tel.: 47 73 90 40 00 report - ngu · sediment components. the xri system consists of an x-ray tube...

Geological Survey of NorwayN-7441 Trondheim, Norway Tel.: 47 73 90 40 00 Telefax 47 73 92 16 20 REPORT

Report no.: 2003.021 ISSN 0800-3416 Grading: Open Title:

Results of analytical tests on sediment cores collected by FFI from the Barents Sea

Authors: Aivo Lepland and Reidulv Bøe

Client: NGU, FFI

County: Commune:

Map-sheet name (M=1:250.000) Map-sheet no. and -name (M=1:50.000)

Deposit name and grid-reference: Number of pages: 83 Price (NOK): 150,- Map enclosures:

Fieldwork carried out: Date of report: 10.03.2003

Project no.: 294800

Person responsible:

Summary: Ten gravity cores from the Barents Sea have been profiled with the X-ray inspection system (XRI) and logged for P-wave velocity, bulk density and magnetic susceptibility using multi sensor core logger (MSCL). Sediment cores were opened after these non-destructive analyses, sedimentologically described and undrained shear strength was measured on selected intervals. The cores were subsampled for determining water content, wet density, dry density and grain-size characteristics.

Keywords: Marine geology Seabed sediments Sedimentology

Grain size Sediment density Geotechnical properties of sediments

CONTENTS

1 INTRODUCTION AND MATERIALS ............................................................................ 4 2 METHODS AND RESULTS............................................................................................. 4

2.1 X-ray inspection system (XRI) .................................................................................. 4 2.2 Multi sensor core logger (MSCL) .............................................................................. 5

2.2.1 Gamma ray density............................................................................................. 5 2.2.2 Magnetic susceptibility ...................................................................................... 6 2.2.3 P-Wave velocity ................................................................................................. 6

2.3 Lithostratigraphic description .................................................................................... 7 2.4 Grain-size analyses..................................................................................................... 7 2.5 Determination of geotechnical and physical properties of sediments........................ 7

2.5.1 Undrained shear strength.................................................................................... 7 2.5.2 Water content, wet density and dry density ....................................................... 7

FIGURES

Fig. 1. Correlation diagram for MSCL bulk density and wet density, obtained by determining the weight of known sample volume. Solid line shows the expected correlation; dashed line indicates the offset of 0.3 g/cm3.

Fig. 2. Comparison of stratigraphic MSCL bulk density (solid lines) and wet density (red dots) profiles. Subsamples for wet density determinations were taken with 0.25 m intervals, except the uppermost subsample, which was obtained at 0.10 m sediment depth. The top 0.05-0.15 m sections of profiles with no data above the sediment surface (0 m level) reflect empty spaces in the core liner that are included in original MSCL logs.

APPENDIX

Appendix 1. Stratigraphic profiles of X-ray images (XRI), P-wave velocity, bulk density, magnetic susceptibility, water content, wet density, dry density, undrained shear strength, and median grain size.

Appendix 2. MSCL data treatment guide-lines and core logging notes provided by the MSCL laboratory at the University of Bergen.

Appendix 3. Cumulative grain-size distribution plots and statistical characteristics of individual samples. Note that sample IDs show the core numbers and subsampling depths, i.e. sample GC1-10 stands for the subsample collected from 10 cm depth of core GC1.

4

1 INTRODUCTION AND MATERIALS

This report presents results of analytical tests undertaken on 10 sediment cores collected by FFI from 10 localities in the Barents Sea. The objective of these analyses is to provide sedimentologic and sediment physical properties characteristics, which can potentially be related and/or correlated with sediment acoustic parameters.

2 METHODS AND RESULTS

The laboratory procedures with the sediment cores involved (i) stratigraphic profiling with an X-ray inspection system, (ii) stratigraphic profiling for P-wave velocity, sediment bulk density and magnetic susceptibility using a multi sensor core logger (MSCL), (iii) lithostratigraphic description, (iv) grain-size analysis, (v) determination of geotechnical and physical properties of sediments. Descriptions of methods/procedures are given below. Figures 1-10 in Appendix 1 show compilations of all obtained results and illustrate down-core variations of studied parameters. All tests were carried out at NGU except MSCL logging that was undertaken at the University of Bergen.

