Morphology and composition of drumlins in
the forefield of Nordenskiöldbreen, central
Spitsbergen
Nína Aradóttir
Faculty of Earth Sciences
University of Iceland
2015
Morphology and composition of drumlins in
the forefield of Nordenskiöldbreen, central
Spitsbergen
Nína Aradóttir
10 ECTS thesis submitted in partial fulfillment of
Baccalaureus Scientiarum degree in Geology
Advisor
Ólafur Ingólfsson
Faculty of Earth Science
School of Engineering and Natural Sciences
University of Iceland
Reykjavík, January 2015
Morphology and composition of drumlins in the forefield of Nordenskiöldbreen, central
Spitsbergen
Drumlins in the forefield of Nordenskiöldbreen
10 ECTS thesis submitted in partial fulfillment of Baccalaureus Scientiarum degree in
Geology
Copyright © 2015 Nína Aradóttir
All rights reserved
Faculty of Earth Science
School of Engineering and Natural Sciences
University of Iceland
Askja, Sturlugata 7
107 Reykjavík
Telephone: 525 4000
Registration information:
Nína Aradóttir, 2015, Morphology and composition of drumlins in the forefield of
Nordenskiöldbreen, central Spitsbergen, Bachelor’s thesis, Faculty of Earth Sciences,
University of Iceland, pp. 34.
Printing: Háskólaprent
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_______________________________________
Nína Aradóttir
Kt. 1011903079
Janúar 2015
Abstract
Drumlins are important glaciogenic landforms that can be useful to reconstruct earlier
glaciations. Their morphology and composition can be highly variable and their formation is
still not fully explained. They are among the most studied landforms. Despite that drumlins
have not been described on land in Svalbard. The aim of this study is to investigate the
morphology and composition of five drumlins in the forefield of Nordenskiöldbreen,
Svalbard.
The drumlins were formed during the last glacial advance, The Little Ice Age. Based on aerial
images and field investigation, it has been concluded that the glacier has retreated
approximately 1,5 km on the northern side. The drumlins were exposed in the mid 20th
century. They do support earlier theories that the glacier is polythermal and the direction of
the former ice flow was ENE to WSW. A TopCon was used to reconstruct their morphology
and it does demonstrate how variable the morphology of drumlins can be. Fluvial erosion is
considered to be one of the main reasons for that. The drumlins are smaller compared to
drumlins in earlier literature. To investigate the composition of the drumlins a section in one
of them was logged. It was diveded into two layers based on difference in grain size. They
were both interpreted as a till based on clast morpholgy and composition and fabric analysis.
Further investigation would be needed for more interpretations about the drumlins.
Útdráttur
Jökulöldur eru mikilvæg landform í jökulmótuðu landslagi og eru gagnlegar til að
endurbyggja fyrri jökulskeið. Form og setgerð þeirra getur verið mjög fjölbreytt og myndun
þeirra er enn ekki að fullu útskýrð. Þær eru með mest rannsökuðu landformunum. Þrátt fyrir
það hefur jökulöldum á landi ekki verið lýst á Svalbarða. Markmið þessarar rannsóknar var að
lýsa formi og setgerð fimm jökulaldna á jökulsvæði Nordenskiöldbreen, Svalbarða.
Þær voru myndaðar á síðasta jökulskeiði, Litlu Ísöld. Út frá loftmyndum og rannsóknum í
felti hefur verið staðfest að jökullinn hefur hörfað um 1,5 km á norður hlið hans.
Jökulöldurnar urðu ísfríar um miðja 19. öld. Þær styðja fyrri kenningar að jökullinn sé
blandjökull og að skriðstefna hans var frá ENE til WSW. TopCon mælitæki var notað til að
endurbyggja form þeirra og niðurstöðurnar undurstrikuðu hversu fjölbreytt þar er. Vatns rof er
talin eins helsta ástæðan fyrir því. Jökulöldurnar reyndust vera minni er þær voru bornar
saman við jökulöldur fyrri rannsókna. Uppbyggingu þeirra var lýst með því að skoða snið í
einni þeirra og greina það. Opnunni var skipt í tvö lög vegna breytinga í kornastærð. Bæði
lögin voru túlkuð sem jökulurð út frá formi og uppbyggingu bergmylsnu og veftu mælingum.
Áframhaldandi rannsóknir eru nauðsynlegar til frekari túlkanna á jökulöldunum.
Table of contest
List of figures .................................................................................................................... viii
List of tables ..........................................................................................................................x
Acknowledgements ..............................................................................................................xi
1 Introduction .....................................................................................................................2
1.1 Svalbard ....................................................................................................................3
1.2 Nordenskiöldbreen ...................................................................................................3
1.3 Quaternary background of Nordenskiöldbreen ........................................................4
2 Methods ............................................................................................................................6
2.1 Morphology ..............................................................................................................6
2.2 Composition .............................................................................................................6
3 Results ...............................................................................................................................7
3.1 The forefield of Nordenskiöldbreen .........................................................................8
3.2 The drumlins .............................................................................................................8
3.2.1 Drumlin 1 ....................................................................................................... 9
3.2.2 Drumlin 2 ..................................................................................................... 10
3.2.3 Drumlin 3 ..................................................................................................... 12
3.2.4 Drumlin 4 ..................................................................................................... 14
3.2.5 Drumlin 5 ..................................................................................................... 16
3.2.6 The composition of the drumlin’s surface ................................................... 18
4 Discussion .......................................................................................................................19
4.1 Nordenskiöldbreen .................................................................................................19
4.2 Morphology ............................................................................................................19
4.3 Composition ...........................................................................................................20
4.4 Drumlins on Svalbard .............................................................................................21
5 Summary and conclusion ..............................................................................................23
Reference .............................................................................................................................24
Appendix .............................................................................................................................27
vii
List of figures
Figure 1 Location of the study area a) Billefjorden located on Svalbard archipelago
with a red mark. b) The forefield of Nordenskiöldbreen in Adolfbukta is
marked with a red square. (modified from Norwegian Polar Institute, 2014). .. 4
Figure 2 The retreat of Nordenskiöldbreen after the end of LIA a) The glacier front in
1908 mapped by De Geer (1910). The glacier is green on the map b)
Fragment of an orthophotomap based on Norwegian Polar Institute aerial
photographs taken in 2009. The figure shows were the glacier front was
situated in 1900, 1930, 1960 and 1990 (Strzelecki, 2011). ................................ 5
Figure 3 An aerial image of the forefield of Nordenskiöldbreen. a) In the forefield
various glaciogenic landforms were observed. The most prominent ones
were mapped. They all have similar orientation, ENE-WSW b) The outlines
of the drumlins on a close up figure of the drumlin field. The soil pit is
located in the middle of drumlin 3...................................................................... 7
Figure 4 Drumlin 1 a) A longitudinal profile b) A 3D model, scale is in meters. Both
figures show that the lee side was lower than the stoss side. The morphology
was therefore not typical for drumlins. .............................................................. 9
Figure 5 Drumlin 2 a) A longitudinal profile b) A 3D model, scale is in meters. On both
figures it can be seen that the morphology of it indicates it to be a drumlin.
