Jurassic to Cretaceous stratigraphy of shallow cores on the Møre Basin Margin, Mid-Norway

MORTEN SMELROR, TORGRIM JACOBSEN, LEIF RISE, ODDVAR SKARBØ, JACOB G. VERDENIUS & JORUNN OS VIGRAN

Smelror, M., Jacobsen, T., Rise, L., Skarbø, 0., Verdenius, J. G. & Vigran, J. 0.: Jurassic to Cretaceous stratigraphy of shallow cores on the Møre Basin Margin, Mid-Norway. Norsk Geologisk Tidsskrift, Vol. 74, pp. 89-107. Oslo 1994. I SSN 0029-196X.

Four cores drilled by I KU in summer 1988 southwest of Kristiansund at the Møre Basin Margin close to the Gossa High ( 6206/02) penetrated marginal marine Lower Jurassic coarse clastic and Upper Cretaceous shelf deposits. The lower part of the eastemmost core 3 contains Lower Jurassic matrix-supported terrestrial conglomerates rich in mafic clasts deposited in an alluvial fan environment. This is succeeded by a clast-supported, partly marine-inftuenced very coarse gneiss conglomerate of Pliensbachian-Toarcian age, possibly representing fan-delta deposits. Core 2 penetrated a similar clast-supported conglomerate below a more sandy, partly marine inftuenced unit of Late Toarcian-Aalenian age. Core 8, further west, and the lower part of core l contained similar sandy successions of Late Toarcian-Aalenian age deposited in a distal fan-delta environment. In the latter core there is a major hiatus (some 80 million years) as Upper Toarcian-Aalenian sediments are overlain by Upper Albian Shelf deposits. The Cretaceous succession in the core contained marine mudstones, sandstones and shales/claystones of Late Albian to Turonian/Santonian ages. Distinct seismic reftections are present in the cored succession, but only those in the Cretaceous sequence can confidently be tied directly to the Møre Basin based on the available data. A bedrock map of the Møre Basin Margin is presented.

Morten Smelror, Leif Rise, Jacob G. Verdenius & Jorunn Os Vigran, !KU Petroleumsforskning a.s., N-7034 Trondheim, Norway; Torgrim Jacobsen, Statoil, Postullak, 7004 Trondheim, Norway. Oddvar Skarbø, Møre og Romsdals Bedriftsrddgjeving, Blindheimsenteret, 6012 Ålesund.

Introduction

During the early summer of 1988 IKU drilled eight shallow bedrock cores at seven locations near the coast off Mid-Norway (Fig. 1). A total of 628 m of bedrock was penetrated, and 541 m core was recovered. A high resolution seismic and shallow coring programme was initiated from a regional bedrock mapping project car­ried out by IKU for the Norwegian Petroleum Direc­torate (NPD) and Statoil in early 1987. In this paper the Lower Jurassic to Upper Cretaceous stratigraphy of the four southem cores drilled on seismic line IKU-201-88 southwest off Kristiansund (i.e. on the Møre Basin Mar­

gin) are described. These cores represent Mesozoic bedrocks outcropping on the Møre Basin Margin east of the Gossen High. The cored Lower Jurassic succession is divided into three informal lithostratigraphic units: A ("Early Jurassic mafic conglomerate"), B ("Early Juras­sic gneiss conglomerate") and C ("Early Jurassic sand­stone"). The Upper Cretaceous succession can be related to the formal lithostratigraphy of the mid-Norwegian shelf, as described in Dalland et al. ( 1988). The lithos­tratigraphic units correspond to the major seismic units identified on line IKU-201-88. The Møre Basin Margin has a complex structure of pre-Cretaceous fault blocks situated within the Møre-Trøndelag Fault Zone. It con­stitutes the eastem flank of the More Basin between the Sogn Graben and the Trøndelag Platform (Fig. 1). The Møre Basin Margin is narrow and comprises a westward

tilted sub-Cretaceous sequence between 0.5 and 5.0 s

TWT, onlapped by Cretaceous sediments (Brekke & Riis 1987). The data presented document that at least 700 m of Lower Jurassic strata subcrop west of the present coast in the 6206/02 block. Lower Jurassic sediments were encountered in co res 6206/02-U -03 (the oldest, close to the crystalline basement), 6206/02-U-02, 6206/ 02-U-08 and 6206/02-U-01 (hereafter cores 3, 2, 8 and l , respectively). Core l shows Upper Albian sediments on­lapping Upper Toarcian deposits, with seaward dipping seismic reflectors (Fig. 2).

Core descriptions and interpretations

Three lithostratigraphic units were penetrated m the Jurassic succession, while the cored Cretaceous succes­sion comprises two units (Fig. 2).

Lower Jurassic Unit A

Unit A ( 174.2-124 m) in core 3 consists mainly of poorly sorted, matrix-supported, polymict conglomer­ate with bed thickness varying between 0.3 and 3.0 m. The clasts are of subangular, (in situ) strongly weath­ered, often friable mafic and ultramafic ( amphibolite and serpentinite) cobbles and pebbles as well as some scattered, subangular, less weathered granitic gneiss (up to 30 cm). In some beds the clasts display horizontal orientation.

90 M. Smelror et al.

Fig. /. Main structural elements and location of the stratigraphic cores discussed in this paper.

Cretaceous shale/ mudstone

Early Jurassic sandstone

Early Jurassic gneiss conglomerate

NORSK GEOLOGISK TIDSSKRIFT 74 (1994)

Early Jurassic mafic conglomerate

Crystalline rocks

Fig. 2. Shallow seismic line across the core locations (BQ =Base Quatemary reftection, BC =Base Cretaceous reftection, IJ 1 = intra Jurassic reftection l, IJ2 = intra Jurassic reftection 2). Colour code: blue = Cretaceous sequence, green= Unit C, light brown = Lower Jurassic, Unit B, dark brown = Lower Jurassic, Unit A = Crystalline basement.

NORSK GEOLOGISK TIDSSKRIFf 74 ( 1994)

The matrix consists of dark red to red-brown poorly

sorted mud thåt in some beds shows horizontal lamina­

tion and cross lamination. Some beds are graded. The

upper lO cm comprises a light grey, muddy, kaolinite

weathered horizon with sharp upper and lower

boundaries (Fig. 3). The erosional character of the un­

conformity above the kaolinite horizon is not obvious in

the core, but this level displays a sharp colour change.

The truncation however, is, clearer in the seismic data

(Fig. 2). The palaeontological analyses give no indication of

any marine inftuence on these deposits. The strong in situ

weathering of the mafic clasts and the red-brown colour

of the matrix support deposition in fresh water, probably

E l c: u.. c: ca ø ca ·c:

6206/02-U-01 Depositional Environment:

Jurassic to Cretaceous stratigraphy, Møre basin 91

partly under subaerial conditions. The high concentra­

tion of expandable clay minerals in the muddy matrix and the absence of kaolinite indicate deposition in a dry

and warm climate (Fuchtbauer 1983).

The matrix-supported conglomeratic beds, partly

graded, and partly with horizontal and cross lamination,

are interpreted as altemating de bris ftow jmud ftow and

running water (braided channels or sheet ftood) deposits.

The first two depositional mechanisms are probably rep­resented by the intervals with no sedimentary structures,

while the other two are represented by the horizontal and cross-laminated intervals. An alluvial fan, probably mid­

fan position, as the depositional environment is sug­

gested (Fig. 3).

Depositional Environment:

o·c: o zoE 1-"-ca Outer storminfluenced

shelf 6206/02-U-08

6206/02-U-02 >�Cf) t-=::::C:::=----1 SB ,.. w l . <!) . • c:

zE.c(3 c( U..< . ....J _jW t----! 84/,.. SB

{) c: - ca ·c:

·c: :::> Q) {) ca en< Cf) ' < c: a: ca :::> ·� ...., ca a: o wl-3:$ O ca ....J....J

?mfs

6206/02-U-08

Outer shelf

lnner shelf/ Prodelta

Outer shelf

lnner shelf/ Prodelta

Distal part of fan-delta (front)

6206/02-U-03

Distal part of fan-delta (front)

Proximal fan-delta

Alluvial fan

Fig. 3. Stratigraphy of the cored sequences below the base quatenary (see Fig. 2). BC =Base Cretaceous reftection, IJ 1 = intra Jurassic reftection l, IJ2 = intra Jurassic reftection 2, SB = sequence boundary, TS = transgressive surface, mfs = maximum ftooding surface.

92 M. Smelror et al.

Lower Jurassic Unit B

Unit B in core 3 ( 124-94.5 m) and core 2 ( 133.3-85.05 m) represents the same seismic unit and comprises similar lithologies. In core 3, Unit B rests with a sharp boundary on 124.0 m on Unit A. It consists of poorly consolidated, clast-supported conglomerates where the clasts comprise weathered friable, subangular granitic gneiss cobblesjboulders (max. 70 cm) and subangular quartzic cobbles. The matrix is dark red to red-brown mud.

There are no indications of marine influence in the lower part of this conglomerate. Palaeontological data indicate marine influence in the uppermost metres of the cored unit and can be interpreted as evidence of a gradually approaching shoreline. No break or lithologi­cal changes were observed that could represent a transi­tion from non-marine to marine environments.

Lithology o 94.5 j",.""""'........,.,d-------,

130

140

150

160

170

clsi fmccgl

t

Depositional environment

PROXIMAL

FAN-DELTA

ALLUVIAL FAN

6206/02-U-03

Fig. 4. Sedimentological core log and interpreted depositional environment of core 6206/02-U-03. Legend to the sedimentological log is shown in Fig. 5.