2.1 X-ray inspection system (XRI)

The images of the XRI system reflect variable X-ray absorption (transparency) of different sediment components. The XRI system consists of an X-ray tube and an image intensifier that converts invisible X-rays into visible light. A CCD camera is used to capture the visible image. The size of an XRI image depends upon specific settings, typically covering 10-15 cm long sediment interval. The sediment core is placed between the X-ray tube and the image intensifier; different core sections can be inspected by sliding the assembled X-ray tube and image intensifier along the core. X-ray transparency of a sediment is strongly influenced by the grain-size and the images are generally lighter for the fine-grained sediments and darker for coarse-grained sediments. XRI is a handy, non-destructive method to study the texture and structure of sediments, to characterize the distribution of gas pockets, shells, wood fragments and clasts, and to interpret the disturbances caused by bioturbation, gas escape or shear. The possibility to rotate the core simultaneously with imaging facilitates detailed geometric analyses of specific structural features.

In Appendix 1 the XRI documentation is given as sequences of digital images where each individual image corresponds to 11-14 cm sediment interval. The scale at the side of the images shows the depth in centimetres from the sediment surface or from the core section top in case of multiple sections. Individual images from all cores have been montaged to provide the complete XRI sequence.

5

2.2 Multi sensor core logger (MSCL)

The GEOTEK manufactured Multi Sensor Core Logger (MSCL) at the University of Bergen was used to study physical properties of sediments by means of gamma-ray density, P-wave velocity and magnetic susceptibility. The MSCL consists of a conveyor system, a central unit assembly including three sensors, a microprocessor and a computer. The conveyor system has two track sections, mounted and aligned on either side of the central unit, and a belt driven pusher block which is driven in either direction by a stepper motor and gear box assembly. The central unit assembly incorporates a compressional wave (P-Wave) logger, a gamma ray attenuation logger and a magnetic susceptibility loop. Automation is achieved through the use of an internal processor, interfaced with the rack-mounted computer that controls the entire running process and stores data.

Up to 140 cm long core sections are placed on the right hand track with the top located at the reference position. A conveyor system automatically pushes each core section through the sensor array (incrementally past gamma ray attenuation logger, the p-wave logger and through the magnetic susceptibility coil) with measurements being taken at spatial increments as defined by the user; 0.5 cm and 1 cm step-sizes were used in this study. The computer controlling the conveyor also controls the sensors, so that all data are automatically correlated. Adjacent core sections are loaded on to the conveyor by the user when prompted by the software commands. In this way a complete core can be logged in a continuous process while the raw and processed data are displayed graphically in real time on the monitor. Complete control of the graphic display is provided, both in terms of the presentation and processing protocols. Both raw and processed data are saved in formats suitable for exporting to other software environments for further data manipulation or data presentation.

MSCL data treatment guide-lines provided by the MSCL laboratory at the University of Bergen are shown in Appendix 2. Specific observations made during MSCL analyses of sediment cores treated in this report are also presented in Appendix 2.

2.2.1 Gamma ray density

Density is determined by measuring the attenuation of gamma rays through the cores. The gamma ray attenuation unit comprises a 10 millicurie Cesium-137 capsule (housed in a 150 mm diameter primary lead shield) with both 2.5 and a 5.0 mm collimators and a sodium iodide scintillation detector (housed in a 150 mm diameter collimated lead shielding to minimize any background radiation). A density resolution of better than 1% depending upon counting time used and core condition is normally achieved. The source and detector are mounted diametrically across the diameter of the core.

A narrow (pencil size) beam of gamma rays with energies principally at 0.662 MeV is emitted from the Cesium -137 source and passes through the diameter of the sediment core. At these energy levels Compton scattering is the primary mechanism for the attenuation of the gamma rays in most sedimentary material. The incident photons are scattered by collision with electrons encountered in the core and there is a partial energy loss. This attenuated gamma beam is measured by the Sodium Iodide detector. The Compton scattering of the photons is

6

directly related to the number of electrons in the path of the gamma ray beam. The bulk density of the sediment in each analysed interval is calculated by comparing the attenuation of gamma rays through the sediment core to the attenuation of the gamma rays through a standard of aluminium density calibration billet.

Comparisons of MSCL bulk density results with below described wet density measurements have revealed inconsistencies between different methods; these methodological problems are discussed in section 2.5.2.

