-stressed, shoreface setting.
The Iroquois terrace and cliff result from erosion of a
substantial thickness of Wisconsin sediment (Fig. 1C)
creating a unique opportunity to map the topography of
the ice-scoured surface of the Sunnybrook diamict using
high-resolution, ground-penetrating radar (GPR). Elsewhere in the Toronto area these scours are too deeply
buried by sediments to be mapped geophysically.
GPR methods and data treatment
Fig. 3. Sedimentology of Lower Thorncliffe Formation shoreface
deposits resting on Sunnybrook diamict at Sylvan Park (Fig. 1C).
The contact between them is a major sequence boundary recording
abrupt shallowing of water depths in a large ice-dammed lake with
drifting ice.
024
A RAMAC GPR 250 MHz GPR unit was used for this
study. GPR is an effective way of mapping the form of
the buried Sunnybrook surface, because this mud deposit has markedly contrasting dielectric constants
compared with the overlying sand deposits of the
Thorncliffe Formation and beach gravels of Glacial
Lake Iroquois. The upper surface of the Sunnybrook,
at an average depth of about 5 m, acts as an acoustic
basement for radar providing an excellent reflector that
is readily recognizable on GPR images. Closely spaced
survey lines are 0.5 m apart and 100 m long. The surveyed corridor is about 14 m wide and the area about
1400 m2. An initial reconnaissance survey was completed across the Iroquois terrace using a pulse velocity
of 80 m/ms and a time window of 300 ns. During a second survey, the subsurface stratigraphic resolution was
greatly enhanced by increasing the velocity to 150 m/ms
and reducing the time window to 140 ns. In all cases,
measurements were triggered every 0.1 m by an
odometer wheel.
The processing software program used in this study
was REFLEXW (Sandmeier 2006). While processing of
some GPR data commonly involves use of multiple filters (e.g. Jol & Bristow 2003), only a single gain feature
was employed. The divergence compensation gain acts
on each trace (or pulse) independently and compensates
for geometric divergence losses (Sandmeier 2006). After
processing, reflectors marking the contact between the
Sunnybrook and Thorncliffe sediments were readily
identified on profiles (Fig. 4) and confirmed by direct
visual comparison in the field with the depth below the
ground surface seen in outcrop. The unconformity between the two was then ‘picked’ on each profile and line
traces were stacked together to produce a composite
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diagram of the entire scoured surface (Fig. 5A). A second kriging program (Manifold System 6.50 Enterprise
Edition; CDA International Limited 2005) was used to
produce a three-dimensional image (Fig. 5B).
Results
Figure 5B shows the three-dimensional form of the
buried ice-scoured topography developed on the upper
Pleistocene ice scours
5
surface of the Sunnybrook sediment below the surveyed
area. The surface shows several linear scours flanked on
either side by upstanding berms composed of Sunnybrook mud displaced out of the scour. Individual
scours are subparallel and straight with an overall
northeast/southwest orientation similar to the dominantly westerly orientation of other ice-scoured structures (e.g. soft-sediment striations and micro-ridges,
oriented ice-pushed clasts) reported from Sunnybrook
Fig. 4. Representative processed GPR line traces with upper ice-scoured surface of Sunnybrook diamict picked (see Fig. 5). Horizontal and
vertical scales are the same in all examples.
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Nick Eyles and Thomas Meulendyk
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Fig. 5. A. Composite diagram of stacked line traces of the ice-scoured surface of the Sunnybrook diamict. Note varying scales used. B. Kriged
three-dimensional image of ice scours on Sunnybrook based on composite line traces in A. Note varying scales used.
outcrops by Eyles et al. (2005). This direction of ice
drift was parallel to the inferred shoreline at the time.
Maximum relief across the ice-furrowed surface, defined by the difference in elevation between the lowest
scour base and maximum berm height, is 2.5 m. Some
scours have an irregular long profile showing enclosed
lows that might indicate ‘staggered’ grounding events
where drifting ice is pushed into the substrate only to
float off, drift and then reground. Other scour floors are
flat and smooth, indicating uninterrupted scouring. The
mud surface between furrows is irregular, showing nonoriented depressions consistent with repeated ‘prodding’ of the muddy substrate by immobile, grounded ice
blocks.
The ice-furrowed surface of the Sunnybrook is infilled and buried by shoreface sands (Fig. 3). Subhorizontal GPR sub-reflectors within scour fills identify
undulatory bed contacts within these shoreface sediments (Fig. 4). Numerous point source reflectors are
created by the presence of ice-rafted boulders.
