FACULTY OF SCIENCE UNIVERSITY OF COPENHAGEN

M aster’s thesis

Nina Friis

Stratigraphy and sedimentary properties of drumlinoid landforms in the forefield of Nordenskiöldbreen,

Svalbar d

Academic advisor: Anders Schomacker and Olafur Ingolfsson

Submitted:10th of January 2015

Institutnavn: Institut for Geovidenskab og Naturforvaltning

Name of department: Department of Geosciences and Natural Resource Management

Author: Nina Friis

Title: Stratigraphy and sedimentary properties of drumlinoid landforms in the forefield of Nordenskiöldbreen, Svalbard

Academic advisor: Anders Schomacker and Olafur Ingolfsson

Submitted: 10th of January 2015

Abstract

Drumlins are common streamlined glacial features formed in the subglacial environment, and are left by a retreating glacier as rounded hills in the landscape formed like an egg, half-buried along its long axis. Despite a large amount of literature on drumlins, dating back to 1867, no unifying theory of their formation have been presented, which probably arises from the fact that the subglacial environment is inaccessible, and the scientists are referred to postglacial morphology and internal structures of the drumlins to determine their origin. This thesis describes the internal composition and structure of two drumlins located in a fluted till plain in the forefield of Nordenskiöldbreen, Svalbard, exposed after a recent retreat following its last advance during the Little Ice Age. Standardized field and laboratory techniques such as log drawing, fabric analysis, grain size, roundness, and angularity analysis were performed. The drumlins are composed of sorted sediment and gravely diamict that display no or little deformation. These represent fluvial gravels and ice proximal melt-out till respectively which was deposited in a glacier forefield by an advancing glacier similar to the forefield seen in the Nordenskiöldbreen area today. These sediments are covered by a thin drape of clayey and highly fissile diamict that represents a traction till displaying widespread lodgement and was deposited during high hydraulic pressures in the subglacial environment. The drumlins are thus composed of undeformed pre-existing sediments, and the drumlins represent erosional remnants left by an advancing glacier.Shell fragments found in the interior of the landforms have been dated by radiocarbon dates to 10.5-10.8 cal. ka BP and represent reworked marine sediments deposited during an early Holocene transgression/regression cycle caused by the delayed isostatic rebound of the continental crust following the deglaciation. The dates thus provide a constraining age for the deglaciation of the area. Table of contents

1 INTRODUCTION ...... 3

1.1 Study area ...... 4 1.1.1 General description ...... 4 1.1.2 Short outline of the Holocene climatic evolution in the Arctic ...... 8 1.1.3 Literature review of Nordenskiöldbreen and the surrounding area ...... 10

1.2 Till formation and deposition...... 11 1.2.1 Lodgement, ploughing and deformation ...... 11 1.2.2 The subglacial environment ...... 13 1.2.4 Maturation of clasts during till formation ...... 15

1.3 Drumlins ...... 16 1.3.1 What is a drumlin? ...... 16 1.3.2 How do drumlins form? ...... 18 1.3.3 Morphology of drumlins ...... 20 1.3.4 Drumlin composition ...... 21

1.4 Flutes ...... 23

2 METHODS ...... 25

2.1 Field observations ...... 25

2.2 Sampling ...... 25

2.3 Grain size analysis ...... 26

2.4 Fabric...... 26

2.5 Morphology ...... 27 2.5.1 Clast shape ...... 27 2.5.1 Roundness ...... 27 2.5.2 Striations and clast asymmetry ...... 28

2.6 Radiocarbon dating ...... 28

3 FACIES DESCRIPTIONS AND INTERPRETATIONS ...... 28

3.1 Unit 1, surface features and top layer, DmF(m2)3 ...... 34 3.1.1 Description ...... 34 3.1.2 Interpretation: traction till ...... 38

3.2 Unit 2, sorted sediments in the southern drumlin, Gm, Sp, Sh, Sm, B ...... 39 3.2.1 Description ...... 39 3.2.1 Interpretation: Glacifluvial...... 40

3.3 Unit 3, diamict in the interior of the drumlin, DmM(m3)3 ...... 40 3.3.1 Description ...... 40 3.3.2 Interpretation: meltout of stagnant ice...... 41

3.4 Unit 4, diamicts of the crag-and-tail, DmM(m3)3 ...... 41 3.4.1 Description ...... 41 3.4.2 Interpretation: till ...... 41

3.5 Unit 5, boulders in the bottom of both crag-and-tail and the drumlin, Bm ...... 41 3.5.1 Description ...... 41 3.5.2 Interpretation: glacifluvial ...... 42

4 DISCUSSION ...... 42

4.1 Stratification ...... 42

4.2 Shell fragments and paleoshorelines ...... 44

4.3 Drumlin types and their formation ...... 45

4.4 Depositional model ...... 47

5 CONCLUSIONS ...... 49

ACKNOWLEDGEMENT ...... 49

REFERENCES ...... 50

Appendix 1 – Grain size distribution Appendix 2 – Fabric data Appendix 3 – Clast shape Appendix 4 – Roundness Appendix 5 - Striations and clast asymmetry

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1 Introduction

Until the 1980’s, glaciology and research in paleo ice streams were in effect two separate fields of research (Boulton, 1986). The beds of the Antarctic ice streams were regarded by glaciologists as passive rock/ice interfaces, although geologists working on sediments deposited by ice streams during the last glaciation of the Northern Hemisphere had described widespread glacially induced structures and sediments that related to fast flowing outlets (Boulton, 1986). These included tills, deformation of existing sediments and the presence of elongated streamlined bedforms such as megaflutes and drumlins. Engelhardt et al. (1978) and Boulton (1979) demonstrated the importance of deforming beds and Boulton (1986) suggested a paradigm shift, where the ice bed is regarded as a part of a coupled ice-bed interface (Alley, 2000). Since then research and collaboration between geologists and glaciologists gained momentum and soft deformable beds became widely recognized. The occurrence of bedforms in deglaciated terrains thus provides crucial information about former ice streams (Boulton and Clark, 1990; Shipp et al., 1999; King et al., 2007; Smith et al., 2007). Subglacial bedforms are longitudinal or transverse accumulations of sediments formed below active ice (Benn and Evans, 2010). They are often elongated down-glacier and thus reflect the former ice direction. Bedforms like these can be divided into drumlins, mega-flutes and mega-scale glacial lineations (Clark et al., 2009). These are often regarded as a continuum of bed forms reflecting the flow regime of the ice stream forming them, getting a higher elongation ratio closer to the ice margin (Stokes and Clark, 2002; Clark, 1994; Benn and Evans, 2010), however, no correlation with topographic setting or substrate lithology has been recognized (Patterson and Hooke, 1995). Of these bedforms, drumlins are far the most numerous and geographically widespread (Clark et al., 2009). Drumlins are abundant in the terrestrial environment in the Northern Hemisphere and have also been reported from the fjords of Svalbard and the Barents Sea (Hogan et al. 2010; Winsborrow et al, 2010; Robinson and Dowdeswell, 2011). Numerous papers (dating back to 1867) have been published describing drumlins from different perspectives. Clark et al. (2009) reports more than 1300 contributions of papers, abstracts and theses, but despite this there is still no unifying theory of the formation of drumlins (Clark et al., 2009). This problem arises from the circumstance that the subglacial environment, where drumlins form, is inaccessible for direct observations. Consequently, modern analogs to the formation process are lacking, and researchers must base their observations and interpretations on morphology and internal composition (Shaw, 2002; Clark et al., 2009; Benn and Evans, 2010). Menzies (1979) referred to this as “the drumlin problem”. When reviewing the literature it is clear that drumlins are important features in the fields of Quaternary science, glacial geology and geomorphology. Also, for glaciologists this is an important subject as the velocity of ice streams is thought to be regulated by the nature of the coupling between the bed of the ice and the soft sedimentary bed. Understanding the formation of drumlins may therefore hold a part of the key to understanding the dynamics of ice streams, and thus help

Page 3 of 56 us to predict the course of melting ice caps in a changing climate (Smith et al., 2007; Clark et al., 2009; Stokes et al., 2009). Since drumlins are found widespread in the terrestrial environment of the Northern Hemisphere it is noteworthy that terrestrial drumlins (to the knowledge of the writer of this thesis) have only been reported from one locality on Svalbard namely the forefield of Elisebreen (Christoffersen et al., 2005; Larsen et al., 2006), located on a coastal plain on Western Spitsbergen. Boulton (1970) uses Sørbreen (northern Spitsbergen) and Nordenskiöldbreen to infer a hypothesis for the formation of rock cored drumlins, but he does not refer directly to the drumlins analysed in this thesis. The aim of this study is to contribute to the discussion on drumlin formation, by providing data that highlights the sedimentology and stratigraphy of two newly exposed drumlins that occur in the forefield of Nordenskiöldbreen, Svalbard, by analysing and interpreting different lithofacies. Furthermore the study provides a constraining age for the early Holocene deglaciation by radiocarbon dating of marine shell fragments found in the interior of the examined landforms.

1.1 Study area

1.1.1 General description Nordenskiöldbreen is a polythermal tidewater glacier (Hagen, 1993; Rachlewicz et al., 2007) located in Adolfbukta, a side fjord of Billefjorden, which is a branch- fjord of the big fjord system of Isfjorden in Central Spitsbergen, Svalbard (Fig. 1.1). The glacier is an outlet glacier of the ice cap Lomonosovfonna, and is considered a fast flowing glacier (Blaszczyk et al., 2009) with an ice flow direction roughly from east to west. No surges have been recorded, however, based on mathematical models using geological boundaries, mass-balance conditions and thermal regime on surging, Jiskoot et al. (2000) classified Nordenskiöldbreen as a potential surge type glacier; although Plassen et al. (2004) describe the landform assemblage of Nordenskiöldbreen and compared the landform assemblage to other non-surging glaciers in Svalbard. The geology in the area of Nordenskiöldbreen is diverse. The bedrock exposed at the field side is the Hecla Hoek schists, amphibolites and marbles of varies kind. This is overlain by early and late Carboniferous rocks, displaying everything from sandstone, conglomerate, shale and coal to gypsum, dolomite and limestone (Lauritzen et al., 1989). The glacier is heavily crevassed and produces meltwater that gives the sea water in front of the glacier a milky-grey appearance (Plassen et al., 2004). The tidewater glacier terminates on land at both the southern and northern lateral limits, where the retreat of the glacier has left two exposed till planes, of which the northern plane is the study area of this thesis (Fig. 1.1B). Recent retreat (since around 1990) a small island in the central part of the ice margin has been exposed, on which the glacier is also resting. The outer limits of the till planes are marked by an end-moraine which has been dated to AD 1896 (De Geer, 1910), and the glacier has been retreating ever since, creating recessional moraines (Figs 1.2A and B and 1.3). The bathymetry shows how the end moraine is located right at a

Page 4 of 56 bedrock threshold. Glacial linear features have been recognized by Baeten et al. (2010) (Fig. 1.2).

Fig. 1.1 – A) Overview map of Svalbard (Norsk Polar Institutt, Topo Svalbard, 2014). B) Adolfbukta area and Nordenskiöldbreen (Norsk Polar Institutt, Topo Svalbard, 2014).

Fig 1.2 – Map of the sea floor produced by swath bathymetry map. The data are reproduced according to the permission No 13/G706 by the Norwegian Hydrographic Service. Lilac and blue colours represent relatively deeper waters and pink and yellow represent relatively more shallow waters. B) Interpretation of recessional moraines (Baeten et al., 2010). C) Interpretation of glacial linear features (Baeten et al., 2010).

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Fig. 1.3 – Former positions of the ice margin in the years 1900, 1930, 1960, 1990 and 2009. Aerial photo from 2009 is provided by Norwegian Polar Institute (Strzelecki, 2011). White square show position of field site.

It is not within the scope of this thesis to produce a detailed geomorphological map, but a rough sketch of the main features of the area is seen on Fig. 1.4 for an overview. The area of interest is bounded to north and north-west by an outer moraine, to the south by the fjord and to the east by the still retreating glacier front. Here, a drumlinized till plane (Figs. 1.4 and 1.5) with a superimposed fluted surface is seen, alongside with boulder trains and boulders with bullet-nosed shapes. In several places, the fluvial processes have overprinted and eroded the till plane. In the south eastern part of the field, metamorphic basement rock is exposed, and it has a scattered layer of glacial drift on the surface.

Fig 1.4 – A) Aerial photo from 2009 of the Northern flank of Nordenskiöldbreen provided by the Norwegian Polar Institute. Please note that the glacier has retreated even further since this photo was taken. B) Geomorphological overview. Green: outer lateral moraine. Lilac: fluted and drumlinized till plane. Blue: Erosional channels. Brown: exposed bedrock with scattered glacial drift. Dashed line show location of Fig. 1.5 and 1.6.

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Fig. 1.5 – The drumlinized till plane and the superimposed subparallel flutes. The photo is taken from west towards east, for location see Fig. 1.4. Marked with stippled are the studied landforms (photo taken August, 2014).

Although both striations on the bedrock and the flutes on the till plane are subparallel and thus vary (some places considerably) over small areas depending on the local bedrock slope and boulder obstacles, there is a regional pattern which indicates that the direction of ice movement lies between 220 °N and 255 °N. Throughout the till plane, boulders ranging from 20 cm to several meters occur. Many of them show perfect stoss/lee side, are smooth on the top surface with clear striations and are embedded into the till plane. Many of these boulders have a flute tail away from the glacier. Some even have flutes going around them, as if the ice stream had been disturbed and deflected by the boulder (Fig. 3.9). At least two drumlins and one crag-and-tail was recognized on the till plane (Fig. 1.6). The southern drumlin is clearly defined from head to tail. It is 138 meters long and 32 meters wide at the longest points, and thus has an elongation ratio of 4.3. The northern drumlin marked in Fig. 1.6 is 129 meters long and 20 meters wide and thus has an elongation ratio of 6,45. The crag-and- tail is 128 meters, 14 meters wide and ~5 meters at the highest point. The crag itself is 55 meters long and is clearly much steeper on the southern side than on the northern side. This shape continues to the tail, which is also clearly steeper on the southern side, although slumping processes dominate. The northern drumlin is located in direct continuation of the crag-and-tail, separated by a dry river channel.

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Fig. 1.6 – Location of the two drumlins (solid line) and the crag-and-tail (dashed line). For location see Fig. 1.4. Locations of pits are marked with red dots. Potted box shows the location of Fig. 3.9.

1.1.2 Short outline of the Holocene climatic evolution in the Arctic

Most climate reconstructions seem to agree that an early Holocene warming was initiated after last deglaciation of the northern hemisphere (Svendsen and Mangerud, 1997; Mangerude et al., 1998; Forwick and Vorren, 2009; Baeten et al., 2010; Müller et al., 2009, 2012). The timing of this varies throughout the world but has been dated by Svendsen and Mangerud (1997) and Hald et al. (2004) to have been initiated in 10.8 ka BP in the central western Spitsbergen, and by Forwick and Vorren (2009, 2011) and Baeten et al. (2011) to 11.2 ka PB by interpreting data from proglacial lake sediment cores, marine fjord cores and high- resolution seismic data. Provenance analyses of the mineralogy of illite and mica found in the core JM-97943-GC taken in the central Billefjorden, showed that most of the sediments, deposited at the core location, originated from Nordenskiöldbreen (Baeten et al., 2011; Fig 1.7). As the ice retreated, the sea level rose from 11.32 to 11.2 cal ka BP. From here on to 7.93 cal ka BP, evidence from this sediment core suggests that the climatic conditions got warmer and the glaciers retreated. IRD and provenance analysis show that Nordenskiöldbreen existed as a tidewater glacier during this time span. From 7.93 cal ka BP Nordenskiöldbreen gradually advanced under a regional climatic cooling, producing an increased amount of IRD (Baeten et al., 2011). The climatic period that followed has been referred to as the “neoglaciation” (Miller et al., 2010). Evidence from the JM-97943-GC core suggests that this caused an increase in sea

Page 8 of 56 ice cover that may have restricted the iceberg formation from Nordenskiöldbreen. This late Holocene glacial maximum culminated in AD 1900 and a following retreat produced recessional moraines in the inner part of Adolfbukta (Fig. 1.3). Numerous reconstructions have been produced for the time period that followed (Miller et al., 2012). The extremes of most of these are the Medieval Warm Period and the Little Ice Age (LIA). The LIA for Svalbard usually refers to the period between 600 to 100 years ago (Salvigsen and Høgvard, 2005; Werner, 1993). The moraines created within this time span are argued to represent the Holocene maximum extent of the glaciers on Svalbard (Svendsen and Mangerud, 1997; Sletten et al., 2001). The LIA maximum extent moraines usually occur 1-2 km in front of the present day glacier fronts, and represent significant features in the landscape due to their dead-ice content (Werner, 1993; Plassen, 2004).