The limits were though hard to distinguish in the field. ................................... 10
Figure 6 Drumlin 1 and 2 a) Fluvial erosion has eroded the proximal limit of drumlin 1
and it surroundings b) One of many flutes observed on top of drumlin 2.
This one is mapped on fig. 3 and was used to follow a straight line when
measuring the length with the TopCon............................................................. 11
Figure 7 Drumlin 3 a) A longitudinal profile b) A 3D model, scale is in meters. Both
figures demonstrate the oval-shape of the drumlin very well. ......................... 12
Figure 8 The composition of drumlin 3 a) The log of the 110 cm section was divided into two
layers based on grain size. Both layers were interpreted to be Dmm b) The grain
size distribution in the two layers. The upper layer contains much more clay than
the lower and less gravel c) The fabric analysis was rather weak but showed some
sign of prefered orientation. .......................................................13
Figure 9 Upper layer of the section, a clay rich diamict with an unclear fissure
structure............................................................................................................ 14
Figure 10 A longitudinal profile of drumlin 4. An error was made in the measurements
at the distal limit of the drumlin and therefore the surface above origin
should not be taken into account. ..................................................................... 14
viii
Figure 11 Drumlins 1, 2, 3 and 4 with Nordenskiöldbreen in the back a) Similar height
of the stoss and lee side of drumlin 1 and the pointed distal limit of drumlin
2. Signs of fluvial erosion can be seen in front of drumlin 2 b) The indistinct
proximal limit of drumlin 2 at right, overview of the well-shaped drumlin 3
in the middle with fluvial erosion on its distal end and the elongated drumlin
4 to the left with the crag and tail behind it. Photos: Skafti Brynjólfsson
(2013) ............................................................................................................... 15
Figure 12 Drumlin 3 a) A longitudinal profile b) A 3D model, scale is in meters. The
depressions on the figures are thought to represent the depressions and
channel noted on the drumlin in the field. ........................................................ 16
Figure 13 Drumlin 5 a) The depression on the south limit of the drumlin 5. No cracks or
slides can be observed and vegetation is present in the bottom of it b) The
flute that was composed of different sediment than the drumlin and marked
the limit of it on the northern margin. .............................................................. 17
Figure 14 The surface of drumlin 5, it was interpreted to be a diamict because it
contained clasts of all grain sizes in all shapes with various lithology. The
surface was similar on all of the drumlins. ...................................................... 18
ix
List of tables
Table 1 Drumlin characteristics based on the TopCon measurements. ............................... 8
Table 2 Direction of glacial striations on boulders. ........................................................... 18
Table 3 Drumlin 1, TopCon measurements ........................................................................ 27
Table 4 Drumlin 2, TopCon measurements ........................................................................ 28
Table 5 Drumlin 3, TopCon measurements ........................................................................ 29
Table 6 Drumlin 3, fabric analysis measurements and clast morphology .......................... 31
Table 7 Drumlin 3, grain size distribution .......................................................................... 32
Table 8 Drumlin 5, TopCon measurements ........................................................................ 33
x
Acknowledgements
I want to thank my supervisor, Dr. Ólafur Ingólfsson for his guidance during the project and
assistance in the field work together with Dr. Anne Hormes, Skafti Brynjólfsson and Sverrir
Aðalsteinsson. My classmates from AG-210 are also thanked for all the data collected for the
project during field work. My group mates, Turid Haugen and Esty Willcox, deserve special
thanks for assistance in the field and Allan Audsley for reading over the paper.
My amazing family and friends are thanked for always being there for me and their support
when it was truly needed.
xi
1 Introduction
A significant warming has been recorded during the last century after the subsidence of the
Neoglaciation; that has caused melting of glaciers all over the world. The effects on the Arctic
have been substantial (Miller et al., 2010) and can be seen on Svalbard’s glaciers. Glaciers
cover only 60% of Svalbard archipelago (Hagen et al., 1993) after having covered it all during
a full-glacial mode. Due to the retreat of the glaciers many glaciogenic landforms and
sediments have been exposed. This can be used to reconstruct earlier glaciations (Ingólfsson,
2011).
Drumlins are one of the landforms used for those investigations. They have caught the interest
of many scientists over the years and are one of the most studied landforms. Over 1300
contributions (published papers, abstracts, theses) and 400 papers have been published since
1980 (Clark et al. 2009). Drumlins are oval-shaped hills composed of glacial drift. One of the
most distinguishing characteristic of them is their morphology. The stoss side is steep and
blunt but the lee side is gentler and tapered. Many equations have been suggested to describe
their morphology and the most common one is the elongation ratio (Menzies, 1979).
Drumlins have been observed in all sizes, Clark et al. (2009) concluded the mean lengths and
widths were 629 m and 209 m and the mean elongation ratio to be 2,9:1. They often occur as
swarms of landforms rather than individual ones. Drumlins have a great variety of
composition. They can be composed of everything from stratified sand to unstratified till or
even solid bedrock. Their core can consist of sand, boulders or laminated clay.