A marked feature of these facies is the widespread presence of soft sediment deformations such as ball and
pillow structures (Fig. 3). These deformations result
from abrupt dewatering and are readily interpreted in
024
the light of work on modern ice-scoured surfaces in the
Beaufort Sea of northern Canada mapped by multibeam sonar (Blasco et al. 1998). This recent work demonstrates that the impact and penetration of ice keels
into sea-floor substrate overpressures sub-sea-floor
sands, resulting in the sudden venting of gas and water
leaving a cratered (‘pockmarked’) sea-floor surface. To
date, the effects of this process have not been recognized in the ancient record. The presence of liquefied substrates and an irregular substrate with channels
flanked by berms may be important criteria for the recognition of ice scours in ancient rocks.
Discussion
To our knowledge, this is the first known application of
GPR to the mapping of buried ice-scoured surfaces. By
itself, this is of less significance compared to the fact
that outcrop data are available in the study area to
ground-truth subsurface geophysical information
(Fig. 2). In addition, a shallow cover of coarse-grained
sediments (Fig. 3) allows unhindered propagation of
radar waves. The dense mud into which scours are cut
Pleistocene ice scours
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forms a well-defined ‘acoustic basement’ that is readily
picked on GPR traces (Fig. 4).
There are close similarities between the three-dimensional GPR form of furrowed Pleistocene sediments at
Scarborough (Fig. 5B) and that of modern ice scours
mapped by multibeam bathymetric profiling in the
Beaufort Sea. There, in water depths of about 20 m,
straight furrows predominate, with fewer curvilinear
forms. Most scours are flat-floored, reflecting the shape
of the keel under the multi-year ‘pack ice’ that drifted
across the sea floor. The orientation of scours is predominantly shore-parallel, in keeping with other ancient scours (e.g. Gilbert et al. 1992) where ice was
pushed shoreward and then forced to ground parallel
with bathymetric contours.
The data presented here from Scarborough, Ontario,
may aid identification of scouring in ancient successions. Scours are most likely to be preserved along regressive sequence boundaries marking a reduction in
water depths, thereby allowing ice keels to touch hitherto deep-water muddy substrates. The undulatory
outcrop form of scours and berms of the scoured Sunnybrook/Thorncliffe sequence boundary at Scarborough is distinct. In association with deformed
sediments, upstanding lateral berms and the presence of
ice-rafted debris, the scoured surface is readily discriminated from incised, channelled ‘ravinement’ surfaces resulting from fluvial or shallow marine erosion
along regressive sequence boundaries. In many modern
sand-dominated substrates, scours are typically
ephemeral features readily eradicated by subsequent
storm-wave generated currents. The key to their preservation at Scarborough is that they were cut into cohesive mud that created a resistant topography of
scours and berms that could not readily be reworked by
storm waves. It is likely that scours were cut and then
filled (and thus preserved) by rapid aggradation of
shoreface sands. Such conditions were commonplace in
ice-stressed waterbodies during past glaciations, where
marked fluctuations in water depths occurred through
lake drainage, damming and/or glacio-isostatic and
glacio-eustatic effects on basins. The data presented
here from a glaciolacustrine sequence boundary near
Toronto may aid identification elsewhere.
Conclusions
We employed GPR to map a buried, Pleistocene, icescoured lake floor. The surface comprises a regressive
sequence boundary between deep-water mud and shallow-water sand facies created by a decrease in water
depths. Geophysical data were ground-truthed by reference to outcrops where the subsurface scoured layer
is exposed. GPR readily identifies the geometry of buried scours and the stratigraphy of shoreface sediments
that infill them. Ice scours in the geological record may
024
7
be preferentially preserved along analogous sequence
boundaries where sand rests on mud.
Acknowledgements. – A Natural Sciences and Engineering Research
Council of Canada grant to Eyles and a NSERC scholarship to
Meulendyk supported this research. We thank Mike Doughty for
technical assistance and Jan A. Piotrowski, Brian Todd and Oddvar
Longva for their helpful comments on the manuscript.
References
Anderson, J. B. 1999: Antarctic Marine Geology. 289 pp. Cambridge
University Press, Cambridge.
Barnes, P. W. 1997: Iceberg gouges on the Antarctic Shelf. In Davies,
T. A., Bell, T., Cooper, A. K., Josenhans, H., Polyak, L., Solheim,
A., Stoker, M. S. & Stravers, J. A. (eds.): Glaciated Continental
Margins: An Atlas of Acoustic Images, 154–156. Chapman & Hall,
London.
Bennett, M. R., Huddart, D., Waller, R. I., Cassidy, N., Tomio, A.,
Zukowskyj, P., Midgley, N. G., Cook, S. J., Gonzalez, S. &
Glasser, N. F. 2004: Sedimentary and tectonic architecture of a
large push moraine: a case study from Hagafellsjökull-Eystri,
Iceland. Sedimentary Geology 172, 269–292.