2.2.2 Magnetic susceptibility

The magnetic susceptibility Bartington loop (150 mm) sensor (MS2B) is used in the MSCL system. A low intensity non-saturating alternating magnetic field is produced by an oscillator circuit in the sensor loop. Changes in the oscillator frequency caused by the sediment in the sensor loop are measured and converted into volume specific magnetic susceptibility values (SI units). The magnitude of the magnetic susceptibility values is dependent on the type of sediment, content of magnetic minerals and the volume of sediment within the coil. Identical cores of varying diameters will give different magnetic susceptibility values but will show the same down core profile. The calibration of the magnetic susceptibility loop, performed using a standard of known magnetic susceptibility, gives 5% calibration accuracy.

Density and magnetic susceptibility profiles shown in Appendix 1 display a general correspondence of these two parameters. However, density signal is obtained from thinner (< 1 cm) sediment intervals compared to magnetic susceptibility (4-6 cm thick intervals) hence the density logs have proven to be more specific and useful defining stratigraphic boundaries.

2.2.3 P-Wave velocity

The P-Wave logger system consists of two rolling compressional wave transducers (PWT), with soft couplings and a centre frequency around 220 kHz. These PWT’s are spring-located on either side of the core to generate and detect short ultrasonic pulses. A short 220 kHz compressional wave pulse is produced at the transmitting transducer at a repetition rate of 1 kHz. This wave pulse travels through the core and is detected by the receiving transducer and the time of flight of the wave pulse is measured. Timing measurements have an accuracy of 50 ns providing velocity accuracy of about 0.2%, depending on core thickness and condition. Calibration can be achieved using a length of core line filled with distilled water of known temperature and velocity. The p-wave travel time is corrected for the P-wave travel time delay caused by the core liner and the electronics of the system.

P-wave velocity logs given in Appendix 1 often show scattered profiles with values spread over the wide range. Most of the abrupt jumps on P-wave velocity profiles are evidently not controlled by changes in the sediment character, but most probably reflect open, air-filled spaces in sediment liner (most likely in between liner wall and core sample) that blunder the measurement. It has to be also noted that the absolute P-wave velocity values appear systematically ca. 400 ms higher than would be expected for analysed clayey and silty sediments. This systematic error is possibly due to the incorrect calibration; there was no liner

7

to be found in the laboratory to match the liner that was used for coring and the calibration (which apparently was not quite correct) was done on the closest available.

2.3 Lithostratigraphic description

Lithostratigraphic description was undertaken on split cores that were obtained by cutting through the liner plastic lengthwise and pulling a steel wire through the sediment. The stratigraphic logging focused upon sedimentary structures and texture.

2.4 Grain-size analyses

For grain size analyses ca. 2 cm thick sediment slices were obtained from the following sediment depths depending upon the core length; 10, 25, 50, 75 100, 125, 150, 175 and 200 cm. Altogether 60 samples were analysed using sieving for fractions coarser than 2 mm and laser diffraction technique using Coulter LS 200 for fractions finer than 2 mm. Samples were oxidised with H2O2 to remove organic matter prior to analyses. The sample suspensions used in Coulter LS 200 were dispersed in ultrasonic bath.

Stratigraphic variations of median grain size are given in Appendix 1. Complete sets of obtained grain size characteristics are found in Appendix 3.

2.5 Determination of geotechnical and physical properties of sediments

The sampling scheme (10 cm, 25 cm, 50 cm etc.) deployed for grain size analyses was also used to study the geotechnical and physical properties of sediments and the down-core trends of these parameters.

2.5.1 Undrained shear strength

The Falling Cone apparatus was used to measure sediment shear strength. The split core was placed underneath the cone holder with the tip of the cone touching the sample. The penetration depth of the cone into the sediment after releasing the cone is proportional to the undrained shear strength. Note that the values of undrained shear stress may bear a systematic error due to compaction and dewatering during transport and storage prior to analyses.

2.5.2 Water content, wet density and dry density

These parameters were determined with the aid of a thin-wall steel cylinder with known volume and weight. This cylinder was inserted into the sediment and known volumes of wet, undisturbed sediments were subsampled. Weights of wet and dry (drying at 105 ºC for 24

8

hours) subsamples, combined with the known volume, allowed calculating water content, wet density and dry density according to the following formulas:

Water content = Weight of pore water / Weight of dry sediment

Wet density = Weight of wet sample / Volume of wet sample

Dry density = Weight of dry sample / Volume of wet sample

Wet density values obtained by determining the weight of known volume should ideally coincide with the MSCL bulk density values. Figures 1 and 2 show the correspondence between wet and bulk densities, and illustrates that MSCL bulk density values are typically lower than wet density values. Most of the cores display ca. 0.05-0.1 g/cm3 offset, whereas the offset for cores GC8, GC9 and GC10 is ca. 0.3 g/cm3 (Figs. 1 and 2). Although the ultimate cause for these offsets is yet to be proven, the incorrect MSCL calibration appears as the probable reason (Appendix 2). However, the wrong MSCL calibration would presumably result in the systematic offset and data points from the same core should ideally plot along the line which is parallel to the expected correlation line (solid line; Fig.1). Such alignment (systematic offsets) can be seen for data from GC10, whereas data points from cores GC1-GC9 display irregular offsets and scatter rather than give good alignment (Fig. 1). Assuming insignificant drifts during MSCL analyses of individual cores, the scattering of bulk density–wet density offsets for individual cores can presumably be ascribed to the accuracy of wet density measurements. The standard deviations of these offset are in the range of 0.02-0.06 g/cm3 for most of the cores.

Wet density (g/cm3)

1,4 1,6 1,8 2,0 2,2

MSC

L bu

lk d

ensi

ty (g

/cm

3 )

1,4

1,6

1,8

2,0

2,2

GC1GC2GC3GC4GC5GC6GC7GC8GC9GC10

Fig. 1. Correlation diagram for MSCL bulk density and wet density, obtained by determining the weight of known sample volume. Solid line shows the expected correlation; dashed line indicates the offset of 0.3 g/cm3.

9

dept

h (m

)

0,0

0,5

1,0

1,5

2,0

GC2Density (g/cm3)

1,0 1,4 1,8 2,2

GC3Density (g/cm3)

1,0 1,4 1,8 2,2

GC1Density (g/cm3)

1,0 1,4 1,8 2,2

GC4Density (g/cm3)

1,0 1,4 1,8 2,2

GC5Density (g/cm3)

1,0 1,4 1,8 2,2

GC6Density (g/cm3)

1,0 1,4 1,8 2,2

GC7Density (g/cm3)

1,0 1,4 1,8 2,2

GC8Density (g/cm3)

1,0 1,4 1,8 2,2

GC9Density (g/cm3)

1,0 1,4 1,8 2,2

GC10Density (g/cm3)

1,0 1,4 1,8 2,2

Fig. 2. Comparison of strtigraphic MSCL bulk density (solid lines) and wet density (red dots) profiles. Subsamples for wet density determinations were taken with 0.25 m intervals, except the uppermost subsample, which was obtained at 0.10 m sediment depth. The top 0.05-0.15 m sections of profiles with no data above the sediment surface (0 m level) reflect empty spaces in the core liner that are included in original MSCL logs.

APPENDIX 1

Stratigraphic profiles of X-ray images (XRI), P-wave velocity, bulk density, magnetic susceptibility, water content, wet density, dry density, undrained shear strength, and

median grain size.

106,77

84,39

125,58

118,13

130,04

165,18

79,24

PW velocity (m/s)(MSCL)

1200 1600 2000

Density (g/cm3)(MSCL)

1,0 1,4 1,8 2,2

Magnetic susceptibility(MSCL)

0 20 40 60 80 100

Water content (%)(weight of pore water /weight of dry sediment)

80 100 120 140 160

1,92

2,04

1,80

1,80

1,77

1,63

2,14

Wet density (g/cm3)(weight of wet sample /volume of wet sample)

1,5 2,0 2,5

1,31

1,53

1,15

1,19

1,11

0,91

1,63

Dry density (g/cm3)(weight of dry sample /volume of wet sample)

0,5 1,0 1,5 2,0

3,00

3,00

4,90

4,90

6,30

7,80

21,00

Undrained shearstrength (kPa)

(falling cone)

4 8 12 16 20

18,30

26,57

9,54

9,93

10,38

6,23

18,03

Median grain-size (µm)

(Coulter counter)25 50 75 100

GC1

0-0.05 mgravely sandyclayey silt

XRILithology

0.05-0.22 mlaminated gravelysandy silty clay

0.22-1.33 mlaminated siltyclay

1.33-1.69 mgravely sandysilty clay

0,0

0,5

1,0

1,5

dept

h(m

)