NORSK GEOLOGISK TIDSSKRIFT 74 ( 1994)

LITHOLOGY. SEDIMENT ARV STAUCTUAES & FOSS l LS

� Granite 1"""1 Hummocky bedding

§ - Claystone/ shale rn Slumping

D Siltstone B Convolute bedding

C2J Sandstone B Lood east

� Gneiss cgl. ITJ Clastic dike

t:�•,:� Mafic cgl. l ..A.. l Water escape structure

Q;J Shale -/ clay streaks 0 Oish structure

D . Coarse sand grains 0 Soil horizon (early stage)

B Sand laminae [I]J Roots

EE3 Sand bed/lense rn Plant fragment

lvvvvl Bentonite [!] Coal fragments

0 Dolomite/ Ankerite streaks !Bill lncreasing bioturbation

0 Calcite cement [QJ Vertical burrow

0 Oolomite ·/ Ankerite cement [ff] Mott led

G Siderite cement [!] Fecal pellets

rn Wheowvellite rn Fossils in general

B Clay clasts � � Unspecified fossil fragments l0o0l Pebble ·l cobble clasts

rn Micro faults rn Bivalves

El Erosional boundary rn � Belemnite fragments B Sharp boundary � E3 Gradational boundary GJ Echinoderms

§ Horizontal lamination rn Ammonites

l� l Large scale cross laminat ion rn Cephalopod hooks

� lndistinct large scale a Fish remains cross laminat ion

lo-<'\ l Ripple lamination [§] Pyrite

w Wave ripples rn Glauconite

[§] Ouatemary

Fig. 5. Legend to the sedimentological logs in Figs. 4, 7, 10 and 12.

The clast-supported conglomerate is interpreted as rep­resenting a debris flow and/or rock fall depositional mechanism. The dark red to red-brown colour of the muddy matrix and partly of the clasts indicates deposi­tion under good oxidizing conditions. The granitic gneiss clasts have suffered from much stronger weathering in Unit B than in Unit A. In Unit B there are also consid­erable amounts of kaolinite (Fig. 3). Unit B was proba­bly deposited in a proximal position on an alluvial fan/fan delta under warm and humid climatic conditions.

In core 2, Unit B ( 133.3-85 m) comprises a similar clast-supported massive conglomerate as that penetrated by upper core 3. The matric in the lower part ( 133-94 m) is composed of a dark reddish brown mudstone. In the upper part (94-85 m) the matrix is a dusky yellow green to olive green mudstone. Over the interval 112 to 94 m (Fig. 6) there is a gradual transition from the dark reddish brown matrix to the yellow-green coloured matrix.

The upper 2.5 m of the unit displays a gradual change from a clast-supported texture to a matrix-supported texture, and the uppermost metre consists of a dusky yellow green mudstone with some scattered grave! frag-

NORSK GEOLOGISK TIDSSKRIFT 74 (1994)

:::; ;;; "' ;;; ... "' CD o o � "'

;;; . . "' in ;. "' "'

. ... ... "'

Jurassic to Cretaceous stratigraphy, Møre basin 93

PAL YNOMORPHS CORE 6206/02-U-03

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TOARCIAN EARL Y JURASSIC AG E

Fig. 6. Range chart of palynomorphs in core 6206/02-U-03.

LOWER JU RASSIC UNIT A l . JURASSIC UNIT B

L I T H OST R AT I G RAPH I C U N I T

ments. The palaeontological analyses show no indication of marine inftuence in Unit B in core 2 ( 133.3-85 m). The non-graded mudstone in the uppermost two metres was probably deposited by a mud ftow. The depositional environment is intepreted as the proximal part of an alluvial fan (Fig. 6).

Lower Jurassic Unit C

Unit C comprises Lower Jurassic strata, mainly sand­

stones represented in the upper part of core 2 (85.0-73.0 m), the entire core 8 and the lower half of core

1(181.8-98.3 m). The base of Unit C in core 2 is a 10 to 15 cm thick

coal-rich, muddy horizon with some subangular quartzitic cobbles. Above, there are poorly sorted sand­stones and mudstolies with coal fragments, and fining

upward cycles capped by silty claystones. These graded units have thicknesses from 0.3 to 1.5 m. Between 81.5-

81 m and 80.7-80.5 m there is a clast-supported con­g1omerate. The clasts are subangu1ar granitic gneiss and quartzitic cobb1es, and the gneiss clasts have suffered from in situ weathering. No structures or preferred clast orientation were seen. Between 78.7 and 77.6 m the cored

unit consists of a mudstone with gravet fragments, and disp1ays the same facies as in the interva1 133.3-85 m. Between 74.2 and 73.9 m there is a mudstone with angu­

lar clasts of cobble size that makes up the lower part of a graded interval. Most of Unit C has an olive grey

colour. Some horizontal lamination and large-scale cross

lamination can be seen in the sandstones in the upper two metres.

The palaeontological analyses indicate marginal marine environments just above the lag that marks the

boundary between Unit B and Unit C. This lag consists

of a coaly horizon, including some quartzltlc cobbles, and is interpreted to be a transgressive erosional lag.

Unit C in core 2 (85-73 m) includes erosive, graded and non-graded beds (conglomerate to silty clay) with few primary sedimentary structures (horizontal lamina­tion, cross lamination, and a few slumping phenomena in the upper part), interpreted as debris ftowjmud ftow and stream channel deposits. Sorting is poor, especially in the conglomerates. Marine inftuence is documented also by the microplankton Phallocysta eumekes at the 76.67 m level. The presence of Botryococcus suggests an inftux of fresh water. The foraminifera Hap/ophragmoides cf. kingakensis at 76.67 m and some echinodermal debris at 74.62 m (Fig. 7) also suggest marine inftuence. These observations suggest a depositional environment in a submarine delta front position within a fan delta. The whole succession ( 133.3-73 m in co re 2) is thus inter­preted to reftect a deve1opment from proximal parts of an alluvial fan/fan delta to submarine delta front de­posits within a fan delta (Fig. 6). No signs of subaerial exposure were observed above 85 m. The palaeontology does not indicate any major break at the boundary to this transgressive unit.

Core 8 penetrated the same sedimentary sequence as Unit C in core 6. Core 8 comprises poorly sorted, weakly cemented sandstonesjconglomerates that mainly show fining upward cycles capped by silty claystones (Fig. 9) varying from 0.2 m to 2.5 m in thickness. Most of the core has a greenish grey to light greenish grey colour, but also contains a few thin (3-5 cm) light brownish grey layers. These intervals are composed of clayey silt with coal fragments.

Between 57 m and 98.5 m some 0.5-1.5 m thick are comp1etely calcite cemented horizons mostly associated with zones of coarse and conglomeratic material. The conglomeratic beds are mainly clast-supported, have well

94 M. Smelror et al.

al z <

1- (3 z a: :l < (.) o 1-iii l C/) < z a: $ :l � .., a: al w C/) ;: z w g ::; 0..

90

1 00

1 1 0

1 20

1 30

Lithology

Q

1 33.3 ��.:.__-+----'

cl si f m c eg!

Depositional envi ronment

Fan·de�a front

PROXIMAL

FAN-DELTA

Core 6206/02-U-02

Fig. Z Sedimentological core log and interpreted depositional environment of core 6206/02-U-02. Legend to sedimentological log is shown in Fig. 5.

rounded clasts of cobble to gravel size, and are 0.2 to about 2 m thick. The clasts consist of granitic gneiss, quartzdiorite as well as some mafic and ultramafic clasts which are restricted to the calcite cemented beds.

Sedimentary structures are rare, but horizontal lamina­tion, large-scale cross lamination, some ripple lamination and slumping structures occur. Some calcite cemented

intervals have large-scale, low-angle cross lamination. The graded units in the sandy parts display a develop­ment from large-scale cross lamination and horizontal lamination in the coarser parts to ripple lamination and horizontal lamination in the finer grained upper parts.

The few red-brown fine graine horizons, mainly associ­ated with coal fragments, are interpreted as an early stage of soil development, suggesting that the sediments have periodically been subaerially exposed.

The sedimentary facies mainly consist of stacked, ero­sive, graded units with varying amounts of primary sedimentary structures and are interpreted as represent­

ing deposition in running water, where the water path is switching backwards and forwards over a braided plain. It is difficult to judge whether the flow was confined to channels or reflects sheet floods.

The sedimentary observations suggest a depositional environment of a braided river system with shallow poorly confined channels, e.g. distal parts of an alluvial fan/fan delta. Palaeontological analyses indicate some marine influence through parts of the succession, and thus a delta plainjdelta front of a fan delta is suggested (Fig. 9).

NORSK GEOLOGISK TIDSSKRIFT 74 ( 1994)

This model can also explain the calcite cemented gravelfconglomeratic horizons, which may have formed in a mixing zone of fresh and marine water in a beach/ foreshore position: a beach rock. Low angle, large-scale cross lamination in some of these coarse grained hori­zons supports this interpretation, as do the well-rounded clasts.

The Lower Jurassic sequence recovered in core l (179.8-98.3 m) is coeval and represents the same seismic unit, and the lithology has much in common with Unit C in cores 2 and 8. The Lower Jurassic sequence of core · t is consequently given the same informal unit name as the upper unit in core 2 (Unit C).

In core l , Unit C (179.8-98.3 m) displays one facies association: erosive cycles of graded, poorly sorted, medium-grained, micaceous sandstones (0.2- 1.5 m) in­terbedded with silty claystones and gravel containing a few rootlets and abundant coal fragments. Apart from a few darker clayey intervals, and numerous thinner (5-15 cm) light brownish grey intervals, most of the unit displays a greenish grey to light greenish grey colour. The light brownish grey intervals contain some coaly material (plant debris).

The whole unit shows an overall upward tining trend. There is a dominance of gravel and conglomeratic mate­rial in the lower part, and medium and finer-grained sandstones in the upper part (Fig. 11). Sedimentary structures comprise horizontal lamination, large-scale cross lamination, some ripple lamination and slumping structures. The graded units generally have large-scale cross lamination in the coarse-grained parts, and hori­zontal lamination and ripples in the finer parts.

Most of the unit is poorly cemented, but some inter­vals are completely calcite cemented. These intervals are generally associated with zones of coarse sand, gravel or conglomeratic material, and they vary in thickness be­tween 0.5 m and 1.5 m. They are homogeneous except for a few intervals with low angle, large-scale cross lamination.

The palaeontological analyses indicate marine influ­ence throughout the whole succession. The light brown­ish-grey fine-grained horizons, with coal fragments and rootlets, suggest soil development and frequent subaerial exposure during deposition.

