Quaternary of the Norwegian Channel: glaciation history ... · Glaciation) is situated directly on top of the angular unconformity and suggests glacial erosion as the major process

Quaternary of the Norwegian Channel: glaciation history and palaeoceanography

HANS PETTER SEJRUP, INGE AARSETH, HAFLIDI HAFLIDASON, REIDAR LØVLIE, ÅSE BRA TIEN, GUNNAR TJØSTHEIM, CARL F. FORSBERG & KARI L. ELLINGSEN

Sejrup, H. P., Aarseth, I., Hafiidason, H., Løvlie, R., Bratten, Å, Tjøstheim, G., Forsberg, C. F. & Ellingsen, K. L.: Q uatemary of the Norwegian Channel: glaciation history and palaeoceanography. Norsk Geologisk Tidsskrift, Vol. 75, pp. 65-87. Os lo 1995. I SSN 0029- 196X.

Sediment cores from a borehole penetrating the upper fiat-lying refiectors (ca. 200 m) above the angular unconformity in the Norwegian Channel off western Norway have been investigated. Lithological, biostratigraphical (foraminifera) and geochronological ( 14C, amino acid, strontium isotopes and palaeomagnetism) analyses, combined with shallo w seismic data from· the region, have been used to interpret the Quatemary depositional history of the Norwegian Channel. Three thick and extensive till imits, each with sharp, erosional lower bo undaries are interbedded with marine sediments. The o ldest till unit (representing the Fedje Glaciation) is situated direct ly on top of the angular unconformity and suggests glacial erosion as the major process in the formation of the Norwegian Channel. The age of this ti ll unit is ca. I.l Ma. A bove this unit follows a ca. 50-m thick marine unit deposited between I. l Ma and ca. 0.6 Ma. A war m phase with conditions c lose to the present ones (the Radøy Interglacial) is recorded in the lower part of this unit, suggesting a strong advection of Atlantic water into the Norwegian Sea region. Following a relatively coo l interval, a f urther warm period (the Nor wegian Trench lnterg lacial) is recorded a bove the Br unhes/Matuyama boundary (0.7 Ma). Above this follows a ti ll unit of Middle P leistocene age. Between this and a Weichse lian till, a pocket of more sorted materia l is identified at the Troll Field. Within this pocket, sediments of last interglacial age have been recorded in a neigh bouring core. The ca. 50 m thick li ll unit above this represents at !east two phases of g laciation during the Weichselian. The last deglaciation occurred at 15 ka. The Troll Fie ld record suggests that some of the Middle and Early Pleistocene clirnatic oscillations attained amplitudes compara ble with those recorded for the Late Q uatemary in this region. However, during the period bet ween ca. I. l and ca. 0.6 Ma the Fennoscandian ice sheet did not expand o ut on to the shelf.

Hans Petter Sejrup, Inge Aarseth, Haflidi Haflidason, Åse Bratten & Gunnar Tjøstheim, Department of Geology, University of Bergen, N-5007 Bergen, Norway; Reidar Løvlie & Kari L. Ellingsen, Institute of Solid Earth Physics, University of Bergen, N-5007 Bergen, Norway; Carl F. Forsberg, Norwegian Polar Research Institute, P.O. Box 5072 Majorstua, N-0301 Oslo, Norway.

Introduction The Norwegian Channel off western Norway offers unique possibilities for study of the relationship between palaeoceanographic changes and glaciation history. The channel was inundated by glacial ice several times through the Quaternary, leaving a record of till units with overlying marine packages. The proximity of the channel to the Norwegian Sea has resulted in records including oceanic planktonic microfossils in the marine sequences (Fig. 1). Since the earliest seisrnic investigations of the channel, the geometry and seismic character of the 100-200-m thick upper sequence have been well documented in several studies (Floden & Sellevoll 1972; Sellevoll & Sundvor 1974; Rokoengen & Rønningsland 1983; Rise et al. 1984). In the Troll area (Figs. l and 2) the upper sequence consists of relatively well-defined, flat-lying reflectors which can be mapped over long distances. The lower boundary of this sequence is defined by a regional angular unconformity and below this, westward-dipping sedimentary units are found. The units below the unconformity comprise sediments from Jurassic (in the east) to Pliocene (in the west) in age (Rokoengen & Rønningsland 1983; Sigmond 1992). Owing to the depth of the water ( 400-300 m), the upper flat-lying sequence was not subjected to channelling

and subaerial processes during low sea level stands through the Quaternary.

Both the chronology and the genesis of the angular unconformity have been discussed for two decades. This debate has mainly centred around seismic data and correlation to neighbouring areas, as little high quality core material have been available. However, some studies of the upper 100 m of the sequence have been performed (Green et al. 1985; Sejrup et al. 1 989a). In addition, several studies dealing with the upper soft sediments from the last deglaciation and the Holocene have been published during the past decade (Nagy & Ofstad 1980; Rokoengen et al. 1982; Rise & Rokoengen 1984; Rise et al. 1984; Skinner et al. 1986 ; Long et al. 1988; Lehman et al. 1991; Sejrup et al. 1994). In the present study we report on stratigraphic studies on a 219-m long shallow borehole obtained from the Troll Field in 1989.

Core 8903 (60°38.4 'N, 3 °43.4 'E) was raised from 320 m water depth in the central part of the Norwegian Channel, off western Norway (Fig. 2). The coring was performed with a hydraulic piston system ( < 70 m) and wireline drilling system (Ard us et al. 1982) and penetrated to 219 m below the sea floor. The upper 70 m of the core has a recovery el ose to l 00% while below this

66 H. P. Sejrup et al .

North Atlantic

ltr q,

CiJ c::

/ �o

� .

> <

Fig. l. Location map of the studied area with the main surface ocean circulation pattern prevai ling in the Norwegian-Greenland Sea at present.

Norwegian

Narth Sea P la tea u

n/2 . 81126 • Fladen

Fig. 2. Location map showing the position of core 8903 and the seismic profiles (thick so lid lines) investigated. The location of other site s and the oil fie lds (T = Troll Fie ld, G = G ullfak s Fie ld) mentioned in the text are also indicated. Water depths in metres based on soundings by the Hydrographic Office of Nor way.

the recovery was 25%. The quality of the core segments obtained was very high with little sign of coring disturbance. A gravity core (91-1) 3 m in length was raised from the same position to ensure a good record of the upper part of the section.

NORSK GEOLOGISK TIDSSKRIFT 75 (1995)

An extensive analytical programme, including sedimentological, geochronological, and biostratigraphical techniques, has been carried out on the cores. In addition to the results from the cores, long shallow seismic profiles both along and across the channel are presented. These results and their implications for climatic changes (glaciation history and palaeoceanography) and the sedimentation dynamics of the channel are discussed. The lithology and geochronology of the top 17 m (Lithozone L1 ), which spans the last 15 ka, are presented in Sejrup et al. (1994) and will not be treated in detail here.

Lithology Based on visual descriptions, X-radiographs, geotechnical and sediment petrographic data, the sequence penetrated was divided into seven informal lithozones denoted L1 to L7. The palaeoclimatic significance of one of the lithozones (L6) warranted naming after a geographic feature. The lithology and the depositional environment of the lithozones are discussed in the following section. The genesis of the diamictons in units L6, L4 and L3 will be treated more thoroughly in the discussion. Some of the analytical results are presented in Fig. 3 .

L7- Black pelite (208.0 -> 219.0 m)

This lower unit consists of a relatively homogeneous, dark, hard pelite. Occasional faint, thin laminae of fine sand were also observed. The content of organic carbon is generally higher than that in the rest ·of the core ( 4-6%) and the amount of CaC03 is lower ( only a few percent). These parameters clearly differentiate this sediment from the glacigenic sediments above. L 7 possibly represents an inner shelf - lagoonal environment of pre-Quaternary age.

L6 - The Fedje diamicton (188.0 -208. 0 m)

This unit consists of matrix-supported diamicts interbedded with thin beds/laminae of sorted sand, especially in the lower parts. The unit has a higher con tent of particles (%) > 1.0 mm (including chalk) than the units above and below. This unit as a whole is interpreted as glacigenic. Most of it is probably deposited as a till, but some of the more sorted subunits could represent proximal glacial marine sediments. The unit is named after the small island of Fedje, north of Bergen (Fig. 2). The climatostratigraphic event corresponding to the glaciation during which L6 was deposited is denoted Fedje Glaciation.

L 5 - Pelite (ca. 135. 0 -JBB. O m)

This unit consists of a well-sorted, fine-grained sediment with less than 5% of material > 63 J.Lm. The water con-


TROLL 8903

Quaternary of the Norwegian Channel 67

LEG END

�Gravet O sand Qsilt/Clay �Deformed �Larninated

Fig. 3. Lithological, petrographica l and geotechnical properties of core 8903. (Grain-size distri bution, particles >l mm, Ca C03, organic C, cha lk > 1.00 mm, glauconite grains > 125 JJffi, water content, effective unit weight in kN/m3).

tent is generally higher and the effective unit weight is lower than in the zones below and above (Fig. 3). Despite relatively poor recovery, the lithology and the seismic signature (see below) suggest that this unit represents normal marine sedimentation, possibly during one depositional period. The CaC03 content shows some variation throughout the zone with a peak around 180 m (ca. 30%). This suggests that the marine environment (production of carbonate fossils and/or sedimentation rates) has changed during the period of deposition.

L4 - Diamicton (1 0 9.5- ca. 1 35. 0m)

Lithozone L4 consists of a massive matrix-supported diamicton with small variations in grain-size distribution, CaC03 and TOC (total organic carbon). The lower boundary of this unit is not well defined as there is no core recovery between 120 and 140 m. L4 has a generally higher effective unit weight and lower water content than the unit below (Fig. 3). This unit has a character very similar to L2 and parts of L6.

L3- Sandy- gravelly p elite ( 74.0- 1 09.5m)

The lower boundary of this unit is defined by the transition from a massive diamicton to a series of bedded

(partly laminated) sediments. L3 is characterized by large variations in all the sedirnentological parameters analysed. Some of the subunits are well sorted sandy and gravelly sediments and others are poorly sorted with a considerable amount of fine particles. In both the upper and lower part of the unit, sorted, bedded sand and pelitic sediments dominate. The middle part is a sandy pelite with lenses of fine sand and gravel. At ca. 85 m a coarse crystalline boulder ( size > 10 cm) was penetrated. L3 has a lower content of chalk and glauconite than the zone below and above (Fig. 3). The lithology of this lithozone suggests a wide range of environments from strongly glacial influenced to normal marine.

L2- Diamicton (16. 9- 74. 0m)

The lower boundary of L2 is defined by the change from sorted sandy sediments into a massive diamicton. The lithology of this unit is very homogeneous and there is little variation throughout its thickness. Close to 30% of the particles are > 63 }lm and between 2 and 3% are > 1.0 mm. The number of chalk particles > l mm decreases towards the top of the unit. The TOC values also vary somewhat with highest values in the lower part (ca. 3%). The unit has higher shear strength values (Sejrup et al. 1994) and effective unit weight than the superimposed

68 H. P. Sejrup et al .

unit Ll, yet is similar to the diamicton units below (L4 and L6). There are also significant changes in water content at the upper boundary. This parameter also displays some stepwise changes with depth which suggest that the unit might represent two to three different depositional events or episodes. The stratigraphy of this unit was also studied by Rise et al. (1984), Sejrup et al. (1988a, 1994), Lehman et al. (1991) and was interpreted to represent deposition at the base of a glacier ( till).

LI - Pelite (0.0- 16. 9m)

This unit consists of an unconsolidated, mostly pelitic sediment with high water content and low shear strength values (Sejrup et al. 1994). A 1.5-cm thin sand layer is found at the base of the unit. The unit is described in more detail by Sejrup et al. ( 1994) and represents sediments from the last deglaciation and the Holocene.

Chronology Owing to dramatic changes in sediment supply and periods with extensive erosion, North Sea sediments usually reveal a very fragmentary record of events through the Quaternary. In addition to reworking processes, this makes it difficult to obtain a reliable chronology. In this article we rely on the approach used by Sejrup et al. ( 1987, 1989a), Haflidason et al. (1991 ), Sættem et al. (1991), and Knudsen & Sejrup (1993), which includes a combination of several methods with special emphasis on amino acid diagenesis combined with palaeomagnetic evidence. In this section we consider the palaeomagnetic, amino acid and strontium isotope results obtained on core 8903. Supporting evidence from the biostratigraphy is discussed later. The radiocarbon AMS chronology for the upper 16 m (Sejrup et al. 1994) will not be reconsidered here.

Palaeomagnetic investigations

The results of the palaeomagnetic investigations are listed in Table l and the palaeomagnetic polarity of 69 sampels (6 cc) inferred from the sign of inclinations is presented in Fig. 4. Samples were obtained from the top and bottom surfaces of core sections either by using a special sampling device (Løvlie 1989) or by shaping cubic subsamples with a knife to fit into 6-cc cubic plastic boxes. The latter procedure is thought to eliminate subsampling effects (Gravenor et al. 1984; Løvlie et al. 1986). The directions and intensities of the natura! remanent magnetization (NRM) were determined on a threeaxis cryogenic magnetometer (SCU 400/500). Low field susceptibility (k) was measured on a KL y-z induction bridge. NRM intensities from 0.5 to 300 mA/m (Table l ) and show a general gradual decrease with depth. Magnetic susceptibilities range from 19 to 2380 10-6 SI and


reflect only a weak lithological dependence. The type of magnetic constituent was investigated by isothermal remanent magnetization (IRM) acquisition experiments on samples from each lithozone revealing major saturation below 250 mT. The ratio between remanent acquisition coercive force and remanent coercive force range between 1.45 and 1.6, which is indicative of magnetite as a dominating magnetic mineral (Dankers 1981). Thermomagnetic analyses define slightly irreversible curves with features characteristic of magnetite with some fraction of maghemite which is thermally destructed upon heating above 350-400°C.

Anhysteretic susceptibility (O.l mT DC/70 mT ACfields) versus bulk susceptibility (King et al. 1982) indicates a larger spread in relative grain sizes and concentrations of magnetite within the pelite zones (20-150 ,um) compared to a more confined grain-size range of the diamicton units (2-5 ,um). Although the rock magnetic investigations unambiguously suggest that magnetite is the dominating bulk magnetic mineral, the remanent magnetization may nevertheless reside in minute concentrations of minerals undetected by the methods applied. Recent rock magnetic investigations of Quaternary and Tertiary sediments from the southern North Sea suggest the presence of greigite (Thompson et al. 1992) which may carry a stable remanent magnetization of chemical origin (Snowball & Thompson 1990). The presence of greigite may be inferred from ratios between saturation IRM (SIRM) and susceptibility exceeding ca. 80 kAm-• (Snowball 1991). In the present core, high ra ti os ( 50-195 kAm -l) are confined within the zone between 75 and 140 m, apparently independent of the lithological changes within this zone.

Alternating field (af ) demagnetization performed in a two-axis tumbler in 5 to lO mT steps to 60 mT, reveals a narrow range of low median destructive fields (MDG) above ca. 75 m (2.15-9.55 mT) increasing to 3.89-46.29 mT below this lithozone boundary (Ll-L2). Vector analysis of progressive af demagnetization results reveals linear segments towards origin in 68 of the samples, 1 1 of which define directions with negative inclinations. A positive mean inclination of 56 (N = 56, kappa= 9.5 1, McFadden & Reid 1982) is significantly lower than the Late Quaternary geomagnetic field at the site latitude suggesting some compactional effects (Blow & Hamilton 1978; Anson & Kodama 1987). The reversed polarity samples define a mean inclination of -43 (N = 13, kappa= 4.31) which is also too shallow and attributed to compactional effects as well as unsuccessful removal of normal polarity components.

The visually non-deformed structures of the sediments in conjunction with the uniform mineralogy suggest that the remnant magnetization was acquired at the time of, or shortly after deposition and is carried by detrital magnetite grains. Hence, the negative inclinations are concluded to reflect geomagnetic field conditions at the time of sediment deposition. The negative inclinations in the upper ca. 157 m of the core probably represent short

NORSK GEOLOGISK TIDSSKRIFT 75 (1995) Quaternary of the Norwegian Channel 69

Tab le l. Pa laeomagnetic parameters for core 8903. Pa laeomagnetic po larity: N = Normal, R = Reversed, U= Undetermined.