Fig. 1.7 – Conceptual illustration of the glacial evolution of Billefjorden from >11.23 cal. ka BP to now (Baeten et al., 2010).

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The climatic evolution described above is supported by an extensive study of species of molluscs from Isfjorden done by Feyling-Hanssen (1955). The isostatic rebound following the deglaciation has caused the formation of raised beaches (Mangerud et al., 1998; Forman et al., 2004) to up to 90 m a.s.l. in Billefjorden (Feyling-Hanssen, 1965). As the marine waters of Svalbard got warmer during the Holocene, more and more mollusc species migrated northwards and made the species assemblage more diverse as the cold water species continued living in the still warmer waters. Feyling-Hansen (1955) mapped the occurrence and relative abundance of the variety of molluscs on the raised beaches and from this, he divided the Holocene into three climatic periods: late-glacial cold period, post- glacial temperate period, and sub-recent period.

1.1.3 Literature review of Nordenskiöldbreen and the surrounding area From an expedition in the early 1920’s, Slater (1921) published some observations of Nordenskiöldbreen. By this time the glacier was in a much more advanced state than that of today (see Fig. 1.3 for an indication of the position of the ice front in AD 1920), and thus the field site of the present thesis was covered by ice. Slater reported low amounts of englacial material in the basal layers of the glacier averaging not more than 25 feet (7.62 m). He relates this to the nature of the highly metamorphosed bedrock. Baeten et al. (2010) produced a reconstruction of the deglaciation and the climatic evolution of the Billefjorden area using bathymetry and a sediment core. From the bathymetric data of the innermost part of Adolfbukta an outer terminal moraine located at the onset of a bedrock slope leading to abruptly deeper waters, has been recognized. This moraine has been dated to AD 1896 by De Geer (1910). On the glacial proximal side of the moraine glacial linear features and recessional moraines have been interpreted (Baeten et al., 2010; Fig. 1.2). On land Boulton (1970) analysed the till of the same forefield area of Nordenskiöldbreen as described in this thesis. He reports vast amounts of stagnant ice found under a surface of melt out till and exposed in river down cuts. From man-made vertical profiles in the hummocky terrain he reported subglacially derived till displaying shear planes, tension crags and rafts of marine deposits containing whole unbroken delicate shells. He assigns the fact that shells have survived the glacier overriding to the main deformation process being brittle fracture of the sediment rafts rather than intergranular flow. Based on fabric analysis and slickensides on sub-horizontal till joints and slickensides on the till/ice interface he also argues that the direction of ice flow not only varies spatially with the topography, but also with time. However, the observations made in the Boulton (1970) study were from an area east of the area in focus in this study, but in a later study (1976) he used, amongst others, observations from the forefield of Nordenskiöldbreen to derive a model for flute formation in general. As noted in the introduction, few studies have been published describing terrestrial drumlins. Christoffersen et al. (2005) reports drumlins in the forfield of Elisebreen, Western Spitsbergen. In a cross section of one of these, mud is found immediately above the bedrock. This is overlaying by openwork gravel and clast supported sand and gravel, which is draped by a coarse grained diamict. They interpret this succession as marine sediments deposited during the late

Page 10 of 56 glacial/early Holocene transgression, but do not discuss the formation processes of the drumlin.

1.2 Till formation and deposition

In the geological record, tills displaying different properties have been assigned different names according to their genetic processes, e.g. lodgement till, melt-out till, comminution till and glacitectonite. Recently, researchers have suggested that tills are not formed by a single process, but are a part of a continuum of processes that cannot be specified by sedimentological criteria (Evans et al., 2006; Alley, 2000). In a review of the subglacial environment and the sediments deposited within it Evans et al. (2006) therefore set up a new model of the subglacial environment and suggested the term “subglacial traction till” to be a unifying term for the different tills. In this thesis, this approach is adopted. The following section describes its model and is largely based on the work of Evans et al., (2006) who defined traction till as:

“sediment deposited by a glacier sole either sliding over and/or deforming its bed, the sediment having been released directly from the ice by pressure melting and/or liberated from the substrate and then disaggregated and completely or largely homogenised by shearing” (Evans et al., 2006).

To understand the main processes involved in the formation of a traction till, the fundamental processes of lodgement, ploughing and deformation must be understood along with the subglacial environment.

1.2.1 Lodgement, ploughing and deformation Lodgement is defined as:

“the plastering of glacial debris from the base of a sliding glacier on to a rigid or semi-rigid bed by pressure melting and/or other mechanical processes” (Dreimanis, 1989).

Imagine a debris-rich glacier sole sliding across a bed where the clasts in the ice are dragged along the bed resulting in a frictional drag. When the frictional drag between the bed and the clasts becomes greater than the force between the clasts and the ice, the clasts will be inhibited from further movement (Boulton, 1982). If this occurs on a rigid bed the clasts will scrape across it creating striations in the bed (Benn and Evans, 2010). If the bed is soft, the clast will plough in to the substrate. Clasts that are already lodged may act as obstacles for other clasts that may create clusters. Sediments interpreted to be deposited by this process are usually high in density and massive in appearance. They are usually highly fissile and may have polished or slicken-sided joints. Lodgement tills have also been recognized by crushing and abrasions of clasts and grains (Evans et al., 2006). Polishing of clasts and boulders are common, and plucking may cause the clasts to develop stoss and lee sides (see section 1.2.4).

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Fig. 1.9 – The process of evolving deformation till. See text for explanation (Boulton, 1987).

Boulton (1987) showed that the till deposited by the Icelandic glacier Breiðamerkurjökull displayed two main sedimentological layers: an upper rapid deforming layer comprising very high shear strain rates and velocities undergoing ductile deformation, termed the A-horizon, and an underlying more slowly moving or stable B-horizon that may deform by brittle failure (Fig. 1.9A; as described in Boulton and Hindmarsh, 1987). During a time span of three years from 1974 to 1980 a range of experiments were performed on the sediment response to the overriding glacier movement (Boulton and Hindmarsh, 1987). One of their main results is shown in Fig. 1.10. At the beginning of the experiment, four strain markers were attached to the A-horizon, and after 136 hours the strain markers had deformed as shown in Fig. 1.10. The experiments also disclosed that the upper A-horizon had high strain rates and a low density whereas the lower B-horizon had low strain rates and a high density. Deformation tills have often been described as massive and lacking any macroscopical evidence of deformation (Boulton, 1987; Evans et al., 2006), and the lack of structures has been regarded as an indication for the encompassing role of the deformation processes. However, Evans et al. (2006) argue that if one cannot see the deformation or any other support for a total homogenisation of the sediment by deformation, how can one ascribe the main process to be deformation?

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Based on data from Breiðamerkurjökull, Boulton (1987) developed a model for formation of deformation till: between the A and B horizons a shear surface or a decollement is found, but it may happen that a part of the B-horizon is incorporated into the A-horizon (Fig. 1.8b), where it is attenuated and may be separated completely from the B-horizon (Fig. 1.8c). If a boulder or another inhomogeneity is encountered, the raft of the B-horizon may fold around it (Fig. 1.9 d and e). Multiple events of this process will produce a laminated till. The sediment may be carried over long distances (up to several hundred kilometres in 10 ka, in case of a major ice stream) where continued shearing, deformation and folding in time will produce a relatively homogenised till that Boulton (1987) named deformation till.

Fig. 1.10 – Deformation patterns of the A-horizon of Breiðamerkurjökull. Straight stippled lines represent the strain markers at the initial state of the experiment. Curved stippled lines represent the strain markers at the final state of the experiment (after 136 hours) (Boulton and Hindmarsh, 1987).

Evans et al. (2006) argue that if this was the major process for till formation, then evidence for deformation should be much more widespread in the geological record. They also argue that clasts ploughing through a soft deformable bed will deform it. It thus seems unlikely that till can form without any form for deformation, and they ask the question: “exactly what proportion of a subglacial diamicton must be lodged before it can be classified as a lodgement till rather than a deformation till?”

1.2.2 The subglacial environment A diamict located subglacially which is saturated with water and under hydraulic pressure, will dilate the sediment and thus lower the density and increase the porosity. In effect, the grains move apart weakening the electrostatic bonds of the cohesive minerals and the frictional forces between the rests of the grains. This makes the diamict less resistant to shear and it flows readily to applied stress (Evans et al., 2006). In contrast if the water pressure is low, grain to grain friction and cohesive forces will develop and cause the sediment to transform from a

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Fig. 1.11 - Hypothetical model for till dilation matching the A/B-horizon hypothesis of Boulton (1987) (Evans et al., 2006). The dilated A-horizon has the highest velocity in the topmost section decreasing downwards along with the amount of dilation and pore water content. The A/B-horizon marks the transition to the lower solid state and stabile B-horizon. liquid state to a semi-solid or a solid state that is more resistant to stress. The response to applied stress may be folding, faulting and foliation, all related to solid state deformation. Evans et al. (2006) states furthermore that because of the frictional force between the grains of sand and gravel they are more resistant to deformation than clay, and may show apparent lower amount of deformation than clayey counterparts. Both of these states of dilation and non-dilation may occur at the same time within the same vertical unit (Fig. 1.11) where the topmost part of the unit may be dilated and flow more or less freely, and further down into the unit the weight of the overlying burden causes the sediment to be more compact and thus more resistant to flow. This results in what can be divided into the two-horizon-model of Boulton (1987) and a transition zone between the two (Evans et al., 2006). However, a critical pore water pressure must be maintained to sustain the dilations, especially if the sediment is clay rich. This is because, as the dilation weekends the grains gets closer to each other, and at some point the electrostatic forces of the clay minerals becomes high enough for them to rapidly increase the

Page 14 of 56 till matrix density (Smally and Unwine, 1968; Boulton and Hindmarsh, 1987; Alley, 1991). The “collapse” of the dilated sediment may form a sharp transition to the underlying B-horizon according to Evans et al. (2006). The amount of meltwater available for the bed may vary from day to night and from season to season and thus the pore water pressure cannot be permanently sustained. When pore water pressure falls under this critical value the movement of the glacier bed may shut down (Smally and Unwine, 1968). Also the mechanical properties of the sediment may affect the glacier motion. Fischer et al. (1999) presented a numerical model showing how areas of low drainage (e.g. areas of high clay content) have higher pore water pressures and areas of high drainage (e.g. sand or gravel) had lower pore water pressures, and thus provide a complex hydraulic system (Iverson, 2010; Stone and Clarke, 1996). Contrastingly, sediments that have high clay content are more resistant to initial dilation than sand because of the cohesive forces.

1.2.4 Maturation of clasts during till formation Surface texture of a clast is determined by two factors: internal texture due to the lithology and the markings, such as striations, due to contact with other rocks (Barrett, 1980). If a rock is mainly being abraded by contact with other rocks or the bedrock that has a relative velocity to itself, it is likely that it leaves erosive lines on the rocks. If the movement of the rock relative to the surrounding rocks are uniform, the striations will be parallel, but if the rock is affected by turbulent forces the striations will be randomly orientated (Boulton, 1978; Hicock, 1991).

Fig. 1.12 – Wear patterns of subglacially derived asymmetric clasts (modified from Krüger, 1984, and Benn and Evans, 1996, and presented in Evans et al., 2006).

When clasts are lodged on to the glacier bed, the overriding debris rich ice (or an overriding till unit) may scrape across the surface of the clast and abrade it on the stoss side and fracture it on the lee side, leaving the clasts with a miniature rouches moutonné like shape (or bullet-nosed shape) (Fig. 1.12; Boulton, 1978; Krüger, 1984). Thus the smooth upper stoss side of the in situ clasts will indicate

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Fig. 1.13 – Schematic reconstruction of boulders deeply embedded into a till unit. Till has piled up in front of the boulder and a flute is found downstream from it (Boulton, 1978). where the ice came from (Boulton, 1978, Krüger, 1984). However, this asymmetric shape of clasts is not diagnostic for lodgement as it may also develop by ploughing or differential shear and ductile deformation of the till unit (Benn, 1995). This characteristic shape is also seen on larger boulders (0.5-1 m) that are embedded into the till units (Fig. 1.13; Boulton, 1978). In general these show well defined striations parallel to the ice flow. These boulders are often found at the starting point of flutes (se section 1.4). Boulton (1987) notes that this phenomenon is strongly associated to lodgement till surfaces, and refers here, amongst others, to the Nordenskiöldbreen. He suggests that these boulders have been subject to “steady, rotating resistance to ice flow around it after it has been lodged on the bed” (Boulton, 1987). Striations may also be found on clasts that do not show asymmetry and stoss lee sides. On such clasts the striations may either be parallel reflecting stable conditions, or have a wide range of orientations indicating turbulent conditions under the time of formation (Benn, 1995).

1.3 Drumlins

1.3.1 What is a drumlin? Drumlins were first recognised in 1867 by M.H. Close in Ireland, who named them after the Gaelic word druim meaning hill, and have been defined by Menzies (1979) as ‘typically smooth, oval shaped hills or hillocks of glacial drift resembling the morphology of an inverted spoon or an egg half-buried along its long axis. Generally the steep, blunter end points in the up-ice direction and the gentler sloping, pointed end faces in the down-ice direction, these two ends being respectively known as the stoss and lee sides (Menzies, 1979). Drumlins are thus, most often oriented parallel to the ice flow direction, and have been, alongside with other bedforms such as crag-and-tails, flutes and mega-scale glacial lineations, widely used to indicate paleo-ice streams and basal ice velocities (Menzies and Shilts, 1996; Patterson and Hook, 1996; Howe, 2003; Horgan, 2010; Batchelor et al., 2011). Drumlins are found preserved in both marine and terrestrial environment. In the terrestrial environment they often occur in swarms of a few tens to several

Page 16 of 56 thousand (Fig 1.14A ; Menzies, 1979; Shaw and Kvill, 1984, Clark,1994). They are especially abundant in Canada (e.g. Dyke, 1988; Clark, 2003; Sharp, 1987), USA (e.g. Miller, 1972), Ireland (e.g. Clark et al., 2009; McCabe, 1989), Britain (e.g. Clark et al., 2009), and Fennoscandia (e. g. Raukas and Tavast, 1994; Zelčs and Dreimanis, 1997) where they cover large areas of glacier beds left by the last glaciation (Clark et al., 2009; Menzies and Shilts, 1996). Lately, drumlins have been observed emerging for underneath retreating glaciers like Brúarjökull (Schomacker et al., 2006), Eyjabakkajökull (Schomacker et al., 2014), and Múlajökull (Fig. 1.14B; Johnson et al., 2010). Also at Antarctica, drumlins have been reported (Shipp et al., 1999; King et al., 2007), e.g. by Smith et al. (2007) who argue that drumlins are actively forming and growing underneath the Rudford Ice Stream.