The sedimentary facies, which consists of stacked, erosive, graded beds ( conglomeratic to silty ela y) with varying amounts of primary sedimentary structures (cross lamination, horizontal lamination, a few slumping phenomena and current ripples) is interpreted to reflect deposition in flowing water, where the main water path switched backward and forward over a braided plain. It is difficult to judge whether the water was confined to channels or was a sheetflood.

Because of the marine influence, we infer delta-front/ lower delta plain of a braided delta or fan delta as the depositional site for these sediments.

The calcite cemented gravelfconglomeratic horizons are probably caused by marine reworking in a beach/

NORSK GEOLOGISK TIDSSKRIFf 74 (1994)

foreshore setting and may represent beach rock. The

upward decrease in beach rock horizons and an increase

in signs of subaerial exposure ( soil horizons) indicate a regression. Very few palynomorphs have been observed in

the uppermost part, implying hetter oxidizing conditions. The boundary at 98.3 m between Unit C and the

overlying Lange Formation (98.3-76.0 m) is sharp and defines a major hiatus.

The Lower Cretaceous Lange Formation

The Lange Formation in core l is subdivided into three sub-units ( displaying two types of lithofacies).

Sub-unit l (98.3-90 m) shows a disorganized, hetero­geneous facies of clasts containing, greyish black mud­stone. The clasts are of both intra- and extra-formational origin, and comprise claystone, carbonate, quartz and glauconitic sandstonejclay clasts. They are subangular and from 0.5 to 1 0 cm (mainly 1 - 3 cm) in diameter (carbonate clasts are the !argest ones). Two medium­graded sandstone units ( l 0-1 5 cm thick) capped by clay­stones are observed between 94 m and 90 m. The upper­most is calcite cemented. The whole sub-unit displays numerous slump structures and strong bioturbation. There are fossil fragments of bivalves and belemnites.

Sub-unit 2 (90-79.5 m) consists of a glauconite-rich, fine to medium-grained sandstone that is calcite ce­mented. The lowermost 3 m of this sub-unit is well sorted, and shows horizontal lamination and some bur­rowing. From 87.5 m and upwards there is a gradual increase in the siltjclay content. This part shows occa­sional horizontal lamination and large-scale cross !ami­nation, but is mainly strongly bioturbated.

Sub-unit 3 ( 79.5-76 m) shows the same type of litho­facies as sub-unit l , i.e. a rather heterogeneous mudstone with abundant clasts.

Depositional mechanisms for the clast containing mudstone in sub-units l and 3 (98.3-90 m; 79.5-76 m) (Fig. Il ) are interpreted to comprise partly mass-gravity flows (debris flow, turbidite currents), and partly sedi­mentation from suspension. An inner shelf/prodelta de­positional environment is suggested.

The bioturbated, upward tining, glauconitic sandstone of sub-unit 2 (90-79.5 m) is interpreted as transgressive deposits. The marine coastal sand at the base gradually evolved into a shelf deposit during the transgressive event. This transgression led to a decrease in sedimenta­tion rate, strong bioturbation and glauconitization. The inner shelf/prodelta setting was re-established during de­position of sub-unit 3.

The boundary between the Lange Formation and the Kvitnos Formation (76-54.9 m) is sharp.

The Upper Cretaceous Kvitnos Formation

The Kvitnos Formation is subdivided into two different sub-units (Fig. Il ). Sub-unit l ( 76-63 m) consists mainly of calcareous, greyish black, horizontally laminated shale

Jurassic to Cretaceous stratigraphy, Møre basin 95

with monor amounts of silt and dolomitejankerite !ami­nations as well as bioturbated intervals with some glau­conite. Around 7 1 m there are two thin intervals: a medium-grained, bioturbated glauconitic sandstone and a conglomerate with clasts of pebble size . The clasts mainly comprise quartz, carbonate and glauconite. Sub­unit l is interpreted as representing an outer shelf environment.

There is a gradual change in lithology from sub-unit l to sub-unit 2. Sub-unit 2 (63 - 54.9 m) displays an overall

upward coarsening development resulting in a sandy, calcareous, laminated shale. Most of the sand grains seem to be biogenic silica. The sub-unit contains some erosive, graded, partly laminated, coarse-grained and pebbly glauconitic beds ( 5- 1 5 cm thick). One of these also contains carbonate clasts. Throughout the unit there are shell fragments, mainly bivalves, which are highly concentrated in silica rich, pebbly horizons.

Sub-unit 2 is interpreted as representing and open marine, outer shelf environment with gradually decreas­ing sedimentation rates. The erosive, coarse-grained, strongly glauconitized, graded beds in the uppermost part of he sub-unit imply an environment with variable energy conditions. These beds are interpreted as reflect­ing storm or other current generating events in a sedi­ment-starved shelf area, resulting in condensed sections. The glauconite was eroded from the seabed and re­deposited again in the same area.

In terms of organic geochemistry, the shales of the Kvitnos Formation are homogeneous with poor source rock properties suggestive of a low-energy setting with moderate ventilation. This could imply a deeper water environment relative to that of the upper Albian to lower Cenomanian Lange Formation (Fig. 1 6).

Biostratigraphy Lower Jurassic Unit A

The poor residues of degraded terrestrial material recov­ered from Unit A in core 3 contain sporadic pa­lynomorphs that indicate an Early Jurassic, possibly Hettangian age. A Late Triassic age cannot be excluded, but restricted Triassic taxa are missing. The assemblage includes C/assopol/is spp., Chasmatosporites spp., Tra­chysporites sp. and a poorly preserved specimen iden­tified as cf. Cerebropollenites thiergartii at the 1 66.0 l m leve!. The presence of Lunatisporites rhaeticus at 1 34.23 m is attributed to reworking from Triassic beds (Fig. 4). The palynomorphs characterizing Unit A resem­ble those recorded in the Pinuspollenites-Trachysporites Zone (Lund 1 977) of Hettangian age. No microfaunal elements were recorded in the core.

Lower Jurassic Unit B Unit B in core 3 yielded only poor residues of degraded terrestrial material and rare palynomorphs. No micro-

96 M. Smelror et al.

faunas were recovered. The presence of Cerebropol/enites macroverrucosus at l 02. 1 5 m points to and age not older than earliest Sinemurian at this level. Besides the bisac­

cate pollen grains, the palynomorph assemblages yielded

stratigraphically long-ranging forms such as Quadrae­culina anellaeformis, Deltoidospora minor and Classopollis spp. The dinoflagellate cyst referred to as Comparodinium sp. of Morbey 1 975 is present at 102. 1 5 m. This indicates

limited marine influence. The presence of Granulopercu­latipollis sp. at l 02. 1 5 m is interpreted as being reworked

from Triassic beds. The oldest occurrence of C. macroverrucosus in the Sinemurian of the North Sea ( Lund 1 977; Morbey 1 978; Dybkjær 1 99 1 ) limits the

maximum age for the assemblage.

In core 6206/02-U-02 most samples from Unit B

( 85.07 - 1 22.29 m) pro ved to be barren of palynon­

morphs. The enrichment of resinous matter has been interpreted as evidence of oxidative conditions acting

in an environment formerly rich in leaf remains. The re­

gular presence of Cerebropol/enites macroverrucosus, Chasmatosporites major and Concentrisporites hal/ei ( = Perinopol/enites elatoides in Dybkjær 199 1 ), in this assemblage ( Fig. 8) suggest a Pliensbachian to Toarcian age according to the North Sea ranges ( Berthelsen 1 974; Lund 1977; Hoelstad 1985; Dybkjær 1 988, 1 99 1 ).

Lower Jurassic Unit C

The microfloras found in Unit C (74.5 1-84.97 m) of core

2 are characterized by fairly rich spore-dominated assem­

blages with common Chomotriletes minor and dominant Deltoidospora minor, Lycopodiumsporites spp. and Retitriletes spp. other forms include Acanthotriletes var­ius, Apiculatisporites ovalis, Cerebropollenites macrover­rucosus and Trachysporites spp. The occurrence of

Cerebropl/enites thiergartii and Cal/ialasporites trilobatus suggests a Late Toarcian to Aalenian age ( Fig. 8). This is

supported by the presence of the dinoflagellate Phal/o-

6 2 o 6 l

02-U-03 02-U-02 l 02-U-08 l

NORSK GEOLOGISK TIDSSKRIFT 74 (1994)

cysta eumekes (76.67 m), which is restricted to the

bifrons-opa/inun Zones (Powell 1992).

Core 8 was analysed for palynomorphs and microfau­

nas. The few single occurrences of agglutinated

foraminifera provide little stratigraphic information. The

palynological records (Fig. 1 0) include Cerebropol/enites

macroverrucosus and C. thiergartii, and at 105.77 m

abundant Apiculatisporites ovalis and Baculatisporites spp., Chasmatosporites major, Ischyosporites variegatus, and the dinoflagellate cyst Phallocysta eumekes, which

confirms a Late Toarcian to Early Aalenian age (Powell

1 992). Callialasporites trilobatus is rare, being recorded

only from the 6 1 .56 m level.

Deltoidospora minor and other smooth forms dominate

the spore assemblages, which also include Apiculatis­

porites sp., Ischysporites variegatus, Leptolepidites sp.,

Lycopodiumsporites spp., Retitriletes semimurus, Stereis­

porites spp. and Chomotriletes minor. Pollens include

Araucariacites australis, Cerebropol/enites macroverruco­sus, C. thiergartii, Classopollis classoides and Quadrac­ulina anellaeformis. The palynomorph assemblages characteristic of this unit resemble those of the

Spheripol/enites-Leptolepidites Zone ( Dybkjaer 1 991 ) .

The abundance of spores in parts of the core, which

are rich in degraded and structured wood remains, sug­

gests proximity to a vegetation of ferns and mosses.

Single specimens of Haplophragmoides and Ammobac­ulites demonstrate marine influence in samples from

105.78 m and 103.0 m (Fig. 7), while Botryococcus spp.

at 101.29 m and 65.0 1 -61 .56 m indicate freshwater

influx.