Depth (m)

12.7 1 13.39 15.76 16.36 16.39 16.9 1 16.99 17.59 24.76 25.39 33. 1 1 33.79 4 1.06 4 1.64 49.2 1 49.84 56.96 57.49 64.6 1 65.46 73.36 74.09 74. 10 74.38 74.49 84. 10 84.90 85.45 85.47 85.49 86.30 87.3 1 88.82 89.88 90.64 97.55 99.00

10 1.24 104.48 109.23 109.95 109.96 1 10.86 1 1 1.90 1 17.50 1 18.65 1 18.66 139.80 139.81 140.54 157.22 157.67 158.34 158.36 158.63 169.50 169.00 170.10 170.75 178.68 179.56 179.92 187.10 187.85 188.50 199.25 199.72 200.00 20 1.25

Inclination NRM

45 62 44 50 59 59 50 54 43 77 16 60 38 67 30 6 1

- 16 55 39 50 39 54

-46 -8

- 19 59 6 1 74 56 56 83 58 88 63 75 56

- 18 49 7 1 72 74 67 19

73 68

7 43 39 77 18 85

-43 43

7 -77

77 61 30 82 58

-73 -71

72 69 44 46

-30 59

-43

I ntens ity NRM (mA/m)

68.09 94. 12 86.49

1 14.26 30 1.90

72.62 220. 10 77. 13 37.59

185. 1 1 24.65 84.88 74.42 83.92 54.58 5 1.68 29.90 89.09

199.00 84.43

100.69 133.76 13.4 1 54.29 66.48 45.37 27.70 29. 12 20.27

9.22 22.62 60.60 6 1.77 35.29 16.86 18.27 50.75 38.25 30.38

4.39 5.37 3.09

13. 15 42. 19

8.28 14.34 5.27 5.09 3.24 9. 13 9.07

15.62 8.78

15.91 15.D3 1.56 2.07 2.40 3.02 0.82 0.96 0.50 3.74

1 1. 11 25.00

5.58 0.84

17.89 15.62

S usceptibility 10-6 SI

400.4 387.4 372.2 479.0 588. 1 889.6 548.1 728.2 570.5 726.4 692.0 784.8 727.3 693.0 749.5 759.7 7 17. 1 677.2 685.5 571.4 757.9 763.5 64 1.0 672.5

2380.3 16 1.7 104.4 144.8 105.7 63.0

1 16.5 156.9 t78.6 15 1.2 80.5

154.4 18 1.8 188. 1 144.2

18.5 24.8 24.5 62. 1

103. 1 37.6 18.4 35.7 23.6 18.8 30.6

402.0 400.8 420.0 927.0 62 1.2 163.0 171.6 185.0 234.0 142.4 189.6

107.0 201.6 333.0 810.0 389.2 254.0 9 19.0 374.8

Q-factor (NRM/ SU S)

0. 17 0.24 0.23 0.24 0.5 1 0.08 0.40 0. 1 1 0.07 0.26 0.04 0. 1 1 0. 10 0. 12 0.07 0.07 0.04 0. 13 0.29 0. 15 0. 13 0. 18 0.02 0.08 0.03 0.28 0.27 0.20 0. 19 0. 15 0. 19 0.39 0.35 0.23 0.2 1 0. 12 0.28 0.20 0.2 1 0.24 0.22 0. 13 0.2 1 0.4 1 0.22 0.30 0. 15 0.22 0. 17 0.30 0.02 0.04 0.02 0.02 O.D2 O .Dl 0.01 0.01 0.01 0.0 1 0.0 1 0.01 0.02 0.03 0.03 0.0 1 0.00 0.02 0.04

Median �estruct ive fie ld (mT)

6.58 4.87 5.93 9.55 8.87 6.32 4.02 4.80 2.55 4.84 4.86 3.09 4.60 2.57 5.54 2. 15 5.5 1 3.53 5.07 4.45 4.86 3.56 3.83 2.46 2.58 4.06 8.43 9.27 14.86 25.84 14.66 4.70

16.62 9.66

21. 19 5.07 3.89

19.97 20.73 32.69 29.25 25. 17

5.38 22. 19 13.40 4.34

2 1.95 29. 13 27.75 25.40 38.68 44.72 20.76 32.85 31.73 22'.17 24.87 43.37 10.12 13.51 3 1.41 28.36

3.93 4.62

28.30 23.32 25.35 25.98 46.29

Anhysteretic rem. magnet.

(mA/m)/k

1. 10 0.97 1.09 1.47 1.03 1.78 0.67 1.02 1. 10 1. 12 1. 12 1. 14 1. 14 1. 15 1.08 1. 10 1.04 1. 10 1.09 1.09 1.09 1.09 1. 10 1.94 0.3 1 0.09 0.09 0.09 0.09 0.08 0.09 0.09 0.09 0.09 0.08 0.09 0.08 0.09 0.09 0.08 0.08 0.08 0.09 0. 10 0.08 0.09 0.09 0.09 0.08 0. 10 1.04 I.l l 1.02 1.05 1.06 1.00 1.03 1.0 1 1.05 0.99 1.06 0.92 1.07 1.00 1.3 1 1.06 1. 18 0.98 1. 10

Saturat ion IRM/k

13.49 10.40 6.58

1 1.64 14.70 5.23

13.86 10.27 8.72 8.70 5.54 8.2 1

- 6.99 8.08

309.00 6.36

10.78 9.89

1 1.87 9.42 7.08 8. 19 9.42 5.84

50.53 1 13.55 108.23 9 1.86

108. 13 105.90 82.62

78.04 72.77

102.9 1

82.44 69.87 9 1. 14 67.0 1

92.44 35.97

194.72 1 15.8 1

12 1.95 130.29 74.32 89.06

8. 15

7.07

7.46 2.23 2.28 2.25

1.38 1.28 1.43 3.09

13.34

2.49

4.42

Inclination ChRM

5 1 46 20 7 1 53 75 35 67 36 60 65 63 35 66 26 63 42 13

38 4

32 15 o

-59 - 15

34 47 75 47 83 53 7 1 6 1 37 67

-4 1 20 14

46 73 7 1 50 13 45 72 28 44 44 54 Il 64

-87 -65 -50 -64

6 1 60 29 77 50

-50 -74

52 67 14

-26 -47

-3 -76

Pa laeomagn. polarity

N N N N N N N N N N N N N N N N N N N N N N u R R N N N N N N N N N N R N N N N N N N N N N N N N N N R R R R N N N N N R R N N N R R R R

70 H. P. Sejrup et al.

TROLL 8903

al c al g L2 � Ill 50 ·a;

o: al � "'

...J

L3

Ql Qlæ L4 :ag ·-+-' �.IQ Ql c:

LS

L6

TILL Bl

NORMAL-GLACID-MARINE

82

TILL

NæMAL- c MARINE

GLA Cio-MARINE/ D

TILL

av

c

•

c

c•


•

NRM Polar·

(/) w I z ::::> a:: al

()i� L7 E D Elph. excavatum 30.5� • B. marginata

Fig. 4. Chronostrat igraphy of co re 8903 based on amino acid diagenesis stront ium isotope dat ing and palaeomagnetic ev idence (J = Jaramillo palaeomagnetic event; C= Cobb Mo unta in event). Amino acid rat io in lithozone L2 is based on Sejrup et al. ( 1989a). The ova l boxes in L3 amino data rep resent points with large influx of reworked specimen s. The basal rad iocarbon date ( AMS) of lithozone L l is f rom Sejrup et al. ( 1994).

duration excursions of the geomagnetic field. Recent investigations of Arctic marine sediment cores suggest that at least five excursions have occurred since 150 Ka (Nowaczyk et al. 1994). However, the reversal observed in Lithozone 3 might be a result of the deformation or disturbance of marine strata. Below ca. 157 m reversed polarities dominate, and this zone is tentatively interpreted to represent the Matuyama Chron. The relatively poor recovery of the deeper part of the core makes construction of a detailed palaeomagnetic stratigraphy difficult. However, the two normal polarity zones occurring within the assumed Matuyama Chron (Units L5 and L6) are tentatively suggested to represent the Jaramillo and Cobb Mountain events. These events have been K/ Ar-dated to between 0.90 and 0.97 and to 1.1 Ma respectively (Mankinen & Dairymple 1979; Mankinen et al. 1980; Mankinen & Gromme 1982; Cande & Kent 1992).

Amino acid geochronology

The isoleucine epimerization reaction in fossil foraminifera has proven to be a valuable geochrono1ogical tool in North Sea sediments (Sejrup et al. 1984, 1987 and 1989a). The degree of epimerization, given as the ratio between D-alloisoleucine (alle) and L-isoleucine (Ile), has been measured in 52 samples from 33 levels in the 8903 core. The monospecific samples were prepared after the procedure in Miller et al. ( 1983) and then run on an automatic amino acid analyser at the Bergen Arnino acid Laboratory (BAL). Each sample consisted of ca. 100 individuals of the benthonic foraminiferal species Elphidum excavatum or Bulimina marginata. The results are presented in Table 2 and Fig. 4. As these species are known to have similar reaction rates (Knudsen & Sejrup 1988; Sejrup & Knudsen 1993), they are treated together

NORSK GEOLOOISK TIDSSKRIFT 75 (1995)

Tab le 2. Amino acid epimerization data from core 8903. Degree of iso leucine epimerization in the total (hydrolysed) fraction, given as the ratio bet ween D-alloisole ucine and L-isoleucine (alle/ I le) in monospecific samples of the bethonic foraminifera l species E/phidium exca vatum and Bulimina marginata. The samples were prepared after the procedure descri bed by Mi ller et a l. ( 19 83) and then run on an automated ion exchange HP L C amino acid analyser at the Bergen Amino Acid La boratory ( B A L).

Depth Laboratory a l le/ I le (m) num ber Species ( HYD)

1.92 B A L 2963A Elphidium excavatum 0.05 1 1.92 B A L 2963B Elphidium exca vatum 0.05 1 2. 12 B A L 2934 Elphidium excavatum 0.040 2.32 B A L 2935 Elphidium excavatum 0.06 1 2.42 B A L 2964 Elphidium exca vatum 0.046 2.50 B A L 2958A Elphidium exca vatum 0.047 2.50 B A L 2958B Elphidium exca vatum 0.049 3.70 B A L 296 1 Elphidium exca vatum 0.054 7.90 B A L 2959 Elphidium exca vatum 0.052

12.90 B A L 2960A Elphidium excavatum 0.044 12.90 BAL 2960 B Elphidium excavatum 0.046 15.70 B A L 2937A Elphidium excavatum 0.035 15.70 B A L 2937 B Elphidium excavatum 0.04 1 16.70 B A L 2962A Elphidium excavatum 0.056 16.70 B A L 2962B E/phidium excavatum 0.054 77.50 B A L 2475 Elphidium exca vatum 0.122 77.50 B A L 24 8 1 E/phidium excavatum 0.247 77.50 B A L 2476 Bulimina marginata 0. 196 77.50 B A L 24 80 Bulimina marginata 0. 144 88.45 B A L 2478 Bulimina marginata 0.274 86.57 B A L 2474 Elphidium exca vatum 0.253 86.57 B A L 2473 Bulimina marginata 0.24 8 87.0 8 B A L 24 82 Elphidium exca vatum 0.209 87.0 8 B A L 24 83 Bulimina marginata 0.279 8 8.40 B A L 2495 Elphidium excavatum 0.253 88.60 B A L 1949A Bulimina marginata 0.336 88.60 B A L 1949B Bulimina marginata 0.29 8 88.60 B A L 1950 Elphidium excavatum 0.340 90.22 B A L 2503 Elphidium excavatum 0.270 96.90 B A L 2497 Elphidium exca vatum 0. 137 96.90 B A L 2496 Bulimina marginata 0. 1 17 98.95 B A L 2493 Elphidium excavatum 0.328 98.95 B A L 2492 Bulimina marginata 0.202 99.45 B A L 249 1 Elphidium excavatum 0. 179 99.45 B A L 2490 Bulimina marginata 0.345

10 1.85 B A L 24 88 Elphidium excavatum 0.357 10 1.85 B A L 24 89 Bulimina marginata 0.359 104.55 B A L 24 87 Elphidium exca vatum 0.295 107.60 B A L 24 84 Bulimina marginata 0.092 1 1 8.50 B A L 195 1 A Elphidium excavatum 0.367 138.40 B A L 194 8B Bulimina marginata 0.303 139.95 B A L 304 8A Bulimina marginata 0.3 16 140.17 B A L 3047A Bulimina marginata 0.245

140.17 B AL 3047B Bulimina marginata 0.253 158.93 B A L 2863 Eliphidium excavatum 0.354 158.94 B A L 2336 Bulimina marginata 0.268 169.50 B A L 1947 A Bulimina marginata 0.332 17 8.56 B A L 2365 Bulimina marginata 0.3 12 178.56 B A L 2364 Elphidium excavatum 0.436 179.00 B A L 2864 Bulimina marginata 0.375 186.50 B A L 2340 Bulimina marginata 0.45 1 187.50 B A L 2865A E/phidium exca vatum 0.4 19 1 87.50 B A L 2865B E/phidium excavatum 0.363 20 1.30 B A L 1952 Cretaceous foraminifera > 1.300

and the means given include ratios from samples of both species.

From the marine unit L5, the 14 samples analysed gave a mean alle/Ile-ratio of 0.345 ± 0.067. This is the same degree of epimerization as measured close to the


B/M boundary in cores from the Fladen Ground (Sejrup et al. 1987), from the Devil's Hole area (Knudsen & Sejrup 1993) in the North Sea and from Draugen (Haflidasori et al. 199 1) on the Mid-Norwegian shelf. The amino acid data thus support the corre1ation of the reversa1 at 157 m depth in core to the B/M boundary. Within L5 there is a trend towards lower ratios in the upper part of the unit. In Fig. 4 the epimerization data from L5 are presented and a regression line for the data is shown. Using the regression equation y= -9.8487e -2 + 2.6624e - 3x (r2 = 0.614), an alle/Ile ratio close to 0.28 at the top and 0.40 at the bottom of the unit is calculated. These ratios, plotted on a calibration curve (Fig. 5) provide a rough estimate of absolute age. This exercise yields an age of ca. 600 Ka for the top of unit L5 and ca. 1.1 Ma for the bottom. These resu1ts are tentative but they give some idea concerning the time-span of the deposition of L5. Despite the uncertainties re1ated to temperature history and some scatter in the analytical results, the data support a correlation of the palaeomagnetic reversals recorded through the Matuyama as suggested above. That some of these reversals shou1d represent the Olduvai event (top 1.6 Ma) seems very unlikely from the amino acid data.

One sample of Elphidium excavatum has been measured from L4 which is interpreted as a till. The ratio (0.366) suggests that the few foraminifera found in this unit are derived from L5.

The 24 samples analysed from the sandy/gravelly pelite L3 gave 0.245 ± 0.082. The high standard deviation suggests that the fossils from this level are derived from sediments of different ages. However, on grouping those samples obtained from the unsorted glacially derived part of the unit, it is clear that these account for most of

O.l

0.2 0.4 0.6 Ma

0.8 1.0 1.2

Fig. 5. Calibration curve for the iso1eucine epimerization in Elphidium excavatum

given as the ratio between alloisoleucine and isole ucine (a lle/ I le). Modified from Sejrup et al. ( 19 89a). The error bars represent one standard deviation. The cali bration point for stage 5e is based on Sejrup & Kn udsen ( 1993) and the Brunhes/Mat uyama boundary ca li bration point is based on data from the investigated core (see the regression line in Fig. 4). The shaded area represents the relation between the allele/IIe ratio meas ured in lithozone L5 and the calibrated age estimates for the study area.


this variation (Fig. 4). Unit L3 thus includes foraminifera both from the Lower and Middle Pleistocene units below and probably also from younger sediments. The samples from the sorted interval all gave ratios close to O.l . This value is close to what is obtained on the Eemian interglacial samples from core 5.1/5.2 from the Troll Field (Sejrup et al. 1989a) and from other locations in the North Sea region (Knudsen & Sejrup 1988; Sejrup & Knudsen 1993). The fact that the fauna corresponding to the interglacial ratios reflects cooler environments than the fauna found in core 5.2 suggests that these sediments were probably deposited shortly before or after the last interglacial.

Amino acid analyses were not performed on foraminifera from the thick diamicton L2, interpreted to be a till. However, ten analyses on foraminiferal samples from this same unit in cores 5.1/5.2, 1002 and B l (Sejrup et al. 1989a), yielding a mean 0.108 ± 0.024, are presented in Fig. 4.

From the upper pelitic unit LI, which was extensively AMS dated, 15 samples between 16.70 m and 1.92 m depth were selected for amino acid analysis. These samples, which are radiocarbon dated to 15 -11 Ka, gave 0.048 + 0.008. This corresponds well with the values (0.050 ± 0.005) reported from this unit in core 5.1/5.2 by Sejrup et al. ( 1989a).

Strontium isotopes

The strontium isotope method has mostly been employed as a tool for da ting deposits of Tertiary age (e.g. Hess et al. 1986 ; Smalley et al. 1986 ; Rundberg & Smalley 1989; Richter et al. 1992). Studies of strontium isotopes in marine precipitates have revealed that the 87Sr/86Sr ratio in seawater follows a general trend of increasing values from the Late Cretaceous to the present time (DePaolo & Ingram 1985 ; DePaolo 1986 ; Hess et al. 1986). As the residence time of strontium is much Ionger than the mixing time of the ocean, the 87Srj86Sr ratio of the modem oceans is considered homogeneous (e.g.


Broecker & Peng 1982). Changes in the 87Sr/86Sr ratio are therefore considered as a result of global variations. Detailed records of strontium isotopic ratios in fossils show that the rate of change in 87Sr/86Sr varies through time (e.g. Burke et al. 1982; DePaolo & Ingram 1985 ; DePaolo 1986 ; Hodell et al. 1989) and accordingly there is variation in the theoretical chronostratigraphic resolution for the carbonates analysed. The resolution for the Late Oligocene is estimated to be 0.1-0.5 Ma and for the Pliocene and the Pleistocene the resolution varies between 0.5 and 2.0 Ma (DePaolo & lngram 1985 ; DePaolo 1986 ; Hess et al. 1986 ; Hodell et al. 1989).

The strontium isotopes were measured on monospecific samples of benthonic foraminiferal tests separated from the 125 - l 000 11m fraction. Six samples from co re 8903 were analysed and in addition one recent sample and two last interglacial samples from core (cf. 5.1/5.2 (cf. Sejrup et al. 1989a), also from the Troll area, were analysed. The results are given in Fig. 4 and Table 3. Within one standard deviation, all the age estimates of the samp1es from L5 and those stratigraphically younger fall within the Pleistocene. The strontium isotope analyses therefore further confirm the results of the palaeomagnetic and the amino acid analyses which place the lithologic units L5 to LI within the Pleis!ocene. The calculated age of the Elphidium excavatiun species from the glacigenic unit in Lithozone L6 is, however, indisputably of Pliocene age. The genetic interpretation of this unit and the high frequency of species from different ecological environments imply that the foraminiferal tests we analysed are not necessarily in situ. The 30.5 Ma age (Oligocene) of unit L7 is confirmed by the biostratigraphic investigations.