Fig. 1.14 – A) The Livingstone Lake drumlin field, Northern Saskatchewan, Canada (modified from Shaw and Kvill, 1984; the figure is provided by Google Earth, 2014). B) Drumlins emerging from the ice margin of Múlajökull (Johnson et al., 2010).

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1.3.2 How do drumlins form? Researchers have been struggling with defining a unifying hypothesis of drumlin formation. One of the main criteria for such a hypothesis is that it has to explain all drumlins ever found, including their geographical location, location with respect to the glacier, morphology and internal structures. Three of the most significant hypothesis produced will be discussed here. Menzies (1979) presents a careful review study of the different hypothesis existing at the time and combined them to a new: he describes, that in the subglacial environment, areas of higher drainage, e.g. facilitated by already existing sediments composed of sand or similar that will allow subglacial melt water to dissipate, will create areas of higher basal drag, coursing subglacial material from either lodgement or melt out to accumulate in those areas and thus creating a drumlin. How sufficient material to create large drumlins could be supplied from this process, remained an open question, but Menzies refers to the work of Clayton and Moran (1974) and states “that dirt band stacking by differential velocities close to the snout of an ice mass would appear to be one likely hypothesis”. He ends his discussion by saying that the hypothesis may be held in abeyance until more knowledge about glacial sedimentation is understood.

Fig. 1.15 – Schematic illustration of the meltwater hypothesis (Shaw, 2002).

Shaw and Kvill (1984) investigated the drumlin field of Livingstone Lake, and found apparently undeformed fluvial sediments in the interior of several drumlins. From this Shaw (1983) evolved “the meltwater hypothesis” explaining how these drumlins were formed during catastrophic outbursts of meltwater. During such

Page 18 of 56 events the glacier would detach from the bed allowing large amounts of water and suspended sediments to drain rapidly through the subglacial system, leaving sediments in subglacial cavities thus producing drumlins (Fig. 1.15). Such drumlins would be composed of gravel and sand displaying lamination in a manner that would indicate suspension settling from short-lived violent events (Shaw and Kvill, 1984; Shaw et al., 1989; Shaw, 2002). Boulton (1987) presented a model of the strain in ice as it moves across an obstacle of stiff sediments and from this produced his high regarded hypothesis. A layer or a lens of sand or gravel may be more resistant to movement than the surrounding material and may thus act as an obstacle in the glacier bed. Boulton modelled how a straight line, representing soft deformable sediment transported by the glacier sole, deforms around such an obstacle as time passes (fig. 1.16).

Fig. 1.16 – A) Flow lines of soft deformable sediment at eight different time steps (T1-T8), displaying how the bed deforms around a stiff obstacle during an ice advance. B) The progressive evolution of the drumlin at fire different time steps (a-d). The stippled lines represent the deformation of the core, and contours show elevations with respect to the original surface. Time step 0, the starting point, is not in the figure (Boulton, 1987).

This created a major stress field at the up-glacier part of the obstacle and very high strain rates around the flanks (Fig. 1.16A). This strain causes the obstacle to deform showing a pattern of erosion on the up-glacier part where the flow was accelerating, and deposition on the down-glacier part where the flow was decelerating, hence a tail will grow on the lee side (Fig. 1.16B). But not only does

Page 19 of 56 the tail grow, also the erosional zone and the highest point are growing. Boulton also notes that if the “stiffness contrast” between the A- and the B-horizon is strong, the deformation of the B-horizon is more pronounced than if the stiffness contrast is low. Boulton’s hypothesis was further developed by Hindmarsh (1998) who used a numerical model to show how the shearing between a fast moving basal ice and an underlying deformable till layer could cause an instability that promotes the growth of a basal topography. This idea arose for observations from other fields of the nature where features gather up in piles and enhances its self to form observable patterns. This may for example be current ripples formed in sand by running water, clouts forming repetitive ripple like formations or water forming curtains like patterns as it falls from above (Clark et al., 2009; University of Sheffield, 2014). This concept is called the nonlinear instability theory (Clark et al., 2009). By combining this with Boulton’s hypothesis and allowing ice and till to deform internally and side with respect to each other, Hindmarsh succeeded in producing a physical based numerical model that was capable in producing drumlins under a moving body of ice. Hindmarsh’s model has been confirmed by Fowler (2000) who used a mathematical model rather than a numerical, and reached the same conclusion (Clark et al., 2009). Though Clark et al. (2009) state that the models only predict ribbed moraines and not the instabilities lateral to flow which should be required to form drumlins. Also it does not explain the big variability in internal structures and composition in a satisfactory manner (Hindmarsh, 1998). The melt water hypothesis has been subject to heated debate and was widely criticised by Benn and Evans (2006) under the headline “Subglacial megafloods: outrageous hypothesis or just outrageous?” They argue that the science of Shaw and co-workers is inconsistent and selective. Instead they argue that the deforming bed hypothesis of Boulton (1987) potentially can explain all drumlins and flutings in terms of a single process.

1.3.3 Morphology of drumlins Based on digital elevation models and satellite images of Britain and Ireland Clark et al. (2009) presented a careful study of the shape and dimensions of a total of 58,983 drumlins and compared this to 25,907 drumlins reported in the literature from all over the world (Table 1.1).

Table 1.1 – Drumlin dimensions (modified from Clark et al., 2009). Length [m] Width [m] Elongation ratio Maximum 629 209 21.8 Minimum 99 25 1.2 Mean 6893 1151 2.9 Most common interval 250-1000 120-300 2-2.3

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The frequency distributions of the drumlins were unimodal, thus showing that they all come from the same distribution. This implies that drumlin shape and size are independent of place and the specifics of different ice sheets. They also showed that the maximum elongation ratio (Emax) never exceeded

E=L1/3, where L is the length of the drumlin and E is measured in meters.

1.3.4 Drumlin composition Menzies (1979) states that “the internal composition of a drumlin varies from stratified sand to unstratified till to solid bedrock, with every possible permutation between”. He illustrates that there is a great deal of complexity associated with this topic, but Stokes et al. (2011) managed to divide drumlins, reported in the literature, into five categories based on their internal structures and composition. These are:

1. Mainly bedrock 2. Part bedrock/part till 3. Mainly till 4. Part till/part sorted sediments 5. Mainly sorted sediments

The categories exclude the composition of the surface material of the drumlin that usually makes up <10 % of the drumlin. Since pure bedrock drumlins are not the case in this study, this type will be excluded from the further discussion. The remaining three are briefly outlined in Fig. 1.17 and Table1.2. It is important to note that different types of drumlins can occur in the same drumlin field (Stokes et al., 2011).

Fig. 1.17 - Schematic illustration of the five main types of drumlins reported in the literature, including various sub-types (Stokes et al., 2011).

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Table 1.2 – A description of four different drumlin types as they are presented in Stokes et al. (2011). The list of authors is a selection of main authors of each type. For a complete list of authors the reader is referred to Stokes et al. (2011).

Type Description Authors Partly bedrock This type is derived from the drumlins that are Dionne, 1987; Fairchild, 1907; and partly till often referred to in the literature as “rock Linton, 1963; Glückert, 1973; cored”. The relative proportion of bedrock Raukas and Tavast, 1994; Evans, and till may vary, but in general there should 1996; Heroy and Anderson, 2005; be more than 25 % till for the drumlin to fall Kerr and Eyles, 2007; Boyce and under this category. The bedrock knob may be Eyles, 1991; Fisher and Spooner, surrounded by a single or several units of till 1994; Nenonen, 1994; Meehan et or glaciofluvial sediments and can be al., 1997; Yi and Cui, 2001. positioned in the stoss, middle or the lee side of the drumlin, though this may vary even within a single drumlin field. If the bedrock is positioned and occupies the entire stoss side of the drumlin it may be regarded as a ‘crag- and-tail’.

Mainly till Some drumlins are composed of mainly till. Wright, 1962; Habbe, 1992; These may be homogenies and structure less Boulton 1987; Nenonen, 1994; all the way through, or it may be clearly Menzies et al., 1997; Stea and stratified by distinguishable layers of different Brown, 1989; Johnson et al. tills with well-developed fissility and shear (2010), Wysota, 1994; Raukas and planes. This stratification may obey the Tavast, 1994; Hart, 1997; Kerr and principal of superposition, by Eyles, 2007. glasiotectonically disturbed or display a sock fold. Other drumlins may have stratification that resembles the form of the drumlin. Till units have also been reported to be separated by thin units of glaciofluvial sediments, which may represent subglacially or proglacially derived sediments.

Partly till and Some drumlins have large amounts of both Rattas and Piotrowski, 2003; partly sorted sorted sediments, like glacifluvial sediments Raunholm et al., 2003; Kerr and sediment and till. It may be located as a core, in Eyles, 2007; Hiemstra et al., 2008; between till units or be deformed into the Wysota, 1994; Habbe, 1992; overlying till unit. Other studies have reported Wysota, 1994; Kerr and Eyles, sorted sediment preferably deposited in the 2007; Dardis et al., 1984. leeside and thus interpreted then to be related to leeside cavity deposition that required the presence of an obstacle. Mainly sorted Drumlins may be composed exclusively of Boulton, 1987; McCabe and sediments sorted sediments, draped by a thin till layer. Dardis, 1989; Sharpe 1987; Shaw The sediments are often reported to be and Kvill, 1984; Shaw, 1983; undeformed. Küger and Thomsen, 1984; Habbe, 1992.

Stokes et al. (2011) acknowledged that this kind of subdivision of drumlins is a simplification and thus has its limitations, but states: “…we believe that the identification of these categories is a necessary move to simplify the complexity that has so often inhibited progress towards a satisfactory explanation of drumlin formation”.

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From the above it is clear that the variability of drumlins internal structures is large even with in the same field and it may occur to one that different subglacial processes may account for these differences. Stokes et al. (2011) however, states “This would seem to be introducing additional complexity where it is not required”. It is possible that some of the sediments and structures are inherited from previous sedimentary environments, and are thus not related to the mechanisms of drumlin formation.

1.4 Flutes

Flutes have been defined as:

“a long, parallel-sided ridge which indicates accurately the direction of ice movement, and which occurs when deformable subglacial materials are intruded into tunnels which open up on the ice sides of single, rigid obstructions on the glacier bed. They are thus neither depositional nor erosional features, but result from post-depositional deformation of pre- existing materials” (Boulton, 1976).

Fluted till plains have been observed in several earlier studies (Hoppe and Schytts, 1953; Boulton 1976), and are regarded as a common phenomenon (Boulton, 1976). Boulton (1976) described such planes in the ice marginal zones of both Breiðamerkurjökull and Nordenskiöldbreen. At Breiðamerkurjökull, tunnels leading in under the ice have been constructed for examination of the subglacial conditions. He found that the till was viscous and would flow if applied pressure was removed, and he observed directly how a boulder half embedded in to the till was acting as an obstacle causing the ice to create a lee side cavity into which the sediment would flow, creating a flute (fig. 1.18). The sediment infilling would thus prevent the cavity to close by ice creep. Later studies (Benn, 1994a; Eklund and Hart, 1996) support this interpretation and further states that a-axis fabric of the flutes exhibits a herring bone pattern where clasts from both sites of the flute point towards the centre of the flute, representing the flow pattern of the till during flute formation. In contrast, other studies (Hoppe and Schytt, 1953) have reported frozen till in the flutes that are carried downglacier by the ice (Gordon et al., 1992). Boulton (1976) also describes how the movement of the ice deflects around the boulders, which will cause the other flutes that are approaching it to also deflect (Fig. 1.19).

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Fig. 1.18 – Velocity profile of a boulder first transported englacially but gets retarded by the glacier bed, completed by illustrations of the event. a) The initial state. A boulder is being transported englacially and is approaching the deformable bed. b) The boulder gains contact to the bed and ploughing begins. c) The boulder digs its way into the bed and the pressure from the ice enhances. d) A cavity that is immediately filled with till is formed on the down glacier side of the clast (Boulton, 1987).

Fig. 1.19 – Schematic illustration of flute interaction (modified from Boulton, 1987).

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2 Methods

2.1 Field observations

The fieldwork was carried out in August 2014 during a period of ten days. The first seven days two master students, Lis Allaart and myself, and a camp leader, Alexander Hovland, collected data in the field. On the seventh day a group of bachelor students at The University Centre in Svalbard (attending the course AG-210 supervised by Olafur Ingolfsson) arrived and used the field site as a starting point for a discussion of glacial geology and geomorphology. Pits dug by these studies and fabric data collected by them have been incorporated into this thesis.

All in all eight pits were dug and examined (Fig. 1.6). Data was recorded by drawing logs and describing the sediments in detail using the classification scheme of Krüger and Kjær (1999) for the diamict and the facies model of Miall (1977) for the sorted sediments. Three shallow pits (~0,5 m) were dug into the southwest corner of the southern drumlin to investigate the relation of a pronounced flute to the other sediments in the drumlin (Fig. 3.9). These were named DF1.1 (Drumlin Flute 1.1), DF1.2 and DF1.3. For the same reason another pit was dug closer to the apex of the southern drumlin where two flutes crosscut each other (DF2) (Fig. 1.6). At last a two meters deep pit in the interior of the drumlin close to its apex called Ds (Drumlin South) was dug. One pit was dug into the crag-and-tail in the southern flank 27 meters from the last visible part of the crag, called CTs (crag-and-tail, south). A five meters long cross section was dug in to the western side of the river cut named CTw. An extra small pit was dug into a relatively big flute located in between the two drumlins. This pit is called F.

2.2 Sampling

Twenty samples for grain size analysis were taken from the eight pits. They were collected by carefully scraping the sediment into a sample bag, leaving nothing to fall to the sides. Cobbles larger than 128 mm were left out. The required size for a reliable sample increases rapidly with more poorly sorted sediments and with coarser grains. According to Gale and Hoare (1991), the minimum size for a sample of till with a maximum clast size of 100 mm should be 2 500 kg. This is not practically possible in this study, so as a compromise between what is realistic and a statistically reliable sample, sizes of between 3.6 and 6.5 kg were collected, according to availability and sorting. As a consequence, the diamict grain size data are not statistically representative, but can be used to support the field interpretations.

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2.3 Grain size analysis

In the laboratory the samples were dried at 70 ºC and thereafter sieved using 11 sieve sizes with the standard grain size interval of Wentworth (1922): 64, 32, 16, 8, 4, 2, 1, 0.5, 0.250, 0.125, 0,063 mm and a bottom tray collecting the fines (<63 µm; raw data can be seen in Appendix 1). Since most of the samples contained a relatively large amount of flocculating mud, it was necessary to first dry sieve them, then wet sieve them and then dry sieve them again.

2.4 Fabric

Four fabric analysis were produced using only clasts in the size range 20-128 mm (Kjær and Krüger, 1998) with an axial ratio a/b >1.5 (Evans and Benn, 2004). For each of the clasts, the azimuth (dip direction) and the dip of the a-axis was measured (raw data can be seen in Appendix 2). Clasts that were touching other clasts were discarded. All the clasts were collected and numbered for laboratory quality control. Every clast that did not live up to the size and axial ratio criteria was discarded. The fabric data were plotted on a stereonet using the software SpheriStatTM. Contours were drawn for 2, 4, and 6 standard deviations around the mean density. By performing an eigenvector analysis the strength of the fabric analysis tested. If the normalized eigenvalue of the first eigenvector is below 0.52 the fabric strength is weak and the ice flow direction cannot be inferred from it, but may, however, reveal information about the formation of the sediment. The degree and nature of clustering of the clasts are determined by plotting the eigenvalues given by SpheriStatTM in a ternary diagram using the isotropy index (I=S3/S1) and the elongation index (E=1-(S2/S1)) as axis. The three apices thus represent isotropy (three dimensional fabric signature), grid (two dimensional fabric signature) and cluster (one dimensional fabric signature) (Benn, 1994b; Fig. 2.1).