Many theories about the formation of drumlins have been suggested. The most accepted one
is that it forms under a temperate glacier (Menzies, 1979). They can be either formed by an
erosional process where pre-existing deposits can be eroded into a drumlin, an accretion of
basal deposit or a combination of the two processes (Benn and Evans, 2010). Their long-axes
lies parallel to the ice-flow orientation and therefore it reflects the direction of the former ice
movement. They are found close to the margins of past ice sheets (Menzies, 1979).
Drumlins formed after the Neoglaciation have been described in Iceland in the past decades
(Krüger and Thomsen, 1984). In Svalbard however, research has only been on drumlinoid
hills (Christoffersen et al., 2005) and submarine drumlins (Ingólfsson, 2011). In 1970,
Boulton did though observe what he interpreted to be a rock cored drumlin in the forefield of
Nordenskiöldbreen. This paper therefore reveals the first study on terrestrial drumlins in
Svalbard.
In the forefield of Nordenskiöldbreen drumlins were observed and their morphology together
with their composition investigated. Suitable methods used for that are described in the paper
and it is thought as a guideline for future research. Focus will also be on what the drumlins
can reveal about the behavior and history of Nordenskiöldbreen.
2
1.1 Svalbard
Svalbard is an archipelago consisting of many islands with total area of 63.000 km2. It is
situated in the Arctic Ocean on the edge of the Barents Sea Shelf, located between 74°-81° N
and 10°-35° W. It has an arctic climate with mean temperature of about -5°C and precipitation
around 180 mm at sea level in central Spitsbergen (Humlum et al., 2003). Most of the glaciers
in Svalbard are subpolar or polythermal. Studies on them have revealed that they are
temperate in the accumulation area and deep in the ablation area. The margins of the glacier
and the upper parts of the ablation area are cold based. They are therefore only partly frozen
to the ground (Petterson et al., 2004). Surges are common in glaciers in Svalbard and over
90% of them are thought to be of a surge-type. They are short-lived events characterized by
high flow rates. A relatively longer period of slower flow, the quiescent phase, occurs
between subsequent surges. They can be hard to identify due to their shortness and lack of
access to them. Therefore they can easily occur without them being recorded (Hagen et al,
1993).
1.2 Nordenskiöldbreen
The study area is located in Billefjorden, central Spitsbergen (fig. 1a). Nordenskiöldbreen
drains out from Lomonosovfonna ice cap into Adolfbukta, located along the northern shore of
Billefjorden (fig. 1b). The ice front calves into the sea and is both grounded to the sea floor
and the bedrock edge. The surface of the glacier is crevassed, suggesting that the ice is thin
(Hormes and Ingólfsson, 2013). The glacier is around 242 km2, 26 km long and rises 1200 m
above sea level. Nordenskiöldbreen is a tidewater outlet glacier (Hagen et al, 1993) and has
been described as a polythermal glacier in recent literature (Hagen et al. 1993; Rachlewicz et
al, 2007). Surges have never been observed in Nordenskiöldbreen. No evidence from
landform assemblages or features on the glacier suggests that it has surged in the past (Baeten
et. al., 2010).
The geology in the area is very diverse. The bedrock consists of Precambrian metamorphic
rocks and rocks from late Carboniferous. The north-south Billefjorden Fault Zone lies through
it, making the geology even more varied. The exposed bedrock in front of Nordenskiöldbreen
is very resistance Precambrian metamorphic rock from Hecla Hoek Formation (Dallmann et.
al., 2004).
3
a)
b)
Adolfbukta
Nordenskiöldbreen
Billefjorden
Figure 1 Location of the study area a) Billefjorden located on Svalbard archipelago with a
red mark b) The forefield of Nordenskiöldbreen in Adolfbukta is marked with a red square
(modified from Norwegian Polar Institute, 2014).
1.3 Quaternary background of Nordenskiöldbreen
During the Late Holocene there was an overall cooling trend in the world that resulted in
expansion of glaciers in the Arctic. The growth is called the Neoglaciation (Miller et al.,
2010). The Neoglacial moraines observed and dated in the forefields of Spitsbergen glaciers
show a history of multiple glacial advances during that time (Werner, 1993). The most recent
advance occurred around 1250-1850 AD. It has been termed the Little Ice Age (LIA). The
cooling did not occur at the same time all over the world and in Svalbard it took place from
1500-1900 AD. During that time glaciers reached their maximum length making LIA the
most extensive advance in the Late Holocene (Miller et al., 2010). De Geer (1910) visited
Nordenskiöldbreen in 1882, 1896 and 1908. He noticed that the glacier was almost stagnant
between 1882 and 1896. In 1908 he mapped the situation of the glacier front. Then it had
however retreated 100-200 m (fig. 2a). By comparing his observation with a map from
Strzelecki (2011) (fig. 2b) the location of the glacier front from 1900 to 2009 can be traced.
The retreat was thought to be slow (Boulton, 1970) but recent studies have shown that it
might not have been the case. The mean average linear retreat has been measured 35 m a-1 and
decreased 5,3% from LIA to 2002 with a mean retreat of more than 132.400 m2 a-1. The
retreat was most rapid from LIA to 1961. The maximum retreat is around 3,5 km. In front of
Nordenskiöldbreen about 25 km2 (both on land and on seafloor) of landscape has been
revealed since the ending of LIA exposing glaciogenic landforms and sediments (Rachlewics
et al, 2007).
4
a)
b)
Figure 2 The retreat of Nordenskiöldbreen after the end of LIA a) The glacier front in 1908
mapped by De Geer (1910). The glacier is green on the map b) Fragment of an
orthophotomap based on Norwegian Polar Institute aerial photographs taken in 2009. The
figure shows were the glacier front was situated in 1900, 1930, 1960 and 1990 (Strzelecki,
2011).