Rich assemblages of spores in core l ( Fig. 12) include

Corrugatisporites amplectiformis, Deltoidospora australis, D. minor, lschyosporites variegatus, Leptolepidites spp.,

Marttiasporites scabratus, Stereisporites spp., Retitriletes (Lycopodiumsporites) spp., S. aulosenensis, Striatella see­

bergensis (Asseretospora gyrata), Trachysporites spp., T.

fuscus, Tripartina variabilis and Chomotriletes minor ( Fig.

CORE 02-U-01

� � � � � � j ti � ;:;! � g § � � � � u; g; g: � � � � � � � � � � � ; � � � � � s 6 � � � = § § § :g � EARL Y JURASSIC

MICROFAUNA O O N :.. W O c" å, � N � � O O O � å. � Cn O Cn O Cn O U, O U, O O � O � O O O � O O ;... O ._ .. Cn � :., O O :.,

EARL Y JUR.

UNIT B A

---- 1--- - -

--- ------- -------

--------�-----

-------- ------- ------- -------- -------

LATE TOARCIAN- AALENIAN

LOWER JURASSIC UNIT C

Fig. 8. Range chart of microfossils in the shallow cores from block 6206/02.

BARREN SRMPLE RGGLUTINRTEO FORRMINIFERR HRPLOPHRRGMOIOES CF. KINGRKENSIS HRPLOPHRRGMOIOES SP. RMMOBRCULITES SP-

--- ------- ------ --------... T::;:

R�OC::.;;

H::;:RM�

M::::IN�

R-;;-

S:_;:P::-P ·�=:------! --- RGGLUTINRTEO SP. INOET.

MISCELLRNEOUS ECH l NODERMS

--- BIVRLVES

A G E

L IT HOST R AT I G R APH I C U N I T

NORSK GEOLOGISK TIDSSKRIFT 74 (I994)

Fig. 9. Range chart of palynomorphs in core

6206/02-U-02.

<D CD CD CD CD CD "' "' o c. .. o

"' ....

-------------

: .... .... "' "'

;., o a. .... "' ....

.... •

;" "'

Jurassic to Cretaceous stratigraphy, Møre basin 97

� PAL YNOMORPHS

� CORE 6206/02-U-02

------------------ BOTRYOCOCCUS SP. ------ ·---�------------- L YCOPOO IUMSPOR l TES RUSTROCLRVRT ID ITESI COOK. l POT ON lE 1957

---------- ---------------- RET l TR !LETES SPP.

--------- --------- DEL TO l OOSPORR Ml NOR ! C DUPER l POCOCK 1970

------ ------------ CEREBROPOLLEN l TES HRCROVERRUCOSUS l THIERG. J SCHULZ 1967

------1----------------- CHRSMRTOSPOR l TES MRJORI ROGALSKR JNI LSSON 1958

- ---------------- ---- POOOCRRPIOITES ROUSEI POCOCK 1970

- ------------------ BISRCCRTES l NOETERH l NRTE

-�---------------- CONCENTR !SPOR l TES HRLLEI l NILSSON l WALL 1965

- ------------ ---- L YCOPOOIUMSPOR l TES RE Tl CULUMSPOR l TES l ROUSE IDETTM. 1963 �------------------ TRIPRRTINR VRRIRBILIS MRLJRVKINR 1949 �------------------ CRLLIRLRSPORITES SPP.

�------------------ DICTYOPHYLL IOITES MORT ON! l DE JERSEY J PLRYF. & OETTM. 1965 �------------------ o· LTOIOOSPORR JUNCTR l KRRR- MURZR J SINGH 1964 1-------------------- OELTOIOOSPORR RUSTRRLIS l COUPER l POCOCK 1970

�------------------ STEREISPDRITES RULDSENENSIS l SCHULZ J SCHULZ 1966 1-------------------- RCRNTHOTR l LETES VAR !SP l NO SUS POCOCK 1982 �------------------ PEROTRILITES SP. ------------------- CYCROOPITES NlTIOUS ! BRLME J NORR IS 1969 ----------------- RSSERETOSPORR GYRRTR l PLRYF .4 DETTM.I SCHUURM -1917 ----------------- TOO l SPOR IT ES Ml NOR COUPER 1956

------------ ---.- STEREISPORITES SP. ------- --------- RPICULATISPORITE5 OVRLIS !NILSSON l NORR IS 1965

---------------- RRRUCRRIRCITES RUS TRALl S COOKSON 1947 ---------- C�.>MOTRILETES MINOR l KEOVES J POCOCK 1970 ------------- BRCULRT ISPORITES COMRUMENSIS !COOKSON l POTONIE 1956

--------- ---- PHRLLOCYSTR EUHEKES OORHOFER 4 ORVIES 1980 ------- ---- CEREBROPOLLEN l lES THIERGRRT!I SCHUL Z 1967

PUENSBACHIAN - LA TE TOARCIAN- AGE TOARCIAN MLENIAN

LOWER JURASSIC LOWER JURASSIC LITHOSTRATIGRAPHIC UNIT UNITB UNIT C

12). Pollen grains are represented by Araucariacites aus­

tralis, Cerebropo/lenites macroverrucosus, C. thiergartii,

Concentrisporites ha/lei, Cycadopites nitidus, and

Quadraeculina anellaeformis. The bisaccates generally oc­

cur in very 1ow numbers.

There are marked variations in the relative composi­tion of the organic residues and the palynological assem­

blages, particularly in the content of Corrugatisporites amp/ectiformis, Striate/la seebergensis, /schyosporites var­iegatus, Manumia irregularis, and Marattiasporites scabratus, which have been interpreted as due to the rapidly changing land flora. The abundant and varied pollen and spore assemblage and the presence of megaspores at about 1 36. 21 m, 1 35. 0 m, 1 3 1 .49 m,

1 29.0 m and 1 1 4.44-107. 76 m are interpreted as reflect­ing proximity to a rich vegetation growing under more humid conditions. The enrichment of cuticles and resinous matter reflect a large input of leaves from this environment. The microflora resembles that of core 8

and of the Spheripollenites-Leptolepidites Zone ( Dy­

bkjær 1 99 1 ).

Lithology Depositional environment

Q

60

z 70 DISTAL PART OF o <

t:: z .A"=== A FAN-DELTA z w �

-' ::;) � Fan-de�a front u � Cii en z

80 < � � a: o ::;) a: .., < a: o w 1-� !!:! o 90 -' �

o",.. · ···:-· -:.�. -..r

100 ··: ·.<···.·.· ............. ":

·-· : :: .. .. : .. · · ·-.: ,..... /)1.�;::;;·; = � �

106.7

el si fm c cgl Core 6206/02-U-08

Fig. JO. Sedimentological core log and interpreted depositional environment of

core 6206/02-U-08. Legend to sedimentological log is shown in Fig. 5.

The dinofl.agellate cyst Nannoceratopis ambonis and indeterminate microp1ankton ( 144. 7 1 m) are evidence of restricted marine infl.uence in a generally terrestrial domain.

The age diagnostic taxa, including Callialasporites dampieri, Cerebropo/lenites thiergartii and Nannocera­topis ambonis, suggest a Late Toarcian to Aalenian age for the entire unit. Though confident data are missing above the 1 07. 76 m 1evel, Chomotriletes minor is used to extend this age to the top of the core. In western Canada, C. minor is restricted to J l1, the lowest Middle Jurassic 'Lower Bajocian' ( corresponding to the Aalenian)

(Pocock 1 970) which would favour an Aalenian age for Unit C.

The samples analysed with respect to microfauna were all barren except samples from 1 27. 00 and 107. 76 m,

98 M. Smelror et al.

o o "' "' ..., ..., w .. w ..., ..

;." ;., (" (" :... .. "' Cl) "' ..., w

o w

..., Ol N "' (" o "'

� (" Ol

PAL YNOMORPHS

CORE 6206/02-U-08

---- OELTOIOOSPORR MINOR ICOUPERI POCOCK 1970 -- • • • ·-• • • • • • • • • • • • • • • • • • • • • • • ·

r.C:::;O:::NC':':R�V 1:-:S-::'PO

:-:'R-;;,

1 1:-::E.:;.S �S�Pi:-:. -::-::-:-=:::-:=-�=:--:-:�--------! ----··--···--···-···-·········· RCRNTHOTRILETES VARISPINOSUS POCOCK 1962 -- • • • • • • • • • • • •• • • • • • • • • •• ·--• ·- RNRP l CULRT l SPOR IT ES SP.

-- • • • • ·-• ·-·-· ·--• • ·-• • ·-• • ·-• .l-:pi::H';i; RL-f'L�OC�Y7 ST;.:;R�E;7U�ME;.: K�ES;:-;:-00;;-; R::-; HO;:;F;-;: E;:-R -:-,-;O:::; R;:-:V 1;-;:E-;:- S -:-1-;::98:::;0------t -·-···············--------·-··· CYSTS INOETERMINRTR ALETE -- • • • • --- • • • • • • • ·-• • ·-• • • ·-• _..,:O;,:,U;, RO;;R-",RE:-:C::::UL;_; I�NR�AN::: E:,:.,L .L� A,;,:E;.;FO"=' R::..,MI"" S-,M"'"R,-LJ"'" A""VK'"'t"" NA,.....,.,I 9""'4"""9 -------1 --------------·-···-·······-- CORRUGRTISPORITES RMPLECTIFORMIS IKRRR-MURZRI POCOCK 1970 ---------·--------·------- CERE8ROPOLLENITES THIERGRRTII SCHULZ !967 -- • • ·------• • • • • • • • • • • • • •

..,:C;;,:A;;LA�M:;OS:::, P.;: OR:.:,R""S::;,P,.:. .