Fig. 2.1 – Ternary diagram of fabric eigenvalues, representing the fabric shape (Benn, 1994b).

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2.5 Morphology

Clast morphology has been used to infer processes of transport and deposition (Boulton, 1978). The main intention of this, in this study, is to analyse any differences in the stratigraphical layers, and thereby supporting the descriptions of the lithofacies. During sieving, the samples were separated in 11 grain size fractions and the tree biggest (64, 32 and 16 mm) was used for morphology analysis.

2.5.1 Clast shape The shape of a clast is defined by Evans and Benn (2004) as the smallest box that fits around the clast. The dimensions of the box are defined by three orthogonal axes, termed the long (L) the intermediate (I) and the short (S) axes (raw data can be seen in Appendix 3). The dimensions were measured with a ruler and plotted in a equilateral triangular diagram composed of S/L, I/L and (L-I)/(L-S) (Fig. 2.2; Sneed and Folk, 1958). This diagram plots the most cube shaped clast in the uppermost apex called blocks the flattest in the left apex called slabs and the most elongated in the right apex called elongates. The diagram gives an easy overview of the shape of the clasts relative to each other.

Fig. 2.2 - General shape triangle (modified from Sneed and Folk, 1958, and presented in Evans and Benn, 2004).

2.5.1 Roundness By determining the roundness of clasts in a sediment sample, some idea about the amount of reworking the clast has gone through could be inferred. For evaluation of clast roundness, the scale of Powers (1953) as described in Evans and Benn (2004) has been found most useful (Table 2.1; raw data can be seen in Appendix 4).

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Table 2.1 – Descriptive criteria for clast roundness categories (Powers, 1953; Evans and Benn, 2004). Class Description Very angular (VA) Edges and faces unworn and sharp Angular (A) Edges and faces unworn Sub Angular (SA) Faces unworn, edges worn Sub Rounded (SR) Edges and faces worn but clearly distinguishable Rounded (R) Edges and faces worn and barely distinguishable Well Rounded No edges or faces distinguishable

Powers (1953) provides a good understanding for the different roundness classes, but does not provide any guidelines for how to classify clasts that are clearly rounded or well-rounded but also have clear zone of breakage overprinting the rounded edges (Fig. 3.10B). This occurred quite often in the samples analysed in this thesis. It was decided to use the most rounded edges of the clasts to classify the amount of roundness.

2.5.2 Striations and clast asymmetry For all 18 diamict samples, the percentage of clasts with visible striations and the percentage of bullet shaped clasts with stoss and lee sides were calculated. Both clasts showing parallel and randomly orientated striations were included in the calculation (raw data can be seen in Appendix 5).

2.6 Radiocarbon dating

Six samples of shell fragment have been radiocarbon dated by Ångströmlaboratoriet, Uppsala Univerity, using the accelerator mass spectrometry method. Calibration to calendar years BP is done as in Hormes et al. (2013), using a reservoir effect of 440 ± 52 years. This is a compromise between the two suggestions of Mangerud et al. (2006) in which they suggest 450 ± 52 or 438 ± 52. The calibration is performed using the online calibration software of Fairbanks (http://radiocarbon.ldeo.columbia.edu/research/radcarbcal.htm) with the calibration curve Fairbanks0107 (Fairbanks et al., 2005).

3 Facies descriptions and interpretations

Five units have been recognized in the interior of the drumlin and the crag-and- tail. The first unit is defined by draping the landforms and make up the interior of the superimposed flutes. Sorted sediments found in the interior of the southern drumlin makes up unit 2. The third unit is composed of mainly diamict found in the interior of the crag-and-tail. Unit 4 is composed of a single layer of diamict found in the interior of the southern drumlin. And finally the fifth unit is a layer composed of clast-supported cobbles and boulders. Samples have been taken in each unit except for unit 5, as it was too coarse for sampling. Logs, drawings and photos can be seen in Figs 3.1 to 3.5.

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The clasts shape data (Fig. 3.6) have been plotted in ternary diagrams. From these it is clear that all the samples plot fairly close to each other in the middle left side of the diagram displaying clasts with mainly platy shapes. However, sample DF1.2 plots as the only sample in the other side of the diagram, and shows more elongated clasts (Sneed and Folk, 1958). Clast roundness has been plotted in histograms (Fig.3.7) and shows a general trend of the clasts being angular to sub- rounded. Radiocarbon dates are presented continuously, and is summarized in table 3.8. Please note that the radiocarbon date of DD1 dates to >40 000 yrs. This is regarded as a contaminated sample and is excluded from further discussion.

Fig. 3.1 – Field observations of pit Ds. A) Composite log. B) Cross section.

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Fig. 3.2 – Field observations of pit CTs. A) Composite log. B) Cross section of the CTs constructed in the field and supported by C).

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Fig. 3.3 – Field observations of pit CTw. A) Composite log. B) Cross section of the CTw constructed in the field and supported by C).

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Fig. 3.4 – Three of the four small pits dug into the drumlin. Note that no logs have been produced of these three pits and that no drawing of pit DF1.3 and F has been produced, as inly one facies (unit 1) was visible in these. For location see Figs 1.6 and 3.9.

Fig. 3.5 – A) Legend of the logs. B) Legend for the profile sketches.

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Fig. 3.6 – Clast shapes inferred from clasts bigger than 8 mm. Compere with Fig. 2.2.

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Fig. 3.7 – Data of clast roundness plotted in histograms. Vertical axis in percent of the total amount of clasts bigger than 8 mm.

3.1 Unit 1, surface features and top layer, DmF(m2)3

3.1.1 Description Flutes superimposed on the southern drumlin are subparallel and have a general orientation of 255°N of which they deviate around 8°. Some flutes have been observed to cross each other as seen in Fig. 3.9A. Many of the flutes have a large boulder at their beginning and the width of the flute often matches the width of the boulder. The three drumlins are all parallel with an orientation of 258 °N. Flutes have been observed to deviate from its original orientation if it approaches another boulder (Figs 3.9C and 1.19). Boulders up to two meters in size composed of amphibolite and Hecla Hoek schists were embedded into the unit and exposed at the surface. Many of them had pronounced bullet-nosed shapes and striations on the top surface parallel to the ice flow direction. A few boulders displayed striations in a completely other direction, however, all of these were lying on top of the surface and not rooted in it. Note how the fabric on the stoss side of the initiating boulder has been affected by the boulder.

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Fig. 3.8 – Grain size distributions and ternary diagram displaying the amount of mud relative to sand and gravel. Solid triangles: unit 1, circle: unit 2, grey triangle: unit 3, hollow triangle: unit 4. Note that no samples were taken in unit 5.

Table 3.1 – Radiocarbon dates for shell fragments frond though the bedforms. For specific position of the field codes see Figs 3.1 – 3.3. Reservoirs effect of 440 ± 52 yrs (Mangerud et al., 2006; Hormes et al., 2013). Calibration curve Fairbanks0107 (Fairbanks et al., 2005).

Lab no . Field Species 14C age 1 σ Reservoir cor. 1 σ cal yrs BP ± code BP 14C age Ua-49884 CTw1 Mya Truncata (?) 9 811 58 9 371 110 10 592 160 Ua-49885 CTw2 Mya Truncata (?) 9 791 56 9 351 108 10 564 154 Ua-49886 CTwB Mya Truncata 9 782 58 9 342 110 10 551 156 Ua-49887 Ds1 Macoma Calcarea >40 000 Ua-49888 Ds2 Mya Truncata (?) 9 803 58 9 363 110 10 580 159 Ua-49889 DsB Hiatella arctica 9 957 61 9 517 113 10 816 202

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Fig. 3.9 – A) Flutes as seen on the southern drumlin. For location see Fig. 1.6 B) The big flute seen from above. Put fabric on to here. C) Flute deflected by the boulder initiating the big flute. Photo is taken from East to West in a downglacier direction. Person in the background for scale.

Unit 1 is the unit exposed at the surface and is found in all of the seven pits. The flutes examined in this study are all composed of this lithofacies. It extends 20-50 cm in to the bedforms and is composed of gravelly diamict with a muddy to sandy matrix with clear fissility. The amount of clay is high relative to the other samples taken in this study, 23-45 % compared to 7-15 % in unit 3 and 4-5 % in unit 2 (Fig. 3.8), however, no slickensides were seen. No internal structures were observed in the unit and it was massive and homogeneous. The grain size distribution (Fig. 3.8) varies within a small range reflecting lateral variation in the grain size distribution. Clasts are mostly angular to subangular. Only a few clasts with clear bullet-nosed shapes of the gravel size clasts were found within this unit

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(Figs 3.1-3.3). Of these, only one has stoss and lee sides (Fig. 3.10A). This clast was also the only one to show parallel striations. Only 5-22 % of the gravel sized clasts sampled within each pit from this unit showed randomly orientated striations and they were all limited to softer lithologies such as limestone. The lower boundary was in general sharp but had an undulating appearance, except in unit CTw where the boundary was gradual and an inclusion of the diamict of unit 1 was found in the underlying unit.

Fig. 3.10 – A) Bullet-nosed shaped clast found in unit 1, with parallel striations. B) Well rounded clast broken in half found in unit 2. C) Randomly orientated striations on a clast found in unit 4.

In unit 1 four fabric analyses was made, showing significant fabric orientation (S1 = 0.58-0.68 in a general orientation subparallel (261.1/81.1 to 223.8/43.8) to the ice direction (Figs 3.1 and 3.9). Small shell fragments were found throughout this whole unit, only a few of them however, were recognizable. They were determined to be of the species Mya truncata and possibly Macoma calcarea, (however, the latter is not completely certain) and date to 10,592 ± 160 cal. yrs BP.

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Fig. 3.11 – Data of clast fabric shape eigenvalues plotted in ternary diagram. Compare with Fig. 2.1.

This unit was also found in a flute located in between the northern and the southern drumlin (Pit F). Here, a 40 cm deep pit was dug in to the surface of a large flute, the only flute found in the small area in between these two drumlins.

3.1.2 Interpretation: traction till Unit 1 is interpreted to drape the entire surface of the area investigated in this thesis, and to represent a subglacial traction till based on its diamict nature, its strong fabric, the large boulders with striations and the fluted surface. The fairly low amount of clasts with striations and bullet-nosed shapes is caused by the high hydraulic pressures (Evans et al., 2006). This lifts the grains apart and reduces the grain by grain interaction that causes the striations. In this state, the subglacial sediment is viscous and grains are allowed to rotate with no grain to grain interaction. However, grains will probably collide from time to time, causing the softer grains to gain short randomly orientated striations (Hicock, 1991). Larger clasts like the boulders found on the surface are too big to be affected by the dilation (Evans et al. 2006) and are thus lodged into the bed (Boulton, 1987). As the dilation continues, the ice deforms around it and creates a cavity on the lee side of the boulder, allowing the dilated till to flow into it, forming a flute displaying a preferred fabric orientation (Boulton, 1987). In the meantime the debris-rich ice scrapes across the upper surface of the boulder, polishing and plucking on the lee side, giving it the bullet-nosed shape (Boulton, 1978). For the above scenario to happen the glacier must be at its pressure melting point, and lots of water needs to be present. The glacier has been determined to be a polythermal glacier (Hagen, 1993; Rachlewicz et al., 2007), which means that it has a wide range of thermal structures, including temperate ice which may produce high amounts of melt water (Irvine-Fynn, 2011). Also direct field observation confirms meltwater emerging subglacially.

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According to Boulton (1976) and Menzies and Shilts (1996), both flutes and drumlins should be orientated with the long axis parallel to the ice direction. However, the general orientation of the flutes and the orientation of the drumlins deviate up to 8 °N. Also the flutes internal orientation is variable and show crosscutting relationships in several places. Such deviations from the overall flow trend bear witness of a highly dynamic ice/bed interface in which perturbations causes local movements of the glacier ice (Rose, 1989). Perturbations may originate from the local topography, large boulders embedded into the till and clusters of boulders that are not visible on the surface (Rose, 1989). In this case rather large bedrock outcrops (Fig. 1.6) on the western side cause the flutes to deviate to the south on the southern drumlin and to the north on the northern drumlin.

3.2 Unit 2, sorted sediments in the southern drumlin, Gm, Sp, Sh, Sm, B

3.2.1 Description In the southern drumlin, sorted sediments are found immediately under unit 1. A gravelly clast-supported homogeneous layer makes up the first 20 cm. Clasts up to large cobbles were found alongside with lenses of gravel and lenses of normal graded fine sand to silt 1-2 cm thin. Some of these were slightly deformed by ductile deformation. This top section grades down into a matrix-supported sandy interval. This interval is only seen in its full depth in pit Ds, where it extends 120 cm into the interior of the drumlin. Cobble to boulder sized clasts were embedded in to the sediments along with lenses of fine sand to silt varying in size from a few millimeters to a few centimeters, and with a lateral extent of five centimeters to a few decimeters. Several of them showed clear signs of ductile deformation (Fig. 3.12), however, undeformed lenses were often seen in close vicinity of deformed lenses. Towards the bottom lenses, planar crossbedded coarse sand to gravel was seen.

Fig. 3.12 – Sand lenses of unit 2. A) Lenses of fine normal graded sand show an irregular appearance. B) Lens of silt to fine sand that has undergone ductile deformation.

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The unit is dominated by subangular clasts and the amount of clasts with randomly orientated striations increases towards the topmost interval (Fig 3.1). Minor shell fragments were found throughout this entire unit in all the pits. They may be of the species Mya truncata, however, the fragments were too small to determine with certainty.

3.2.1 Interpretation: Glacifluvial The interpretation of this poorly sorted to sorted sandy-gravely unit with minor beds of sorted sand and silt, in combination with lenses of planar cross-bedded sand and gravel, is that of ice proximal glacifluvial deposits. The major facies found in this unit is Gm, clast-supported, massive gravel, which is deposited by the running water in longitudinal bars in a braided river. There, gravel is deposited and finer sediments get trapped in the voids of the gravel, and thus form an unsorted interval (Miall, 1977). This main facies is commonly interbedded with planar crossbedded, horizontally laminated or massive sands and silts deposited in longitudinal bars in the lower flow regime or in planar bed flows of upper to lower flow regime (Miall, 1977). This facies assemblage resembles the Scott type facies association of Miall (1977), formed by proximal gravelly, often ephemeral, rivers, forming longitudinal bars and small scale-cycles of waning-flood events giving rise to normally graded muddy and sandy lenses. Similar facies associations have been found in late Pleistocene drumlins in northwest Ireland (Darids and Hanvey, 1994), however, here they ascribe the sorted sediments to be deposited as channel fills in the lee side of drumlins. No signs of large-scale glaciotectonism were seen in this unit, but small scale deformation of minor silts and fine grained sands, along with the increased amounts of broken clasts (Fig. 3.10B) and randomly orientated striations witness of stress applied to the unit by the overriding glacier. Radiocarbon dating of shell fragments showed an age 10,580 ± 159 cal. yrs BP.

3.3 Unit 3, diamict in the interior of the drumlin, DmM(m3)3

3.3.1 Description Unit 3 is encountered in both pit CTs and in Ds. It is 50 to 60 cm thick and is composed of a heterogeneous diamict with a medium, silty and sandy matrix and a relatively high amount of clasts (m3 in classification system of Krüger and Kjær, 1999). Lenses composed of medium to coarse sand with a crudely laminated and crossbedded nature was found interbedded into the unit. In pit CTs the unit showed a normally graded tendency. The lower boundary of the facies in CTs was not encountered. The diamict has 7-14 % mud (Fig. 3.8), which is a low to intermediate amount relative to the other diamicts encountered in this study. Clasts were generally angular and not bigger than medium cobbles. Few clasts with randomly orientated striations was encountered and no with parallel striations. Few and small shell fragments were found in this facies.