Biostratigraphy From core 8903 131 samples were examined for foraminifera. The samples were prepared by the method described by Meldgaard & Knudsen ( 1979). The foraminifera were separated using CC14 and the 125 to

Table 3. Strontium isotope analyses from core 5.1/5.2 and core 8903 from the Troll Fie ld area (Fig. 2). The Sr concentrates were analysed on a F innigan MA T 261

in the static multico llector mode at the Institute for Energy Technology, Kje ller, Norway. Measurements of the N BS 987 standard during the period analysed have a 87Sr/86Sr rat io of 0.710150 (2u = 0.()()()()31). The analytical reproduc ib ility was found to be better than 0. ()()()()3 at the 95% confidence level. The ages of the foramin ifera l species were calculated using a curve compiled from data of DePaolo (1986), DePaolo & lngram (1985), and Hess et al. (1986).

Depth (m) L ithozone Co re Species 87Sr/86Sr St. dev iation iJ 87Sr Age (Ma)

O.o3 L I Surface samp le Bulimina marginata 0.709124 0.()()()()11 -1.70 0.3 ± 0. 7

65.45 L3 5.1/5.2 Bulimina marginata 0.709233 0.()()()()19 13.60 <0.0 65.45 L3 5.1/5.2 Elphidium exca vatum 0.709199 0.()()()()18 8.88 <0. 0

138.40 L5 8903 Bulimina margina ta 0.709074 0.()()()()15 -7.80 1.4 ± 1.0 138.40 L5 8903 Elphidium excava tum 0.709097 0.()()()()10 -4.50 0.8 ± 1.0

169.50 L5 8903 Bulimina marginata 0.709046 0.()()()()10 11.70 2. 2± I.l 169.50 L5 8903 Elphidium excava tum 0.709121 0.()()()()20 -1.10 0. 2 ±0.9

201.25 L 6 8903 Elphidium excava tum 0.708991 0.()()()()27 -19.50 3.9 ± 1.4 219.00 L7 8903 Alabamina sp. 0.707951 0.()()()()19 -167.10 30. 5 ± 1.0


l 000 ttm fraction was analysed. The following description and interpretation of the foraminiferal stratigraphy in 8903 follows the lithological division of the core. The faunas of the diamictons in L6, L4 and L2 are discussed at the end of this section. The ecological interpretations are based on knowledge of the foraminiferal distribution in arctic and boreal environments today. The foraminiferal data are presented in Fig. 6 and in Tables 4-8. The high resolution record of Lithozone LI will be discussed elsewhere.

Fauna in L7

Between 207 and 209 m there is a sharp faurial shift, which coincides with the boundary between L6 and L 7. The fauna of Lithozone L 7 (Tables 5 and 6) is characterized by common occurrences of the taxa; Pullenia bulloides ( d'Orbigny), Alabamina sp. Toulmin, Nodosariidae Ehrenberg, Ceratobulimina contraria (Reuss), Melonis bar/eeanus (Williamson), Trifarina germanica (Cushman & Edwards), Gyroidina soldanii girardana (Reuss) and Turrilina alsatica Andreae. More sparsely represented are Cassidulina subglobosa Brady, Bolivina antiqua d'Orbigny and Textularia sp.


P. bulloides, T. alsatica and C. contraria have all been recorded in Oligocene deposits in the North Sea (Batjes 1958; Doppert 1980; King 1983, 1989). Based on the stratigraphic range of the frequently occurring species (King 1983, 1989) L7 is dated to the Oligocene.

Batjes (1958) and Doppert (1980) found a species which they named Nonion affine (Reuss) and which is very similar to M. barleeanus, in Oligocene and Miocene deposits the North Sea basin. It was not possible to make a distinction between Melonis barleeanus in the Quaternary part of 8903/8904 and those in Lithozone L7. The name Melonis barleeanus is therefore used in L7, too.

The small num ber of Plio-Pleistocene foraminifera ( 1-17) found in three of the seven samples analysed from L 7 is interpreted as a contamination during sample preparation.

Fauna in L5

The low recovery (10%) of the thick marine unit of Lithozone 5 imposes restrictions on interpretation of the foraminiferal assemblages of this unit.

TROLL 8903 Benthonic foraminifera Planktonic foraminifera

..J o z o a: I () @ (!)

�

��

Q) c: B g .!!l � 0... Q) ta _J

1---Q)

Q)c: 'OB �g �fil

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50

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·� � 100 � � � 1-

� ��==�t ---- - -_-: --�:---

1- ! ---

150 -·

l= ·=--"' --�

l-�--

-· ----:----:.--, - ------ _ _. __

200 -;-;--::-;�

.�

(/) UJ z o N o I .... :i

L1

L2

L3

L4

L5

L6

L7

E E .!Il � :l � � c: ·u; i "' "' c: Q> > o B Q> '2> Q> fl :t: o "' -.::: c: Q> � 1ii "' >< � o c: "' .o Q> c: u.i u ...: u ai ai �

% 30 60 % 30 60 % 20 % 20 % 30 60 % 20 j% 20

� p o ""? ?'"

� � � �

> �

1 � l

11 l.f \ 1\

7� w,_

� � � �

11""-' v

� 17 L

lf Fig. 6. Benthonic and planktonic foraminiferal biostratigraphy from core 8903.

"' Q> .I.l .I.l .Il c: c: c: 5"' "' jg !!l"' o o "' "' .<::: �8 .c Q> §�� c:., .<:::c: i., :l ... i!:'"' � � g' � Q> Q> o Q> .!li:!:: "' .!ll.g l!! 'al o .o ·o .o 'al o a.c Q.(j c: "' t:Q> · Q> .o Q> · Gl G>Q. � a.:: O a. o a.:: :Ja. O a. ...: ::) .... ., ().,a. z., z.,a. (/)<JI ZU>

% 20% 20 % 40 80 100 200 20 40 20000 % 40 80 2000

,.r- p '>

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;>

l F-

� l

D

i{. rr F=--

t>� t � � [;L 1\_ u- -t- �

<

74 H. P. Sejrup et al. NORSK GEOLOGISK TIDSSKRIFT 75 (1995)

Table 4A . Percentage occurrence s of a ll benthonic forarninifera and plank tonic subpolar foraminiferal species in the samples studied between 0.0 and 88.7 m in co re 8903.

"' "' 1ii 1ii "' il; � ::> >< .. c: E o Q) E "' ::> " .!!l "' ·c -' !:! • ·� "' c: "' .!!l Q) Q) 1ii E E E

� 1: c: � � E Cl g .., ::> E :l Æ "' 1ii "' c: ::> ::> c: o • � � "' "' ::> :.0 u 1ii 1ii J!! u ::> "'

� E 1ii "' Q) .. .!2 ::> o E c: j 1ii ·æ ei a rl li ::> c: j g ::> c "' :; -g ::>

5 5 c:

.a c:

.5! il; 1'i! ·a "' •t: 'El> .5 !!! � 1ii ::> :2 t: � :; c: .. :e :c � C) "' l B :2 i;; c: o .o Q) :.0

X! � >< >< ::> ;;; as J!! ei o � .! c: 1ii C) c: as "' "' "' "' 8. iii Q) Q) "' "' ::> .c: Qj ·� ::> E Æ E E .E .E .E C) .Q J!! c: "' "' .§. "' iii .. "' as :; :; :; .. .. .. E E E E E E E E :i E "' c: "' ·c: o "' "' "' J!! J!! :; Q) ::> Q) ::> ::> ::> ::> ::> ::> ::> ::> c: 'gj Q) c: c: c: @ @ c: .., :2 :2

� .., .., .., :2 u :2 u � � u u .., o '§ c: � o c: ·�

1 E E1 ·� ·� ·� ·� � � '13 '13 '13 .c: :c .c: :c :c :c � ... "' c: 1ii E !2 s s s ::> ::> :; :.0 :.0 :.0 Q. Q. Q. Q. Q. a. Q. Q. ·a jf i;" ,.. < CD CD CD (.) (.) (.) 6 6 6 w w w w w w w w w w I I

0 , 1 0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 4 ,0 27,0 0 ,0 0 ,0 0 ,0 0,0 5,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,3 0 ,0 3,0

0 ,47 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0,0 0,3 22,0 0,0 0 ,0 0,0 0,0 1 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,3 0,0 3,0

2,63 0 ,0 1 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,3 0,0 40,0 0,0 1 ,0 0 ,0 0 ,0 0 ,0 0 ,0 28,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 ,0 0 ,0

3 ,70 0,0 0 ,0 0 ,0 0,0 0 ,0 0 ,2 0 ,0 0 ,0 2,0 4,0 0,0 34,0 0,0 1 ,0 0 ,0 0 ,0 0 ,4 0 ,0 25,0 1 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0

5 ,07 0,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,3 0 ,3 1 ,5 0,0 40 ,7 0,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 20 ,8 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0

5 ,80 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0,0 o .a a ,3 6,8 a.a 59,a a.a o .a o.a a.a 0 ,0 a.a 6 ,8 a.a a .a 0 ,0 o .a o.a a .o 0,3 a.a a,o

1 2,60 o.a a .a 0 ,0 a .a o .a a,o a .a a ,o a.a 4,7 a .a 3,5 a,o 0 ,0 a.o 0,0 o .a a .a 69 ,4 1 0 ,6 a .a o.a a.a o.a a .a a.a 1 ,2 a,o

1 5,70 0,0 o .a 0 ,0 o.a a.a 0,0 a.a o.a a.a 0,0 o.a 1 5,a a.a o .a 0,0 0 ,0 1 ,0 1 ,a 62,0 0 ,0 o .a o .a a .a o .a o .a o .a a .a a.a

1 8,70 1 ,3 a .a a .a 0 ,0 a .a o.a 0 ,0 1 ,3 a.a a .o o .a 1 6,7 0,0 1 ,3 0,0 2,6 0 ,0 o .a 56,4 7,7 0,0 o.a 0,0 0 ,0 0 ,0 0 ,0 2,6 0,0

1 9,30 o.a a .a 0 ,0 a ,s a,o 0 ,0 0 ,0 1 ,a a.a 0 ,0 0,() 32,2 0,0 1 ,0 0,0 0,5 0 ,0 1 ,5 52,3 4,5 a ,o 0 ,0 a . a 0 , 0 a .a 0 ,5 a ,s 0 ,0

1 9,90 0 ,8 a ,4 a ,o 0 ,8 0,0 0 ,4 0 ,0 2,6 a,4 0 ,0 0 ,4 25,4 0,0 1 ,5 0 ,0 2,2 0 ,0 0 ,8 42,2 3 ,0 a .a 0 ,0 a ,8 0 ,0 a .a 0 ,8 3 ,0 0 ,0

2 1 , 1 0 a.o 0 ,5 0 ,0 a .o 0 ,0 0 ,5 0 ,0 1 , 1 0,5 0,0 0 ,0 1 8,5 a,o 1 ,1 a.a 4,8 a .a 0 ,0 62 ,4 2,1 a.o a,s 0,5 0,0 0 ,0 0,0 2,7 a.o

22,30 0,0 1 ,0 0 ,0 o.a 0 ,0 0,5 a ,o 2,4 0,5 0 ,0 0 ,0 1 9 ,5 0 ,0 0 ,5 o.a 1 ,4 1 ,0 1 ,0 57,6 2,9 a ,o 0,0 o.a 0,0 0 ,0 0 ,5 3 ,3 a,o

23 ,50 a .o o.a 0 ,0 0 ,4 a,o 0 ,9 a .a 1 ,8 0,0 0,9 o.a 20,9 a.a 0 ,4 o .a a ,9 a .a 2,2 48,0 5,3 a.a a,4 0,0 a .o o .a 0 ,4 2,2 a.4

24,7a 0 ,0 0 ,8 a .o 0 ,8 0,0 2 ,4 a .a 1 ,6 a ,o 0 ,0 a ,o 1 8,7 a.a 0 ,8 o .a 1 ,6 a .o 0 ,8 46,3 8,1 a ,o a.a 0,0 a .a 0 ,0 o .a 4,9 o.a

25,90 o.a a,6 0 ,0 1 ,a a ,o 0 ,3 a .a 3 ,5 1 ,0 0,3 a,o 20 ,5 a,o 1 ,a a .a 1 ,3 a ,3 1 ,3 53 ,7 3,5 a .a a .a a ,o a.a o .a 0 ,3 1 ,3 a .a

27,50 0,0 0,0 0,0 0,0 0,0 0 ,9 0 ,0 4,4 0 ,4 0 ,0 o .a 1 8,7 0,0 2,2 0 ,0 3 , 1 1 ,3 1 ,8 43 ,6 8,9 0,4 0,4 0,4 0 ,0 0 ,0 0 ,9 1 ,8 0 ,0

29,80 0,7 0 ,0 0 ,0 0 ,7 0 ,0 0;7 0,0 2,4 0,4 0,4 0,0 20,4 0,0 0 ,4 0,0 4,9 0;0 0 ,7 49,2 4,7 0 ,0 1 , 1 0 ,0 0,0 0 ,0 0 ,4 2,2 0,7

3 1 ,30 0 ,0 0 ,4 0 ,0 0 ,4 0 ,0 0 ,8 1 ,2 4,2 0 ,0 0 ,0 0,0 21 ,9 0,0 1 ,5 0,0 2,7 0 ,0 1 ,2 48, 1 4 ,6 0 ,0 0,4 0 ,0 0,0 0,0 0 ,4 3 , 1 0 , 4 32,60 0,0 0 ,3 a,o 1 , 1 0 ,0 0 ,3 0 ,6 2 ,8 0 ,3 0 ,6 0,0 22,7 0,0 0 ,8 0,0 3 , 1 0 ,6 0 ,3 49,0 3 ,3 0 .8 0,0 0,0 0,0 0 ,0 0 ,3 2,2 0 ,0

35, 1 7. 0 ,4 0 ,0 0 ,0 0,0 0,0 1 ,3 0 ,4 2,5 1 ,7 0 ,0 0,0 25,3 0,0 2,1 0 ,0 2 , 1 0 ,0 0 ,4 40 ,9 6,8 o .a 0,0 0,0 0 ,0 0 ,0 1 ,3 2 , 1 0 ,0 35,90 o.a 0,0 0 ,0 0 ,7 0,0 0,7 0,0 2,1 0 ,0 0 ,0 0,0 23 ,5 0,0 0,0 0,0 2,8 o .a 0 ,7 57,2 4 , 1 0 ,0 0 ,7 0 ,0 0 ,0 o .a 0,0 0,0 0 ,0