Beuf, S., Biju-Duval, B., de Charpal, O., Rognon, P., Gariel, O. &
Bennacef, A. 1971: Les Gre`s du Paléozoı¨que Infe´rieur au Sahara:
Se´dimentation et Discontinuite´s, Evolution Structurale d’un Craton
464 pp. Editions Technip, Paris.
Blasco, S. M., Shearer, J. M. & Myers, R. 1998: Seabed scouring by
sea ice: scouring processes and impact rates: Canadian Beaufort
shelf. Proceedings of Ice Scour and Arctic Marine Pipelines Workshop, 13th International Symposium on Okhotsk Sea and Sea Ice,
Mombetsu, Hokkaido, Japan, 1–4 February 1998. C-CORE,
St. John’s, Newfoundland.
Brookfield, M. E. & Martini, I. P. 1999: Facies architecture and sequence stratigraphy in glacially influenced basins: basic problems
and water level/glacier input-point controls (with an example from
the Quaternary of Ontario, Canada). Sedimentary Geology 123,
183–197.
CDA International Limited. 2005: Manifold System 6.50 Enterprise
Edition Online User Manual. Available at: http://exchange.
manifold.net/manifold/manuals/manifold/whnjs.htm
Dowdeswell, J. A., Whittington, R. J. & Marienfeld, P. 1994: The
origin of massive diamicton facies by iceberg rafting and scouring,
Scoresby Sund, east Greenland. Sedimentology 41, 21–35.
Eden, D. & Eyles, N. 2001: Description and numerical model
of a Pleistocene iceberg scour at Scarbororough Bluffs, Ontario,
Canada. Sedimentology 48, 1079–1022.
Eden, D. & Eyles, N. 2002: Case study of an iceberg scour at Scarborough Bluffs, Ontario and implications for pipeline engineering.
Canadian Geotechnical Journal 39, 519–534.
Eyles, N. & Clark, B. M. 1986: The significance of hummocky and
swaley cross – stratification in late Pleistocene lacustrine sediments
of the Ontario Basin, Canada. Geology 14, 679–682.
Eyles, N. & Clark, B. M. 1988: Storm – influenced deltas and ice –
scouring in a Late Pleistocene glacial lake. Geological Society of
America Bulletin 100, 793–809.
Eyles, C. H., Eyles, N. & Gostin, V. A. 1998: Facies and allostratigraphy of high-latitude, glacially-influenced marine strata of the
Early Permian southern Sydney Basin, Australia. Sedimentology
45, 121–163.
Eyles, N., Eyles, C. H., Woodsworth-Lynas, C. & Randall, T. 2005:
The sedimentary record of drifting ice (early Wisconsin Sunnybrook deposit) in an ancestral ice-dammed Lake Ontario. Quaternary Research 63, 171–181.
Fairbridge, R. W. 1947: Possible causes of intraformational disturbances in the Carboniferous varve rocks of Australia. Journal
Proceedings of the Royal Society of New South Wales 81, 99–121.
Gawthorpe, R. L., Collier, R. E. L., Alexander, J., Bridge, J. S. &
Leeder, M. R. 1993: Ground penetrating radar: application to sand
8
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56
57
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body geometry and heterogeneity studies. In North, C. P. &
Prosser, D. J. (eds.): Characterization of Fluvial and Aeolian Reservoirs: Special Publication 73, 421–432. Geological Society of
London.
Gilbert, R., Handford, K. J. & Shaw, J. 1992: Ice scours in the sediments of glacial Lake Iroquois, Prince Edward County, eastern
Ontario. Geographie Physique et Quaternaire 46, 189–194.
Heinz, J. & Aiger, T. 2003: Three-dimensional GPR analysis of various Quaternary gravel-bed braided river deposits (southwestern
Germany). In Bristow, C. S. & Jol, H. M. (eds.): Ground Penetrating
Radar in Sediments: Special Publication 211, 99–110. Geological
Society of London.
Heqeutte, A., Desrosiers, M. & Barnes, P. W. 1995: Sea ice scouring
on the inner shelf of the southeastern Beaufort Sea. Marine Geology
128, 201–219.
Jol, H. M. & Bristow, C. S. 2003: GPR in sediments: advice on data
collection, basic processing and interpretation, a good practice
guide. In Bristow, C. S. & Jol, H. M. (eds.): Ground Penetrating
Radar in Sediments: Special Publication 211, 9–27. Geological
Society of London.
Josenhans, H. W. & Zevenhuizen, J. 1990: Dynamics of the
Laurentide ice sheet in Hudson Bay, Canada. Marine Geology 92,
1–26.
Josenhans, H. W., Zevenhuizen, J. & Klassen, R. A. 1986: The Quaternary geology of the Labrador Shelf. Canadian Journal of Earth
Sciences 23, 1190–1213.