5
2 Methods
2.1 Morphology
The drumlins observed were described, their orientation measured with a compass and
outlines tracked with a GPS. Various landforms in the forefield were mapped in ArcGIS 10.2
using an aerial photo from Norwegian Polar Institute from 2009 together with field
investigation. The tracks from the GPS measurements were used to map the outlines of the
drumlins. A TopCon was used to measure the transverse and longitudinal profile of the
drumlins. From the measurements a longitudinal profile was plotted in excel and a 3D model
using the software Surfer 8.0. A specific measurement error did appear in the transverse
profile at the origin in all of the drumlins. That profile was therefore not taken into
consideration when making the figures. From the length and width of the drumlins the
elongation ratio (E) was calculated with the following eq. (1) (Menzies, 1979):
E = Length / Width
(1)
2.2 Composition
Drumlin 3 was chosen to study the composition of the drumlins. Since there was no clean
exposure a 110 cm deep pit was dug into the middle of it. A section in it was cleaned and
logged using Krüger and Kjær’s (1999) logging procedure in the scale 1:10. Sixty clasts
fabric were collected from the section. The trend and dip was measured on clasts with a:b >
1:5 and axis length between 0,6 – 6 cm following the method given by Kjær and Krüger
(1998). Not all of the clasts were taken with Kjær and Krüger’s guidelines in mind and
therefore there were some exceptions. The data was analyzed by using the software Steronet
7. The morphology and lithology of the clasts were examined together with appearance of
striations.
Samples from the pit were oven-dried at 110°C overnight and dried sieved with 1 mm and 63
µm sizes of sieve. The fraction below 63 µm was sampled as well. These fractions of sieves
were chosen to distinguish between gravel, sand and mud. The samples were then weighed
and plotted up to show the grain size distribution (Evans and Benn, 2004).
6
3 Results
a)
b)
Figure 3 An aerial image of the forefield of Nordenskiöldbreen a) In the forefield various
glaciogenic landforms were observed. The most prominent ones were mapped. They all have
similar orientation, ENE-WSW b) The outlines of the drumlins on a close up figure of the
drumlin field. The soil pit is located in the middle of drumlin 3 (Nína Aradóttir and Vigdís
Bjarnadóttir, 2013).
7
3.1 The forefield of Nordenskiöldbreen
In the forefield of Nordenskiöldbreen five drumlins were observed together with other
glaciogenic landforms (fig. 3a and b). A terminal moraine marked the outline of the forefield,
flutes were dominant and one crag and tail was observed. The forefield consisted of till and an
outwash plain covered in drainage channels that were mostly dry when field work took place.
Close to the glacier margin a lot of bedrock was sticking out. Part of it had the shape of a
roche moutonnée and was covered in glacier striations. P-form were also observed at one
location.
3.2 The drumlins
All of the drumlins are rather small and show sign of fluvial erosion making it difficult to
decide their limits. When that was the case changes in slope angel or sedimentation was used
to mark the outlines. The orientation of the drumlins is from ENE to WSW. It was noted to
have similar orientation as other landforms formed by the glacier, e.g. flutes (fig. 3a and b).
Following is a description of their morphology from field investigation and a longitudinal
profile and a 3D model based on the TopCon measurements (table 1). This was constructed in
an attempt to reconstruct their morphology and to make it possible to visualize them as they
appeared in the field. An arrow indicates the direction of the former glacier flow. The
drumlins are orientated in the same way as on fig. 3a and b. The surface of the drumlins was
also described and in addition, the composition, clast morphology, lithology and fabric for
drumlin 3.
Table 1 Drumlin characteristics based on the TopCon measurements.
Drumlin no.
Length (m)
Width (m)
Area (m2)
Elongation ratio (l/w)
Drumlin 1
51
24
1032
2,13
Drumlin 2
81,2
24,9
1081
3,26
Drumlin 3
135,1
30,8
3140,5
4,39
Drumlin 4
126,7
18,5
1405,5
6,85
Drumlin 5
101,1
28,9
2772,5
3,50
8
3.2.1 Drumlin 1
Drumlin 1 is located 780 m from the glacier front. As seen in table 1 it is the shortest of the
drumlins and has the lowest elongation ratio. It limits are rather indistinct and it did not have a
typical drumlin shape (fig. 4a and b). The proximal limit is very polished and showed obvious
signs of erosion by a fluvial channel that was also visible in the surrounding of the drumlin
(fig. 6a). The distal limit proceeds into a hill making the stoss side higher than the lee side
(fig. 4 and 11a). The left and right margins fade into the landscape.
a)
WSW
ENE
b)
ENE
WSW
Figure 4 Drumlin 1 a) A longitudinal profile b) A 3D model, scale is in meters. Both figures
show that the lee side was lower than the stoss side. The morphology was therefore not
typical for drumlins.
9
3.2.2 Drumlin 2
Drumlin 2 is located 790 m from the glacier front. The proximal limit is very indistinct with
no change in sedimentation and little in the slope angel (fig. 11b). The morphology does
though indicate it to be a drumlin. It has a much higher stoss side than lee side (fig. 5a and b).
It gets thinner quite rapidly towards the pointed distal end that has been eroded by a fluvial
channel (fig. 11a). The outer margins of the drumlin did not have a clear boundary. Many
flutes were observed on the surface of the drumlin (fig. 6b).
a)
ENE
WSW
b)
ENE
WSW
Figure 5 Drumlin 2 a) A longitudinal profile b) A 3D model, scale is in meters. On both
figures it can be seen that the morphology of it indicates it to be a drumlin. The limits were
though hard to distinguish in the field.
10
a)
b)
Figure 6 Drumlin 1 and 2 a) Fluvial erosion has eroded the proximal limit of drumlin 1 and it
surroundings b) One of many flutes observed on top of drumlin 2. This one is mapped on fig.
3 and was used to follow a straight line when measuring the length with the TopCon (Photos:
Nína Aradóttir, 2013).
11
3.2.3 Drumlin 3
Drumlin 3 is located 700 m from the glacier front. It is the longest and widest of the drumlins
with the largest area (table 1). It is considered to be a textbook example of a drumlin; ovalshaped with a high stoss side that gradually tapers towards the lee side (fig. 7a and b). All the
margins are distinct and show little sign of fluvial erosion compared to the other drumlins. A
fluvial channel is present on the distal end (fig. 11b).
a)
ENE
WSW
b)
ENE
WSW
Figure 7 Drumlin 3 a) A longitudinal profile b) A 3D model, scale is in meters. Both figures
demonstrate the oval-shape of the drumlin very well.