36,60 o.a 0,3 0 ,0 4 ,5 0 ,0 o.a a .a 1 4 ,2 1 ,9 0 ,0 0 ,3 1 7 ,4 0,0 1 ,3 o .a 1 ,9 a.a 1 ,6 29,4 3 ,2 a ,3 0 ,7 0 ,0 0,0 0,0 0 ,7 2 ,6 a.a 38,00 o.a 0,6 a .a 0,3 0 ,0 0 ,6 a .a 1 ,2 0,3 0,3 0,3 1 7,0 0,0 a,6 0,0 3,6 a .a 0 ,6 53 ,a 6 , 1 0 ,0 0,3 0,6 0 ,0 0 ,0 0,3 1 ,2 0 ,3 39,20 0 ,0 0,9 0 ,0 0 ,9 0,0 a,o a ,o 3 ,5 0 ,9 0 ,0 o.a 23 ,3 0,0 0,0 0 ,0 3 ,5 a .o o .a 51 ,7 4,3 0 ,0 0,9 0,0 o .a o .a a,o 2,6 0,0 4a,55 0,0 0 ,5 0 ,0 0 ,5 0 ,0 1 , 1 0 ,0 2,6 0 ,5 0 ,0 0 ,0 1 6,2 0,0 0 ,0 0 ,0 1 ,6 a .a 1 , 1 50,3 6,8 0 ,5 0 ,0 0 ,5 0 ,0 0 ,0 0 ,0 2,6 0,0 41 ,53 a,3 o .a a.a a .8 a.a 0,3 o.a 1 ,3 1 ,3 a .3 a.a 20 ,3 a.a a ,8 a.a 3,4 0,5 1 ,0 44,5 6,3 a .3 a .3 0 , 8 a . a a .a 0 ,0 1 ,6 0,8 43,aa a ,4 o.a o .a a.a 0 ,0 1 ,3 0 ,4 3 , 1 1 ,8 0 ,0 0 ,0 1 7,2 0,0 0,4 0 ,0 3 . 1 0 ,4 2,2 51 ,5 3 ,5 0 ,0 0 ,0 1 ,3 0 ,0 0 ,0 0,9 0,9 0 ,9 44,00 0,0 0 ,4 0 ,0 0 ,4 0 ,0 0,0 0,0 3,4 0 ,9 0,4 0,0 20 , 1 0,0 2,1 0 ,0 3 ,4 0 ,0 0 ,9 40 ,6 3 ,0 0 ,4 0 ,4 1 ,3 0,0 0,0 0 ,0 2 ,6 0 ,0 45,00 0,0 0 ,0 0 ,0 2,3 0 ,0 0,0 0,0 5,5 0 ,5 0 ,0 0,0 22 ,4 0,0 2,7 0,0 3,2 0,5 0,5 46,6 4,6 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 ,4 0 ,0 46,90 0,0 1 ,5 0 ,0 0,9 0 ,3 1 ,2 0 ,3 2,7 1 ,2 0,0 0,0 27,7 0,0 2,4 0,0 3 , 1 0,0 0 ,6 44,8 4,0 0,0 0,3 a ,9 0 ,0 0 ,0 0,0 1 ,2 0,0 49,25 0 ,0 0,4 0,0 1 ,3 0,0 0,0 0 ,4 5,1 0 ,4 0 ,0 0,0 22 ,8 0,0 a ,4 0 ,0 5,9 0 ,0 0 ,4 43 ,5 5 , 1 0 ,0 a ,4 0,4 0,0 o .a 0,0 0,4 0 ,0 50 ,30 0,0 0,0 0 ,0 1 ,3 o.a 0 ,0 0 , 0 1 ,3 1 ,3 o.a 0,0 21 ,8 0,0 1 ,3 0,0 1 ,3 0,0 1 ,3 44 ,9 2,6 0,0 a.o 1 ,3 o.a a ,o a,o 5,1 0 ,0 51 ,30 0,0 0,7 0,0 1 , 1 o .a 0 ,7 0 ,0 2,9 0 ,4 0 ,0 0,0 1 8,6 a,o 0 ,7 0 ,0 5,0 0 ,4 0 ,7 37,9 1 1 ,4 0 ,0 0,7 0,0 0 ,0 0 , 0 0 ,0 2 , 1 0 ,0 52,40 0,3 0,0 0,0 5,2 0 ,0 1 ,0 0 , 0 9,4 1 ,3 1 ,3 0,0 1 2,3 0,0 1 ,0 0 ,0 2,9 0,3 0,3 41 ,6 7,5 0 ,7 0,3 0 ,0 0,0 0 ,0 0,0 2,0 0,0 53 ,70 0 ,0 o.a 0,0 2,2 0,0 0 ,8 0 ,0 5,9 0 ,8 1 ,4 0,0 1 8,9 0,0 0 ,6 0 ,0 4,5 0 ,0 1 ,4 42,6 4,5 0,0 0,6 0,0 0,0 0 ,0 0,6 0 ,8 0 ,3 54,70 0,3 0 ,0 0 ,0 2 ,9 0,3 0,3 0,0 1 6 ,6 0,0 0 ,6 0 ,0 1 3 ,7 0,0 0,9 0,0 2,3 0,3 0 ,6 44 ,5 0 ,0 0 ,0 0 ,6 0 ,3 0 ,0 0 ,0 0,3 2,3 0,0 56,00 0,5 0 ,0 0 ,0 5 ,7 0 ,0 0,0 0 ,0 9,8 2 , 1 1 ,6 0,0 1 7 ,0 0,0 1 ,O 0 ,0 4,6 0,0 0 ,0 37, 1 7 ,2 0 ,0 0 ,0 0 ,0 0 ,0 a ,o 0 ,0 0 ,0 0 ,5 56,60 0,0 0,0 o.a 4,0 o.a a,6 o .a 1 5,a 1 ,7 a .a a .a 1 1 ,a a.a o .a a ,o 2,9 o .a a ,9 44, 1 4,9 a .a o.a a .a a .a a .a a,6 3 ,2 a .a 57,20 o.a 0,0 o.a 5,6 0,0 0 ,0 0 , 0 1 4,3 0,8 0 ,0 a ,o 1 3 ,9 o.a 0,4 0,0 3,2 0 ,4 1 ,6 40 ,5 6,4 0,0 0,0 0,4 o.a 0 ,0 0,4 0,0 0 ,0 58, 1 0 0,0 a,3 0 ,0 4 ,3 0,0 0 ,7 0 ,0 1 1 ,3 0,7 0,3 a.o 1 5,0 a.a 0 ,0 0 ,0 4,0 0 ,7 0 ,7 41 ,5 5,7 0 ,0 0,0 1 ,0 0 ,0 a .o 0 ,7 1 ,7 0 ,3 59,40 0 ,3 0 ,3 0 , 0 6,3 0 ,0 0 ,3 0 , 3 1 0 ,5 1 ,4 0 ,3 0 ,0 1 4,2 0,3 0 ,6 0 ,0 2 ,0 0 ,0 0 ,9 38,9 4,3 0 ,0 0 ,3 0 ,0 0 ,0 0 ,0 0 ,3 1 ,7 0 ,0 60 ,60 0,2 0 ,2 0 ,0 6,2 0,0 0,4 0,0 1 1 ,5 1 , 1 0 ,2 0 ,0 1 6,9 0,0 1 ,3 0,0 3 ,7 0 ,4 1 ,3 37,2 4,4 0 ,4 0 ,2 0 ,4 0 ,0 0 ,0 0 ,4 3 , 1 0 , 2 61 ,87 0,5 0,0 0,0 3,7 0 ,0 0 ,5 0 ,0 1 1 ,5 2 , 1 1 ,3 0 ,0 1 8,0 0,0 0,0 0,0 3 , 1 0 , 0 0 , 8 37,6 4,7 0,5 0,5 0,0 o .a 0 ,0 0,0 1 ,6 0,0 63,30 0,0 0,4 0 ,0 4 ,6 0 ,0 0 .4 0 ,4 1 5,9 0,0 0 ,0 0 ,0 1 4,2 0,0 0 ,8 0,0 2,9 0,0 0 ,4 39, 8 5,4 0 ,4 0,4 0,0 0 ,0 0 ,0 0,0 5,0 0 ,0 64,60 0 ,5 0 ,5 0 ,0 7,3 0 ,5 0 ,0 0 ,0 1 4 ,0 0 ,0 0 ,0 0,0 1 3 ,0 0,0 1 ,0 0,0 2,6 0 ,0 1 ,6 44,6 3 , 1 0 ,0 0 ,5 0 ,5 0,0 0 ,0 0 ,0 1 ,0 0,0 66,00 0,3 0,0 0 , 0 6,6 0,0 1 , 1 0 ,0 1 4 ,3 1 , 1 0 ,0 0.0 1 6 ,0 0,0 0 ,0 0,0 4.0 0,0 0 ,9 34,6 4,9 0,0 0,3 0.3 0,0 0 ,0 0 ,3 2 ,0 0 ,0 66,40 0,0 0,3 0,0 5,6 0 ,0 0 ,5 0 ,3 1 6,3 1 ,3 0 ,5 0 .0 1 5 ,0 0,0 0,5 0,0 1 , 1 0 ,0 0 ,3 38,0 4,8 0,0 0,0 0,0 0 ,0 0 ,0 0,3 0,5 0 ,0 66,92 0,0 0,0 0,0 6,0 0 ,0 2,2 0 ,0 9,8 1 , 1 1 ,6 0 .0 1 6,9 0,0 1 , 1 0,0 2,2 0 ,0 0 ,6 36, 1 4,9 0,6 0,0 0 . 0 0 ,0 0 ,0 0,0 2,7 0 ,0 68,00 0,8 0 ,3 0 ,3 6 ,7 0 ,0 0,3 0,3 1 5, 1 0 ,6 0 ,0 0 ,0 1 5 ,4 0,0 1 , 1 0,0 1 , 1 0,3 0 ,6 35,3 4,8 0,0 0,0 0,0 0,0 0 ,0 0,0 2.0 0 ,0 69,50 0,0 1 ,4 0 ,0 2 ,8 0 ,0 0 ,9 0 ,0 1 8,4 0,5 0,0 0 ,0 1 2,9 0,0 0 ,9 0,0 4,6 0,0 0 , 5 43 ,3 1 .8 0 , 5 0 , 0 0 ,0 0 ,0 o .a 0 ,0 1 ,4 0 ,0 70,40 0 ,0 0,3 0,0 6,3 0 ,0 0 ,3 0 ,3 1 3 ,0 1 ,7 0 ,0 o.a 1 4 ,3 0,0 1 ,4 0 ,0 3,6 0 ,0 0 ,3 41 ,9 3 ,6 0 ,3 0 ,6 0,3 0,0 0 ,0 0,0 1 , 1 0,3 72,60 0,0 0,0 0 ,0 7 ,0 0 ,3 0 ,9 0 ,0 1 5,8 1 ,2 0 ,0 0 ,0 1 5,5 0,0 1 ,5 0,0 2,1 0,0 0 ,0 38,6 5,0 0,0 0 ,0 0 ,0 0 ,0 0 ,3 0 ,3 1 ,5 0 ,0 73,30 0,0 0,0 0 ,0 4 ,5 o.a 1 ,4 0 ,9 1 4,4 1 ,8 2,7 0,0 1 1 ,7 0,0 2,2 0,0 0,9 1 ,8 0 ,5 29,2 1 1 ,2 0 ,0 0 ,0 0 ,0 0,0 0 ,0 1 ,4 2,7 0 ,0 74,00 0,0 0,0 0 ,0 2 ,8 0 ,0 0 ,6 0 ,0 20,5 1 ,4 0 ,0 0,0 1 8,3 0,0 0 ,3 0,0 1 ,4 0 ,0 0 ,8 36,0 6,4 0,0 0,3 a.o a.o 0,0 1 , 1 1 ,7 a,o 77,50 0,0 0 ,0 0 ,0 0,3 0 ,0 0 ,0 0 ,0 1 7,6 0 ,0 1 ,3 0 ,0 1 2,2 0,0 1 ,3 0 ,0 1 ,9 0,0 0 ,0 45,5 0,0 0 ,0 5 , 1 0 ,0 o .a 0 ,0 a ,3 0 ,6 0 ,0 84 , 1 5 0,0 0,0 0,0 1 , 1 0 ,0 0,0 0,3 1 9,5 0,3 5,5 a ,o 1 3 ,2 0,0 0,5 0,0 1 , 1 0,0 0 ,5 40 ,9 4,5 0,0 0,0 0,0 0,0 0 ,0 0 ,0 1 , 1 0 ,3 84,45 0,0 0 ,0 o .a 0,6 a .o 0,8 o .b 1 4 ,4 2,5 4,2 a ,o 1 6,9 0,0 0 ,3 a .a 2,5 0,0 0,3 41 ,a 4,4 a.o o.a o.a 0 ,0 0 ,0 a .a a .a o .a 84,88 0 ,0 0,5 a .o 1 ,9 0,3 a,3 0,0 1 5,8 3,5 5,9 0 ,0 1 2 ,0 0,3 1 , 1 0 ,0 1 , 1 0 ,0 0 ,3 38,5 7,8 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0,3 1 , 1 0 ,0 85,85 a.o 0 ,0 a ,o 1 , 1 0 ,0 0,6 0,0 20,2 0,8 1 ,7 o .a 1 0 , 5 0 , 0 0 ,6 o.a a,8 0 ,0 0 ,6 3 1 ,2 1 4 ,6 a ,o 0 ,0 0 ,0 0.0 0 ,0 0,0 1 , 1 0 ,0 86,20 0,0 0 ,0 0 ,0 1 ,2 0 ,0 0 ,0 0 ,0 1 6,5 1 ,5 2,9 0 ,0 1 9,4 0,0 o .a o .a 0 ,9 0,0 0 ,0 4 1 ,7 2,6 0 ,0 0 ,6 0 , 0 0 ,0 0 ,0 0 ,0 0 ,3 0 ,0 86,57 0,0 0,0 0 ,3 1 ,3 0 ,0 1 ,7 0 ,0 1 6,8 5,0 0 ,0 0 ,0 8,7 0,0 1 ,7 0 ,0 2,4 0,7 o.a 42 .3 4,0 0,0 1 ,0 a .o 0 ,0 o .a 0,3 0 ,0 o .a 86,85 0,0 0,3 0,0 0,3 0,0 0,0 a .o 22,6 1 ,8 0 ,9 a .a 1 2,5 0,0 0 ,6 0 ,0 0,6 0,0 a ,o 43 ,0 4 ,2 0 ,0 0 ,0 0 ,0 o.a 0 ,0 a .o 0 ,9 o.a 87,08 0,0 0 ,0 0 ,6 1 ,6 0 ,0 1 ,0 0 ,0 1 8,7 0 ,0 5 , 1 0 ,3 1 3 ,3 0,0 1 ,3 0 ,0 1 ,3 0 ,0 1 ,0 34,2 5,4 0,0 0,0 0,0 0 ,0 0 ,0 0 ,0 1 ,9 0 ,0 87,55 0 ,0 0,0 0,3 0 ,3 0 .0 0 ,6 0 ,0 23,5 0 ,6 6,5 0 ,0 1 0 ,6 0 ,0 0 ,9 0 ,0 1 ,8 0.0 0 ,0 38,8 2,4 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 1 ,2 0 , 0 88,40 0,0 0,3 0 ,0 2 ,2 0 ,0 a.o 0 .0 1 5,8 3,0 3,3 o .a 1 3 . 9 0 , 0 1 ,0 0,3 1 ,9 0 ,0 0 ,0 40 , 1 6,3 0 ,0 a .o 0 , 0 a . o o .a a .3 a ,6 a .o 88,60 a ,o 0,7 0,0 1 ,8 0,0 0,4 0,0 1 7 ,9 a,7 3 ,3 0 ,0 1 4 ,6 a, a a .4 a.a a,7 a,7 0 ,0 33,2 9 , 1 0 ,0 a ,o a,4 a .a a .a a ,4 2,6 a.o 88,70 a.a 0,3 a,3 4,2 0 ,0 a.a o .a 23,4 6,3 a .o a .o 8 , 1 o .a 2 , 1 a ,3 a,3 a.a o .a 24,a 3,9 a.a a .a a,6 0 ,0 0 ,0 a .a o .a a .o

NORSK GEOLOGISK TIDSSKRIFT 75 (1995) Quaternary of the Norwegian Channel 75

0 , 0 0 ,0 0,0 0 ,0

4,0 1 ,0 4,0 2.0

1 ,8 0,0 0 ,0 0 ,0

1 ,2 0 ,0

1 ,0 0,0

3,9 0,0

0 ,5 0 ,0

0 ,0 0 ,4

0 ,5 0 ,5

1 ,9 0 ,0

0 ,4 0 ,0

3 ,3 0 ,0

0 ,3 0 ,0

1 ,3 0 ,0

0 ,4 0 ,0

0 ,8 0,0 0 ,0 0,0

2 ,5 0,0

1 ,4 0 ,0

2,6 0 ,7 0,6 0,0

1 ,7 0,0

1 ,6 0 ,0

2 , 1 0 ,0

1 ,3 0 ,4

0 ,9 1 ,7

0,0 0 ,9

0 ,6 0 ,0

0 ,0 1 ,3

7,7 1 ,3

0 ,4 0 ,0

1 ,0 0 ,0

1 ,4 0 ,6

2,9 0 ,0

3,6 0,0

1 ,4 0,9

1 ,2 0 ,0

1 ,0 0,7

1 ,4 0,3

2 ,9 . 0,0

1 ,0 0 ,0

2,9 0 ,0

2,6 0 ,0

0 , 3 0 ,3

4,3 0 ,0

0 ,6 0,0 3 ,6 0,0

3,2 0,0

0 ,3 0,6

2 ,9 0,0

1 ,4 0 ,5

0 ,6 0,3 1 ,6 0,0

0 ,5 0,0

1 ,4 0 ,3 0 , 5 0,0

1 ,9 0,3

0 ,0 0,0

0 ,7 0,0

3 ,6 0,0

1 ,6 0,0

2,4 0,0

0 ,6 0,6

3 ,3 0,0

5,1 0 ,0

l � .!!l c o Gi :::;;

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0 ,0 0 ,0 O.D 0,0 0 ,0 3 ,0 0 ,0 0,0 0,0 0,0 1 ,O 0,0 0,3 1 ,O 0 ,0 0,0 5,0 0,0 0,0

o� o p o p o� op 3� op op op Dl 1p o p op op o p o p o� op op 3 ,0 0 ,0 0 ,0 0,0 0 ,0 3 ,0 9,0 0,0 0,0 0,0 0,0 0,0 0 ,3 0 ,0 0,0 8,0 0,0 0 ,0 0,0 1 ,O 0 .2 0 ,0 0,0 0 ,0 2,0 1 2,0 0,0 0,0 0,0 0,0 0,0 0,4 0 ,0 0 ,0 7,0 0,0 0,0 0,0

0 ,3 0 ,0 0,0 0 ,0 0,0 0 ,0 1 8, 1 1 ,8 0,0 0,0 0 ,0 0,0 1 ,2 0,0 0 ,0 1 2.7 0 ,0 0 ,0 0,0 Dl op o p o� op o� 1 �7 �7 o p o� o� o p op op o p �3 op op o p 0 , 0 0 ,0 0,0 0 , 0 0 ,0 0 , 0 1 , 2 0 ,0 1 , 2 0,0 0,0 0,0 0,0 0 , 0 0 ,0 2,4 0,0 0 ,0 0,0

0,0 0,0 0,0 0,0 0 ,0 0 ,0 1 7,0 0 ,0 0 ,0 0,0 0 ,0 0,0 0,3 0,0 0,0 2,0 0,0 0 ,0 0,0

0 , 0 0,0 0,0 0,0 0,0 0 ,0 0 ,0 0 ,0 0,0 0,0 0,0 0,0 0,0 0,0 2,6 1 ,3 0,0 0 ,0 0 ,0

1 ,O 1 ,O 0 ,0 0,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0,0 0,0 0,0 0 ,0 0 ,0 0,0 0,0 1 ,O 0,0

3 � 0 .4 o p o� o p 0.4 o � o � op o p op o p op 0.4 o • �8 o• o• op 1 , 1 0 ,0 0 ,0 0,0 0,0 1 , 1 1 ' 1 0 ,0 0,0 0,0 0,0 0,0 0,0 0 ,0 0,0 0,0 0,5 0,0 0,0

1 ,O 0,0 0 ,5 0 ,0 0,0 1 .4 0 ,0 0 ,5 0,0 0,0 0,0 0,0 0,0 0 ,5 0,0 0,5 0.0 0,5 0,0

1 ,3 0,4 0,9 0,0 0 ,4 0 ,9 0 ,4 0 ,4 0,4 0,4 0 ,0 0,0 0 ,9 0,0 1 ,3 0,9 0,0 1 ,8 0 ,0

1 ,6 0,0 0,0 0,0 0,8 0,8 0 ,8 0 ,0 0,0 0,0 0 ,0 0,0 0 ,0 0 ,0 1 ,6 0,8 0,0 0 ,8 0,0