:-:-"".,.=....,.".",...,.,"..,...'===....,."-:-:------1 ---·-···---------·---·--·-··· STRPLINISPORITES CRMINUS 18ALMEl POCOCK 1962 --·-• • • • • • • • • • • --- • • • • • • • • • ·- LYCOPOD l UMSPOR l lES RUSTROCLRVRT l O ITESI COOK. lPOTON lE !957 ------------------··--·- RRAUCARIACITES AUSTRRLIS COOKSON 1947 ---·······---------------- OELTO!OOSPORR RUSTRRLIS ICOUPERI POCOCK 1970 --------------·-········· STEREISPORITES RULOSENENSIS ISCHULZI SCHULZ 1966 --------------------------- CHOMOTRILETES MINOR IKEOVESl POCOCK 1970 -·-···--------------------- RPICULRTISPORITES OVRLIS INILSSONI NORRIS 1965 ---------------········· LYCOPOOIUMSPORITES SEMIMURIS REIS.& W!L. !969 --------------....0------------ PERINOPOL'LENITES ELRTOIDES COUPER !9S8 --···-···-···----···········- VITREISPORITES PRLLIDUS IREI.SSINGERI JANSONIUS 1962 ---··········--------·-······ ISCHYOSPORITES VRRIEGRTUS ICOUPERl SCHULZ !967 ------------············ CONCENTRISPORITES HALLE! IN!LSSONI WALL 1965 ---- ---··--·- CYCADOPITES NITIOUS 18ALMEl NORR!S !969

---------------- CEREBROPOLLENITES MRCROVERRUCOSUS l THIERG.l SCHULZ 1967 -----------········ TOOISPORITES MINOR COUPER 1958

--- ------------- BRCULATISPORITES SP. ----- ------------------ BISRCCRTES INOETERMINRTE -- • • • • ---• ----• ·-• • • --"'c"'H� RS:"' M�RT:;;O� SP:..,O�R':"!IT�E.;.;S '-"M':"RJ:,;;O"'"R I�R""'OG"" R"" LS"' K""" R "'1 N"'l L""s""'so"' N,....,..,I 9""'5 8,...-------i

----------------------- STEREISPORITES C!CRTRICOSUS IROG. l SCHULZ 1967 ---····-··············· OSMUNORCITES WELLMRNNII COIJPER 1953 -----·-------------- BOTRYOCOCCUS SP.

---·---···-··--···-··· GLEICHENIIDITES SENONICUS ROSS 1949 -------------------- CLRSSOPOLLIS CLRSSOIDES l PFLUGI POCOCK & JRNSONIUS 1961

----··············· RSSERETOSPORR GYRRTR IPLRYF.& DETTM.J SCHUURM. 1977 --·············· LEPTOLEPIDITES SPP·.

-- • • • • • • • • • --t-;S;;;T:,.;E R:i=E-'i-:1 S'i:P� OR:-;1-;.: T E;.::S,...R� N�T i-::1 0::-;U R;:; S� PO;:;R:-;-1 ;-;TE;-;: S,...I�W�I L- .-:-, �W::-;E B:-.-:-1 -::D::" E T;-:1-:;- M .--:-:1 9::-;: 6-:;-3 --i ----··--··--- MRNUMIR IRREGULRRIS POCOCK 1970 ----·---·---- OELTO!DOSPORR JUNCTR IKRRR-MURZRI SINGH 1964 ------------- EUCOMMIDITES MINOR GROOT & PENNY 1960

- CRETRCEOUS CONTRMINRT ION - CRLLIALRSPOR!TES SPP.

LATE TOARCIAN- AALENIAN AGE

LOWER JURASSIC UNIT C LITHOSTRATIGRAPHIC UNIT

NORSK GEOLOGISK TIDSSKRIFT 74 ( 1994)

Fig. Il. Range chart of palynomorphs in core

6206/02-U-08.

which contained single occurrences of Trochammina spp.

and T. cf. squamataformis respectively ( Fig. 7). These

observations add little to the stratigraphic informa­

tion, but demonstrate a marine influence in parts of the

succession.

is further supported by the presence of Litosphaeridium arundum, C aue a parva and Ovoidinium scabrosum ( Fig.

13). Litosphaeridium arundum is normally restricted to

the Albian (Heilmann-Clausen 1987), while the latter two species may also range into the Early Cenomanian (Foucher 1981).

Lower Cretaceous Lange Formation

The Lange Formation (98.3- 76.0 m) in core l can be

divided into two biostratigraphical units, possibly sepa­rated by a minor hiatus at approximately 79.5 m. Below

this level a Late Albian-Early Cenomanian section is

documented based on palynomorphs and foraminifera

supported by nannofossil and belemnite records ( Figs.

13-15). The 79.5-76 m interval contained different as­

semblages with respect to palynomorphs, nannofossils

and foraminifera, and a general Cenomanian age was

concluded separately. A Late Cenomanian age is possi­

ble, but not documented.

Following the stratigraphic distribution given by Davy

and Costa ( 1992), the occurrence of the dinoflagellate

Apteodinium grande between 98.25 and 94.80 m and at

88.00 m suggests a Late Albian age for this interval. This

0/igosphaeridium comp/ex is common in the lower part of this interval, i.e. from 98.25 to 96.5 m and at 94.8 m. An acme of Ch/amydophorella nyei is observed at 88 m. Surcu/osphaeridium /ongifurcatum is common at 97.25 m.

The presence of Apteodinium maculatum from 79.71 to 78.00 m suggests an age not younger than Cenomanian.

According to Foucher (1981) and Marshall & Batten

( 1988), Litosphaeridium siphonophorum may be used to

distinguish Cenomanian and Turonian deposits in

Northwest Europe. The presence of this species at

78.00 m is probably indicative of a Cenomanian age. A

pre-Turonian age is also suggested by the presence of

Gonyau/acysta helicoidea at 79.71 m.

The microfaunas recorded vary considerably with re­

spect to both richness and composition (Fig. 14). Below

89.24 m the samples were very poor or barren except those from the lowermost samples at 98.00 and 97.00 m.

The latter were composed of both calcareous and agglu-

NORSK GEOLOGISK TIDSSKRIFT 74 (I994) Jurassic to Cretaceous stratigraphy, Møre basin 99

Lithology Depositional environment

Fig. 12. Sedimentological core log and interpreted

depositional environment of core 6206/02-U-01. Leg­

end to sedimentological log is shown in Fig. 5.

tinated elements, and the former of agglutinated elements

only, e.g. BathysiphonfRhizammina spp., Glomospira charoides, Dorothia gradatra, Textularia foeda, Reophax minuta, Psammosphaera spp. and Verneuilinoides sub­fusiliformis. Sample 97.00 m contained some of these taxa in addition to calcareous element composed of Hedbergella planispira (abundant), Globigerinelloides bentonensis ( common), Gavelinella schloenbachi, Nodosaria humilis and Dentalina lorneiana. The abundant occurrence of the planktonic species H. planispira to­gether with G. bentonensis support the Late Albian pa­

lynological a·ge assignment.

The samples between 86.59 m and 79.71 m all con­tained the index form Lingulogavelinella jarzevae and

were dominated by the planktonic H. delrioensis and

calcareous benthonic species. The more important taxa

recorded were Cibicides gorbenkoi and Arenobulimina advena praeadvena ( 86.59 m), H. delrioensis, Praebulim­

ina evexa and L. kaptarenkae (85.0 1 m). The presence of

Q

el s1 fm c eg!

OUTER SHELF Storm influenced

OUTER SHELF

OUTER SHELF

INNER SHELF/PRODELTA

DISTAL PART OF A FAN-DELT A

Fan-delta front environments

Probably less marine influence

upwards

CORE 6206/02-U-01

L. jarzevae restricts the age of this interval to latest

Albian or Early Cenomanian (Hart et al. 198 1 ). Barnard

& Banner ( 1982) report A. advena praeadvena from Early

Cenomanian in England, with questionable specimens in the very latest Albian, supporting the suggestion of and Early Cenomanian age at the 86.59 m level.

The two uppermost samples in this interval also repre­sent Cenomanian sediments, as shown by the presence of G. cenomanica and G. baltica (Hart et al. 1 98 1 ) . No forms were found in these samples that could exclude a Late Cenomanian age.

There is no nannofossil evidence below the 90.04 m level of this core. The highest occurrence of Predis­cosphaera columnata at 83.00 m and Gartnerago prae­obliquum at 90.04 m ( Fig. 1 5) suggests an Albian age.

One sample at 80. 1 6 m could be of Albian to Middle

Cenomanian age judged on the presence of Cribro­sphaerella primitiva, but because of the very poor diver­

sity of the nannoftora the evidence is insufficient to

1 00 M. Smelror et al. NORSK GEOLOGISK TIDSSKRIFT 74 (1994)

� � � .... .... "' "' "' � � � . w w w w "' � . "' o "' "' "' � o . "' "' � . � � o o o -;: o o o w ;" � o "' o . "' "' <D

"' "' "' "' "' "' � . w w .... . . o o ;" . . . "' .... "' - w

o o o - "' � � o o � o - .. -

o o w o o - -

"' "' o

::: PAL YNOMORPHS :;: CORE 6206/02-U-01

�------------------------------------------------------------------------------ -----------------�C�O�L�LI�O�LOgS�P�ORgi�TE�S�S�P�P�. ============j �----------------------·--·-------------·-----·------------------ .. ................. ..... ..... ...... .. BACULRTISPORJTES SP . �-.............................. ·-------- ----.................... --------........................ --.......... -............ - ----------------- TRACHYSPORI TES SPP . �---------------------------------- ------------------------------------------------ -- DEL TOIOOSPORR JUNCTR ( KARA-11URZR l SINGH 1964 �-.......... -.............. .......... .... -- ----- - ----.... ---------.... .. --- .. .. .. .. .......... ---------- ·-............. --........ -- CHRS"RTOSPOR I TES MAJOR l ROGALSKR INJ LSSON 1958 �-- ................................................... ---------------- ·-·-----·------------------ ------------------ BACULAT l SPOR l lES COrtAUMENSIS l COOKSON l POTONIE 1956 �------------------------------------·---------------------------------------------- PERINOPOLLENITES ELATOIOES COUPER 1958 �--------.... ...; .......... ----------------------------------------------------------.... ------------- DENSO l SPOR I lES VELATUS WEYL.( KR JEG. 1953 �- --1"'--· .......... -----...................... ----------------------------------------------------------- BOTRYOCOCCUS SP.