Lewis, J. P., Weaver, A. J., Johnston, S. T. & Eby, M. 2003: Neoproterozoic ‘snowball Earth’: dynamic sea ice over a quiescent ocean.
Paleoceanography 18, 1092.
Longva, O. & Thoresen, M. K. 1991: Ice scours, iceberg gravity craters and current erosion marks from a gigantic Preboreal flood in
southeastern Norway. Boreas 20, 47–62.
Miall, A. D. 1985: Sedimentation on an early Proterozoic continental
margin under glacial influence: the Gowganda Formation (Huronian), Elliot Lake area, Ontario, Canada. Sedimentology 32,
763–788.
Neal, A. 2004: Ground-penetrating radar and its use in sedimentology: principles, problems and progress. Earth Science Reviews 66,
261–330.
Palmer, A. C. 1997: Geotechnical evidence of ice scour as a guide
to pipeline burial depth. Canadian Geotechnical Journal 34,
1002–1003.
Rocha-Campos, A. C., dos Santos, P. R. & Canuto, J. R. 1994: Ice
scouring structures in Late Paleozoic rhythmites, Paraná Basin,
Brazil. In Deynoux, M., Miller, J. M. G., Domack, E. W., Eyles,
N., Fairchild, I. J. & Young, G. M. (eds.): Earth’s Glacial Record,
234–240. Cambridge University Press, Cambridge.
024
BOREAS
Sandmeier, K. J. 2006: REFLEXW: version 4.0 instruction manual.
Zipser Straße 1, D-76227 Karlsruhe, Germany. Available at: http://
www.sandmeier-geo.de.
Vandenberghe, J. & Van Overmeeren, R. A. 1999: Ground penetrating radar images of selected fluvial deposits in the Netherlands.
Sedimentary Geology 128, 245–270.
Visser, J. N. J., Colliston, W. P. & Terblanche, J. C. 1984: The origin
of soft-sediment deformation structures in Permo-Carboniferous
glacial and proglacial beds, South Africa. Journal of Sedimentary
Research 54, 1183–1196.
Vorren, T. O., Hald, M., Evardsen, M. & Lind-Hansen, O. H. 1983:
Glacigenic sediments and sedimentary environments on continental
shelves: general principles with a case study from the Norwegian
Shelf. In Ehlers, J. (ed.): Glacial Deposits in North-West Europe,
61–76. A. A. Balkema, Rotterdam.
Winsemann, J., Asprion, U., Meyer, T., Schultz, H. & Victor, P. 2003:
Evidence of iceberg-ploughing in a subaqueous ice-contact fan,
glacial Lake Rinteln, NW Germany. Boreas 32, 386–398.
Woodward, J., Ashwort, P. J., Best, J. L., Sambrook Smith, G. H. &
Simpson, C. J. 2003: The use and application of GPR in sandy fluvial environments: methodological considerations. In Bristow, C. S.
& Jol, H. M. (eds.): Ground Penetrating Radar in Sediments: Special
Publication 211, 124–142. Geological Society of London.
Woodworth-Lynas, C. M. T. 1995: Ice scour as an indicator of glaciolacustrine environments. In Menzies, J. (ed.): Glacial Environments: Sediments, Facies and Techniques, 161–178. ButterworthHeinemann, Oxford.
Woodworth-Lynas, C. M. T. & Dowdeswell, J. A. 1994: Softsediment striated surfaces and massive diamicton facies produced
by floating ice. In Deynoux, M., Miller, J. M. G., Domack, E. W.,
Eyles, N., Fairchild, I. J. & Young, G. M. (eds.): Earth’s Glacial
Record, 241–259. Cambridge University Press, Cambridge.
Woodworth-Lynas, C. M. T. & Guigne, J. Y. 1990: Iceberg scours in
the geological record: examples from glacial Lake Agassiz. In
Dowdeswell, J. A. & Scourse, J. D. (eds.): Glacimarine Environments: Processes and Sediments: Special Publication 53, 217–233.
Geological Society of London.
Woodworth-Lynas, C. M. T., Seidal, M. & Day, T. 1986: Relict ice
scours on King William Island, N.W.T. In Lewis, C. F. M., Parrot,
D. R., Simpkin, P. G. & Buckley, J. T. (eds.): Ice Scour and Seabed
Engineering: Report No. 049, 64–72. Environmental Studies Revolving Funds, Ottawa.
Zeng, X., McMechan, G. A., Bhattacharya, P. J., Aiken Carlos, L. T.,
Xu, X., Hammon III, W. S. & Corbeanu, R. M. 2004: 3D imaging
of a reservoir analogue in point bar deposits in the Ferron Sandstone, Utah, using ground penetrating radar. Geophysical
Prospecting 52, 151–163.
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