4 ,2 0,0 0 ,3 0,0 0,0 1 ,O 0 ,0 0,3 0 ,0 0,0 0,0 0,0 0,0 0,0 0,0 0,3 0,3 0 ,3 0,0

0 , 9 0 ,0 0,0 0 ,0 0,0 0 ,4 0 ,9 0 ,4 0,4 0,0 0 ,0 0,0 0,4 0,0 0,4 0,9 0 ,0 2,2 0,0

0 ,9 0,2 0,0 0 ,0 0 ,2 0,2 1 ,3 0,0 0,0 0,0 0,0 0,2 0,2 0,0 0 ,2 0,2 1 , 1 1 ,3 0 ,0

1 ,2 0,8 0,4 0,0 0 ,4 0,8 1 ,5 0 ,4 0,4 0,0 0 ,0 0,0 0 ,0 0,0 0,0 0,0 0 ,0 0 ,8 0,0

1 ,9 0 ,3 0 ,3 0,0 0,0 1 ' 1 1 ' 1 0 ,0 0 ,3 0,0 0,0 0,0 0,0 0 ,3 0 ,3 0,3 1 ' 1 1 ,4 0,0

1 ,7 0,4 0 ,0 0,0 0,0 1 ,3 0 ,8 0 ,4 0 ,4 0,0 0,8 0,0 0 ,0 0 ,0 0,4 0,0 0,0 2,5 0,0 0 , 0 0,0 0,0 0,0 0,0 0 ,0 0 ,0 2 , 1 0 ,0 0,0 0,7 0,0 0 ,0 0,0 0 ,7 0,7 0,7 0 ,0 0,0

3 ,6 0,0 1 ,3 0 ,0 0 ,0 2,3 1 ,3 0 ,7 0,0 0,3 0 ,0 0,0 0,0 0,3 0,0 1 ,3 1 ,3 0 ,7 0 ,0 1 � o � o � o � o p o � 1 .2 o � op o p Dl o p op o p o p 1 .2 op op op 0 ,9 0 ,0 0,0 0,0 0,9 0,0 1 ,7 0 ,0 0,0 0,0 0,0 0,0 0,0 0,0 0 ,0 0,9 0,0 0 ,0 0,0

2,1 0 ,0 0,5 0,0 0,0 1 ' 1 2,1 0 ,5 0,5 0,0 0,0 0,0 0,5 0 ,5 0,0 0,5 0 ,0 2,6 0 ,0

2,9 0,3 0,3 0,0 0,3 1 ,3 1 ,6 0,3 0,3 0,0 0 ,0 0,0 0 ,3 0 ,3 0,3 0,8 1 ,3 1 ,3 0,0

1 � o p 0 .4 o� op o� o � o � op o p 0 .4 o p o p o p o p o p o� 0 .4 op 3,4 0 ,4 0,4 0,0 0,0 2,1 1 ,3 0 ,4 1 ,7 0,0 0 ,0 0,0 0 ,0 0,0 0,0 0,4 1 ,3 0 ,9 0,0

1 ,8 0 ,0 0,0 0,0 0 ,0 0 ,5 0 ,9 0 ,5 0 ,0 0,0 0,0 0,0 0,0 0 ,0 0 ,5 0,0 0,5 0,5 0 ,0

0 ,3 0 ,3 0 ,0 0 ,0 0.3 0,0 2 , 1 0 ,3 0 ,0 0,0 0,3 O.D 0,0 0 ,0 0,0 0,9 0,9 0,0 0,0

2 , 1 1 ,3 0,0 0,0 0,0 0,4 1 ,3 0,0 0,8 0,0 0,0 0,4 0,0 0,0 0,0 0,4 0 ,0 1 ,3 0 ,0

0 ,0 0,0 0,0 0,0 0,0 1 ,3 2 ,5 1 ,3 0,0 0,0 0 ,0 0,0 0,0 0 ,0 0 ,0 0,0 0 ,0 2 ,6 0,0

2,1 1 ,8 0,0 0,0 0 ,0 2,9 0 ,4· 0 ,0 0 ,4 0,0 0,0 0,7 0,0 0 ,0 0,0 1 , 1 0 ,0 0 ,0 0,0

2 ,9 0 ,7 o,o o ,o o,o o ,o 1 ,6 1 ,o o ,o ·o,o o ,o o .o o,o o .o o ,o o .o 2.0 o ,3 o.a 2 .5 0 ,0 0,6 0 ,0 0,0 0 ,0 2 ,0 1 , 1 1 ,4 0,0 0,3 0 ,0 0,0 0 ,0 0,0 0,0 0,8 0,3 0,0

0,0 46,0

0,0 67,0

0,0 0 ,0 0 ,0 0 ,0

0,0 0 ,3

0 ,0 0,0

0,0 0,0

0,0 0 ,0

0,0 0,0

0 ,5 0 ,0

0,0 0,8

0 ,0 0 ,0

0,0 0 ,5

0,0 0 ,4

0,8 0,0

0,0 0 ,0

0,0 0 ,0

0 ,2 0 ,7

0 ,0 0,4

0,0 0 ,8

0,0 0 ,0 0,0 0 ,0

0,0 0 ,3

0,0 0,6

0,0 0,0

0,0 0 ,0

0,0 0 ,3

0,0 1 ,3

0,0 0,0

0,0 0,9

0,0 0 ,0

0,0 0 ,8

0,0 0,0

0,0 0 ,0

0,0 0 ,0

0 ,3 0 ,0

1 .2 o p o � o� o� o � 1� o � op Dl o� o p op D l o p �9 1 � OM o p o p o� 1 ,O 0 ,5 0 ,0 0 ,0 0 ,0 2 , 1 2,6 0 ,0 0 ,0 0 ,5 0 ,0 0,0 0,0 0 ,0 0,0 0 ,5 1 ,O 0,5 0,0 0 ,0 0 ,0

2 ,0 0,3 0 ,0 0 ,0 0,0 0 ,6 0 ,9 0,6 0,0 0,0 0,0 0,0 0 ,0 0,0 0 ,6 2,3 2 ,0 0 ,3 0,0 0,0 0 ,0 1 .2 0 .4 o p op o p o � o � o p op o p o p o p o p op o p 1 .2 0 .4 0 .4 o p op op 0 , 0 0 ,0 0,3 0,0 0 ,0 1 ,O 1 ,7 0 ,0 0,0 0,3 0,3 0,0 0,0 0 ,0 0 ,3 2 ,0 0,7 0 ,3 0 ,0 0 ,0 0 ,3

0 , 0 0,3 0,0 0,0 0,0 1 , 1 1 , 1 0 ,0 0 ,6 0,0 1 ,4 0 ,0 0 ,3 0 ,6 0 ,0 1 , 1 1 ,7 0 ,3 0 ,0 0 ,3 0 ,0

1 , 1 0 ,0 0 ,0 0 ,0 0,0 0 ,7 1 ,5 0,2 0,0 0,2 0 ,2 0 ,0 0,0 0 ,0 0 ,2 0,6 1 , 1 0 ,0 0,0 0,0 0,2

2,1 0 ,0 0 ,5 0 ,0 0,0 1 ,3 1 ,O 0,0 1 ,O 0,0 0,0 0,3 0,3 0,3 0,0 0 ,5 1 ,O 0 ,8 0,0 0,0 0,0

1 l o p o p op op o � 1 � 0.4 op o p op o p op o• o p �4 0.4 op o p op op 1 ,6 0 ,0 0 ,0 0 ,0 0 ,5 0 ,0 0 ,0 0 ,0 1 .6 0,0 0,5 0,0 0,0 0 ,0 0 ,0 1 ,O 0,5 0,5 0,0 0 ,0 0 ,0

1 , 1 0 ,3 0 ,0 0 ,0 0,0 2,3 1 ,7 0,0 0,3 0,3 0,0 0,6 0,0 0 ,6 0 ,3 0,6 1 , 1 0 ,0 0,0 0 ,0 0 ,0

1 ,6 0,3 0 ,0 0,0 0,0 1 ,6 0 ,8 1 ,3 0,0 0,0 0,8 0,0 0,0 0 ,0 0,0 1 ,6 1 ,3 0 ,0 0 ,0 0 ,3 0 ,0 5 ,5 0,0 0 ,0 0,0 0 ,0 0 ,6 1 , 1 1 , 1 0,0 0,6 0,0 D.D 0,0 0 ,0 0 ,0 0,0 0,6 0 ,6 0,0 0 ,0 0 ,0

3 ,4 0,0 0 ,0 0 ,0 0 ,3 0 ,6 1 ,7 0 ,6 0,0 0,0 0 ,3 0,0 0,0 0 ,0 0 ,0 1 ,4 1 ,4 0 ,6 0 ,0 0 ,0 0 ,6

o� op op op op o � 1 .4 DM op op o� op op op o� op OM o� op o p o p 1 ,7 0 , 3 0 , 0 0 , 0 0 ,0 0 , 3 0 , 8 0 , 0 0,3 0 , 3 0 , 0 0 , 0 0,3 0 , 0 0 , 3 1 ,4 0 ,6 1 ,4 0 ,0 0 , 0 0,0

3 , 5 0,0 0 ,0 0 ,0 0 ,0 0,6 0 ,3 0 ,0 0 ,0 0,0 0,0 0,0 0,0 0 ,0 0 ,0 0,3 1 ,5 0 ,3 0 ,0 0 ,0 0 ,0 2,2 0,0 0 ,5 0,0 0 ,0 0 ,5 0 ,9 0,0 0 ,0 0,5 0,5 0 ,0 0,0 0,0 0 ,0 1 ,4 1 ,4 1 ,4 0,0 0 ,0 0 ,0

0 ,8 0,0 0,0 0 ,0 0 ,0 1 ' 1 1 ,7 0 ,6 0,0 0,0 0,0 0,0 0 ,3 0 ,0 0 ,0 1 ,7 1 ,4 0 ,0 0,0 0 ,0 0 ,3 2,2 0 ,0 0,0 0,0 0,0 1 ,3 0 ,6 0 ,0 0 ,0 0,0 0,0 0 ,0 0 ,6 0 ,3 0 ,0 1 ,O 2,2 0,0 0 ,0 0,0 0 ,0

1 ,9 0,8 0 ,0 0 ,0 0,0 1 ,6 0 ,0 0 ,5 0 ,0 0,3 0,0 0,0 0,0 0 , 0 0 ,5 2,4 1 ,6 1 , 1 0 ,0 0,0 0 ,0

3 ,9 0 ,0 0,3 0 ,0 0 ,0 1 ,7 0 ,8 0,0 0,0 0,0 0,0 0,0 0 ,0 0,0 0,3 1 ' 1 0,8 0,8 0 ,0 0,0 0,0 3 ,2 0 ,0 0,0 0,0 0,0 1 ,3 0 ,5 0 ,0 0,0 0,3 0,0 0,0 0 ,0 0 ,0 0,3 2,4 0,5 0,3 0,0 0 ,0 0,0

3 ,3 0,0 0,6 0 ,0 0 ,0 2,2 1 ' 1 0 ,0 0 ,0 0,0 0,0 0,3 0,0 0,0 0,3 2.5 2,2 0 ,8 0,0 0 ,0 0 ,0 5,2 0,0 0 ,0 0 ,0 0 ,0 1 ,5 0 ,6 0 ,0 0,0 0,0 0 ,0 0,0 0 ,0 0,3 0,0 1 ,7 2,0 0,0 0,0 0,0 0 ,0

3 ,4 0 ,0 0,0 0,0 0 ,0 1 ,7 1 ,O 0,0 0 ,0 0,0 0,0 0,0 0,7 0 ,0 0,0 2,7 3,0 0,3 0,0 0 ,0 0 ,0

2 , 1 0 ,0 0 ,0 0 ,0 0 ,0 1 ,2 0 ,3 0 ,3 0,0 0,0 0,0 0,0 0,0 0 ,0 0,0 2, 1 1 ,8 0,3 0,0 0,0 0 .0

2 ,5 0 ,3 0 ,6 0 ,0 0 ,0 3,8 0 ,3 0,3 0,0 0,0 0 ,3 0,0 0 ,0 0 ,0 1 ,O 2,5 0 ,0 0 ,6 0,0 0,0 0 ,0

2 , 1 0 ,0 0 ,0 0,0 0,0 2.4 0 ,9 0 ,6 0 ,0 0,3 0,0 0,0 0,3 0 ,0 0,6 0,3 0,3 1 ,8 0 ,0 0,0 0 ,0

1 ,3 0,0 0 ,3 0,0 0,0 2,8 0 ,6 0 ,0 0,0 1 ,3 0,0 0,0 0 ,6 0 ,0 0 ,0 1 ,9 0,6 1 ,3 0,0 0,0 0,0

0 , 7 0 ,0 0,0 0 ,0 0,0 1 ' 1 0 ,7 0 ,4 0,0 0,0 0,0 0,0 0 ,0 0 ,0 0 ,4 1 ,5 0.7 1 ,5 0,0 0 ,0 0 ,0

2 ,7 0 ,0 0,3 0 ,0 0,0 6,0 1 ,5 0 ,6 0,3 0,0 0 ,0 0,0 0,0 0 ,0 0,3 2,7 3 ,3 0 ,3 0 ,0 0,3 0 ,0

-g "' "' g .E � CD E l "' o o z

Sl l "' o � E " z

74000 1 8,0

69000 1 5,0

7400 1 5,0 7000 21 ,O 5400 1 3 ,0

2200 1 2 ,0

200 1 0 ,0

7000 1 2,0

1 00 1 2,0

300 1 7 ,0

300 37,0

300 1 8 ,0

300 24 ,0

300 32,0

200 22,0

400 28,0

400 26,0

500 33,0

300 29,0

400 35,0

300 25,0 200 1 7 ,0

700 32,0

400 34,0

1 00 1 6,0

300 27,0

400 37,0

300 28,0

300 31 ,O 300 24,0

400 26,0

300 29,0

1 00 1 7,0

300 33,0

800 29,0

500 31 ,O 400 27,0 200 21 .o 500 23,0

300 25,0

400 32,0

600 39,0

800 38,0

700 35,0

300 23 .0

300 23,0

600 31 ,O

500 27,0

300 25,0

500 30 ,0

300 24 ,0 1 000 34,0

600 22,0

350 27,0

550 24,0 2000 1 9 ,0

5300 24,0 4800 22,0 4500 25,0

3900 25,0

6600 1 8 ,0

3800 22,0

4 1 00 21 ,0

2600 25,0

4 1 00 24,0

6900 25,0

2600 27,0

1 900 29,0

� c .. a: o o z

26800 97,0

5200 95,0

1 04 1 5,0 1 98 20 ,0

280 25,0

1 35 75,0

5 2,0

200 1 ,0

5

255

1 00

35

70

55

35

70

55

75

40

45

75 6 1 5

85

85

20

70

90

50

65

75

500

1 50

50

1 00

1 25

1 00

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35

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40

60

85 90

80 40

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60

"' o o .� E ·� "' !!l � � u o z

o o o o o o o o 4

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24

o o o o 8

o o o o

0,0

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0 ,0

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1 ,3

0,0

0,7

1 ,0

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0,0

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0,6

0,2

0,3

0,0

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0 ,6

76 H. P. Sejrup et al. NORSK GEOLOGISK TIDSSKRIFT 75 (I 995)

Table 4B. Percentage occ urrence s of a ll benthonic foraminifera and planktonic subpolar foraminiferal species in the samples st udied between 88.7 and 29.0 m in core 8903 .

.. .. 1ii 1ii

"' � (; ::> )( i c E 13 "' E

.!!l "' -� ::> ...: ...: Q • "i "' c .!!l "' "' 1ii E E E 't: c § .. � E "' g "O ::> E � il � � .. .. 1ii .. "' c il 'O ::> ::> c .!.1 ::> "' "' 1ii I

"' "' Sl ::> ::> "i 1ii 1ii .. � "(;j ::> il: ::> � c E c &i ::> .. :; o E c � � c 1ii c ei � -� � 'ijj as -� j5 ·c:

� -g ::> ::> � .a :; U) .5! "' "' ·a "O -� !!' 1ii il :;z t lii .c ! � .. i B ·c, c o .o "' æ .. )( )( ::> 1ii .!l! ei o � c 1ii c .. .. .. .. .Q 8. ;;; .o Cl) "' "' "' ::> .c a; o ::> E J!! E "' U) .. .. ;;; "' "' .!: .!: .!: .!: E E E E E E E E .!l! c .. c .5. ·c: .. .. :; :; :; :; "' "' lll ]! E .. c o .. .. .. .!!! c Cl) ::> ::> ::> ::> ::> ::> ::> ::> ::> c $ Cl) z:; o c c c c @ § "O :2 :2 "O "O "O "O 'O 'O � � 'O 'O 'O 'O � o ·c c !