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3.3.2 Interpretation: meltout of stagnant ice The heterogeneous appearance of this diamict, its relatively clay poor matrix and interbedded lenses of sorted sediments leads to the interpretation of it being a re- sedimented diamict probably formed in an ice marginal or supraglacial environment, displaying meltout of stagnant ice (Johnson, 1995; Krüger and Kjær, 1999; Schomacker and Kjær, 2008; ).

3.4 Unit 4, diamicts of the crag-and-tail, DmM(m3)3

3.4.1 Description In pit CTw and CTs, crudely stratified clast-rich massive and homogenous diamicts with a medium-grained, silty to sandy matrix were encountered immediately below the surface unit (unit 1). The unit makes up 85 cm in the cross section (CTw) and 40 to 50 cm in the pit closer to the crag (CTs). In both pits the lower boundary was gradational, and the top of the unit is very clast rich and almost clast-supported, but grades downward into fewer clasts. In the top part of pit CTw, 32 % of the sampled clasts showed randomly orientated striations (Fig. 3.10C). Only few of these were found in other levels of the unit. No clasts with parallel striations were found and only few bullet-nosed clasts were found (0 to 4 %). Week fissility was observed throughout the unit in both pits. Grain size analysis shows that the mud content of the unit varied from 18 to 23 %. In pit CTw interbedded lenses of gravel were observed.

3.4.2 Interpretation: till The diamicts of unit 4 is, as mentioned above, found in both the crag proximal and crag distal end of the crag-and-tail. The presence of fissility indicates that the sediments have undergone shear, which leads to the idea of a till. However, the low amounts of clasts with bullet-nosed shapes and the fact that no clasts with parallel striations were found indicate that in the case of the unit being a till, the amount of lodgement and internal shear must have been limited. The high amounts of clasts with randomly orientated striations may be a result of the later Neoglacial advance causing the top most part of the sediment to undergo slight deformation. A more precise interpretation of the unit cannot be obtained from the data available. The unit is in the following regarded as deposited in association with the early stage of the Neoglacial advance. Shell fragments dated in this unit are of the age 10,564 ± 154 cal. yrs BP.

3.5 Unit 5, boulders in the bottom of both crag-and-tail and the drumlin, Bm

3.5.1 Description In the bottom of Ds and CTs a layer of clasts-supported cobble to small boulder sized subangular to subrounded clasts. Single, but otherwise unbroken shells of the species Mya truncata and Hiatella arctica were found in both pits. The unit was very poorly excavated in the southern drumlin but well exposed in the crag-

Page 41 of 56 and-tail cross section. Here, the upper boundary is gradational and of strongly undulating character. In the left side of the cross section the layer displays a dome like shape, about 40 cm higher than the rest of the layer and approximately one meter wide. Elongated and slab shaped clasts are orientated parallel to the boundary, suggesting a non-erosive boundary. No striated or bullet-nosed clasts were found in this unit and its lower boundary was not encountered.

3.5.2 Interpretation: glacifluvial The massive cobble/boulder unit encountered in the lower most part of Ds and CTw is interpreted as fluvial, representing ice proximal river discharge of high energy, washing the finer material away leaving cobbles and boulders that were too big for the water to transport. However, periods of lower discharge have allowed sands, gravels and whole shells to be deposited in the voids of the cobbles and boulders. Even though layers of the same properties have been found in two different pits, it is not certain that the layers correlate, especially in an environment like this, where facies may have great spacious variability. Dating of the shell fragments found within them may help answer this question. However, the shell fragments were whole, which suggests that the amount of glacial reworking is little or none. Radiocarbon dating showed an age 10,551 ± 156 and 10,816 ± 202 cal. yrs BP.

4 Discussion

4.1 Stratification

The field site is located in a topographical low surrounded by bedrock outcrops. The outcrops display a thin cover of diamict whereas the field site is covered by till, ice marginal and glacifluvial sediments with thickness exceeding three meters. The field site thus represents a depocentre for sedimentation. The glacifluvial cobble and boulder unit of unit 5 has been interpreted as having undergone little or no glacial reworking based on the presence of whole unbroken shells. These sediments may thus have been formed before the neoglacial advance in a proglacial or ice marginal environment. The facies closely resemble sediment that occurs in the present day fluvial channels in the glacier forefield (Fig. 4.1). Furthermore the deposit was found in the same elevation as the gaps between the drumlins, suggesting this unit makes up a “base level” for the drumlins, representing the paleosurface from before the Neoglacial advance. However, it is unclear whether these fluvial sediments are formed by runoff from the mountain sides or melt water from the glacier. Similar surfaces have been reported in the literature (Krüger and Thomsen, 1984; Krüger, 1997). The facies association of unit 5, 3 and 2 found in the southern drumlin witnesses of an ice-marginal environment in which fluvial and ice-marginal reworking of sediments melted out of the glacier ice coexist.

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Fig. 4.1 – Present day glaciofluvial sediments used as an analogy for unit 5. Polar bear for scale.

Unit 1 is interpreted to reflect the main Neoglacial advance that has formed the drumlins, flutes and the outer moraine. This advance has eroded the glaciomarine sediments and reworked them in to the traction till of unit 1 under high hydraulic pressures. Such high pressures found subglacially of a polythermal glacier have been assigned to a frozen snout, restricting the water to the subglacial environment (Moran et al., 1980), which Patterson and Hooke (1995) suggested to be a triggering factor for drumlin formation. However, judging from the fluted nature of the glacier bed, that extends all the way out to the outer moraine, and on the fjord termination margin, this is not regarded as a possibility in this case. However, the high water pressures may have been facilitated by two factors. Firstly, the Hecla Hoek bedrock is a massive resistant crystalline rock type that facilitates little or no drainage of ground water. Secondly, the location of the sediments in a topographical low may have caused subglacial waters to gather in this area, further increasing the hydraulic pressures. Subglacial processes such as lodgement, dilation and melt-out have been the dominating factors for the till formation. Gravel found in the top most part of unit 2 exhibits large amounts of randomly orientated striations (Figs 3.1 and 3.5). This may have been caused by the applied stresses from the overriding glacier, causing the otherwise frictional and dilation-resistant gravel to scrape against each other. Small ductile deformation structures of lenses of fine grained material witnesses of small scale deformation caused by the same mechanism. The boundary between unit 1 and unit 4 in pit CTs also show signs of deformation and incorporation of unit 4 into unit 1, however, the same boundary found in pit CTw does not show any signs of deformation or erosion. This coincides with the fact that sediments of unit 4 in pit CTw have a noteworthy higher amount of clay, making it more resistant to dilation because of the cohesive forces of the clay minerals (Evans et al., 2006).

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This model of a highly deformable and dilated layer underlain by a more resistant unit of low deformation closely resembles the A/B-horizon model of Boulton (1987) (Section 1.2.2 and Fig. 1.11), where unit 1 is an analogy for the A-horizon and unit 2 and 4 resembles the B-horizon. In pit CTw the A/B transition zone have been small, whereas in the transition zone of pit Ds and CTs have been bigger. This suggests a highly dynamic subglacial environment. In summary, the facies association of the southern drumlin and the crag- and-tail represents a sequence of an advancing glacier, from the ice marginal environment to the advance of the glacier. Such an association is not unfamiliar in the literature and has been reported from both Elisebreen in Svalbard, from Iceland and from Denmark (Krüger and Kjær, 1999; Christoffersen et al., 2005).

4.2 Shell fragments and paleoshorelines

In Fig. 1.4 an area outside of the outer moraine has been marked as possible beach sediments. To my knowledge no studies have described these sediments, and only a quick look at them makes up the foundation for this assumption. However, in the case that these sediments resemble the upper marine limit of the early Holocene transgression/regression cycle, the paleoshoreline has probably followed the topography of the terrain (Fig. 4.2). This means that since the field site is below this hypothetic paleo-shoreline, this area must have been under glaciomarine conditions (Fig. 4.3), where muds must have been deposited from suspension fall out, probably mainly supplied by Nordenskiöldbreen that, according to Baeten et al. (2010), most likely still existed as a tidewater glacier. It thus seems likely that the shell fragments found throughout this study area, and the relatively high clay content found in unit 1, originates from these glaciomarine conditions. This interpretation is supported by the findings of shell fragments in the land forms. These comprises Macoma calcarea, Mya truncata and Hiatella arctica and were found in all the samples taken in this study, that is, both from the surface and all the way into the interior of the drumlins. These mollusc species live in habitats of low waters down to relatively deep marine waters (Feyling- Hansen, 1955), and has been dated by radiocarbon to 10.5-10.8 cal. ka BP (Table 3.1). The shell fragments are interpreted to reflect the delayed isostatic rebound that occurred as a consequence of the early Holocene deglaciation, and resulted in a marine transgression/regression cycle that flooded newly deglaciated areas (Boulton, 1974; Mangerud et al., 1998; Forman et al., 2004). The elevation of the upper marine limit varies throughout Svalbard (Forman et al., 2004), but has been determined to occur 90 meters above present day sea-level at Kapp Ekholm (a delta in Billefjorden south of the field site) (Feyling-Hansen, 1965; Salvigsen, 1984). At Kapp Ekholm four glacial advances followed by a marine transgression dating back to Saalian has been recognized (Mangerud and Svendsen, 1992). Till deposits from the most recent major glaciation event has not been encountered in this study, but the marine deposits that have been reworked in the landforms may, for the above reasons, correspond to what has been named formation H in the paper of Mangerud and Svendsen (1992). Marine deposits from this unit have

Page 44 of 56 been dated by radiocarbon, optically stimulated luminescence and amino acid to have formed between 10 and 9.5 ka BP (Mangerud and Svendsen, 1992; Salvigsen, 1984). This coincides with a warmer climatic period initiated 11.2 ka BP and lasting to 7.94 ka BP (Beaten et al., 2010). This allowed a richer fauna of mollusc species to live in the fjord as the climate progressively got warmer, starting with the species of Macoma calcarea, Mya truncata and Hiatella arctica (Feyling-Hansen, 1955), the same species as found in this thesis. The sediments of the landforms examined in this study partly consist of reworked glaciomarine sediments with an age of 10.5-10.8 cal. ka BP representing a late deglaciation/early Holocene marine transgression and partly of erosion of erosional material provided by glacier erosion, erosion of the mountain sides etc. Similar successions have been observed at Scottbreen at south western Spitsbergen (Magerude and Landvik, 2007) and Erdmannflya in Isfjorden (Salvigsen, 1990).

Fig. 4.2 – Hypothetic paleoshoreline as the writer imagine it to have been located in early Holocene. The shoreline is inferred from the possible beach deposits found on the outer side of the end moraine (Fig. 1.4). Aerial photo are provided by the Norwegian Polar Institute, 2009.

4.3 Drumlin types and their formation

The process of drumlin formation has been a subject of debate for more than a century; however, recent work (Hindmarsh; 1998; Fowler, 2000; Clark et al., 2009; Stokes et al., 2011) has shed light on the subject. The presence of different drumlin types within the same drumlin field is not unknown in the literature (Hill, 1971; Hart, 1995) and has been described as a continuum of forms (Flint, 1971; Dardis, 1985) produced by a single drumlin-forming process that is largely affected by the properties and mechanics of the pre-existing sediments, thus the internal composition holds the key to the process of the drumlinization. This approach is adopted here.

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Fig.4.3 – Hypothetical geographical scenario before the neoglacial advance. The black square marks the location of the field site. For legend see Fig. 4.5.

The two drumlins investigated in this study are mainly composed of pre- existing sediments draped with a thin cover of subglacially formed traction till. The southern drumlin is composed exclusively of sediments, whereas the other drumlin is composed of a bedrock obstacle with pre-existing sedimentary deposits in its lee, and is thus regarded as a crag-and-tail. As the tail of this drumlin-form has the same shape as the obstacle, with steep sides to the south (only disturbed by post depositional slumps) and close to horizontal to the left, and the fact that more or less undeformed horizontal bedded sediments occur in its interior, the drumlin is here interpreted as an erosional landform left as a remnant by the Neoglacial advance. Like the crag-and-tail, the southern drumlin is composed of melt out of stagnant ice and glaciofluvial deposits draped by a thin traction till unit, and is thus also regarded as an erosional unit. However, this drumlin does not have an obstacle in its front, thus the process of drumlinisation must differ significantly from the crag-and-tail. Undeformed sediments in drumlins are not unusual in the literature (Krüger and Thomsen, 1984; Sharp, 1987; Boulton, 1987; Sharpe, 1987; McCabe and Dardis, 1989; Shawe and Kvill, 1984; de Jong et al., 1982) where various explanations such as the meltwater hypothesis of Sharp et al. (1993), deformable bed hypothesis of Boulton (1987) and the formation of lee side cavity fill behind a rigid obstacle (McCabe and Dardis, 1989). In the hypothesis of the deforming bed of Boulton (1987) he states that gravels and sands have high internal friction and are relatively resistant to deformation, and may thus act as an obstacle for the soft deformable glacier sole (Fig.1.16) The bed then deforms around it and creates a field of high stress on the stoss side of rigid obstacle, and most likely causes the

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Fig. 4.4 – Internal structure of drumlins in relation to the stiffness contrast of the sediments (Boulton, 1987).

obstacle to deform. However, if the stiffness contrast between the A- and the B-horizon is high, limited deformation of the B-horizon will occur (Fig. 4.4). In the case of the southern drumlin examined in this study, the amount of mud found in unit 1 varied from 23 % to 34 % of which a relatively high amount probably is clay derived from the early Holocene transgression/regression cycle, compared to the 4-5 % in the top most part of unit 2 which is probably mostly silts derived from internal comminution of the clasts during the glacier advance. This contrast in clay content is here regarded as a significant contrast, and Boultons model from 1987 for drumlin formation (Fig. 1.16) is proposed as the main formation process for the southern drumlin. Alley (1991) states that if the velocity of the glacier slows down towards the snout of the glacier, the decrease in basal shear stress will result in net deposition and form a sharp boundary to the underlying sediments and protect them from deformation.

4.4 Depositional model

After the last deglaciation the delayed isostatic rebound of the continent allowed the marine environment to flood the newly deglaciated areas in the early Holocene (Boulton and Rhodes, 1974; Mangerud et al., 1998; Forman et al., 2004). As the continent slowly emerged, marine muds and gravel were left on the mountainside. These sediments contained shell fragments that date back to 10.5-10.8 cal. ka BP, and thus provide a constraining age for the deglaciation. In the time period that followed, little glacial activity has been observed (Baeten et al., 2010). In late Holocene a new advance of Nordenskiöldbreen was initiated, which culminated in a terminal moraine approximately two kilometers from the present day ice margin. As the glacier advanced from east to west, the ice marginal sediments, such as glaciofluvial sediments and ice meltouts from the snout of the glacier, were deposited in at least two meters thickness at the site of the southern drumlin

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Fig. 4.5 – Simplified schematic illustration of the geological evolution of the field site. Understanding of the drumlin formation should be accompanied by Figs 1.16 and 4.4. A) Figure continued from Fig. 4.3. The early Holocene marine sediments located in close vicinity of the glacier as it is advancing. B) As the glacier advances it deposits interfingering layers of ice marginal and fluvial sediments, which is then exceeded by the glacier and preserved in the lee side of the bedrock outcrop as a tail. The rigidity of the coarse-grained fluvial and ice marginal sediments causes the sediment to act as an obstacle for the glacier flow and the ice starts to deform around it. Erosion occurs on the stoss side and the flanks of the obstacle where the glacier flow is accelerating. As higher pressures are needed for the formation of lodgment till, this facies is restricted to deeper parts of the glacier and drapes the landforms in later faces of the landform formation. Because of the soft properties of this till the interior of the drumlinised bedforms are protected from large scale deformation. C) As the glacier retreats it leaves a fluted and drumlinised glacier forefield where fluvial and glaciofluvial processes dominate.