2,0

97,59

144,47

137,88

137,77

134,85

135,05

133,33

120,70


1200 1600 2000


1,0 1,4 1,8 2,2


0 20 40 60 80 100


80 100 120 140

1,97

1,73

1,71

1,73

1,82

1,72

1,73

1,79


1,5 2,0 2,5

1,40

1,03

1,05

1,06

1,11

1,07

1,08

1,17


1,0 1,5 2,0

3,00

2,00

5,00

2,50

4,70

6,70

7,40

11,50


(falling cone)

4 8 12

54,66

15,87

13,64

12,43

20,80

9,65

10,05

8,31



GC2

0-0.08 mgravely sandysilty sand

XRILithology

0.08-0.15 mlaminated siltysandy gravelyclay

0.15-0.55 msilty clay

0.55-1.93 msilty sandygravely clay,occasionallylaminated

0,0

0,5

1,0

1,5

dept

h(m

)

2,0

72,12

105,97

105,81

120,27

141,95

145,60

79,82


1200 1600 2000


1,0 1,4 1,8 2,2


0 20 40 60 80 100120


80 100 120 140

2,10

1,88

1,90

1,78

1,73

1,64

2,03


1,5 2,0 2,5

1,67

1,29

1,31

1,16

1,04

0,99

1,57


1,0 1,5 2,0

6,30

6,30

6,70

6,70

9,10

12,00


(falling cone)

4 8 12

95,82

19,48

22,17

7,69

7,70

6,58

34,03



GC3

0,0

0,5

1,0

1,5

dept

h(m

)

0-0.07 mvery fine sand

XRILithology

0.16-0.70 msilty sandygravely clay,occasionallylayered/banded

0.07-0.16 malternatinglayers of siltyclay and veryfine sand

0.70-1.05 mlaminated siltysandy clay

1.05-1.46 msilty clay, gravelclast at 1.15m

1.46-1.67 mgravely sandyclayey silt

103,79

139,17

151,95

146,08

157,35

161,84


1200 1600 2000


1,0 1,4 1,8 2,2


0 20 40 60 80 100


100 120 140 160

1,86

1,71

1,66

1,68

1,67

1,65


1,5 2,0 2,5

1,30

1,04

0,97

1,00

0,96

0,93


0,5 1,0 1,5

6,30

3,80

4,90

6,70

9,10

11,00


(falling cone)

4 8 12

10,66

8,67

8,00

7,06

6,00

5,13



GC4

0,0

0,5

1,0

1,5

dept

h(m

)0-0.07 mclayey sandy silt

XRILithology

0.07-1.42 msilty sandygravely clay;,sand and gravelrich interlayers at0,72 and 1,05

116,22

158,56

142,60

129,85

145,40

131,65

134,79


1200 1600 2000


1,0 1,4 1,8 2,2


0 20 40 60 80


100 120 140 160

1,82

1,63

1,68

1,75

1,69

1,73

1,78


1,5 2,0 2,5

1,20

0,94

1,02

1,10

1,01

1,09

1,09


0,5 1,0 1,5

3,80

3,00

4,90

3,70

6,50

2,80

6,40


(falling cone)

4 8 12

76,46

15,03

13,19

12,59

10,86

16,78

8,94



GC5

0,0

0,5

1,0

1,5

dept

h(m

)0-0.21 mclayey sandy siltwith shells andshell fragments

0.21-1.40 msilty caly

1.40-1.66 mclayey sandysilt

XRILithology

111,31

160,70

158,94

169,15

147,50

156,93

207,72

173,91

138,41


1200 1600 2000

2,0


1,0 1,4 1,8 2,2


0 10 20 30 40 50


120 150 180 210

1,89

1,63

1,68

1,61

1,72

1,66

1,51

1,59

1,74


1,5 2,0 2,5

1,27

0,93

0,95

0,89

1,01

0,95

0,75

0,87

1,06


0,5 1,0 1,5 2,0

6,50

3,80

4,90

4,90

5,20

4,90

5,50

5,30

6,70


(falling cone)

4 8 12

37,95

14,32

8,56

6,53

10,30

7,24

4,82

7,00

11,89



GC6

0,0

0,5

1,0

1,5

dept

h(m

)0-2.16 msilty clay

XRILithology

135,08

123,96


1200 1600 2000


1,0 1,4 1,8 2,2


0 10 20 30 40


80 100 120 140

1,74

1,79


1,5 2,0 2,5

1,07

1,15


1,0 1,5 2,0

3,40

3,80


(falling cone)