E e :;; :;; :;; ·� -� � � -� ·u ·u ·u :.E :.E :.E :.E :.E :.E '[ ::> c 'åi il il il a. a. a. a. a. a. a. a. a. U) � E � � � � ::> ::> :; .!!l ... c( CD CD CD o o o o 6 6 6 w w w w w w w w w w u. :I: :I:

88,98 0 ,0 0 ,0 0 ,0 2 , 1 0 ,0 0 ,5 0 ,0 25,5 0 ,8 3 ,5 0,0 1 2,9 0,0 0,0 0,0 0,8 0 ,0 0 ,8 38, 1 4,8 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 1 ,3 0 ,0

89, 1 0 0 ,0 0 ,0 0 ,0 1 ,7 0 ,6 0,3 0 ,0 24, 1 0 ,3 2,8 0,3 1 6,6 0,0 0,8 0 ,0 1 ,4 0 ,0 0 ,3 30,2 6,1 0,0 0,0 0,0 0 ,0 0 ,0 0 ,0 0,6 0 ,3

89,50 0 ,0 0,0 0 ,0 1 ,8 0 ,0 1 ,5 0 ,3 25,4 0,0 5,6 0,0 9,4 0,0 0,0 0 ,0 1 ,2 o,o 0,6 37,5 2 , 1 0 ,0 0,3 0 ,0 0,0 0 ,0 0 ,0 2 , 1 0 ,0

90,22 0 ,0 0 ,0 0 ,0 1 ,9 0 ,0 1 ,4 0 ,8 1 6,5 0 ,0 6,2 0 ,0 1 1 ,6 0,0 0,3 0 ,0 0 ,3 0 ,0 0 ,0 36,2 5,4 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,3 0 ,8 0 ,0

90,65 0,0 0 ,0 0 ,0 1 ,8 0 ,9 0 ,9 0 ,0 1 6, 1 2 , 1 2 ,9 0,0 1 2,0 0,0 0,9 0,0 1 ,8 0,0 0 ,0 31 ,7 8,8 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 ,2 0 ,0

96,90 0 ,0 0 ,0 0 ,6 2,4 0 ,0 0 ,0 0 ,0 23 ,8 1 ,2 5 , 1 0,0 6,9 0,0 2,7 0,0 0 ,0 0 ,3 0 ,0 25,9 2,4 0 ,0 1 ,8 0 ,0 0 ,0 0 ,0 0 ,3 0 ,9 0,0

97, 1 6 0 ,0 0 ,0 0 ,0 1 .4 0 ,0 0,3 0 ,0 1 8,7 0 ,3 1 ,4 0,0 1 5,8 0,0 0,9 0,0 0,9 0 ,3 1 ,4 43 ,7 2,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,3 0 ,3 0 ,0

97,65 0 ,0 0 ,0 0 ,0 3 , 1 0 ,0 0 ,0 0 ,0 1 5,9 0,9 7,3 0,0 1 1 ,9 0,0 0,6 0 ,0 1 ,8 0 ,0 0 ,3 39, 1 2,8 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0,6 0 ,0

98,95 0 ,0 0 ,3 0 ,0 0,6 0 ,0 0 ,6 0 ,3 8.4 0 ,6 1 ,7 0,0 20,2 0,0 0,6 0 ,0 2,0 0 ,0 0 ,3 40 ,9 6,6 0 ,0 0 ,0 0 ,3 0 ,0 0 ,0 0 ,3 2 ,9 0 ,3

99,27 0 ,0 0 ,0 0 ,0 2,5 0 ,3 0,3 0 ,0 1 0 ,7 0 ,0 4,4 o.c 1 6,5 0,0 0,0 0,0 1 ,4 0 ,0 0 ,6 49,7 1 ,4 0 ,0 0,3 0 ,0 0 ,0 0 ,0 0 ,3 0,6 0 ,0

99,45 0 ,0 0 ,0 0 ,0 1 ,2 0 ,0 0,6 0 ,3 1 0 ,7 0 ,6 5,5 0,0 1 6,5 0 ,0 0,3 0,0 1 ,2 0 ,0 0,6 43 ,6 6,1 0,0 0,0 0 ,0 0 ,0 0 ,0 0 ,6 0,9 0 ,0

1 0 1 ,25 0,0 0 ,0 0 ,0 2,9 0 ,0 0 ,9 0 ,0 1 1 ,4 1 ,8 1 ,8 0,0 1 5,5 0,0 1 ,2 0 ,0 1 ,2 0 ,0 0 ,0 50,7 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0

1 0 1 ,85 0 ,0 1 ,0 0 ,0 1 ,3 0 ,0 0,0 0 ,3 9,3 0 ,7 3 ,7 0 ,0 1 9,3 0,3 0,3 0 ,0 0 ,7 0 ,0 0 ,0 45,0 4,0 0 ,0 0,0 0 ,3 0,0 0 ,0 0 ,0 2,3 0,0

1 04,05 0,0 0 ,0 0 ,0 2,4 0 ,0 1 ,3 0 ,3 1 8,4 0,0 5 , 1 0 ,0 1 3 ,9 0,0 0,8 0,0 1 ,3 0 ,0 0 ,5 35,2 2,9 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 ,6 0 ,0 1 04, 1 0 0 ,0 0,3 0 ,0 1 ,7 0 ,0 0 ,9 0 ,0 22,9 1 ,7 0,0 0,0 1 4 ,9 0,0 0,0 0,3 0,9 0,0 0 ,0 43 ,8 2,3 0,0 0,0 0 ,0 0,0 0 ,0 0 ,0 1 ,2 0 ,0

1 04,55 0,0 0 ,3 0 ,0 2 ,5 0 ,0 0,6 0,3 1 1 ,5 0 ,6 7,4 0,0 1 6,4 0,0 0,3 0,0 2,5 0 ,0 1 ,9 40 ,6 2,2 0 ,0 0,0 0 ,0 0,0 0 ,0 0,3 0,6 0 ,0

1 06,77 0 ,0 0 ,0 0 ,0 3 , 1 0 ,0 1 , 1 0 ,0 7,7 1 ,4 2,6 0,0 21 ,8 0,0 0 ,0 0 ,0 0 ,6 0 ,0 0 ,0 44,2 6,5 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0,0 0,6 0 ,0

1 07,60 0,0 0 ,0 0 ,0 0,0 0 ,0 1 , 1 0 ,3 1 9.4 0 ,6 2,0 0,0 1 2,0 0,0 2,0 0 ,3 0,3 0 ,0 0 ,3 33 , 1 5,7 .0 ,0 1 , 1 0 ,0 0,0 0 ,0 0,3 1 ,4 0 ,0

1 09, 1 0 0 ,0 0,0 0 ,0 0 ,9 0,0 3,5 0 ,3 2,3 0 ,9 1 ,4 0,6 22,4 0,0 o.a 0,0 4,0 0 ,0 2,0 41 ,7 4,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 2,9 0,0

1 09,25 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0,0 0 ,0 3,5 0 ,0 0 ,0 0,0 1 6 , 1 0,0 0,0 0,0 2 , 1 0 ,0 0 ,0 69,9 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,7 0 ,0

1 09,30 0,0 0,0 0,0 1 ,0 0,0 1 ,0 0 ,0 8,3 0 ,0 1 ,0 0,0 7,3 0,0 2 , 1 1 ,0 4,2 0 ,0 0 ,0 58,3 7,3 o.a 0 ,0 0 ,0 0,0 0 ,0 0 ,0 3 , 1 0 , 0

1 09 ,95 0 ,0 0 ,0 0 ,6 3,4 0,0 0 ,0 0 ,0 1 7 ,9 1 ,5 1 ,5 0,0 1 4,5 0,0 1 ,9 0 ,0 1 ,2 0 ,0 0 ,6 37,9 3 ,4 0 ,0 0 ,3 0 ,0 0 ,0 0 ,0 0 ,3 1 ,5 0 ,3

1 1 0 ,90 0,0 0 ,0 0 ,0 2,7 0 ,3 0,0 0 ,0 22,0 5,8 1 ,7 0,0 1 2,5 0 ,0 1 ,7 0,0 3 , 1 0,0 0,0 31 ,2 2,7 0 ,0 0,3 0,0 0,0 0 ,0 0 ,7 2,7 0 ,0 1 1 1 ,85 0 ,0 0 ,0 0 ,0 4,3 0 ,0 2,0 0 ,0 1 9,7 2,9 1 .4 0,0 1 0 ,0 0,0 1 , 1 0 ,0 2,3 0 ,0 0 ,3 32,8 8,3 0 ,0 0,3 0 ,0 0 ,0 0 ,0 o .a 0,3 0 ,3 1 1 2,50 0 ,0 0 ,6 0 ,3 3 , 1 0,6 0,3 0 ,0 1 3 .4 5,2 0 ,9 0,0 1 5,2 0,0 0,3 0 ,0 2 , 1 0 ,0 0 ,6 39,9 1 ,8 0 ,0 0 ,3 0 ,0 0 ,0 0 ,0 0,9 0,0 0 ,0 1 1 4,95 0 ,0 0,3 0 ,3 4 , 1 0 ,0 0,9 0 ,3 1 7,7 1 ,7 1 ,7 0,0 1 1 , 1 0,0 1 ,2 0,3 1 ,5 0,0 0,9 35,5 2,6 0,0 0,0 0,3 0 ,0 0 ,0 0 ,0 1 ,5 0 ,0 1 1 5,25 0 ,0 0 ,0 0,9 5,6 0 ,0 0 ,0 0 ,0 24 ,4 1 ,5 1 ,5 0 ,0 1 1 , 1 0,0 0 ,6 0 ,0 1 ,9 0 ,0 0 ,0 37,4 0 ,9 0 ,0 0 ,0 0 ,3 0 ,0 0 ,0 0 ,0 0 ,6 0 ,0 1 1 7,45 0,0 0 ,2 0,7 1 ,7 0 ,0 0 ,5 0 ,0 1 9,9 1 ,7 2 , 1 0,0 1 7,0 0,0 0,5 0,2 0,4 0 ,0 0,4 33,2 5,5 0,2 0,0 0,0 0 ,0 0 ,0 0 ,0 1 ,0 0 ,0 1 1 7,68 0,0 0 ,0 0 ,0 4,5 0 ,0 0,3 0 ,0 1 9,0 1 ,5 0 ,3 0 ,0 1 2,8 0,0 1 ,2 0 ,0 2 , 1 0 ,0 0 ,3 40 ,7 3,6 0,0 0,6 0,0 0 ,0 0 ,0 0,0 0 ,3 0 ,3 1 1 7 ,98 0 ,0 0,0 0,3 5,2 0,0 0,0 0 ,0 1 9,0 0 ,6 0,9 0,0 1 4 ,4 0,0 0 ,9 0 ,0 0 ,6 0 ,0 1 ,2 41 ,3 4,9 0 ,0 0 ,0 0 ,3 0 ,0 0 ,0 0,0 0 ,9 0 ,3 1 1 8 ,50 0 ,0 0,0 2,5 5,6 0,0 0 ,0 0 ,0 1 1 ,3 0,0 1 ,3 0,0 1 6,4 0,6 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 35,9 1 0 , 1 0 , 0 0,0 0,0 0,0 0 ,0 0 ,0 2,5 0 ,0 1 1 8,98 0 ,0 0,0 1 ,2 4,3 0,0 0 ,3 0 ,3 1 2 , 1 2,0 0,6 0 ,0 1 6,8 0,0 0 ,9 0 ,0 2,0 0 ,6 0 ,0 37,0 1 0 ,4 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 ,2 0 ,0 1 1 9,60 0 ,0 0,0 0 ,9 2,6 0,0 0,3 0 ,0 20.4 1 ,7 0 ,0 0 ,0 23 ,5 0,3 0 ,3 0 ,0 2,9 0,0 0 ,3 37,8 3,5 0,0 0,3 0,0 0 ,0 0 ,0 0,0 1 ,2 0 ,0 1 38,40 0,0 0 ,0 1 2,4 0 ,0 0 ,0 0 ,0 0 ,0 67,2 0 ,0 0 ,0 0 ,0 2,9 0,0 0 ,0 0 ,0 0,0 0,0 0,0 5 , 1 9,5 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 39,85 0,0 0 ,0 29,7 0 ,0 0 ,0 0 ,0 0 ,0 36,4 0 ,0 0 ,0 0 ,0 2,5 0,0 0,3 0 ,0 0 ,0 0 ,0 0 ,0 20,2 4,3 0,0 0,0 0,0 0,0 0 ,0 0 ,3 0 ,0 0 ,0 1 40 ,20 0,0 0,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 33,5 0 ,6 0 ,0 0 ,0 0 ,6 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 52,6 9 , 1 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 1 40 , 50 0 ,0 0,0 0 ,0 0 ,3 0,0 0,0 0 ,0 1 7,8 0 ,0 7,8 0,0 6,5 0,0 0 ,0 0 ,0 0,3 0 ,0 0 ,0 33,3 9,4 0 ,0 0,0 0,0 0 ,0 0 ,0 0 ,0 1 ,0 0 ,0 1 40 ,90 0,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 36, 1 0 ,0 3 ,7 0 ,0 1 , 1 0,0 0,0 0 ,0 1 , 1 0 ,0 0,8 28,2 1 8,2 0 ,0 0 ,3 0 ,0 0,0 0 ,0 0 ,0 0 ,5 0 ,0

1 57,55 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0,3 0 ,0 1 3 ,0 0 ,3 26,6 0,0 1 0 ,0 0,0 0 ,7 0 ,0 0,7 0 ,0 0 ,7 20 ,3 2,7 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0,0 0 ,0 0 ,0 1 58,60 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 34,0 1 ,5 27,2 0,0 9,3 0,0 0 ,6 0 ,0 0 ,0 0 ,0 0,3 21 ,0 3 ,4 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,3 0 ,0 158,92 0,0 0 ,0 0 ,0 0,0 0 ,0 0,3 0 ,0 25,2 0 ,6 1 6,7 0,0 2,8 0,0 0,0 0 ,0 0 ,0 0 ,0 0 ,3 35, 1 1 6,4 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 69,50 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 73 ,0 0 ,0 0 ,6 0 ,0 0 ,0 0,0 3 ,7 7,6 0,0 0,0 0,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 1 ,3 0 ,0 0 ,0 1 69,53 0,0 0 ,0 0 ,3 0,6 0 ,0 0,0 0 ,0 1 6,2 0 ,0 38,6 0,0 0 ,3 0,0 4,2 1 ,8 0 ,0 0 ,0 0 ,0 1 ,5 1 ,5 0 ,0 0 ,0 0 ,0 0,0 0 ,0 1 ,5 0 ,0 0,0 1 70 ,00 0 ,0 0,0 0,0 0 ,6 0 ,0 0 ,0 0 ,0 62,8 0 ,0 0 ,0 0 ,0 0 ,0 0,0 1 3 ,4 1 ,9 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,6 0,0 0 ,0 1 70,60 0,0 0,3 0 ,0 0,0 0 ,0 0,0 0 ,0 46,5 0 ,0 7,9 0,0 1 ,5 0,0 0 ,3 0 ,6 0 ,0 0 ,0 0 ,0 24 ,3 1 0 ,8 0 ,3 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 70 ,83 0 ,0 0,9 0,0 0 ,6 0 ,0 0 ,0 0 ,0 66,7 3 ,2 2,9 0.0 2,0 0,0 0 ,9 1 ,2 0,3 0 ,0 0 ,3 7,0 2,3 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,3 0,3 0,0 1 78,30 0,0 0,0 0 ,0 1 ,0 5,4 0 ,0 0 ,0 3 ,2 1 ,0 0 ,0 4,8 0 ,0 0,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 1 6 ,9 40,8 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0,0 0 ,0 1 78,56 0,0 0 ,0 0 ,0 0 ,0 2,9 0 ,0 0 ,0 29,3 0 ,3 0 ,0 0 ,3 5,4 0,0 0 ,0 0 ,0 0 ,0 0 ,6 0 ,0 1 ,9 0 ,6 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,6 0,0 1 ,3 1 78,75 0 ,0 0,0 0,0 0,9 5,5 0,0 0 ,0 42,2 4,9 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 .0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0,3 0,0 0 ,0 1 79,00 0,0 0 ,3 0 ,0 0 ,0 3 ,2 0,3 0 ,0 58 ,0 0,3 0 ,0 0 ,3 0 ,0 0,0 0,3 0 ,3 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 ,0 0 ,0 0 ,0 1 79,33 0 ,0 0 ,0 0 ,0 1 ,7 0,0 0,3 0 ,3 0 ,6 0 ,0 0 ,0 0 ,0 3 , 1 0,0 2,6 0,0 0,0 0,0 0,0 0 ,6 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,9 0,0 0 ,0 1 79,52 0,0 0,0 0,0 7 ,2 0 ,0 0,0 0,0 2,2 0 ,0 0 ,0 0 ,0 1 ,4 0,0 1 ,8 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,9 0 ,0 0 ,0 1 79,73 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 ,2 9,9 0 ,0 0 ,0 0 ,0 0,0 1 ,2 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,9 0,0 0 ,0 1 87,50 0 ,0 0,0 0,0 0,0 0 ,0 0 ,0 0 ,0 29 ,8 0,3 0,0 0,0 2,3 0,0 0,0 0 ,0 0 ,3 0,0 0 ,0 32, 1 28,7 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,3 0,0 1 88 ,53 0,0 0,0 0,0 0 ,0 1 ,8 1 ,5 0 ,0 23,9 1 ,5 1 ,8 0 ,0 9,5 0,0 0 ,6 0,0 2,2 0 ,0 0 ,0 22,4 1 9 ,6 0 ,0 4,9 0 ,3 0 ,0 0 ,0 0 ,3 0 ,0 0 ,0 1 88,99 0,0 0,0 0,0 2,0 0,0 0 ,0 0 ,0 6,0 2,0 2,0 0,0 8,0 0,0 1 4 ,0 0,0 0 ,0 0 ,0 0 ,0 30,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 2,0 0 ,0 1 89,00 0,0 0,0 0,0 0,0 0 ,0 0,0 0 ,0 60,1 0 ,6 0 ,0 0 ,0 21 ,5 0,0 0 ,6 0,6 1 ,9 0,0 0 ,0 5 , 1 3,2 0 ,0 0 ,6 0 ,0 0,0 0 ,0 0,0 0,0 0 ,0 1 98,73 0 ,5 0,0 0 ,0 0 ,0 0 ,0 0 ,9 0 ,0 1 ,8 0,0 0 ,0 0 ,0 5 , 1 0,0 0 ,0 0 ,0 3,7 0 ,0 1 ,8 65,9 2,3 0 ,0 0 ,9 4 ,2 0 ,0 0 ,0 0 ,5 4 ,6 0 ,0 1 99,20 0 ,0 0 ,0 0 ,0 ' 0 ,0 0 ,0 2,8 0 ,4 0 ,4 0,4 2,4 0 ,0 2,4 0,4 1 ,6 0 ,0 4,4 0 ,0 1 ,2 63,6 4,8 0,0 0 ,0 0 ,0 0 ,4 0 ,0 0,0 0,8 0 ,0 200,30 0,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 66,7 0 ,0 0 ,0 0 ,0 0 ,0 8,3 0 ,0 0 ,0 0,0 0 ,0 0 ,0 8,3 0 ,0 0 ,0 0,0 4,2 0,0 0 ,0 0 ,0 4 ,2 0 ,0 200,70 2,4 0,0 0 ,0 0,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 2,4 0 ,0 0,0 0,0 2,4 1 9 ,5 0,0 0,0 0,0 0,0 0,0 1 2,2 0,0 4,9 0 ,0 20 1 ,25 0,0 0,0 0 ,0 0 ,5 0 ,0 1 ,6 0 ,0 7,0 0 ,0 2,7 0 ,0 2,2 0,0 1 , 1 7,0 0,0 0 ,0 0 ,0 9,1 0 ,0 0 ,0 0 ,0 0 , 5 0 ,0 0 .0 0 , 5 1 , 1 0 ,0 20 1 ,97 0,0 0,0 0,0 0,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 4 ,2 0 ,0 0,0 0 ,0 0 ,0 20,8 0 ,0 0 ,0 0 ,0 0 ,0 4,2 0 ,0 0 ,0 0 ,0 0 ,0 207,00 0,0 0,0 0 ,0 0,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 3 ,9 0 ,0 0 ,0 0 ,0 3 ,9 1 1 ,2 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 3,9 0 ,0 3 ,9 0 ,0 209,30 0 ,0 0,0 0,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0,0 3 ,5 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 o.a 0,0 0 ,0 0 ,0 2,0 0 ,0 0 ,0 21 2,00 0,0 0,0 0,0 0,0 0 ,0 2,2 0 ,0 3 ,0 0 ,0 0 ,0 o .a 3 ,0 0,0 0 ,7 0,7 0,0 0 ,0 0 ,0 2,2 1 ,5 0 ,0 0,0 0,0 0,0 1 ,5 0,0 0 ,0 0 ,0 21 2,95 0,0 0,0 0,0 0,0 0 ,0 0,0 8,2 0,0 0 ,0 0 ,0 0,0 0,0 0,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 21 5,90 0,0 0,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0,0 0,0 0 ,0 0 ,0 0 ,0 0,0 1 ,6 2 1 9,00 o,o 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,5 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 2,6 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0 1 ,0 0 ,0 0 ,0