12
The composition of drumlin 3
To investigate the composition and sedimentology of drumlin 3 a pit was dug into it (fig. 3).
The section was then divided into two layers. The main difference observed between them
whilst in the field was that the top layer contained much finer material and fissile structure
(fig. 8a and 9). The contact between the two layers is gradual. The grain size distribution after
sieving samples from both layers (fig. 8b) supports that there is more clay in the upper layer.
It also contains less gravel than the lower layer but there is a similar amount of sand in both of
them. Both layers were matrix supported. Fabric analysis (fig. 8c) from the section shows
some sign of preferred orientation, 276°/0°, although it is very weak, S1 = 0,50. The lithology
of the clasts was over 90% metamorphic but was noted to be from various origins. Striations
were only found on seven clasts and none of them were highly metamorphic. Most of them
were subangular or subrounded but rounded and angular clasts were also present.
a)
b)
a)
c)
S1=0,50
V1=276°/10°
Figure 8 The composition of drumlin 3 a) The log of the 110 cm section was divided
into two layers based on grain size. Both layers were interpreted to be Dmm b) The
grain size distribution in the two layers. The upper layer contains much more clay than
the lower and less gravel c) The fabric analysis was rather weak but showed some sign
of prefered orientation.
13
Figure 9 Upper layer of the section, a clay rich diamict with an unclear fissure structure
(Photo: Nína Aradóttir, 2013).
3.2.4 Drumlin 4
Drumlin 4 is located 730 m from the glacier front. It is the longest and narrowest of the
drumlins with the highest elongation ratio (table 1). As seen on fig. 11b it is located on the lee
side of a crag and tail. The proximal side of the drumlin appears to have developed from it. It
was decided that the drumlin began in the deepest point between the two landforms. Other
limits of the drumlin were hard to distinguish and the shape of it would not be considered
typical for drumlins (fig. 10). Due to the morphology of the drumlin a 3D model was not
made of the drumlin from the TopCon measurements.
WSW
ENE
Figure 10 A longitudinal profile of drumlin 4. An error was made in the measurements at the
distal limit of the drumlin and therefore the surface above origin should not be taken into
account.
14
a)
Drumlin 1
Drumlin 2
b)
Drumlin 4
Drumlin 3
Drumlin 2
Figure 11 Drumlins 1, 2, 3 and 4 with Nordenskiöldbreen in the back a) Similar height of the
stoss and lee side of drumlin 1 and the pointed distal limit of drumlin 2. Signs of fluvial
erosion can be seen in front of drumlin 2 b) The indistinct proximal limit of drumlin 2 at right,
overview of the well-shaped drumlin 3 in the middle with fluvial erosion on its distal end and
the elongated drumlin 4 to the left with the crag and tail behind it
(Photos: Skafti Brynjólfsson, 2013).
15
3.2.5 Drumlin 5
Drumlin 5 is located 970 m from the glacier front. It is high at the proximal end and in the
middle but tapered rather fast towards the distal end. It is at least partly rock cored. Bedrock
was observed on the south proximal side but not elsewhere. The proximal and distal limits
show signs of fluvial erosion and near the proximal side there is a channel that cuts through
the drumlin (fig. 12a and b). The south margin is very steep that could be a result from the
fluvial channel. On the south margin a depression was noted, no cracks or slides were
observed in it (fig. 13a). On the north margin there’s a big flute next to the drumlin that is
composed of different sediment. Therefore it is not considered to be a part of the drumlin. It
was used to mark the limit of it (fig 13b). There were also three to four small depressions
noted on that side.
a)
ENE
WSW
b)
ENE
WSW
Figure 12 Drumlin 3 a) A longitudinal profile b) A 3D model, scale is in meters. The
depressions on the figures are thought to represent the depressions and channel noted on the
drumlin in the field.
16
a)
b)
Flute
Drumlin 5
Figure 13 Drumlin 5 a) The depression on the south limit of the drumlin 5. No cracks or
slides can be observed and vegetation is present in the bottom of it b) The flute that was
composed of different sediment than the drumlin and marked the limit of it on the northern
margin (Photos: Nína Aradóttir, 2013).
17
3.2.6 The composition of the drumlin’s surface
The surface on all of the drumlins was classified as a diamict. The grain size was from clay to
boulders, angular to subangular for larger clasts that got more rounded with decreasing grain
size (fig. 14). The clasts were of multiple lithology and glacial striations were present,
especially on boulders. The direction of glacial striations on boulders was also measured
(table 2) with a mean direction of 238° or WSW. Flutings were observed all over the
forefield. They were however slightly less defined in the surroundings than on the drumlins
(fig.3 and 6b).
Table 2 Direction of glacial striations on boulders.
Striation no.
Direction (°)
1
251
2
217
3
230
4
254
5
239
6
234
Figure 14 The surface of drumlin 5, it was interpreted to be a diamict because it contained
clasts of all grain sizes in all shapes with various lithology. The surface was similar on all of
the drumlins (Photo: Nína Aradóttir, 2013).
18
4 Discussion
4.1 Nordenskiöldbreen
Drumlins can only form under a glacier that is at least partly temperate. No basal sliding
occurs beneath them so they do not erode or carry enough debris for them to form (Menzies,
1979). The drumlins and other glaciogenic landforms in the forefield therefore support earlier
research that Nordenskiöldbreen is a polythermal glacier (Hagen et al., 1993 and Rachlewics
et al, 2007). They are capable of eroding and transporting sediments, which is essential in the
formation of drumlins (Benn and Evans, 2010). Surge-type glaciers can be identified by
looking at combination of geomorphological landforms (Ottesen et al., 2008 and Evans and
Rea, 2003) and glaciological features (Copland et al., 2003). The only feature observed from
that criteria were long flutes. Therefore there was no evidence to indicate a former surge in
the glacier.