4 8 12

12,93

13,71



GC7

0,0

0,5

dept

h(m

)0-0.27 mSilty clay

XRILithology

93,87

97,73

112,31

92,10


1200 1600 2000


1,0 1,4 1,8 2,2


0 20 40 60 80 100120


70 80 90 100 110 120

1,93

1,91

1,83

1,95


1,5 2,0 2,5

1,40

1,36

1,23

1,42


1,0 1,5 2,0

6,50

4,90

3,70


(falling cone)

4 8 12

72,81

61,42

20,40

31,94



(MSCL)

GC8

0,0

0,5

1,0

dept

h(m

)

0-0.27 mLaminated siltand very finesand, frequentshells and shellfragments at0.15-0.27 m.


0.58-0.63 msandy silty claywith up to 3 cmgravel clasts

XRILithology


0.75-0.99 msandy silty claywith gravelclasts

116,45

86,17

83,62

76,32

81,93


1200 1600 2000


1,0 1,4 1,8 2,2


0 20 40 60 80 100


70 80 90 100 110 120

1,80

2,07

2,02

2,08

2,03


1,5 2,0 2,5

1,20

1,53

1,53

1,63

1,55


1,0 1,5 2,0

4,60

7,60

9,20

10,00

10,40


(falling cone)

4 8 12

16,93

29,48

19,96

17,01

21,70



GC9

0,0

0,5

1,0

1,5

dept

h(m

)0-1.20 msandy silty claywith up to 6 cmgravel clasts

XRILithology

94,13

110,40

81,16

88,11

96,07


1200 1600 2000


1,0 1,4 1,8 2,2


0 20 40 60 80 100120

GC10


70 80 90 100 110 120

2,01

1,86

2,07

1,99

1,95


1,5 2,0 2,5

1,44

1,26

1,57

1,48

1,39


1,0 1,5 2,0

5,30

7,10

5,50

6,30


(falling cone)

4 8 12

54,92

18,59

58,81

28,99

22,74



0,0

0,5

1,0

1,5

dept

h(m

)0-0.20 mfine to very finesand rich in siltand clay

0.20-0.35 mclayey silt

0.35-1.17 mlaminatedcalyey sandysilt

XRILithology

APPENDIX 2

MSCL data treatment guide-lines and core logging notes provided by the MSCL laboratory at the University of Bergen.

Multi Sensor Core Logger University of Bergen, Department of Geology, Att. Dr. Haflidi Haflidason

Data treatment MSCL

Like any form of numeric data gathered with geophysical equipment, the values measured with the MSCL need further treatment to obtain valid information.

P-wave velocity The p-wave velocity is measured with two movable transducers pressed against the liner or the sediment. Bad contact due to dirt, air in the liner, dryness,… occurs occasional resulting in bad data. Also cracks and holes in the sediment cause wrong values. Bad data points are characterised by low p- wave amplitude and sharp drops in p- wave velocity.

• Points with very low p-wave amplitude should be deleted. • To remove the large jumps in the p-wave velocity due to bad contact it is best to apply

a moving average (5 to 10 points) over the data in a spreadsheet.

Magnetic Susceptibility • Error messages occur sometimes in the mag.sus. data and should be deleted. They

show up under the form of large negative values. • The values around section brakes are mostly incorrect and should be removed.

Density and porosity data • Again the values just around the section brakes should be removed. • Very low values in density due to cracks in the sediment should also be removed. To

identify these values a visual inspection of the cores is advised.

Notes for SWASI 2002 cores:

• The end caps weren’t removed due to the unstable state of the sediment in cores. This will result in wrong values 3cm around the section brakes.

• On most cores large paper labels were attached with the core info. These labels resulted in bad transducer contact and wrong p-wave values.

• An identical liner wasn’t available to calibrate the system so we used a similar type. The slight difference could mean a difference in absolute values for density and velocity. Relative changes however will be accurate, being the strongest point of the MSCL data.

Contact:Wim Lekens [email protected] MSCL lab University Bergen Allegaten 41 5007 Bergen

APPENDIX 3

Cumulative grain-size distribution plots and statistical characteristics of individual samples. Note that sample IDs show the core numbers and subsampling depths, i.e. sample GC1-10 stands for the subsample collected from 10 cm depth of core GC1.

tel.: 47 73 90 40 00 report - ngu · sediment components. the xri system consists of an x-ray tube...

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