NORSK GEOLOGISK TIDSSKRIFT 75 (1 995)

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0 ,6 0,3 0 , 0 0 ,0 0 ,9 0 ,0 0,0 0 ,0

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2,8 0 ,0 0 ,0 0 ;0 0,0 0 ,0 0,0 0 ,0

0 ,0 1 ,O 3 , 1 0 ,0 0 ,0 0 ,0 0 ,0 0 ,0

1 ,2 0 ,0 2,8 0 ,0 0,3 0 ,0 0,0 2,2

0 ,0 0 ,0 2 ,7 0 ,0 0,3 0 ,0 0 ,0 2,0 0,6 0 ,3 4,8 0,6 0,0 0 ,0 0,0 0,9

0 ,3 0 ,0 1 ,2 0 ,0 0 ,3 0 ,0 0 ,0 2,4

0 ,9 0 ,0 4 , 1 0 ,0 1 ,2 0,0 0 ,0 3,2 0 , 0 0 ,3 3 ,4 0 ,0 0,3 0 ,0 0 ,0 0 ,6

1 ,2 0 ,7 5 ,0 0 ,0 0 ,2 0 ,0 0 ,0 1 ,4

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0 ,0 0 ,0 0 ,0 0 ,0 0,0 0 ,0 0,0 0 ,0

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0 ,0 0,3 0,0 0 ,3 1 ,8 0,9 0 ,3

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0 ,0 0,3 0 ,3 0 ,6 0,6 1 ,8 1 ,2 op op op o� 1 � 2;0 o� op op o p o � 1 ,7 1 � OJ op op op o� 1 2 OJ OJ

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o p op 1 ;0 1 .7 1 � 0.7 1 ;0

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�3 o� o� op 1 � 1 .7 op 0,3 0 ,0 0 ,0 0 ,0 0,9 1 ,5 0,0

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0 ,0 0,0 0 ,0 0,0 0,0 1 ,2 0 ,3

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Table 5. Benthonic foraminifera in sample 2 1 9.00 m.

Species

Nodosariidae Ehrenberg 1 839 Pullenia bul/oides ( d'Orbigny 1 826) Trifarina gemumica ( Cushman & Edwards 1 938) Turrilina a/satica Andreae 1 884 Cassidulina subglobosa Brady 188 1 Ceratobulimina contraria ( Reuss 185 1 ) Gyroidina so/danii girardana (Reuss 1 8 51) ls/andiella injlata ( Gudina 1 966) Cibicides pseudoungerianus ( Cushman 1922) Buliminel/a parvula Brotzen 1948 Quinque/ocu/ina seminulum ( Linne 1 758) Lenticulina gibba ( d'Orbigny 1 839) Textularia bocki Høg)und 1 947 G/obulina lande si ( Hanna & Hanna 1 924) Buccella frigida ( Cushman 1 922) Rosalina vi/ardeboana d'Orbigny 1839 Ca/carina sp. d'Orbigny 1 826 Bolivina variabilis ( Williamson) Heron-Allen & Earland 1 922 Polymorphinidae d'Orbigny 1 839 Me/onis barleeanus ( Williamson 1 858) Pyrgo williamsoni ( Silvestri 1 923) Dentalina sp. d'Orbigny 1 826 Guttulina sp. d'Orbigny 1 826 Fissurina fasciata ( Egger 1857)

Sum

6 species < l% each of total population No. benthonic specimens/ 1 00 g sediment: ? No. planktonic specimens/100 g sediment: O

Tab/e 6. Benthonic foraminifera in sample 209.30 m.

Species

Turrilina alsatica Andreae 1 884 Melonis barleeanus ( Williamson 1 858) Alabamina sp. Toulmin 1 94 1 lslandiella injlata ( Gudina 1 966) Quinqueloculina seminulum ( Linne 1758) Cassidulina subglobosa Brady 1 8 8 1 Pul/enia bul/oides ( d'Orbigny 1846) Trifarina germanica ( Cushman & Edwards 1 938) Bolivina pseudopunctata Høg)und 1947 Cibicides /obatulus ( Walker & Jacob 1798) Gyroidina soldanii girardana (Reuss 1 8 5 1 ) Ceratobulimina contraria ( Reuss 1 8 5 1 ) Nodosariidae Ehrenberg 1839 Fissurina sp. Reuss 1 850 Guttulina sp. d'Orbigny Bulimina elongata d'Orbigny Globulina sp. Thalman

Sum

9 species < 1% each of total population No. benthonic specimens/100 g sediment: 300 No. planktonic specimens/100 g sediment: O

Percentage

1 5.90 1 2.31 1 0.26

7.69 5.13 3.59 3.08 3.08 2.56 2.56 2.05 2.05 2.05 2.05 2.05 1 .54 1.54 1 .54 1 .54 1 .03 1 .03 1 .03 1 .03 1.03

87.21

Percentage

1 4.50 13.50 1 0.00

7.00 6.50 6.00 5.50 5.00 3.50 3.50 3.50 3.00 3.00 2.00 2.00 1.50 1 .50

91.50

The interval188-180m.- Three samples from this interval were analysed. The fm;aminiferal fauna is dominated by Elphidium excavatum and Buliminia marginata. Cassidu/ina reniforme and Nonion labradoricum are frequent accessory species. This assemblage indicates arctic marine conditions (Nagy 1965). However, some infl.uence of warmer (Atlantic) water is indicated by the occurrence of Bulimina marginata. One of the samples is relatively


Table 7. Benthonic foraminifera in sample 1 78.56 m.

Species

Trifarina angulosa ( Williamson 1 858) Bulimina marginata d'Orbigny 1 826 Melonis barleeanus ( Williamson 1 858) Cassidulina reniforme Nørvang 1 945 Uvigerina mediterranea ( Cushman 1923) Bolivina subspinescens ( Cushman 1 922) Elphidium excavatum f. c/avata Cushman, 1 930 Trifarina fluens (Todd 1 947) Elphidium excavatum Hyalinea balthica ( Schroeter 1 783)

Sum

13 species < l% each of total fauna No. benthonic specimens/100 g sediment: 2320 No. planktonic specimens/ 1 00 g sediment: 1 240

Tab/e 8. Benthonic foraminifera in sample 1 39.85 m.

Species

Bulimina marginata d'Orbigny 1 826 Brizalina a lata ( Seguenza 1 862) Elphidium excavatum f. c/avata Cushman 1930 Jslandiel/a norcrossi ( Cushman 1933) E. excavatum f. selseyensis (Heron-Allen & Earland 1 9 1 1) Cassidu/ina reniforme Nørvang 1 945

Sum

3 species < l% each of total fauna No. benthonic specimens/100 g sediment: 2300 No. planktonic specimens/ 1 00 g sediment: 70

Percentage

36.63 29.30 10.20

5.42 4.46 2.87 1 .9 1 1 .59 1 .27 1.27

94.92

Percentage

36.39 29.66 20. 1 8

5.50 4.28 2.45

98.46

rich in foraminifera ( 17100/ l 00 g sediment), which may be due to high productivity, or due to a low sedimentation rate of fines.

The interval 180-170 m. - Eleven samples from this interval were analysed. Both the benthonic and planktonic foraminiferal faunas are relatively rich in number of individuals and species in this part of the sequence. Bulimina marginata, Trifarina angulosa. Melonis bar/eeanus and Uvigerina mediterranea dominate the benthonic assemblage in parts of this zone (Tables 4 and 7). These species are common in the northern North Sea and Norwegian Channel in recent and Holocene faunas. (Sejrup et al. 1981; Mackensen et al. 1985; Sejrup & Knudsen 1993). This suggests bottom water conditions similar to those prevailing today; temperatures dose to 7.5°C with small seasonal amplitude (Lee & Ramster 1981). There is a peak of planktonic foraminfera abundance at around 179 m depth in the core. Six samples were analysed near this level. They show a l 00% dominance of the polar species Neogloboquadrina pachyderma (sin.) in the two lowermost samples. Subpolar species such as Globigerina bulloides, Globigerina quinqueloba and Neogloboquadrina pachyderma (dex.) dominate around 178-179 m, with a frequency of 60% (Fig. 6 and Table 7). Above, the frequency of polar fauna increases and dominates the uppermost samples. Such high percentages of


subpolar planktonic foraminifera have so far only been recorded for oxygen isotope stage 5e and the Holocene in deep sea Quaternary sediments in the Norwegian Sea (Kellog 1976, 1980; Ramm 1989). Thus, both the planktonic and benthonic foraminifera indicate that an influx of Atlantic waters to the Norwegian Sea region, compatible with that of today (and stage 5e), occurred during deposition of this interval. We denote this warm period the Radøy Interglacial after Radøy island east of the site (Fig. 2).

The interval 170-140m. - Nine samples from four core segments were analysed in this interval. The faunas found in these sediments indicate a cooler environment, where boreal species such as Trifarina angulosa and Uvigerina mediterranea are replaced by Cassidu/ina neoteretis Seidenkrantz, Jslandiella norcrossi and Elphidium excavatum. The fauna) assemblages do not represent a typical arctic fauna but indicate some inflow of North Atlantic water. Further upwards, the abundance of the arctic species Islandiella norcrossi reaches 20%. This, and the low numbers of the normal salinity indicator Cassidulina reniforme (Nagy 1965; Sejrup & Guilbault 1980) suggest arctic marine water masses, with relatively low salinity. Only small amounts of planktonic foraminifera were recorded from this interval, and these faunas were dominated by the polar species Neogloboquadrina pachyderma (sin).

The interval 140-135m. - Three samples from one core segment were analysed in this part of the core. A sudden appearance of Brizalina alata, together with Bulimina marginata at ca. 140 m, marks an abrupt fauna) shift. A similar fauna with a high amount of a species called Bulimina ulata? was recorded at 118.9 m in the neighbouring core 5.1/5.2, and the corresponding warm event was denoted the Norwegian Trench Interglacial (Sejrup et al. 1989a; Sejrup & Knudsen 1993). Bulimina ulata? is synonymous with Brizalina alata in the present work. Because of the similar depth in core and the special fauna) composition, we correlate the peak of B. alata in core 8903 with the Norwegian Trench Interglacial. The warm, low-diversity benthonic fauna with B. alata in this core (Table 8) could indicate low-oxygen water masses, as Brizalina alata is found in low-oxygen zones in the Mexican Gulf today (Perez-Cruz & Machain-Castillo 1990; Denne & Sen Gupta 1991 ).

The numbers of planktonic foraminifera are low, but in one of the samples the amount of subpolar species (Neogloboquadrina pachyderma ( dex.) and G/obigerina quinqueloba) reaches 70%. This peak of subpolar planktonic foraminifera is somewhat higher than that in the Radøy lnterglacial. Compared with core 5.1/5.1, which had a content of 30% subpolar planktonic fauna, core 8903 indicates a much larger influx of warm water than previously suggested for the Norwegian Trench Interglacial.

Fauna in LJ


The fauna) assemblages in Lithozone 3 are quite similar to the foraminiferal content in the diamictons. One exception is the smaller amount of pre-Quaternary species and also the higher number of individuals in the sediments. Mixtures of boreal and arctic species assemblages are also prominent in parts of the unit. In core 5.1/5.2, dose to 8903, a last interglacial fauna was found in sediments from the same stratigraphic level as unit L3 (Sejrup et al. 1989a). This fauna also included high numbers of subpolar planktonic foraminifera (80%) suggesting a strong inflow of Atlantic water and was correlated to the Eemian Interglacial (Sejrup et al. 1989a; Sejrup & Knudsen 1993). No such fauna is found at this level in 8903.

Fauna in the diamictons L2, L 4 and L6

The mixture of Quaternary and pre-Quaternary species, and of species of arctic and boreal affinities, are characteristic features of Lithozones 2, 4 and 6. This, together with high numbers of benthonic species and with low numbers of individuals per l 00 g of sediment clearly suggest that these units were not deposited as water-lain marine sediments. The lowest diamicton (L6) is almost barren with regard to foraminifera, while the upper diamictons are somewhat richer in number of individuals.

Seismostratigraphy

Shallow seismic profiles along and across the Norwegian Channel (Fig. 2) reveal a relatively continuous seismic stratigraphy (Figs. 7, 8), contrary to the complex reflection pattern in the other parts of the northern North Sea (i.e. Stoker et al. 1985; Long & Stoker 1986). Some reflectors can be traced along the Channel for several hundred kilometres. Seisomostratigraphic interpretation of the sequences in the Norwegian Channel has been impeded by the Jack of core control. The first attempts were made by Floden & Sellevoll ( 1972) and Sellevoll & Sundvor ( 1974) who all interpreted the angular unconformity as the result of glacial erosion, and the sediments above as Quaternary deposits.

Godvik ( 1981) interpreted two shallow seismic profiles across the Norwegian Channel in the Troll area and divided the sequence above the angular unconformity into four seismic units. The two lowermost of these units (D and C) were interpreted as being deposited before glaciers reached the Norwegian Channel. Aarseth et al. (1984) and Aarseth & Godvik (1984) placed the PlioPieistocene boundary between units D and C, and thus arrived at a 150-m (175 ms TWT) thick Quaternary sequence at the location of the Troll core. This was later disputed by Holtedahl ( 1993), who placed this boundary above Godvik's unit C. Rokoengen & Rønningsland


N

E

59°

o 50

NORSK GEOLOGISK TIDSSKRIFT 75 ( I995)

o

s

[ 100

200 <il .§.

300 w :::E i=

400 ul � li 1-

500 >-

� 600 �

100km 700

800

Fig. 7. Interpretation of a sparker profile among the Norwegian Channel from 61 °00'N to 58°30'N. Seismic units interpreted as diamictons are shaded. The profile runs through the location of core 8903 .

(1983) and Rise et al. (1984) placed the Pliocene-Pleistocene boundary in the upper part of the sequence above the angular unconformity, which they gave a MidPliocene age. In their interpretation, the Quaternary sediments near Troll amount to only ca. 60 m.

We divide the sequence above the angular unconformity into four seismostratigraphic units (A-D) in addition to a single unit (E) below. The distribution of these

w

units is shown on the two interpreted sparker profiles; one along the channel through the location of 8903 (Fig. 7) and one across the channel ca. 9 km north of core 8903 (Fig. 8).

Unit E. - overlies acoustic basement ( crystalline rocks and displays semi-parallel reflectors dipping 3-4°W and WNW. Unit E represents Mesozoic sediments close to

800

Fig. 8. Interpretation of a sparker profile across the Norwegian Channel at 60"4 1 - 60"48'N. Seismic units interpreted as diamictons are shaded. Core site 8903 is located 9 km south of the arrow. For location, see Fig. 2.


the coast and Tertiary sediments further west (Floden & Sellevoll 1972; Sellevoll & Sundvor 1974; Rise et al. 1984; Sigmond 1992). Reflector E/D is occasionally weak and in places can only be traced by virtue of truncated dipping beds. Lithozone L 7 in co re 8903 corresponds to the top of seismostratigraphic unit E.