(Fig. 1.6). The glacier first encountered the bedrock outcrop of the crag-and-tail, where gravely tills were deposited subglacially on the lee side of the outcrop (Fig. 4.5A and B). The interior of the southern drumlin is composed exclusively of proglacial and ice marginal sediments, and draped by a thin layer of traction till. Traction till is associated with high hydraulic pressures, which require a certain amount of overburden and is thus associated with later faces of glacier advance (Evans et al., 2006). This means that the drumlinisation of the sediment must have occurred before or simultaneously with the till deposition. The coarse nature of the glaciofluvial and ice marginal sediments facilitated good drainage, and thus acted as an obstacle for the glacier flow that the ice deformed around in the manner of Boulton (1987) (see Figs 1.16 and 4.5B). The rigidity contrast between this

Page 48 of 56 sediment and the still forming traction till has protected the sediment from deformation and only limited small scale deformation is seen (Fig. 4.4). The advance terminated in AD 1896 (De Geer, 1910) and has retreated ever since (Fig. 1.3), forming recessional moraines in the central part of the fjord; however, no recessional moraines have been observed at the field site. The landforms are left as the glacier formed them, only affected by post-glacial slumps and fluvial down cuts (Fig. 4.5C).

5 Conclusions

The stratification and sedimentological properties of two drumlinoid landforms and a fluted surface in a glacier forefield in Svalbard have been examined. • The landforms contain shell fragments of the species Macoma calcarea, Mya truncata and Hiatella arctica with an age of 10.5-10.8 cal. ka BP, and originate from a late glacial/early Holocene marine landward transgression coursed by the delayed isostatic rebound of the continental crust that followed the last major deglaciation (Boulton and Rhodes, 1974). The radiocarbon dates thus provide a constraining age for the early Holocene deglaciation of the area. • The crag-and-tail reflects the formation of a non-erosive cavity formed distal to a major bedrock outcrop while the surroundings are being eroded by the advancing glacier. In the crag-proximal end of the tail the sediments comprises till associated with an early stage of the glacier advance. • The southern drumlin has a core of rigid coarse sediments of glacifluvial and ice-marginal origin, covered by a thin drape of clay rich traction till. The difference in stiffness between these two sediments have protected the core from deformation and thus acted as an obstacle for the deforming glacier ice and ice bed, resulting in the formation of the drumlin. • The drumlin forming process is largely controlled by the topography of the bedrock and the rigidity of the pre-existing sediments. • Till formation is largely facilitated by lodgement. Comminution and deformation processes may play minor roles.

Acknowledgement

Aerial photographs were obtained from Norwegian Polar Institute. The data are reproduced according to the permission No 13/G706 by the Norwegian Hydrographic Service. UNIS logistics is thanked for fieldwork support along with Alexander Hovland, Lis Allaart and the students of AG-210. I would like to thank Birgitte Clematide for graphical support, and Jeppe Roeber-Christensen for proofreading. Anne Elina Flink and Oscar Fransner from UNIS is thanked for housing me, and providing moral support during early faces of the work.

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Appendix 1 – Grain size distribution

0,11 0,05 0,08 0,16 0,07 0,10 0,09 0,12 0,06 0,10 0,13 0,08 0,06 0,09 0,10 0,10 0,08 0,07 Sample lost [%] 5,91 2,84 3,98 6,59 3,69 5,47 3,88 6,71 2,78 4,23 5,77 2,96 3,41 5,34 4,42 4,75 3,91 4,53 Sample lost [g] 5184,57 5704,54 5167,59 4234,82 5492,90 5264,39 4517,61 5598,76 4600,97 4266,19 4339,18 3699,21 5257,38 5731,34 4559,22 4675,94 4939,69 6531,11 Weight [g] 5178,66 5701,70 5163,61 4228,23 5489,21 5258,92 4513,73 5592,05 4598,19 4261,96 4333,41 3696,25 5253,97 5726,00 4554,80 4671,19 4935,78 6526,58 Sum [g] 262,20 271,68 902,02 976,29 267,01 430,76 785,66 580,80 865,57 573,85 450,88 1177,29 1171,30 1469,61 1037,72 1031,41 1018,79 1248,77 <0.63 72,65 221,78 186,16 245,76 286,21 146,86 312,15 197,13 285,17 327,25 122,54 134,35 258,40 346,61 177,26 363,21 116,55 258,83 0.125-0.63 428,10 309,26 450,01 484,76 204,39 807,13 588,03 258,58 365,88 265,94 751,25 206,32 424,03 461,30 582,30 446,30 123,01 340,51 0.25-0.125 293,09 382,70 284,93 273,01 220,43 390,77 327,72 250,08 409,03 450,49 318,15 224,55 392,21 411,07 359,21 370,75 311,12 357,39 0.5-0.25 284,53 451,83 282,54 134,52 258,90 468,57 297,61 287,80 447,06 457,76 264,64 241,96 415,82 436,58 383,96 335,54 407,54 417,34 1-0.5 309,61 530,90 311,33 155,90 338,80 467,44 330,53 334,52 507,52 501,33 287,38 290,98 459,43 469,44 401,19 331,72 531,18 514,96 1 301,45 564,09 300,64 292,61 409,00 283,34 327,72 382,66 468,87 441,92 287,97 337,91 487,38 489,75 367,61 315,87 559,08 710,92 4-2 Sive size [mm] 351,88 643,17 357,51 339,40 563,41 331,33 369,12 532,80 441,77 329,56 345,47 486,13 660,91 605,77 470,29 351,60 585,53 736,60 8-4 395,58 852,79 439,30 436,05 706,44 313,95 261,27 567,76 441,41 197,02 352,53 565,75 702,38 797,38 487,83 541,49 549,76 1014,72 8-16 356,21 993,34 416,83 275,98 302,53 297,62 648,52 218,36 314,40 354,71 354,72 547,27 922,44 263,65 586,16 382,27 800,40 1033,04 32-16 0,00 0,00 0,00 80,18 428,74 363,50 304,67 543,99 610,05 812,33 111,10 586,57 475,38 480,70 162,98 592,79 924,03 1336,26 64-32 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 630,40 161,76 598,79 301,08 203,10 > 64

Sample no. DF1.1 Df1.2 DF1.3 DF2.1 DF2.2 F1 CTw1 CTw2 CTw3 CTw4 Ds1 Ds2 Ds3 Ds4 CTs1 CTs2 CTs3 CTs4 Appendix 2 – Fabric data

F1, n=50 F2, n=48 F3, n=50 F4=151 F1, n=50 F2, n=48 F3, n=50 F4=151 Azimuth Dip Azimuth Dip Azimuth Dip Azimuth Dip Azimuth Dip Azimuth Dip Azimuth Dip Azimuth Dip 9 4 24 19 182 31 61 9 310 25 355 48 125 6 210 12 260 8 180 40 66 10 98 22 193 6 270 18 250 4 100 5 246 4 260 12 68 22 25 20 259 22 170 39 10 4 88 18 260 10 230 4 94 4 43 5 220 8 250 10 230 42 198 14 230 9 88 7 59 9 148 22 232 4 29 16 75 8 289 2 118 40 212 38 22 3 256 9 84 16 105 19 208 20 62 2 105 6 42 14 44 12 196 33 194 6 88 10 24 28 222 29 252 14 90 1 310 1 67 3 110 16 232 26 58 5 75 12 86 16 10 9 257 2 248 22 126 40 130 25 27 12 270 10 72 3 32 38 29 2 75 0 281 5 54 8 242 4 250 8 255 7 274 30 233 19 30 54 628 10 158 9 249 13 240 5 324 29 294 18 234 13 217 4 59 7 256 21 89 26 124 20 190 14 160 33 354 17 56 12 265 14 206 7 150 2 266 16 320 22 270 11 193 29 205 1 285 5 55 14 124 48 197 35 47 11 297 4 135 22 246 7 17 3 260 24 104 10 220 11 324 35 185 43 245 38 30 10 80 11 120 42 185 50 66 2 159 24 65 10 46 7 16 15 260 1 297 20 342 13 132 25 62 79 232 10 15 7 95 10 109 5 63 5 20 20 100 18 60 11 133 31 308 6 53 11 150 17 148 12 172 22 253 20 222 4 205 18 245 20 290 36 265 15 220 8 11 20 40 6 21 18 77 3 250 60 57 28 95 17 120 43 205 59 315 61 283 1 90 54 229 9 97 10 199 25 48 18 82 16 255 20 201 43 213 4 38 22 240 14 114 12 160 62 232 20 16 6 100 35 101 1 44 20 188 35 258 1 248 12 244 9 52 24 152 20 55 21 230 25 221 9 264 25 99 21 94 10 270 12 113 6 250 109 282 38 272 29 50 15 111 7 25 22 335 46 102 2 90 30 263 9 59 2 319 24 265 4 95 30 60 8 98 31 220 3 305 20 25 10 35 50 80 19 213 23 277 60 260 21 221 30 142 9 180 31 245 4 82 18 239 19 63 4 69 2 84 10 278 10 76 6 62 12 9 5 155 20 268 2 127 5 28 19 58 20 100 2 261 13 49 3 50 45 80 8 190 10 107 15 188 35 95 50 105 20 70 17 230 5 240 2 30 5 270 35 30 40 260 10 150 10 280 0 185 25 280 25 88 6 270 0 92 12 240 0 127 20 275 0 130 20 260 10 188 5 290 5 115 4 160 5 68 22 278 0 255 10 295 20 240 20 0 20 260 10 255 0 77 18 63 20 82 36 48 38 274 4 270 10 269 2 232 7 273 4 285 0 120 9 258 11 173 22 241 9 84 20

Appendix 3 – Clast shape

DF1.1 DF1.2 DF1.3 DF2.1 DF2.2 L I S S/L I/L DRI L I S S /L I/L DRI L I S S /L I/L DRI L I S S/L I/L DRI L I S S/L I/L DRI 99 82 27 0,27 0,83 0,24 70 37 22 0,31 0,53 0,69 42 22 17 0,40 0,52 0,80 39 22 26 0,67 0,56 1,31 95 62 41 0,43 0,65 0,61 82 61 37 0,45 0,74 0,47 73 65 27 0,37 0,89 0,17 36 23 16 0,44 0,64 0,65 28 18 13 0,46 0,64 0,67 98 43 23 0,23 0,44 0,73 54 42 22 0,41 0,78 0,38 66 36 26 0,39 0,55 0,75 29 30 23 0,79 1,03 - 0,17 28 22 8 0,29 0,79 0,30 81 57 38 0,47 0,70 0,56 83 42 29 0,35 0,51 0,76 59 48 20 0,34 0,81 0,28 37 32 13 0,35 0,86 0,21 30 18 14 0,47 0,60 0,75 56 28 16 0,29 0,50 0,70 26 17 9 0,35 0,65 0,53 50 38 17 0,34 0,76 0,36 43 26 20 0,47 0,60 0,74 45 21 17 0,38 0,47 0,86 40 40 38 0,95 1,00 0,00 42 20 12 0,29 0,48 0,73 44 39 17 0,39 0,89 0,19 45 19 15 0,33 0,42 0,87 21 19 15 0,71 0,90 0,33 105 60 39 0,37 0,57 0,68 28 17 12 0,43 0,61 0,69 33 19 17 0,52 0,58 0,88 42 25 12 0,29 0,60 0,57 25 24 13 0,52 0,96 0,08 43 35 25 0,58 0,81 0,44 26 18 15 0,58 0,69 0,73 28 19 18 0,64 0,68 0,90 43 25 23 0,53 0,58 0,90 21 20 12 0,57 0,95 0,11 53 47 22 0,42 0,89 0,19 37 27 18 0,49 0,73 0,53 56 30 22 0,39 0,54 0,76 27 19 18 0,67 0,70 0,89 21 15 11 0,52 0,71 0,60 39 39 29 0,74 1,00 0,00 37 21 15 0,41 0,57 0,73 47 29 21 0,45 0,62 0,69 40 25 20 0,50 0,63 0,75 51 28 14 0,27 0,55 0,62 33 24 13 0,39 0,73 0,45 51 24 18 0,35 0,47 0,82 32 23 10 0,31 0,72 0,41 38 31 12 0,32 0,82 0,27 33 28 18 0,55 0,85 0,33 32 29 13 0,41 0,91 0,16 55 20 14 0,25 0,36 0,85 38 24 14 0,37 0,63 0,58 31 28 14 0,45 0,90 0,18 37 30 10 0,27 0,81 0,26 45 31 17 0,38 0,69 0,50 43 36 16 0,37 0,84 0,26 37 27 21 0,57 0,73 0,63 27 20 15 0,56 0,74 0,58 39 22 16 0,41 0,56 0,74 41 28 15 0,37 0,68 0,50 45 25 24 0,53 0,56 0,95 38 20 12 0,32 0,53 0,69 28 20 11 0,39 0,71 0,47 32 19 14 0,44 0,59 0,72 31 24 17 0,55 0,77 0,50 22 18 17 0,77 0,82 0,80 44 27 17 0,39 0,61 0,63 30 20 13 0,43 0,67 0,59 37 20 15 0,41 0,54 0,77 32 29 12 0,38 0,91 0,15 26 21 10 0,38 0,81 0,31 38 19 17 0,45 0,50 0,90 26 22 12 0,46 0,85 0,29 37 26 13 0,35 0,70 0,46 36 23 12 0,33 0,64 0,54 38 31 16 0,42 0,82 0,32 32 21 10 0,31 0,66 0,50 28 21 10 0,36 0,75 0,39 31 25 18 0,58 0,81 0,46 24 22 12 0,50 0,92 0,17 24 18 14 0,58 0,75 0,60 28 28 14 0,50 1,00 0,00 32 23 9 0,28 0,72 0,39 23 20 13 0,57 0,87 0,30 26 23 11 0,42 0,88 0,20 31 23 13 0,42 0,74 0,44 28 27 21 0,75 0,96 0,14 35 24 12 0,34 0,69 0,48 34 26 14 0,41 0,76 0,40 30 23 11 0,37 0,77 0,37 32 21 13 0,41 0,66 0,58 29 22 13 0,45 0,76 0,44 29 22 20 0,69 0,76 0,78 26 20 6 0,23 0,77 0,30 38 33 20 0,53 0,87 0,28 33 20 15 0,45 0,61 0,72 29 21 9 0,31 0,72 0,40 42 19 13 0,31 0,45 0,79 29 21 10 0,34 0,72 0,42 30 27 14 0,47 0,90 0,19 24 22 10 0,42 0,92 0,14 33 18 14 0,42 0,55 0,79 26 22 11 0,42 0,85 0,27 26 19 13 0,50 0,73 0,54 33 21 10 0,30 0,64 0,52 37 24 12 0,32 0,65 0,52 32 27 16 0,50 0,84 0,31 29 28 13 0,45 0,97 0,06 43 33 28 0,65 0,77 0,67 33 23 11 0,33 0,70 0,45 32 25 18 0,56 0,78 0,50 29 22 10 0,34 0,76 0,37 32 20 11 0,34 0,63 0,57 50 31 20 0,40 0,62 0,63 27 27 14 0,52 1,00 0,00 27 27 14 0,52 1,00 0,00 27 21 11 0,41 0,78 0,38 32 20 14 0,44 0,63 0,67 42 38 29 0,69 0,90 0,31 34 23 7 0,21 0,68 0,41 22 16 14 0,64 0,73 0,75 33 23 17 0,52 0,70 0,63 27 24 11 0,41 0,89 0,19 37 21 14 0,38 0,57 0,70 25 23 14 0,56 0,92 0,18 26 20 9 0,35 0,77 0,35 29 25 17 0,59 0,86 0,33 35 25 10 0,29 0,71 0,40 26 23 7 0,27 0,88 0,16 28 21 13 0,46 0,75 0,47 37 22 11 0,30 0,59 0,58 32 22 8 0,25 0,69 0,42 31 25 14 0,45 0,81 0,35 29 26 17 0,59 0,90 0,25 30 24 17 0,57 0,80 0,46 27 21 10 0,37 0,78 0,35 32 23 17 0,53 0,72 0,60 26 21 14 0,54 0,81 0,42 21 16 11 0,52 0,76 0,50 52 47 19 0,37 0,90 0,15 35 30 20 0,57 0,86 0,33 23 19 18 0,78 0,83 0,80 102 75 23 0,23 0,74 0,34 27 17 13 0,48 0,63 0,71 36 30 13 0,36 0,83 0,26 24 19 14 0,58 0,79 0,50 81 60 56 0,69 0,74 0,84 26 19 17 0,65 0,73 0,78 34 20 13 0,38 0,59 0,67 32 20 17 0,53 0,63 0,80 90 43 30 0,33 0,48 0,78 54 28 18 0,33 0,52 0,72 25 20 14 0,56 0,80 0,45 26 19 13 0,50 0,73 0,54 60 41 28 0,47 0,68 0,59 45 23 19 0,42 0,51 0,85 32 24 13 0,41 0,75 0,42 25 23 13 0,52 0,92 0,17 28 22 13 0,46 0,79 0,40 29 24 9 0,31 0,83 0,25 19 14 8 0,42 0,74 0,45 25 20 12 0,48 0,80 0,38 26 22 17 0,65 0,85 0,44 30 23 16 0,53 0,77 0,50 24 20 14 0,58 0,83 0,40 35 32 12 0,34 0,91 0,13 52 20 12 0,23 0,38 0,80 33 19 14 0,42 0,58 0,74 42 18 12 0,29 0,43 0,80 36 21 12 0,33 0,58 0,63 36 27 18 0,50 0,75 0,50 54 46 22 0,41 0,85 0,25 20 19 15 0,75 0,95 0,20 26 23 15 0,58 0,88 0,27 33 27 8 0,24 0,82 0,24 36 21 12 0,33 0,58 0,63 33 25 16 0,48 0,76 0,47 28 21 10 0,36 0,75 0,39 30 23 15 0,50 0,77 0,47 30 24 13 0,43 0,80 0,35 41 29 17 0,41 0,71 0,50 30 28 8 0,27 0,93 0,09 28 23 14 0,50 0,82 0,36 36 30 20 0,56 0,83 0,38 34 23 20 0,59 0,68 0,79 31 21 10 0,32 0,68 0,48 32 23 11 0,34 0,72 0,43 38 24 14 0,37 0,63 0,58 25 22 14 0,56 0,88 0,27 30 24 12 0,40 0,80 0,33 41 29 12 0,29 0,71 0,41 31 21 9 0,29 0,68 0,45 32 27 13 0,41 0,84 0,26 32 22 12 0,38 0,69 0,50 39 29 17 0,44 0,74 0,45 47 26 7 0,15 0,55 0,53 40 29 14 0,35 0,73 0,42 29 26 5 0,17 0,90 0,13 47 27 13 0,28 0,57 0,59 32 23 11 0,34 0,72 0,43 26 24 10 0,38 0,92 0,13 34 19 17 0,50 0,56 0,88 27 20 13 0,48 0,74 0,50 35 25 16 0,46 0,71 0,53 28 21 15 0,54 0,75 0,54 36 24 16 0,44 0,67 0,60 36 22 15 0,42 0,61 0,67 40 28 14 0,35 0,70 0,46 26 23 9 0,35 0,88 0,18 38 25 18 0,47 0,66 0,65 37 22 13 0,35 0,59 0,63 24 22 13 0,54 0,92 0,18 24 22 7 0,29 0,92 0,12 23 19 11 0,48 0,83 0,33 41 21 14 0,34 0,51 0,74 43 33 27 0,63 0,77 0,63 36 24 10 0,28 0,67 0,46 47 27 27 0,57 0,57 1,00 41 28 24 0,59 0,68 0,76 58 25 19 0,33 0,43 0,85 50 27 27 0,54 0,54 1,00 41 23 20 0,49 0,56 0,86 36 22 15 0,42 0,61 0,67 29 28 11 0,38 0,97 0,06 50 33 27 0,54 0,66 0,74 34 25 12 0,35 0,74 0,41 28 22 11 0,39 0,79 0,35 24 20 11 0,46 0,83 0,31 20 17 12 0,60 0,85 0,38 38 30 23 0,61 0,79 0,53 30 20 16 0,53 0,67 0,71 33 25 19 0,58 0,76 0,57 26 21 15 0,58 0,81 0,45 26 23 11 0,42 0,88 0,20 35 23 14 0,40 0,66 0,57 25 21 15 0,60 0,84 0,40 29 33 17 0,59 1,14 - 0,33 39 25 15 0,38 0,64 0,58 37 26 14 0,38 0,70 0,48 25 22 13 0,52 0,88 0,25 29 18 17 0,59 0,62 0,92 28 26 14 0,50 0,93 0,14 23 22 7 0,30 0,96 0,06 29 20 15 0,52 0,69 0,64 34 23 13 0,38 0,68 0,52 33 26 4 0,12 0,79 0,24 34 24 11 0,32 0,71 0,43 33 16 7 0,21 0,48 0,65 30 25 15 0,50 0,83 0,33 32 18 17 0,53 0,56 0,93 36 21 15 0,42 0,58 0,71 30 26 13 0,43 0,87 0,24 28 23 12 0,43 0,82 0,31 28 27 10 0,36 0,96 0,06 46 32 27 0,59 0,70 0,74