�--·::::::::::=:::=====�========:::::::::-========::::::::::::::::::::::::::: ��������:����SA:��!:��!S�����:�� !���CK 1910 �------------------------------------------------------------------------- TRIPARTINA VARIABILIS rtALJAVKINA 1949 �--------------------------------------------------------------------.: ................ .. CYCAOOPJTES NITJOUS IBALMEI NORRIS 1969 �-- ----- - ---------------------------------------------------------------- CEREBROPOLLENITES "ACROVERRUCOSUS ITHIERG. l SCHULZ 1961 �---------------------------------------------------------- ------------------ TOOISPORJTES rt!NOR COUPER 1958 �-------------------------------------------------------------- ................................... CERE8ROPOLLENITES THJERGARTII SCHULZ 1967

t----=============-----------

--------====================== ::::::�::::::::::: :�������::o�:O�;�:��N���AYf ·' OETTrt. l SCHUURrt, 1911

�----··---------------------------------------------------------------·-- ------ CHOMOTRILETES Ml NOR l KEOVESI POCOCK 1970 �- -------------------------------------------------------------------------- --------------- GLE l CHEN l l O l TES SENONICUS ROSS 1949 t--------------------.............. ---------------------------------------.. ----........ ---------- OSrtUNOAC l TES WElUtANNII COUPER 1963 �------------------------------------ ---------------------------------- ISCHYOSPORJTES YARIEGATUS l COUPER l SCHULZ 1961 �--------------------- - -- ---------------�-- - ----------------------- STERF.:ISPORITES RULOSENENSIS ISCHULZI SCHULZ 1966 �--- --- OELTOIOOSPORO MINOR ICOUPERI POCOCK 1970 --------------------· ----------·--............ ------------------------...... ---------------............ -........ -- OUAORAECUL INA FINELLAHORMI S rtALJAVKI NA 19(9 ---................................................................. ----------...... ----...... ---................. -------------------------- DEL TO fOOSPORA SP .0 -----------.............. ------.... -.............. -.... --... .. • .... --.................... -----........... ---.... -----.. --------------- RP l CULRT l SPOR l lES OVAL IS l NILSSON l NORR IS 1965 ------------_-------------- • ........ -------------------.... --------...... ------.... ----------- L YCOPOOJUnSPORI TES AUSTROCLRVAT ID ITESI COOK. IPOTONI � 1957

--.............. ------------------------------------------------------------------...... -........ -- MAN Urt lA JRREGULARI S POCOCK 1970 ------------------------------------------------------------------------------------- SPHER IPOLLENI TES CLASSOPOLLOI OESI NILS. IPLOYF ·•DETT. l 965 --------------................ ---.... -----.... -----------------------.... -------------·------- l YCOPOOIUMSPOR l lES RET ICULUMSPOR l lES l ROUSE IOETTM. 1963

=::::::::::.:.::::::::::::::::::=:=:: ====:::::::::::::::::.:.:.. : :::: ::::=:::::: ����:!�:�:!��� 1��c:����(�:��:���: :�:�L� 9�:61

-..................................................... _ ........................................................... _ ---------------- ANNUL I SPORA fOLLICULOSA l ROGALSKA JOE JERSEY 1959 -- ...................... ·---...... ---........ ---.............................. -----...... -------------------- TAUROCUSPOR l TES SEGMENTATUS STOVER 1962 --• .... --.............................................. ------• ----------------- ----- .......... • ------- NE ORA ISTR l CK lR TFIYlOR l PLATf .c, OETTrt .)965 ----.. .................... ---- • -------................ ----- ............. ---- --- .. · .. -- • .... -------- STE RE I SPOR l TES ANT IOUASPOR l TES f Wll .( WEB. l 0ETTr1. 1963 ------------------------------------------------- ................................... EUCOMrtiOITES MINOR GROOT & PENNY 1960 ---................. -------------............. ------.................... - ------------------ MARAT T ISPORI TES SCABRATUS COUPER 1958 --................ ---........ -..................................... -------------------------------- CALAMOSPORA SP,

------------------------------------------- ------------------ INOETERrtlNE ALETE CYSTS ---..................... -------.................... ---.................... - ------------------ NANNOCERATOPSIS AHBONIS O RUGG 1978

----............ --.............. -----...................... - ---.... ------------- NE ORA ISTRICK JA GRJSTHORPENS l S COUPER 1958

----------.... --- ........ ----------.............. ----· - ------------ AUR l TUL lNASPOR l lES l NTRASTR l RTUS NILS. 1958 ------------------------------ ------------------ LAEVJGATOSPORITES SP. -----·----.. --------.. -------- ---------------_1-;C;;iOi;RR�U�GO;;;T,.;:I�SP�O�R 1;-;T�ES�A=MP;;-L<,EC:-;T""I F<'<O;o'RM;;; I;;; S�I�K';;:OR;;;O;-_;;; MU;;; R-;:ZA�I:-P:;;O;';'C�OC;-::K,.-;-;l9::;7�0

--------------------------------- ------------------ UNOULATASPORITES ARANEUS NORRJS 1969 ------------------------------ ------------------ PEROTRiliTES SP. ------------------------------- ------------------ VlTREISPORITES PALLIOUS IREISSINGERI JANSONIUS 1962 ----------------------------- ------------------ LEPTOLEPIOITES SP.

-------------------------- ------------------ CONCAVISPORITES CRASSEXINIUS -------------------·-------- CHASrtATOSPORlTES APERTUS IROGALSKAJ POL ( JANS. 1969 -----·- - -------- ---------- CLASSOPOLLIS CLASSOIDES IPFLUGI POC. (JANSON. 1961

LATE TOARCIAN- AALENIAN AGE

LOWER JURASSIC UNIT C LITHOSTRATIGRAPHIC UNIT

Fig. 13. Range chart of palynomorphs in the Jurassic succession of core 6206/02-U-01.

conclude a Cenomanian age. The occurrence of both Retecapsa /oriei and Prediscosphaera cretacea in a sample at 79.2 1 m is evidence of a Cenomanian age at this level. The common presence of Staurolithes matalosus has also been observed frequently in the Cenomanian.

A belemnite epirostrum from 96.50 m has been deter­

mined as Neohibolites minimus ( Lister). This supports a

Late Albian age for this level.

Upper Cretaceous Kvitnos Formation

A general Turonian to Santonian age is assigned to the

Kvitnos Formation in core l based on the overall micro-

fauna and floral content. The biostratigraphic evidence indicates a hiatus of approximately 2 My at the boundary between the Lange and the Kvitnos forma­tions, and that upper Cenomanian and lowermost Turo­nian deposits are missing at this locality.

The earliest appearance of dinoflagellates Hystrichos­phaeridium difficile and Chantangiella granulifera at 76.00 m immediately above the unconformity show that Turonian or younger Cretaceous deposits are reached.

According to the 'Cycle chart' by Haq et al. ( 1987), H. difficile ranges from the Late Turonian to Early Santo­nian, but according to Jarvis et al. ( 1 988) this species occurs in the Early Turonian in southeast England. The occurrence of Subtilisphaera pirnaensis up to 55.02 m

Fig. 14. Range chart of dinoftagellate cysts in the Cretaceous succession of core 6206/02-U-01.

NORSK GEOLOGISK TIDSSKRIFT 74 (1994)

�-----------------------------------------­�------------------------------------------�----------------------------------1------------------------------------------1--------------------------- ---------------

Jurassic to Cretaceous stratigraphy, Møre basin

PALYNOMORPHS

Core 6202102-U-01 ---------------------------·---------- PTEROOINIUH CINGULFITU" IWETZEll BELOW 1981 -----------------------------··------- EURYOINIUH SAXONIENSIS MRRSHRLL C BAllEN 1988 -------------------------------------- ELLIPSOIOICTYUH IHPERFECTUH IBRIO.& HCINT.ILEN.& WILL.I977 -------------------------------------- LITOSPHRERJOIUM RRUNDUJ1 (CQQK. C EJS. l ORVEY 1919 ------------------------------------·- ACHOnDSPHAERA SAGENA OAVEY & WILLIAHS 1966 -------------------------------------- OVOIOINIUH SCABROSUH ICOOKSON & HUGHESI OAVEY 1970 -------------------------------------- APTEOOINIUM GRANDE COOKSON C HUGHES 1964

1--------------------·········-·-····---- -------------------------------------- GONTAULACTSIA HELICOIDEA IEJS. & CDOKSONI SARJEANT 1966 �--------------------------------- --------------------------------·----- CRIBROPERIOINIUH EOWRROSII ICOOKSON C EIS.I ORVEY 1969 �--·······---------·····-··············- --- ··-······-·--------------------------- SPIHIFERJTES SCABROSUS ICLARKE & VERO.ILENT. t WILL. 1975 1-------------·····--····------------ ---------------------------------- CYCLONEPHELIUH HTSTRIX IEISENACKI OAVEY 1978 �-------------------------------- ----------------------·······-··- ACH0110SPHAERA RAt!ULIFERA IOEFLANOREI EVITT 1963

!--+-------· · ---- ----· ---· · ·------ KIOKAHSIUH POLTPES ICDOKSON & EISENACKI BELDW 1982

10 1

�-- - ·------------- ---1----- - - - ------- BATICASPHAERA SPP. 1-----------··········------····-- ----------------- f-c;-;O;-:H;; E-;:1 0;;;0;';1-;; N'f:IU:;;H;:-'-;-S;: PP;;' • ....;_-----------------i

----------·--------- CHU:U1Y00 PHORELLA NYE! COOKSON C EISENACK 1958 ---····--······-------------------- --- -------------------------------------- LITDSPHAER. SIPHONIPHORUH ICOOK.&EIS.IDAVEY & WILL· 1966 ---------·-···············---------- --- -------------------·--·--·-···- CRLUUOSPH.ASYt1HETRICUI1 IOEFL.C COURT. l ORVEY C WILL-1966

---------------------·---------- CRLIGOO J NIUt! RCERAS lt1ANUt! C COOKSONI LENTIN C WILL· 1913 --------------------- -------- ··---�---------------------------------- CLEISTOSPHAERJOIU11? 11ULTJSPINOSU11 ISINCHI BRIDEAUX 19'71 -------·---------·------------------�-----·------------------- EXOCHOSPHAER. BIFIOUH ICLARKE & VERO.I CLARKE ET AL-1968 ---------------- ---1----·--·------------------ SPIHIFERITES RAMSUS IEHREN.I LOE8LICH & LOEBLICH 1966