Menzies (1979) discussed that drumlins are found close to the ice margin front suggesting that
they are formed during the last glacial advance. The last one was The Little Ice Age. Based on
field investigations and fig. 3 the maximum advance is considered to have reached the
terminal moraine. Earlier researches in the area (De Geer, 1910; Rachlewics et al, 2007;
Strzelecki, 2011) confirm those observations. It is thought to have reached it in the end of 19th
century according to De Geer’s (1910) observations from 1882-1908. Since then the glacier
has retreated approximately 1,5 km on the northern side. On fig. 2a and b the position of the
glacier margin from 1900 can be seen. By comparing fig. 2 and fig. 3 it can be interpreted that
drumlin 1-4 were exposed between 1930 and 1960 and drumlin 5 was probably exposed
before 1930.
Boulton (1970) measured the direction of ice movements during last glaciation in the forefield
of Nordenskiöldbreen and found out that it lay between 220° and 255°. That correlates to the
orientation of the drumlins and the glacial striations measured, which was found out to be
ENE to WSW (fig. 3). From that it can be interpreted that the long-axis of the drumlins lies
parallel to the direction of last ice flow as was suggested by Menzies (1979). The direction of
the former ice flow can also be seen on other landforms in the area, such as flutes, crag and
tail and the terminal moraine.
4.2 Morphology
In this study a TopCon was used to investigate the morphology of the drumlins. The
measurements from it were both used to make longitudinal profiles and a 3D model of the
drumlins. They were useful to describe the morphology of the drumlins and to make it easier
to visualize them. From the figures made it was demonstrated how variable the morphology
of drumlins can be and that it is not given that they look like a text book example of drumlins.
The drumlins observed are much smaller than the drumlins described in earlier literature
(Menzies, 1979; Clark et al., 1999). Three of the drumlins did though fall in the range of the
smallest drumlins, 99 m, which were described by Clark et al. (1999). The drumlins do show
more similarity in size to those which have been described recently in Iceland although the
19
ratio is much greater (Krüger and Thomsen, 1984; Mark et al., 2010). As can be seen in table
1 the elongation ratio is greater than the mean value, 2,9:1 (Clark et al., 1999) for all of the
drumlins except drumlin 1. Menzies, 1979 did though point out that the elongation ratio could
be from 2:1 up to 60:1. Earlier studies have revealed that elongated drumlins, >10:1, indicate
fast flowing ice streams (Briner, 2007). From that it can be interpreted that former ice flow in
Nordenskiöldbreen was not fast flowing.
All of the drumlins showed some sign of fluvial erosion that had affected their shape. Due to
the retreat of Nordenskiöldbreen since the end of LIA the glacier has produced a lot of
meltwater. Studies on the proglacial river system have revealed that it is constantly changing.
The change is highly effective on the landscape and happens annually. This has been studied
from the landform assemblage and sediments in them. It suggested that the river has been
changing between braided and a straight channel (Stacke et al., 2013). Krüger and Thomsen
(1984) in their study observed a similar process in Iceland where fluvial erosion had affected
the shape of the drumlins.
In drumlin 5 there was evidence of dead ice melting from a depression on the south and north
margin of it. Krüger and Thomsen (1984) described similar collapsed structure in one of their
drumlins that they interpreted as a kettle hole due to dead ice melting. The vegetation and the
smooth surface of it suggest that it is inactive, meaning all the dead ice that was in it has
melted.
4.3 Composition
The sediment in the section in drumlin 3 was interpreted to be a diamict because it was poorly
sorted, it contained all grain sizes, the clasts were angular to rounded and contained different
lithology. Based on the following interpretation from fissile structure, fabric analysis and clast
morphology the diamict was interpreted to be a till (Evans and Benn, 2004; Benn and Evans,
2010). The surface of the drumlins is also classified as till. It cannot be concluded that all of
the other drumlins are composed of it since it was not investigated further.
An uncertain fissile structure was observed in the upper layer of the section (fig. 9). It forms
in clay rich till due to stress that is applied on it from the glacier. When glacier slides over
compacted till it becomes brittle and gets a plate-like form. The fissile structure appears as
irregular bedding that often becomes more distinctive when the section is cleared (Menzies,
2002). The fissile structure observed in the upper layer confirms that the section is composed
of till that has been overridden by a glacier. The absence of it in the lower layer is a
consequence from how little clay it contains. Fissile structure has frequently been observed in
drumlins and is thought to be a result of either stress because of glacier sliding over it or of
pressure release because of ice retreat. Menzies (1979) concluded that if there is no sign of
lateral movement it is a result of pressure release. The fissure structure in drumlin 3 was not
distinct enough to diagnose any movement in it. Therefore it could not be interpreted if it was
made during pressure or relief.
Measurements of fabric analysis from till are usually rather strong and have preferred
orientation. In drumlins the fabric is usually parallel to the long-axis of it and can therefore
reveal former direction of ice flow (Benn and Evans, 2010). The preferred orientation, 276°,
was close to the orientation of the drumlins but it was rather weak, 0,50 (fig. 8c). Despite that
it still suggests that the section is composed of a till since it is thought to show some sign of
preferred orientation. Studies have shown that fabric is weaker in till that contains coarser
20
clast since they are more likely to collide (Menzies, 1979). Larger clasts were abundant in the
diamict and many of them were in contact. Due to that it was hard to find clasts for fabric
analysis and is thought to be one of the reasons for the weak fabric. More data is would be
needed to determine that. To be able to get a reliable result from fabric analysis more clasts
should be measured in different places of the drumlin. Measurements should be taken both at
the stoss and lee side, in the middle and on the margins of it. The fabric analysis was not
taken systematically in the pit between the two layers and therefore it is only one steronet for
the whole section. From that no difference between the two layers can be interpreted.
Drumlins are composed of till that is usually similar to the till surrounding them and contains
clast from the local bedrock (Menzies, 1979). Boulton (1970) noted that the bedrock in the
area is the highly metamorphic schist and gneisses from Hecla Hoek Formation. The clast
from the pit was noted to be from similar origin. Striations were observed on a few clasts and
they are evidence for a glacier flowing over the area. The striations on boulders on the surface
indicate direction of former ice flow. The reason for their low preservation value is due to the
origin of the rock as metamorphic rock is resistant to abrasion. The roundness of the clast can
indicate that sediment is passively, actively or glacifluvially transported. If the transport is
active most of the clast is subangular and subrounded due to fracture and abrasion process
(Benn and Evans, 2010). The clast collected from the pit was mostly subangular and
subrounded which indicates that the till was transported from an active glacier.