F1 CTw1 CTw2 CTw3 CTw4 L I S S/L I/L DRI L I S S/L I/L DRI L I S S/L I/L DRI L I S S/L I/L DRI L I S S /L I/L DRI 40 25 14 0,35 0,63 0,58 88 60 32 0,36 0,68 0,50 47 28 19 0,40 0,60 0,68 51 18 15 0,29 0,35 0,92 35 26 8 0,23 0,74 0,33 22 20 15 0,68 0,91 0,29 78 37 17 0,22 0,47 0,67 25 24 13 0,52 0,96 0,08 53 38 26 0,49 0,72 0,56 43 33 13 0,30 0,77 0,33 26 22 13 0,50 0,85 0,31 67 34 22 0,33 0,51 0,73 33 29 22 0,67 0,88 0,36 55 36 20 0,36 0,65 0,54 39 20 9 0,23 0,51 0,63 30 26 11 0,37 0,87 0,21 60 33 19 0,32 0,55 0,66 22 19 12 0,55 0,86 0,30 38 22 21 0,55 0,58 0,94 30 19 9 0,30 0,63 0,52 27 24 12 0,44 0,89 0,20 66 48 23 0,35 0,73 0,42 40 24 17 0,43 0,60 0,70 30 20 15 0,50 0,67 0,67 48 27 15 0,31 0,56 0,64 32 25 5 0,16 0,78 0,26 46 27 20 0,43 0,59 0,73 30 28 16 0,53 0,93 0,14 28 26 12 0,43 0,93 0,13 27 23 17 0,63 0,85 0,40 33 28 8 0,24 0,85 0,20 34 18 11 0,32 0,53 0,70 43 30 12 0,28 0,70 0,42 34 27 13 0,38 0,79 0,33 38 24 14 0,37 0,63 0,58 55 23 11 0,20 0,42 0,73 24 23 18 0,75 0,96 0,17 26 24 15 0,58 0,92 0,18 30 25 19 0,63 0,83 0,45 31 21 9 0,29 0,68 0,45 47 34 25 0,53 0,72 0,59 27 27 12 0,44 1,00 0,00 48 24 21 0,44 0,50 0,89 37 27 15 0,41 0,73 0,45 26 22 11 0,42 0,85 0,27 51 32 15 0,29 0,63 0,53 28 19 12 0,43 0,68 0,56 30 26 16 0,53 0,87 0,29 30 24 15 0,50 0,80 0,40 38 25 17 0,45 0,66 0,62 31 29 11 0,35 0,94 0,10 26 19 11 0,42 0,73 0,47 28 21 8 0,29 0,75 0,35 29 25 13 0,45 0,86 0,25 52 26 20 0,38 0,50 0,81 31 25 13 0,42 0,81 0,33 46 32 15 0,33 0,70 0,45 41 30 14 0,34 0,73 0,41 32 23 12 0,38 0,72 0,45 27 21 17 0,63 0,78 0,60 32 19 16 0,50 0,59 0,81 41 27 18 0,44 0,66 0,61 40 24 16 0,40 0,60 0,67 39 33 14 0,36 0,85 0,24 45 19 13 0,29 0,42 0,81 29 24 13 0,45 0,83 0,31 25 20 9 0,36 0,80 0,31 38 30 10 0,26 0,79 0,29 20 20 11 0,55 1,00 0,00 37 26 19 0,51 0,70 0,61 42 41 13 0,31 0,98 0,03 44 29 9 0,20 0,66 0,43 23 18 9 0,39 0,78 0,36 27 22 10 0,37 0,81 0,29 29 21 9 0,31 0,72 0,40 43 25 21 0,49 0,58 0,82 35 24 12 0,34 0,69 0,48 47 32 23 0,49 0,68 0,63 29 27 11 0,38 0,93 0,11 27 18 10 0,37 0,67 0,53 46 25 24 0,52 0,54 0,95 51 26 16 0,31 0,51 0,71 23 19 15 0,65 0,83 0,50 28 18 17 0,61 0,64 0,91 27 20 12 0,44 0,74 0,47 29 28 13 0,45 0,97 0,06 31 28 15 0,48 0,90 0,19 24 22 10 0,42 0,92 0,14 20 18 15 0,75 0,90 0,40 41 30 17 0,41 0,73 0,46 85 57 41 0,48 0,67 0,64 25 23 22 0,88 0,92 0,67 25 20 8 0,32 0,80 0,29 22 18 16 0,73 0,82 0,67 54 47 15 0,28 0,87 0,18 35 22 18 0,51 0,63 0,76 49 28 25 0,51 0,57 0,88 35 21 9 0,26 0,60 0,54 70 42 34 0,49 0,60 0,78 40 34 28 0,70 0,85 0,50 31 27 21 0,68 0,87 0,40 33 25 9 0,27 0,76 0,33 29 17 16 0,55 0,59 0,92 29 24 8 0,28 0,83 0,24 23 21 12 0,52 0,91 0,18 33 22 10 0,30 0,67 0,48 45 29 20 0,44 0,64 0,64 23 19 12 0,52 0,83 0,36 27 23 13 0,48 0,85 0,29 40 32 20 0,50 0,80 0,40 23 22 13 0,57 0,96 0,10 30 28 10 0,33 0,93 0,10 26 21 12 0,46 0,81 0,36 26 24 9 0,35 0,92 0,12 29 29 11 0,38 1,00 0,00 49 24 15 0,31 0,49 0,74 38 25 9 0,24 0,66 0,45 34 22 12 0,35 0,65 0,55 44 36 19 0,43 0,82 0,32 38 31 15 0,39 0,82 0,30 27 19 15 0,56 0,70 0,67 26 18 18 0,69 0,69 1,00 32 26 12 0,38 0,81 0,30 28 24 9 0,32 0,86 0,21 22 17 11 0,50 0,77 0,45 30 22 22 0,73 0,73 1,00 31 23 9 0,29 0,74 0,36 27 23 9 0,33 0,85 0,22 36 33 13 0,36 0,92 0,13 39 32 23 0,59 0,82 0,44 29 28 13 0,45 0,97 0,06 25 20 10 0,40 0,80 0,33 26 23 12 0,46 0,88 0,21 57 34 29 0,51 0,60 0,82 72 48 24 0,33 0,67 0,50 58 43 30 0,52 0,74 0,54 65 44 26 0,40 0,68 0,54 52 39 29 0,56 0,75 0,57 49 44 25 0,51 0,90 0,21 50 50 30 0,60 1,00 0,00 64 40 33 0,52 0,63 0,77 56 33 18 0,32 0,59 0,61