----------------------------------- ----- -------------------------------------- PTERODINIUM VERRUCOSU"' BRIDEAUX C 11CINTYRE 19'75 --• • • --• ·-·-• ·--·---• • ---• ·---- • ·-·----------------------· --·---------·---- M ICROOIN IUM SPACUM BR l DE AUX 1971

------------------------- -------------------------------------- CHLAI1YOOPHOAELLA HUGUONIOTI l l VALENS li OAVEY 19'78 ------------------------ --- ---------------------··--------------- RHOt!BOOELLA PAUCISPINA !ALBERT! l DUliBURY 1980 -------------------·······------ ------------------------------------ SPINIFERI lES ALIGERUS SINGH 1983 ---····--------------------- ----- ------------------------------------ SENONJRSPHAERA ROTUNORTA CLRRKE ' VERDIER 1967

--------·-·············-- ----- ······-··-···-··············--·······- CAUCA PRRVA IAL8ERTII ORVET < VERDIER 1971 --------------------------- -----------------------······-···- STEPHOOINIUH CORONATUH OEFLANORE 1936

Legend: l Present l Common

-------·····---------· ----- ------------------------------------·- HYSTRICHOSPHRERIOIU11 BOWERBRNKII ORVEY C Wlll- 1966 ---------------------- ----- -------------------------------------- CHLAI1YDOPHORELLA TRABECULOSR IGOCHTJ OAVEY 19'76 ----•• • ••• ••• • ------·- ------------·------------• -�K"; A�L"= L:;:; OS:;P,: H::: R:: ER"'I:: O"'I::: UH=S:::P:"P:_,· c:-====-::-:="-,,-.,.,.,.,-,..,."=-...,-"=� ---------�----- --------------· M ··------······· ···-------- FICH0t10SPHRERA7 NEPTUN! l IEISENACKI ORVEY C WILLIAMS 1966

-------------------------------------- FLORENTINIR HANTELLII l ORVET & WILL. l OAVEY & VERD. 1973

=��== ======= === = ==== = == :::::::::::::::::::::::::::::::::::: =f-,�:i:�:-i������������::-:T:.::��;:_� :.;;

RX:....;:

S::..P.:..· ----------------1

------------ ---�---······-········-·············---- APTEA POLTHORPHA EISEHACK 1958 ------------------ -------------------------------------- - - CANNINGIR COLLIVERI COOKSON' EISENRCK 1960 -------•••• ·-····---------·------------------------------ ENDOSCRI Hl UH CAMPAHULA l GOCHTI VOZZHEHH IKOVA 1967 -------····--····---···-----·······-----------·······---- STIPHROSPHAERIDIUH ANTHOPHORUH ICOOK. & EIS.I DAVE• 1982 -------------------------------------------------------- EPELIDOSPHAERIOIR SPINOSR ICOOKSON C HUGHESI DRVEY 1969 ----------- ·-··---···--·-----------------------------·- DLIGOSPHAERIDIUH TDTUH 8RIOEAUX 1971 -------------------------------------------------------- MEI'IBRRNOSPHAf�

.C"A",

S'-i

P:-:

.",A::'

D'-i

A,_.;

V.;;E",T";

I::;9.,;7.:..9,-."==",-=",-------I -----------+--i--------------------------------------- APTEOOINJUH t1RCULATUI1 EISENACK ' COOKSON 1960

·-···!----·-··························-····· HTSTRICHOOINIUH VOIGTII IAL8ERTII ORVET IS74 ----------- ------------------------------------------ 11ICROOINJUrt7 OENTATUrt VOZZHENNIKOVA 196'7 ------- ------------ PALEOHTSTRICHOPHORR INFUSORDIOIDES OEFLRNDRE 1935 ----------------·········---------------------- CLEISTOSPHAERIDIUH? ACICULARE DAVEY 1979

---·"'··------------------------------------------------ XIPHOPHORIOIUrt RLATUI't ICOOK. C EJS. l SRRJERNT 1966 -------------1----------------------·····---·-··-- DRPSIL IDINIUH SPP . --· · · · · · ·- ----·i--· · ··········-----·---···------· -�D::I::.N�O;,:P T::-:E::Rc,T:;.G I;.: U:;: H�CL._;A,: O"=o"J D'"' E"'s """="oE'"' F"" L"= A"'HO:-: R:-:E--,.,19:-:3:-: 5---------1 ----------- ----------------------------- HTSTRICHOOINIUH PULCHRUH DEFLANORE 1935 ---------· -----�------------------------------ HICROOINIUH ORNATUH CDDKSON & EISENACK 1960 -------- ----- ------------------------------------ LEBERIOOCYSTA CHLAMYOATR ICOOK., EJS,ISTOVER C EVJTT 19'78

···-····-··········--··-···········-·------· CTCLONEPHELIUH BREVISPINOSUH IPOCOCKI LENTIH & WILL. 1981 ·---- -------------------------------------- SUBTILISPHAERR? TERRULR IOAVEYI LENTIN' WllLIRI'tS 19'76

EXOCHOSPHAERIOIUM PHRRGMJTES ORVEY ET RL.l966 - -----�---······---------------------- HICROOINIUH? CRINITUH ORVET 1969

- ----- -------------------------------------- CANNINGIR SP.R 11ARSHRLL C BRTTEN 1988 - --------------------------------------�-CF CRASSIPELLIS IOEFL.& COOKSONI STOVER & EVITT 1978

-1---------------------------- OOONTOCHITINA COSTATA ALBERT! 1961 SUBTILISPHAERR PIRNRENSIS (ALBERT! l JAIN l 111LLE· 1973 -1------------ DICONODINIUH SPP. �-- • ·- • • • • •• • ·-·--·--·-• • • • • • ·- • • • ·--�T;:A�N=OS:iP�H�A�ER�Ii:;D�I�UH::-'::V:;::A;:- R ;1-; E:-;:C:;::A� LA;;:H� U�S�O::; A;::V� E":"T �,:-:;W�I L:-; L-;I0A�MS;-;I09;;:66;--- -I

1-------· --------------------------- TRITHTROOINIUM SUSPECTU11 IMANUM C COQK.I nAVEY 1969 1----····-----------·-------------- · PALAEOTETRAO l NIUH Sl LI CORUH DEF LAHORE l 936 1------------------------------ CHATANGIELLR GRRNUJ,.IFERA IMRNUt11 LENTH• C WILLIAI1S 1976 1------------------------ XENASCUS CERATIOIOES IOEFLANOREI LENTIN l WILL· 1973 1---------------------------------- PERVOSPHAEAIOIUM PSEUOHYSTRICHOOJNH;n IOEFL.I YUN 1981 �--- --

-----.---�����;-;\���:;::o;:-;1 �,:�::;��!�::�;;:����":;.;1 0;:;�:::�-=-� -;D;;I<F:;" F ;;l C:-;1-;- L:;-E -;H:;; A::; H;::UH::-;&--;::CO::; O;;; K<sO:OH:;-;1°96;;-4;--- -I ------ ·----------------------- CHRTANGJEllA TRJPARTITA tCOOK. 4 EJS.I LENTIN' WILL.t976

----------------·-·······-- SPIHIFERITES POROSUS IHANUH < COOKSONI HARLAHO 1973 ------------------- FROHER FRAGILIS ICOOKSOH t �ISEHRCKI STOVER < EVITT 1978 ------------------ TR1CH001NIU11 CASTANER IOEFL.I CLAAKE l VERDIER 1961

---------------•·- DOROCTSTR SP.A BUJRK & WILLIAHS 1978 OLIGOSPHAER. PULCHERRIHUH IOEFL.& COOK.IORVET & WILL. 1966

----------------- C.CF.VICTORIENSJS ICOOKSON C 11RNU111LENTIN l WILLIR115 19'76

-----�::::::::::::������������:���:��H�IU�:;p��:�·�I�O;;:AN::;N;;I�O;;:ESo-;1°9;;:86;----------------------l ----------- ISABELIOINIUH BELFRSTENSE CCOOK.& EJS.lLENT • & WILL • 1977 ----------- TRJTHYROOINIU11 FRAGILE OAVEY 1969

THALAS610PHORA? SP. ISABELIDI•IUH ACUHINATUH ICOOK.& EJS.ISTOVER & EVITT 1976

Late Albian -- Early Cenomanian Cen. Turonian - Santonian AGE

Lange Fm. Kvitnos Fm. LITHOSTRATIGRAPHIC UNITS

1 02 M. Smelror et al.

l�# �-� � : :: l� : � l� g �

� : : � '"' ' • a;

g : : � l� ; g

Legend :

l 1 3 l 4 7

l 8 1 5

l 1 6 30 l 3 1 60 l 6 1 1 20 • ;> 1 2 1

l;;! ; � lil> ; "' l;;; ; ;;; 1 -' ' -' " lg ; g lg ; � ; �

LATE TOARCIAN • AALENIAN

LOWER JURASSIC UNIT C

. : :: :i : : :: ;;: : g · ·-

-- -

-- · · · -- -

.:g : :;: 1<::: : � �� : g: * '" "' � ' : u: g : g li5 : �

r-- -f · ·

+ -f - · -[ - ·

-- - · - · ·

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. . .

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· · - - · · - · - · · · - - - · - - - - · f · · . - --r-

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. . . . . - - -

- - - - - - -

, . . . . .

· - - - - - · · - - · · · · ·

r-- - - - · · · · · · -- - - - - · -

- - - - · · · f - - - - - - ----- - -f- -=�---1--- --· - - - - - · ·

NORSK GEOLOGISK TIDSSKRIFT 74 ( 1 994)03

.� : g: l� � g: lg: � � MICR OFOSS ILS :: : : ;::; l� � � l� � � GOR E 6206/02-U-01

. . . . . . .

� . . . . . . . · · · · · · · f · ·

· · · - · · · · · - - -- - - - - - -. . . . . . . - - - - - · . . . . . - - - - - - -

r---·

l

- - - - - - -· - - - - - - - · - - - - - - - · .