Since no stratification was observed in the layers and the sediment was poorly sorted it could
be excluded that the layers were glaciofluvial deposits (Benn and Evans, 2010). As mentioned
earlier, fluvial channels were observed all around the drumlins. Previous studies have
concluded that they cause a constant change on the landscape around them and glaciofluvial
deposits in the surrounding of the drumlins (Stacke et al., 2013). Braided rivers are common
in the forefield of glaciers and Krüger and Thomsen (1984) observed two layers of tills resting
on glaciofluvial deposits. Drumlin 3 also contained two layers of till. The section in the pit did
not penetrate the bottom of the drumlin and therefore it is unknown what lies underneath the
lower till. One option could be glaciofluvial deposits based on its distribution around the
drumlin. It has also been noted in subglacial till that lower layers often contains less clay than
upper layers. That is due to water at the base of the glacier that washes the finer material, like
clay, away and leaves coarse material behind (Menzies, 1979). This could therefore explain
why there is less clay in the lower layer and the fluvial erosion observed supports that.
4.4 Drumlins on Svalbard
As mentioned in the introduction drumlins have never been described on land in Svalbard
before (Christoffersen et al., 2005; Ingólfsson, 2011). One of the reasons could be how
variable their morphology is as demonstrated on the profiles and 3D models. Therefore they
might have been observed before but not classified as drumlins. Another reason could be
glaciofluvial erosion; it has been highly effective on Svalbard, especially after LIA when the
glaciers started to retreat. The drumlins are not large and erosion can therefore make a
remarkable change on their morphology. Boulton (1970) did though describe what he
interpreted to be a rocked cored drumlin that had evolved from a roche moutonnée during his
observations. It was not investigated further since the main focus of his study was on roche
moutonnée. The location of Boulton’s drumlin was compared to the drumlins observed in
field after the aerial images and a map that Boulton did of the forefield. The location of it did
not fit with the other drumlins. It could though suggest that there might be another drumlin in
21
the area that was not observed. It is a part of further research to investigate the landform he
described. It would be interesting to look into if roche moutonnée could be the reason for the
genesis of some of the drumlins. Bedrock was observed at the proximal end of drumlin 5
indicating that it had a core consisting of bedrock. Therefore it could be similar to the
landform Boulton described.
22
5 Summary and conclusion
The drumlins are a good indicator of the behavior of the glacier. From them, together with
other landforms, it could be interpreted that the glacier is polythermal and in the direction of
the former ice flow; ENE to WSW. The landforms assemblage in the forefield did not suggest
that it is a surge-type glacier. Together with other landforms they can reveal were the glacier
front was situated during the last glacial advance; The Little Ice Age. By comparing aerial
images with old maps and earlier research in the area, it has been concluded that it has
retreated approximately 1,5 km on the northern side and 3,5 km in total.
The TopCon measurements were thought to be a suitable method for describing the
morphology of the drumlins. They were useful to visualize the drumlin shape and how
variable they can be. The drumlins observed were much smaller and had greater elongation
ratio than the average value for drumlins. Fluvial erosion was observed in the forefield of the
glacier and on all of the drumlins. It is thought to be one of the causes for the variable
morphology of the drumlin.
The composition of drumlin 3 was interpreted to be a till from evidence of fissure structure,
fabric analysis and clast morphology. It consisted of two layers based on difference in grain
size. The upper layer contained more clay and fissure structure. That could be due to fluvial
erosion at the bottom of the drumlin that washes the finer material away. The surface of the
other drumlins was similar to the till in drumlin 3 and it is therefore suggested that they are all
composed of till although more investigation would be needed to prove that. Drumlin 5 was
observed to be at least partly rock cored.
Further investigation would be needed for more interpretations about the drumlins. It would
be beneficial to have several pits dug into the drumlins across the entire profile. They should
be taken both on the lee and stoss side to find out if the core is composed of different
sediments. Sections should be both parallel and transverse to the long axis of the drumlin to
get a three dimensional representation of the stratigraphy. The pits would also need to be dug
deeper to find out if there is a layer composed of glaciofluvial deposits under the lower layer.
Fabric analysis should be taken systematically from the sections. Measurements between
layers should be kept separate to make it possible to study if there is a difference between
places in the drumlins or if it is composed of uniform sediment.