Unit D. - 0-30 ms thick on the E- W profile, is seismically homogeneous and wedges out in the western part of the channel. On the N-S profile it increases in thickness to a maximum of 60 ms between 60°10'N and 59°30'N, but wedges out in the southern part of the profile (Fig. 7). The unit is correlated to lithozone L6 in core 8903. At the L6/L5 boundary the geotechnical properties change abruptly as shown by an increase in the effective unit weight (Fig. 3). This is thought to give rise to the D/C reflector which can be traced across most of the Channel usually with a characteristic phase reversal.

Unit C. - is strongly acoustically laminated. On most of the E- W profile and north of 60°N on the N-S profile the unit reaches thicknesses of 50-70 m. The unit is correlated to L5 in the Troll core. From the present data the continuation of this unit southwards is not quite clear. A thick sequence of acoustically laminated sediments which is located outside Jæren (58°40'N; Fig. 7) may represent unit C.

Unit B. - is divided into two subunits (Bl and B2) by a relatively strong reflector often with indications of shallow gas at the base of Bl. Within unit B there are erosional and depositional discordances best seen on the E- W profile (Fig. 8). Unit B2 is thickest in the eastern part while Bl is thickest on the western side of the channel (max. 70 ms). Unit B2 possibly represents L4-L3 and Bl represents L2 in core 8903. In the area around this core a lens-shaped sequence in the upper part of B2 (Fig. 7) is thought to represent Lithozone L3. In the southern part of the N-S profile (Fig. 7) where the Bl unit crops out at the sea bed, a short gravity core 91-12 (Fig. l) penetrated in to an overconso1idated diamicton interpreted as till (Aarseth, unpublished data). Unit Bl also crops out near the coast in the Troll area (Fig. 8). A short gravity core examined from this area revealed a overconsolidated diamicton below 1.5 m of glacialmarine sediments (Godvik 1984). The B/A reflector differs from most of the other reflectors by its hummocky pattern. Close to the coast where unit B crops out at the sea floor, ridges may represent iceberg scouring (Lien 1983), or moraine accumulations as indicated on detailed bathymetric maps. Iceberg scouring may also be the last morphological genesis of this reflector further west. Unit B is the equivalent of the Norwegian Trench Formation (Rise et al. 1984).

Unit A. - is strongly acoustically larninated and drapes


unit B with thicker layers in three main troughs across the channel (Fig. 8). On this profile the unit is thickest in the western part of the channel with a maximum of 70 ms, while it is mainly less than the resolution of the instruments in the depression dose to the coast where the strong Norwegian coastal current precluded deposition. Unit A represents LI in the Troll core 8903 and is also the equivalent of the Kleppe Senior Formation (Rise et al. 1984).

Discussion

Mode of deposition

Interpretation of diarnictons deposited on continental shelves during the glacial phases through the Quaternary is not straightforward. Differentiation of a true subglacial till, glacial-marine sediments and debris flows can be problematic (Vorren et al. 1983, 1989; Elverhøi et al. 1989; Stewart & Staker 1990; Syvitski 1991; King 1993). We present below several lines of evidence that the diamicts in the Norwegian Channel were deposited subglacially and should be considered true tills. Though each argument may be inconclusive on its own, the collective evidence leads to a more reliable conclusion.

We propose that the lithological/seismostratigraphic units above the angular unconformity in the Norwegian Channel can be grouped into three sequences in which the general development is repeated. Each sequence starts with an erosional boundary (F/D, C/B2 and Bl/ B2). These erosional boundaries can be traced on seismic records over large parts of the channel. The erosion is a result of scouring by glacial ice and, subsequently, thick tills were deposited (L6, L4 and L2). Within some of the till units other erosional features are observed which suggest that the glacial history is more complex than simply the three diamictons separated by marine units. Conformably above the tills, follow glacial marine/ marine sedimentation. Evidence of other marine events may have been eroded away leaving no sedimentary records. The pocket of marine sediments from the last interglacial in the Troll area is probably an isolated example of preservation. Conditions are clearly different from those on land and this is reflected in the thickness and continuity of the units, the broad erosion surfaces and broad, low-lying moraines in the outer part of the channel (King et al. in press).

Further mapping and study of the various deposits and their erosion and depositional character (King et al. in press) will shed more light on the directions and types of ice flow and ice margins that prevailed.

The most complete record, and that with the most secure chronology, is in the uppermost sequences, but the seismic data and the available core material suggest a repetition of the same pattern. Our arguments for interpreting units L6, L4 and L2 as tills can be summarized as follows:


Seismic character. - The homogeneous seismic internal pattern only with a few reflectors of erosional surfaces suggests, especially for L2 and L4, deposition in contact with glacial ice (Vorren et al. 1989; Syvitski 1991). The general regional geometry of the units precludes a marine deposition and suggests a process acting in the same manner along the entire channel.

Lithological character. - The proposed till units differ strongly from glacial-marine deposits of indisputable genesis deposited after the last deglaciation (grain size, particle counts, etc). No structures invoking marine sedimentary processes were found in the units interpreted as tills.

Geotechnical character. - The geotechnical character differs between the diamictons and the marine units (higher shear strength values and lower water content in the former). Several different processes are known to invoke an increased degree of consolidation in sediments. However, the depth below sea level and the chronology of the sediments make it most reasonable to conclude that the consolidation of these units is a result of ice load.

Chronological analyses. - The chronological analyses support the till theory in two ways. Firstly, for the upper part of the record we know from coastal sites that the ice has expanded several times during the Weichselian out into the channel from western Norway (Larsen & Sejrup 1990; Larsen et al. 1991; Mangerud 1991) and the oldest basal date from lake sediments in western Norway is ca. 14 Ka (Paus 1990). This fits with the evidence for several glacial phases in the channel after the Eemian and a basal date in the following marine sequence there of 15.1 Ka. Secondly, the range in amino acid ratios supports a derivation of the faunas in the proposed till unit from sediments of different ages. The AMS date at > 42 Ka reported by Lehman et al. (1991) in the upper part of L2 is also compatible with a mixed foraminiferal faunal assemblage, in contrast with the glacial-marine unit just above.

Biostratigraphic data. - The biostratigraphic data seem to be incompatible with deposition of the diamictons in a normal marine or glacial marine environment from several reasons:

(a) Remains of molluscs are found throughout large parts of the core. All the remains within diamictons consist of abraded fragments of relatively thickwalled molluscs, whereas the other units yield thin, paired bivalves.

(b) Pre-Quatemary foraminifera are almost lacking in the normal marine and undoubtedly glacial marine parts of the cores (Ll) but are a characteristic component of the fauna found in the diamictons (Fig. 6).


(c) The num ber of benthonic Quatemary foraminifera is extremely low in the diamictons, usually less than 400 per l 00 g sediment. This is an order of magnitude less than that recorded by Nagy ( 1965) in very ice-proximal glacial marine environments on Svalbard. With only a few exceptions, the marine/glacial marine units (Ll , L3, L5) contain more than 3000 individuals of benthonic foraminifera per 100 g sediment.

We conclude that the diamictons in L6, L4 and L2 were deposited subglacially as tills. Diamictons with a similar acoustic appearance, sedimentological composition, fossil content and thicknesses have been recorded, and interpreted as tills, in shallow corings from the Fladen area, North Sea (Sejrup et al. 1987), Draugen area, Mid-Norwegian shelf (Haflidason et al. 1991) and in the Bear Island Trench, Barents Sea (Sættem et al. 1991). On a more global scale, similar acoustic units have been identified off Canada (Josenhans et al. 1986; Fader & Morgan 1986; King 1993), and Antarctica (Hambrey et al. 1991; Alonso et al. 1992; Anderson & Bartek 1992).

Glaciation history

Though little or no information exists on the waxing and waning of the Fennoscandian ice sheet through the Quatemary prior to the Eemian, the general opinion is that expansions occurred during the heavy (glacial) isotopic stages. From ODP records in the Norwegian Sea (Vøring Plateau) there is evidence, in the form of ice-rafted debris (IRD), for glacial expanaion as early as 5.5 Ma ago (Jansen & Sjøholm 1991). Whether these peaks of IRD can be linked directly with expansion of the Fennoscandian ice sheet onto the shelf is not yet proven. On Iceland, there is firm evidence for extensive repeated glaciations as early as ca. 2.5-2.6 Ma ago (Eiriksson & Geirsd6ttir 1991; Geirsd6ttir & Eiriksson 1994). In Great Britain no evidence of pre-Brunhes/Matuyama glaciations is recorded. In the southem part of the North Sea Basin some of the most continuous records of Quaternary climatic changes in the region are found in The Netherlands (Fig. 9). The first cold period with deforestation in The Netherlands occurred during the Praetiglian ca. 2.3 Ma ago (Zagwijn 1985, 1989). However, the first evidence of major expansion of the Fennoscandian ice sheet in the form of rock fragments of Scandinavian origin is found in the Menapian ca. 1.1 Ma (Zagwijn 1985).

The Fedje Glaciation, which is defined by the glacigenic Lithozone L6, represents the oldest direct evidence for expansion of the Fennoscandian ice sheet in the form of a till unit. Similar evidence for such an event has earlier been reported from Draugen Field (Mid-Norwegian shelf) by Haflidason et al. (1991). From the central northem North Sea, Sejrup et al. (1987) recorded a glacial event within their unit F and suggested an age


:X:

li: w o

m

!:::,.

50 !:::,.

!:::,.

!:::,. 100

150

200

THE NORWEGIAN CHANNEL

LITHOLOGY

!:::,.

!:::,.

!:::,.

!:::,.

INTEAGLACIAU Gl.ACIAL EVENTS

Holocene

Weichsel Glaciation

Eemian

Norwegian Trench

Radøy

Fedje Glaciation


(/) w ::r: z :::) c: CC

THE NETHERLANDS

CLIMATQSTRATIGRAPHY

Cromerian

Baverian

Menapian

Waalian

Fig. 9. Compilation of lithology and interglacials as evidenced by percentage of subpolar planktonic foraminiferal fauna. 'GES' ·is an abbreviation for widespread

Glacial Erosion Surfaces recognized in seismic profiles. Possible correlation with The Netherlands composite stratigraphy ( Zagwijn 1 985) is depicted.

dose to ca. 900 Ka. We now correlate this event with the Fedje Glaciation and the corresponding warm event with the Radøy Interglacial. This suggests that the Fedje Glaciation was a regional event with a magnitude similar to the Weichselian maximum in this region (Sejrup et al. 1994). As discussed earlier, the lower surface of the till units in the channel usually represent erosional unconformities. Therefore it is difficult to determine if L6 represents the first major glaciation of Fennoscandia. However, seismic records from the Draugen area and the central North Sea indicate this, as channelling, irregular reflectors, discontinuous seismic units and internat seismic character assumed to indicate glacial conditions are only found stratigraphically above the Fedje Glaciation sediments. Vøring Plateau sediments document an increase in IRD and retransportation of shelf material at 1.1-1.0 Ma (Spiegler 1987; Jansen & Sjøholm 1991). Also, the evidence from The Netherlands supports the idea that the ca. 1. 1 Ma old Fedje Glaciation was the first major glaciation of the Fennoscandian ice sheet during the Quaternary.

The till represented by unit L4 in core 8903 was

deposited sometime in the mid-Pleistocene. Possibly there is a major regional unconforrnity at the base of this unit. The only record of a Saalian ( stage 6) till in western Norway is at Fjøsanger in Bergen. Here, a till superimposed by Eemian interglacial sediments was recorded by Mangerud et al. ( 1981). The L4 could well be correlative with the Paradis Till at Fjøsanger, but could also represent one of several mid-Pleistocene advances.

The lithological and geotechnical data together with its seismic character suggest that L2 represents at least two phases of glaciation during the last glacial stage. Each of these would have a corelative in one of the at least three advances of the Fennoscandian ice sheet across the coast of west Norway throughout the Weichselian (Larsen & Sejrup 1990; Larsen et al. 1991; Mangerud 1991).

Palaeoceanography and climatic oscillations

The palaeoceanography and climatic implications of the deglacial Holocene sequence in LI will be discussed in detail in a separate article, nor will we go into any detail


here about the fauna recorded in unit L3. However, for comparison, we have included information in Fig. 9 on the warm faunas found at these levels.

Unfortunately, the core has a very low recovery in the interesting marine, Unit LS. It is therefore important to note that the fauna) changes we report probably constitute a minimum number of events. We also stress the problems with the chronology beyond the Brunhes/ Matuyama boundary at l S7 m and that the amino acidbased estimate of ca. SOO ka for the duration of the depositional phase should be considered tentative. The climatic evolution in the region through this period of marine sedimentation is of special interest. During this time-span several proxy climatic data recorded in deepsea sediments in the North Atlantic change from a mode of 41 Ka oscillations to cycles dominated by 100 Ka oscillations (Jansen et al. 1988; Ruddiman et al. 1989; Raymo et al. 1990). This global shift is a result of a change in the earth climatic system's response to the insolation changes and is also reflected in longer and more extreme glaciations.

Even if the recovery is low, we feel confident that the marine sediments from the top of L6 and up to the subpolar peak representing the Radøy Interglacial (Fig. 9) represent one deglacial period very similar to that found in L l . This is based on a similar change in fauna, approximately the same thickness of the sequence and similar types of sediment. Both the high number of planktonic foraminifera and the percentage of subpolar fauna (60%) suggest a strong advection of Atlantic water into the Norwegian Sea dose to I . l Ma. In studies by Kellogg (1976, 1980), and later by Jansen et al. (1983), Ramm ( 1989), Sejrup et al. ( 1989b), Spiegler & Jansen ( 1989), planktonic foraminifera have been used to map the intensity of the Norwegian current (Atlantic water) into the Norwegian Sea region. However, other than the Holocene and Stage Se there is no report of the amount of subpolar fauna exceeding 5% in the deep-sea sedi

ments, which implies summer temperatures higher than soc (Be & To1derlund 1971; Kellogg 1980; Johannessen 1987). 'Warm' interglacial periods have also been identified in Stages 1S, 13 and 11, based on the number of planktonic foraminifera (Spieg1er & Jansen 1989) and on the cocco1ith assemblages (Henrich & Baumann 1994) from the Vøring Plateau. However, in these studies the intensity of the interglacial stages has not been quantified. The interglacial interval at 180 m depth at the Troll Field is thus the first pre-Eemian subpo1ar planktonic foraminiferal spike recorded in Quaternary sediments from the Norwegian Sea region where the frequency of subpolar fauna reaclws present conditions. A sea surface temperature dose to the present is also supported by the benthonic foraminiferal evidence.

Between this warm interval and the warm fauna in the top of LS there are signs of changes in the circulation. However, the benthonic record shows generally cool conditions with a clear input of cold water species such


as Islandiella norcrossi and Neocassidulina teretis. The input of warm water in this period was lower than in the interglacia1 below, but neither were conditions fully glacial with year-round ice cover. Possibly an intermediate circulation pattern similar to that prevailing during the early Weichselian interstadia1s (Sa to Sd) pertained with seasona1 open water and summer temperature below the critical limit ( soq. for expansion of the subpolar planktonic foraminifera (Larsen & Sejrup 1990; Sejrup & Larsen 1991). We emphasize that due to the poor core recovery, events could be missing in this interval. However, it can be concluded with some confidence that Scandinavian ice sheets of this time did not expand out into the Norwegian Channel in the period from ca. I . l to 0.6 Ma.

· Both the benthonic and the planktonic foraminiferal fauna from ca. 140 m depth in the core suggest a climate similar to, or somewhat coo1er than the present. This 1evel corresponds to the Norwegian Channel Interglacial, recorded in the neighbouring core S.l (Sejrup et al. 1989a).

Conclusions and implications

l . The sediments above the angular unconformity in the Norwegian Channel (ca. 200 m thickness) span the last 1.1 Ma and record repeated expansions of the Fennoscandian ice sheet out towards the shelf edge.

2. 70-80% of these sediments were deposited as glacial tills. Each till disp1ays a sharp erosional boundary at its base and is occasionally overlain by marine/glacial marine sequences. Extensive glacial erosion has caused a fragmented preservation of the Quaternary record.

3. During the more extensive glaciations much of the eroded material was transported towards the North Sea Fan at the mouth of the Norwegian Channel.

However, the channe1 has acted (and present1y acts) as a major temporary depocentre for the flux of sediments from southern Fennoscandia to the deep sea in glacia1 times.

4. The presence of a thick marine sequence spanning ca. SOO Ka during the Ear1y and Middle P1eistocene indicates that the climatic conditions throughout several climatic cycles were not sufficiently extreme to facilitate growth of the Fennoscandian ice sheet to the maximum western position.

S. Sediments of the Fedje Glaciation (ca. 1.1 Ma) provide the o1dest direct evidence of a Fennoscandian ice sheet reaching its maximum position at the shelf edge.

6. During the Radøy (ca. I . l Ma) and the Norwegian Trench (ca. 0.6 Ma) Interglacia1s the influence of Atlantic water in the Norwegian Sea reached magnitudes dose to what has been recorded for the Eemian and the Ho1ocene.

NORSK GEOLOGISK TIDSSKRIFf 75 (1995)

Acknowledgements. - Masaoki Adachi did parts of the drafting and some �f the

sediment petrographic analyses were performed by Gerd Solbakken, Stig Monsen and Vigdis Hope. This publication is a NORMAST contribution. NORMAST is

the Norwegian section of the ENAM project ( European North Atlantic Margins: sediment pathways, processes and fluxes), funded by the EU Commission through the MAST Il programme. On behalf of the Troll Unit Partners, Norske Shell granted us permission to publish the results obtained on core 8903 from the Troll field. Professors Eystein Jansen, Jørn Thiede and Kåre Rokoengen carefully reviewed the paper, and gave valuable suggestions for improvements. Edward L. King critically read the manuscript and corrected the English language. To these persons and institutions we proffer our sincere thanks.

Manuscript received Jul y l 994

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Quaternary of the Norwegian Channel: glaciation history ... · Glaciation) is situated directly on top of the angular unconformity and suggests glacial erosion as the major process