Ds1 Ds2 Ds3 Ds4 CTs1 L I S S/L I/L DRI L I S S /L I/L DRI L I S S /L I/L DRI L I S S /L I/L DRI L I S S /L I/L DRI 39 21 10 0,26 0,54 0,62 49 28 20 0,41 0,57 0,72 66 49 38 0,58 0,74 0,61 83 43 43 0,52 0,52 1,00 77 52 25 0,32 0,68 0,48 33 18 17 0,52 0,55 0,94 46 33 20 0,43 0,72 0,50 43 37 23 0,53 0,86 0,30 81 55 22 0,27 0,68 0,44 63 48 20 0,32 0,76 0,35 41 20 12 0,29 0,49 0,72 35 26 9 0,26 0,74 0,35 50 43 18 0,36 0,86 0,22 61 39 25 0,41 0,64 0,61 52 24 25 0,48 0,46 1,04 42 24 15 0,36 0,57 0,67 39 22 19 0,49 0,56 0,85 50 42 25 0,50 0,84 0,32 65 39 18 0,28 0,60 0,55 61 41 19 0,31 0,67 0,48 43 22 17 0,40 0,51 0,81 36 28 14 0,39 0,78 0,36 47 37 21 0,45 0,79 0,38 44 42 25 0,57 0,95 0,11 47 35 16 0,34 0,74 0,39 37 25 12 0,32 0,68 0,48 34 25 13 0,38 0,74 0,43 47 43 14 0,30 0,91 0,12 57 45 30 0,53 0,79 0,44 48 39 25 0,52 0,81 0,39 27 18 8 0,30 0,67 0,47 44 31 18 0,41 0,70 0,50 53 39 25 0,47 0,74 0,50 63 46 31 0,49 0,73 0,53 33 23 16 0,48 0,70 0,59 23 20 10 0,43 0,87 0,23 35 28 12 0,34 0,80 0,30 34 26 20 0,59 0,76 0,57 50 36 20 0,40 0,72 0,47 23 22 12 0,52 0,96 0,09 36 18 14 0,39 0,50 0,82 47 38 18 0,38 0,81 0,31 41 21 15 0,37 0,51 0,77 60 35 20 0,33 0,58 0,63 34 28 12 0,35 0,82 0,27 30 20 11 0,37 0,67 0,53 47 32 20 0,43 0,68 0,56 41 28 25 0,61 0,68 0,81 31 25 7 0,23 0,81 0,25 39 17 12 0,31 0,44 0,81 37 24 20 0,54 0,65 0,76 42 29 12 0,29 0,69 0,43 38 29 20 0,53 0,76 0,50 40 25 15 0,38 0,63 0,60 25 24 10 0,40 0,96 0,07 37 21 11 0,30 0,57 0,62 28 28 14 0,50 1,00 0,00 39 24 11 0,28 0,62 0,54 42 28 23 0,55 0,67 0,74 25 21 12 0,48 0,84 0,31 48 28 28 0,58 0,58 1,00 51 32 28 0,55 0,63 0,83 42 28 19 0,45 0,67 0,61 43 19 13 0,30 0,44 0,80 32 19 16 0,50 0,59 0,81 42 27 16 0,38 0,64 0,58 56 45 14 0,25 0,80 0,26 28 20 16 0,57 0,71 0,67 33 30 14 0,42 0,91 0,16 33 24 15 0,45 0,73 0,50 39 26 11 0,28 0,67 0,46 55 34 20 0,36 0,62 0,60 23 23 16 0,70 1,00 0,00 32 25 15 0,47 0,78 0,41 25 21 9 0,36 0,84 0,25 42 33 16 0,38 0,79 0,35 37 25 13 0,35 0,68 0,50 25 20 16 0,64 0,80 0,56 32 30 14 0,44 0,94 0,11 33 27 15 0,45 0,82 0,33 42 28 21 0,50 0,67 0,67 45 22 8 0,18 0,49 0,62 22 19 9 0,41 0,86 0,23 53 27 13 0,25 0,51 0,65 21 17 10 0,48 0,81 0,36 28 21 14 0,50 0,75 0,50 29 24 14 0,48 0,83 0,33 27 23 10 0,37 0,85 0,24 27 26 15 0,56 0,96 0,08 24 24 10 0,42 1,00 0,00 25 18 18 0,72 0,72 1,00 33 23 13 0,39 0,70 0,50 26 22 10 0,38 0,85 0,25 34 33 6 0,18 0,97 0,04 33 25 12 0,36 0,76 0,38 33 32 19 0,58 0,97 0,07 48 35 21 0,44 0,73 0,48 25 22 16 0,64 0,88 0,33 27 21 13 0,48 0,78 0,43 33 23 13 0,39 0,70 0,50 44 28 17 0,39 0,64 0,59 26 20 16 0,62 0,77 0,60 32 21 11 0,34 0,66 0,52 37 18 15 0,41 0,49 0,86 44 31 25 0,57 0,70 0,68 22 18 14 0,64 0,82 0,50 41 37 16 0,39 0,90 0,16 34 23 14 0,41 0,68 0,55 36 34 13 0,36 0,94 0,09 24 21 12 0,50 0,88 0,25 40 30 20 0,50 0,75 0,50 28 20 14 0,50 0,71 0,57 53 40 37 0,70 0,75 0,81 22 19 12 0,55 0,86 0,30 39 25 14 0,36 0,64 0,56 45 32 18 0,40 0,71 0,48 33 20 16 0,48 0,61 0,76 31 26 21 0,68 0,84 0,50 37 32 18 0,49 0,86 0,26 32 17 16 0,50 0,53 0,94 23 22 10 0,43 0,96 0,08 32 28 18 0,56 0,88 0,29 45 25 13 0,29 0,56 0,63 38 37 10 0,26 0,97 0,04 40 35 28 0,70 0,88 0,42 26 22 12 0,46 0,85 0,29 39 30 21 0,54 0,77 0,50 27 19 11 0,41 0,70 0,50 33 26 11 0,33 0,79 0,32 33 30 12 0,36 0,91 0,14 44 38 25 0,57 0,86 0,32 36 25 17 0,47 0,69 0,58 25 20 12 0,48 0,80 0,38 27 21 12 0,44 0,78 0,40 50 36 21 0,42 0,72 0,48 38 30 28 0,74 0,79 0,80 33 25 18 0,55 0,76 0,53 29 21 14 0,48 0,72 0,53 27 27 25 0,93 1,00 0,00 45 36 16 0,36 0,80 0,31 25 20 9 0,36 0,80 0,31 25 18 16 0,64 0,72 0,78 26 21 9 0,35 0,81 0,29 31 25 24 0,77 0,81 0,86 38 26 19 0,50 0,68 0,63 42 20 15 0,36 0,48 0,81 30 20 12 0,40 0,67 0,56 32 29 16 0,50 0,91 0,19 35 33 21 0,60 0,94 0,14 32 28 10 0,31 0,88 0,18 28 23 9 0,32 0,82 0,26 30 26 13 0,43 0,87 0,24 38 24 11 0,29 0,63 0,52 34 29 13 0,38 0,85 0,24 21 19 13 0,62 0,90 0,25 31 23 16 0,52 0,74 0,53 36 23 15 0,42 0,64 0,62 26 22 12 0,46 0,85 0,29 33 21 14 0,42 0,64 0,63 13 12 9 0,69 0,92 0,25 28 27 19 0,68 0,96 0,11 38 26 25 0,66 0,68 0,92 34 37 11 0,32 1,09 - 0,13 31 22 16 0,52 0,71 0,60 38 24 17 0,45 0,63 0,67 26 20 18 0,69 0,77 0,75 62 41 31 0,50 0,66 0,68 41 27 21 0,51 0,66 0,70 38 26 24 0,63 0,68 0,86 67 50 22 0,33 0,75 0,38 29 28 15 0,52 0,97 0,07 32 21 13 0,41 0,66 0,58 56 48 18 0,32 0,86 0,21 33 21 17 0,52 0,64 0,75 25 17 14 0,56 0,68 0,73 59 41 28 0,47 0,69 0,58 32 24 11 0,34 0,75 0,38 39 19 15 0,38 0,49 0,83 54 37 22 0,41 0,69 0,53 27 24 11 0,41 0,89 0,19 23 22 6 0,26 0,96 0,06 77 47 29 0,38 0,61 0,63 41 19 12 0,29 0,46 0,76 23 19 18 0,78 0,83 0,80 43 39 31 0,72 0,91 0,33 32 21 19 0,59 0,66 0,85 33 27 19 0,58 0,82 0,43 60 30 28 0,47 0,50 0,94 29 24 14 0,48 0,83 0,33 34 20 11 0,32 0,59 0,61 53 35 19 0,36 0,66 0,53 37 25 10 0,27 0,68 0,44 34 18 18 0,53 0,53 1,00 60 30 27 0,45 0,50 0,91 34 26 21 0,62 0,76 0,62 56 45 34 0,61 0,80 0,50 32 25 22 0,69 0,78 0,70 27 25 7 0,26 0,93 0,10 27 19 18 0,67 0,70 0,89 28 24 11 0,39 0,86 0,24 25 20 12 0,48 0,80 0,38 21 19 10 0,48 0,90 0,18 22 19 5 0,23 0,86 0,18 23 19 15 0,65 0,83 0,50 29 20 7 0,24 0,69 0,41 23 19 9 0,39 0,83 0,29 23 19 12 0,52 0,83 0,36 37 34 19 0,51 0,92 0,17 25 28 12 0,48 1,12 - 0,23 25 20 10 0,40 0,80 0,33 23 17 12 0,52 0,74 0,55 27 22 13 0,48 0,81 0,36 30 23 17 0,57 0,77 0,54 33 16 15 0,45 0,48 0,94 38 29 20 0,53 0,76 0,50 35 26 13 0,37 0,74 0,41 29 27 11 0,38 0,93 0,11 33 23 13 0,39 0,70 0,50 29 24 13 0,45 0,83 0,31 31 22 8 0,26 0,71 0,39 26 21 8 0,31 0,81 0,28 33 17 13 0,39 0,52 0,80 36 32 15 0,42 0,89 0,19 23 23 15 0,65 1,00 0,00 28 27 12 0,43 0,96 0,06 23 18 15 0,65 0,78 0,63 42 27 17 0,40 0,64 0,60 46 20 14 0,30 0,43 0,81 37 23 18 0,49 0,62 0,74 31 27 15 0,48 0,87 0,25 20 19 18 0,90 0,95 0,50 30 24 11 0,37 0,80 0,32 41 32 22 0,54 0,78 0,47 31 22 18 0,58 0,71 0,69 28 24 21 0,75 0,86 0,57

CTs 2 CTs 3 CTs 4 L I S S /L I/L DRI L I S S /L I/L DRI L I S S /L I/L DRI 48 30 17 0,35 0,63 0,58 95 46 25 0,26 0,48 0,70 67 46 38 0,57 0,69 0,7 2 66 42 15 0,23 0,64 0,47 55 42 38 0,69 0,76 0,76 67 58 23 0,34 0,87 0,2 0 36 32 11 0,31 0,89 0,16 75 63 24 0,32 0,84 0,24 54 37 33 0,61 0,69 0,8 1 35 22 15 0,43 0,63 0,65 69 41 18 0,26 0,59 0,55 61 44 23 0,38 0,72 0,4 5 52 28 18 0,35 0,54 0,71 80 68 22 0,28 0,85 0,21 57 51 12 0,21 0,89 0,13 32 18 15 0,47 0,56 0,82 39 39 8 0,21 1,00 0,00 51 35 21 0,41 0,69 0,5 3 22 20 10 0,45 0,91 0,17 22 21 9 0,41 0,95 0,08 54 33 15 0,28 0,61 0,5 4 23 20 12 0,52 0,87 0,27 50 33 16 0,32 0,66 0,50 58 46 27 0,47 0,79 0,3 9 48 31 20 0,42 0,65 0,61 46 30 28 0,61 0,65 0,89 48 38 18 0,38 0,79 0,3 3 30 21 11 0,37 0,70 0,47 38 22 13 0,34 0,58 0,64 37 36 28 0,76 0,97 0,11 40 32 11 0,28 0,80 0,28 29 22 14 0,48 0,76 0,47 58 40 23 0,40 0,69 0,5 1 30 18 18 0,60 0,60 1,00 26 19 14 0,54 0,73 0,58 62 42 22 0,35 0,68 0,5 0 27 20 10 0,37 0,74 0,41 35 27 13 0,37 0,77 0,36 41 40 19 0,46 0,98 0,0 5 39 28 17 0,44 0,72 0,50 22 20 15 0,68 0,91 0,29 36 18 12 0,33 0,50 0,7 5 24 22 10 0,42 0,92 0,14 41 31 15 0,37 0,76 0,38 25 22 10 0,40 0,88 0,2 0 39 32 11 0,28 0,82 0,25 37 23 11 0,30 0,62 0,54 36 27 13 0,36 0,75 0,3 9 39 37 14 0,36 0,95 0,08 54 30 20 0,37 0,56 0,71 40 22 15 0,38 0,55 0,7 2 40 26 19 0,48 0,65 0,67 25 21 10 0,40 0,84 0,27 34 25 14 0,41 0,74 0,4 5 38 23 14 0,37 0,61 0,63 35 24 17 0,49 0,69 0,61 23 16 7 0,30 0,70 0,4 4 32 20 14 0,44 0,63 0,67 23 17 16 0,70 0,74 0,86 49 24 17 0,35 0,49 0,7 8 26 17 15 0,58 0,65 0,82 33 23 15 0,45 0,70 0,56 36 29 20 0,56 0,81 0,4 4 32 27 20 0,63 0,84 0,42 32 20 14 0,44 0,63 0,67 32 24 13 0,41 0,75 0,4 2 40 25 14 0,35 0,63 0,58 27 20 15 0,56 0,74 0,58 37 36 15 0,41 0,97 0,0 5 35 23 18 0,51 0,66 0,71 32 23 11 0,34 0,72 0,43 28 28 19 0,68 1,00 0,0 0 26 22 11 0,42 0,85 0,27 49 23 12 0,24 0,47 0,70 30 20 12 0,40 0,67 0,5 6 33 27 8 0,24 0,82 0,24 23 21 11 0,48 0,91 0,17 27 20 15 0,56 0,74 0,5 8 31 23 22 0,71 0,74 0,89 30 27 16 0,53 0,90 0,21 29 22 16 0,55 0,76 0,5 4 25 18 16 0,64 0,72 0,78 30 25 11 0,37 0,83 0,26 38 19 12 0,32 0,50 0,7 3 22 20 17 0,77 0,91 0,40 39 32 20 0,51 0,82 0,37 33 20 18 0,55 0,61 0,8 7 41 25 19 0,46 0,61 0,73 35 23 13 0,37 0,66 0,55 41 32 14 0,34 0,78 0,3 3 21 19 15 0,71 0,90 0,33 29 21 9 0,31 0,72 0,40 33 25 14 0,42 0,76 0,4 2 28 22 10 0,36 0,79 0,33 22 17 14 0,64 0,77 0,63 23 20 12 0,52 0,87 0,2 7 40 28 15 0,38 0,70 0,48 25 23 8 0,32 0,92 0,12 35 20 17 0,49 0,57 0,8 3 25 18 15 0,60 0,72 0,70 27 26 17 0,63 0,96 0,10 33 20 10 0,30 0,61 0,57 24 25 9 0,38 1,04 - 0,07 32 18 12 0,38 0,56 0,70 25 23 14 0,56 0,92 0,18 30 23 15 0,50 0,77 0,47 25 17 12 0,48 0,68 0,6 2 35 21 12 0,34 0,60 0,61 31 21 18 0,58 0,68 0,7 7 24 18 10 0,42 0,75 0,43 30 21 14 0,47 0,70 0,5 6 31 22 12 0,39 0,71 0,47 28 27 18 0,64 0,96 0,10 37 22 16 0,43 0,59 0,71 43 33 16 0,37 0,77 0,3 7 26 20 12 0,46 0,77 0,43 40 32 18 0,45 0,80 0,3 6 23 20 12 0,52 0,87 0,27 29 19 14 0,48 0,66 0,6 7 27 18 12 0,44 0,67 0,60 34 29 13 0,38 0,85 0,2 4 26 23 15 0,58 0,88 0,27 35 27 20 0,57 0,77 0,5 3 42 39 18 0,43 0,93 0,13 28 24 15 0,54 0,86 0,3 1 30 23 19 0,63 0,77 0,6 4 29 19 13 0,45 0,66 0,6 3 31 20 15 0,48 0,65 0,6 9 24 23 12 0,50 0,96 0,0 8 30 25 14 0,47 0,83 0,3 1 24 14 10 0,42 0,58 0,7 1 24 23 10 0,42 0,96 0,0 7 27 23 14 0,52 0,85 0,3 1 32 20 13 0,41 0,63 0,6 3 35 24 19 0,54 0,69 0,6 9 40 33 20 0,50 0,83 0,3 5 36 23 13 0,36 0,64 0,5 7 25 26 12 0,48 1,04 - 0,08 25 23 16 0,64 0,92 0,2 2 36 20 14 0,39 0,56 0,7 3 42 27 16 0,38 0,64 0,5 8 28 17 17 0,61 0,61 1,0 0 36 30 20 0,56 0,83 0,3 8 29 24 10 0,34 0,83 0,2 6 28 19 10 0,36 0,68 0,5 0 25 24 18 0,72 0,96 0,14 25 25 21 0,84 1,00 0,0 0 25 18 16 0,64 0,72 0,7 8 27 19 12 0,44 0,70 0,5 3 27 25 12 0,44 0,93 0,13 33 20 10 0,30 0,61 0,5 7

Appendix 4 – Roundness

VA A SA SR R VR DF1.1 0 5 26 8 0 0 Df1.2 0 20 49 15 1 0 DF1.3 0 10 18 6 0 0 DF2.1 0 11 11 3 0 0 DF2.2 0 37 33 13 0 0 F1 0 5 13 9 1 0 CTw1 0 7 16 5 0 0 CTw2 0 22 19 5 1 0 CTw3 0 9 10 1 0 0 CTw4 0 0 12 6 0 0 Ds1 0 12 6 2 0 0 Ds2 0 18 19 10 0 0 Ds3 0 16 26 6 0 0 Ds4 0 39 33 11 2 0 CTs1 0 13 7 2 1 0 CTs2 0 21 20 4 1 0 CTs3 0 19 8 6 0 0 CTs4 0 32 23 3 0 0

Appendix 5 - Striations and clast asymmetry

Sample Sum of Striations Bullet-nosed Bullet- no. clasts [no.] [no.] Striations [%] [no.] nosed [%] DF1.1 39 1 2,56 2 5,13 Df1.2 85 8 9,41 1 1,18 DF1.3 34 7 20,59 0 0,00 DF2.1 25 1 4,00 0 0,00 DF2.2 83 10 12,05 3 3,61 F1 28 6 21,43 0 0,00 CTw1 28 5 17,86 1 3,57 CTw2 47 13 27,66 1 2,13 CTw3 20 2 10,00 0 0,00 CTw4 18 2 11,11 1 5,56 Ds1 20 1 5,00 0 0,00 Ds2 47 9 19,15 1 2,13 Ds3 48 3 6,25 0 0,00 Ds4 85 7 8,24 1 1,18 CTs1 23 5 21,74 2 8,70 CTs2 46 2 4,35 2 4,35 CTs3 33 2 6,06 0 0,00 CTs4 58 5 8,62 1 1,72