23
Reference
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Holocene sedimentary environments and glacial activity in Billefjorden, Svalbard. The
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26
Appendix
Drumlin 1
Compass direction – 237°
Table 3 Drumlin 1, TopCon measurements
x (m)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7.2
4.7
2.6
-3
-5.1
-7.5
-10.2
-13.2
13.2
10.2
7.2
3.9
y (m)
-29.9
-27.1
-20.6
-16.4
-12
-7.5
-3.6
0
3.1
6.5
9.9
13.7
17.2
21.1
0
0
0
0
0
0
0
0
0
0
0
0
z (m)
-2.4
-2
-1.3
-0.72
-0.4
-0.2
-0.1
0
0
0
0
0
-0.01
-0.2
-0.6
-0.2
0
-0.1
-0.3
-0.7
-1.3
-2.1
-2.5
-1.5
-0.8
-0.2
27
Drumlin 2
Compass direction – 234°
Table 4 Drumlin 2, TopCon measurements
x (m)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
14.4
12.7
10
7.3
4.4
2.3
0
-2.6
-5
-7.3
10.7
9
7.1
y (m)
-29.9
-26.5
-22.9
-19.4
-15.5
-11.8
-8.1
-4.4
0
3.27
6.2
9.2
12.2
14.4
17.5
20.7
24
27.7
29.6
33.5
37
40.7
44.5
47.7
51.28
0
0
0
0
0
0
0
0
0
0
0
0
0
z (m)
0.1
0.1
0.1
0.1
0.1
0.1
0.2
0.2
0
-0.1
-0.3
-0.4
-0.8
-0.9
-1.2
-1.5
-1.9
-2.3
-2.4
-2.8
-3.2
-3.5
-4
-4.3
-4.6
-2.6
-2.2
-1.6
-0.9
-0.4
-0.2
0
0.02
0.02
-0.2
-1.3
-0.8
-0.6
28
5.4
2.9
-3
-6
-9
-12.2
0
0
0
0
0
0
-0.3
-0.1
0.2
-0.2
-0.6
-1
Drumlin 3
Compass direction – 244°
Table 5 Drumlin 3, TopCon measurements
x (m)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
y (m)
-35.2
-32.1
-28.7
-25.4
-21.4
-17.3
-13.4
-9.5
-5.7
-2.7
0
3.7
6.2
9.2
12.1
15.1
17.9
20.5
23.1
26.5
29.2
32
34.7
37.1
40
42.3
44.8
47
49.6
52.4
55
57.5
z (m)
-2.9
-2.6
-2.2
-1.8
-1.3
-0.8
-0.4
-0.2
-0.1
-0.02
0
-0.1
-0.2
-0.4
-0.4
-0.5
-0.5
-0.5
-0.6
-0.7
-0.8
-1
-1.1
-1.3
-1.5
-1.7
-1.8
-2
-2.1
-2.2
-2.3
-2.4
29
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
13.5
10.3
7.1
3.3
0
-3.1
-6.9
-10.6
-14.8
13.4
10.2
6.8
3.7
0
-3.7
-7
-10.1
-13.2
-16
12.4
9.7
6.5
3.6
0
-2.9
-6
-9.5
-12.5
-14.7
60.6
63.4
66
69
71
73.2
76
79
81.7
84.5
87.2
90.2
93.3
96.9
99.9
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-2.5
-2.7
-3
-3.2
-3.3
-3.4
-3.5
-3.6
-3.8
-4.1
-4.4
-4.7
-5
-5.2
-5.5
-2
-1.4
-0.6
-0.5
-0.1
0
0.2
0.3
-0.6
-1.8
-0.7
-0.4
0
0
0
0.1
0
-0.3
-0.7
-1.6
-0.9
-0.7
-0.4
-0.1
0
0.1
0.1
-0.1
-0.6
-0.9
30
Table 6 Drumlin 3, fabric analysis measurements and clast morphology
Clast nr.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Trend (°)
22
350
258
294
74
280
306
64
284
240
36
167
118
294
95
327
152
142
145
280
12
58
112
127
172
72
33
303
211
280
252
240
266
260
289
309
Plunge (°)
22
32
3
52
2
20
60
10
30
26
18
10
19
0
20
10
12
20
26
34
18
3
30
26
8
57
1
29
10
20
23
54
8
18
26
4
37
210
22
38
39
40
41
264
184
6
142
52
38
60
16
Angularity
Subangular
Subangular
Subangular
Subangular
Angular
Subrounded
Subangular
Subrounded
Subangular
Subangular
Angular
Angular
Subangular
Subangular
Subangular
Angular
Angular
Subangular
Subrounded
Subangular
Subangular
Angular
Rounded
Angular
Angular
Subrounded
Subrounded
Subangular
Angular
Subrounded
Subangular
Subrounded
Subrounded
Subangular
Subrounded
Sngular
SubangularSubrounded
Subrounded
Subangular
Subrounded
Subrounded
31
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
92
180
200
281
90
28
275
344
51
238
132
72
126
318
203
290
270
106
246
28
20
32
11
8
9
45
20
5
20
22
10
12
30
40
4
60
8
2
Subrounded
Subangular
Subangular
Subangular
Subangular
Subrounded
Subangular
Subrounded
Subangular/rounded
Subangular
Subrounded
Subangular
Subrounded
Subangular
Subangular-angular
Subrounded
Subangular
Subangular-angular
Subrounded-rounded
Table 7 Drumlin 3, grain size distribution
Top layer,
60-110 cm
Fraction
> 1 mm
63 μm-1
mm
< 63 μm
Empty
beaker (g)
3,3356
Full
beaker (g)
22,4182
Sediment
weight (g)
19,0826
3,3409
3,3651
20,2984
14,8606
16,9575
11,4955
Total sediment
weight (g)
% of fraction in
the sample
40,14
35,67
24,18
47,54
Bottom
layer, 0-60
cm
Fraction
> 1 mm
63 μm-1
mm
< 63 μm
Empty
beaker (g)
3,3566
Full
beaker (g)
36,9785
Sediment
weight (g)
33,6219
3,362
3,3594
20,5941
6,0976
17,2321
2,7382
Total sediment
weight (g)
% of fraction in
the sample
62,74
32,15
5,11
53,59
32
Drumlin 4
Compass direction – 252°
Drumlin 5
Table 8 Drumlin 5, TopCon measurements
x (m)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15.7
13.6
11.5
9
5.4
2.6
0
y (m)
-41.8
-37.4
-34.4
-31.1
-27.7
-24.3
-20.3
-15.3
-11.7
-7.8
-3.3
0
3.4
6.9
10.6
13.8
17.1
20.2
23
25
27.1
29.8
32.2
36.2
39.9
43.5
47.3
51.1
55.2
59.3
0
0
0
0
0
0
0
z (m)
-1.7
-1.6
-1.6
-1.5
-1.5
-1.3
-1.2
-0.7
-0.4
-0.1
0.1
0
-0.1
-0.3
-0.6
-0.8
-1.1
-1.4
-1.8
-2.5
-3.7
-3.5
-3
-3.4
-3.9
-4.3
-4.7
-5.1
-5.6
-6
-1.6
-1.2
-0.9
-0.5
-0.2
0.1
0
33
-2.7
-5.9
-9.3
16.3
14.6
12.3
8.8
5.8
3.1
0
-3.3
-5.8
-10.5
-12.6
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.2
-0.1
-0.4
-2.9
-2.5
-2
-1.1
-0.7
-0.1
0
-0.1
-0.1
-0.8
-1.1
34