· - - - - - - - · - - - - - - - · - - - · · -- - - - · · · - ---·

- - - - - · - - - - - - - · - - - - - · - - - ·

- - - - - - · . . . . . . .

� - - - - - - - · . . . . . . . - - - - - - - · ---·

1---- l

· -·-. . . . . . . - - - · l . . . . . . . · · · · · · · - - - - - - -- - - - - - - [ - -

- - - - -

- - -· - - - - - - - · . - - - - r,� --;;;; ,__ _ _ _ _

· - - - - - - ·

: · - - - - - · · r - - - - - - ·

: c - - - - - · l f - - - - - · ·

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=�::: : : : : -�::: : f---- -r-- - ·

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,_ _ _ r--i-- 1-- -c: --

- -- - -

-f--- - - l l -

� -- - · . . . . . . . l - - - -- - - - - - - -

- - - - --r- - · - - - - - - --r-- - - · · · - - - - -_._ _ _ _ 1--- - - - l

'- - - - · - - - - - - · l --- - - · . . . . . . . � - - - - ·

- - - - - - ·

;;;;:::: . . . . . . .

-- - - - - - · ·

E A R L Y C E N O M - @ SANTO N I A N -A G E

LATE A L B I A N z T U R O N I A N

LANG E F m . K V I TNOS F m . L I T HOST R AT I G R A P H I C UN I TS

Fig. 15. Range chart of microfossils in core 6206/02-U-01.

NORSK GEOLOGISK TIDSSKRIFf 74 ( 1 994)

Fig. /6. Range chart of nannofossils in core 6206/

02-U-01.

Leg end:

l Present l Common

Jurassic to Cretaceous stratigraphy, Møre basin 103

NANNOFOSSILS

CORE 6206/02 - U-01

-- - - P ARHABDOL I T HUS A C H L Y O S T AU R I ON H I L L 1 976 -- • • RHAGOD l SCUS SP , --- - - L U C I ANORHABDUS QUADR I F I DUS F O R C H H E I ME R I 972 -- · - - - --- - - GRAN TARHABDUS CORONADVE N T I S l RE I N H A R D T 1 966 l

-- - - - - --- - - R E T E C APS A ANGUS T I F O R A T R BLACK 1 91 1 - - - GAR T N E RAGO O B L I OUUH l S T R A O N E R i 96 3 1 �- - - - - - BRO I NS O N I A E NORM I S l SHUMENKO 1 968 1 -1--- - · · · · PREO I SCOSPHAERA C R E T AC E A l ARKHANGELSK Y 1 9 1 2 1

--- - - - - - C H I A S T O l Y GUS L I T T ERAR I US I GO R K A 1 95 1 1 -- - - - - - · · · · - --- · - - · · · · ·-- - - H E L I C O L I THUS TRABE C U L A T U S I GO R K A 1 951 1 -- - · · · · · · · · · -- - - - - --- - --- - - ZEUGRHABOOTUS D I PLOGRAMMUS I OE F L A NORE 1 95 < 1 -- - --- - ---- - - - - ----- - - - - --- - - TRRN O L I T H U S SRL I L L U M I NO E L 1 965 1

• • • E I FF E L L I T H U S T U R R I SE 1 F F E L L 1 1 I O E F L A N O R E 1 95 < 1 -- - --- - -- - - - - - --- - - - - - - - - · · - - - --- - - R E T E C A P S A L O R I E I ! GA R T N E R 1 96 8 1 - - - W A T Z N R UE R I R B I PO R T A B U K R Y 1 96 9

-- - - - · - ARKHANGELSK I E L L A C Y M B 1 F ORH I S VEK S H I NA ! 95 9

-- - • - - - - - - - - - - - - - - ·�-:S�T®.AR�,�F�I�V E�T H�I;N�A�R M�Stg;��gj���;::=� -- - - - - - - - - - - - - - - - - -'"'OUAORUH GAR T NE R I S U 8 S P . 2 I N C R U X 1 982 - - - - - - - - - --- - - - - - - - - - - - - - - - - - T E T R AP OOORHABOUS D E C O R U S I OE F L ANDRE 1 95 < 1

-- - - - - - - - - · - -- - - - - --· · · · · - · · · · · · - - · - · - RHAGOO I SC US SP L E NOENS I OE F L A ND R E I 95 3 1 -- - --- - - · · · - - - - - - - - - - - - - - - OUADRUM S P ? -- · - - • -- - - - · - --- · - · - - - - - • • • · - - - - • • • _ t-;S�T:;;;AU:;:R�OL::;I.;:T H::-ii�T E;-;S,.-M::-;:A;TT A;;:'L�OS:;-;-U�S-;S'";'T;;:OV�E:-R "71-:::96�6-----f -- · · · - - · - - - · - · · · · · · - - - · - · - - - RHAGOO I SC U S ANGU S T US I S T R AO N E R I 963 1 -- - - - - - - - - - · · · - - · · - - · - - - - - · - O C T O C Y C L U S R E I NHAROT I I I BUKRY 1 96 9 1 --- - - - - - - - - - - - · - - • - - - · - - - · - · - A X OPOOORHABDUS A L B l ANUS l BLACK 1 961 l - · - · - · · · - - · - - - - - - - - - - - - - - - - - - - - M I CRORHABDUL U S D E C O R A T U S DE FL ANDRE 1 959 - • - · • • • · - • - - - - - - · - - - - - - - - - - - - - - PAAHABOOL I T H U S EMBERGER I l S T R A D N E R 1 963 l -- - -- - - - - - - - - - - - · · - · - - - - - - - · - - - - - - GRANTARHABDU S M E OD I I B L A C K 1 97 1 -- - -- - - - - - - - - · • - - · - - - - - - - - - · - - - · - · - - - - C R I BROSPHAE R E L L A PR ! M I T l V A T H l E R S T E I N ! 91 < -- - - - - - - - · · · · - - - - - - - - - - - - - - - - - - - - - - - H AN I V I T E L L A P E M MA T O I D E A D E F L ANDRE ! 965

- - - · - · · · · · · · - · · · · - - - - - - - - - · · · · · - - - - - R E PAGALUM PARV I D E N T A T UM I DE F L ANDRE ' F E R T L 1 95< 1 -- - - · · - - · · - - - - - · - · · - - - - - - - - - - - - - - - - V E K S H I NE L L A QU�DR I AR C U L L A I NO E L 1 96 6 1 -- • --- - - - - - · - - - - - - - - - - - - - - - - - - - - - - - - - - - - - PRAED l SCOSPH A E R A COL UHNA T A l S T O V E R 1 966 l - - · - - - - - • - - - · - - - - · - - - - · - - - - - - - - · - - - - - - - - - - GAR T N E RAGO PRAEOBL l OUUM JAKUBOWSK l 1 986

CENOMANIAN -

LATE ALBIAN

LANG E F m .

SANTON I AN ­T U R O N I A N

K V ITNOS F m .

AG E

L I T HOST RAT I G R A P H I C U N I T

further supports an age not younger than the Santonian for the top of the core.

kirki, Pelosina caudata, Recurvoides globulosus, Textu­laria cf. plummerae and others . The fauna is entirely different from the fauna following from the 74.01 m leve! and persisting to the top of the core. The association is

dominated by planktonic foraminifera, with calcareous

and agglutinated elements as minor, but indigenous ele­ments. The important new occurrences are as follows:

Other characteristic Late Cretaceous taxa include: Al­terbidinium sp. , Chatangiella tripartita, Diconodinium spp., Dorocysta sp. A of Bujak & Williams 1978, Fromea

fragi/is, /sabelidinium spp., Odontochitina costata and Palaeotetradinium si/icorum.

The presence of Stephodinium coronatum up to 60.50 m may suggest that the interva1 76.00-60.50 m is of Turo­nian age, as this species is normally restricted to pre­Coniacian strata (Haq et al. 1 987).

Cyclonephelium distinctum is the most common species

between 76.00 and 62.00 m. Hystrichosphaeridium diffici/e is prominent at 76.00, 72.00 and 60.50 m. Ch/amydo­phorella nyei and Surcu/osphaeridium longifurcatum which are also common in some samples from the Late Albian and Cenomanian interval, also have acme occurrences at 60.50 m and at 68.50 m and 60.50 m, respectively.

An agglutinated 'ftysch-type' foraminifer fauna at

75.48 m includes Ammodiscus cretaceus, Bathysiphonf Rhizammina spp., Clavulina c/avata, Glomospirel/a charoides, Hap/ophragmium lueckei, Haplophragmoides

Gavelinella cf. sandidgei, Globigerinelloides aspera, Bed­berge/la hoelzli, H. simplex, Heterohe/ix moremani, Pleurostomella reussi, Schackoina cenomana bicornis and Tappania eouvigerinaeformis (74.0 1 m), H. bornholmensis, Valvulineria allomorphinoides Whiteinel/a baltica, Verneu­ilinoides polystrophus (70.55 m), Anomalina gorzowiensis (64 .01 m), Planulina lundegreni, Gaveline/la cf. belorussica (60.50 m) and Valvulineria lenticula (68. 1 3 m).

H. hoelzli, P. lundegreni and W. baltica restrict the age to Turonian or younger. W. baltica ( 57.0 1 m) and H. delrioensis ( 54.9 1 m) make it likely that the age is not

younger than Santonian. The uppermost sample con­

tained few age diagnostic species, though according to

Robaszynski et al. ( 1 980) allow a restriction to Santo­

nian age.

1 04 M. Smelror et al.

The nannoflora assemblage in the Kvitnos Formation

represents a stratigraphic mixture of index species. The

occurrence of early forms of Quadrum gartnerii and the

co-occurrence of Biscutum constans and Ahmuellerella octoradiata and common to abundant Lithastrinus septe­narius and Eprolithus flora/is firmly suggests a Turonian

age at 59.05 m. Rhagodiscus asper at this high level and

Rhagodiscus angustus, Octocyclus reinhardtii and Ax­

opodorhabdus albianus at the 70.55 m leve!, are all consid­

ered as Cenomanian or older reworked material. These

observations support the sedimentological indications

that reworking of older sediments has taken place at this

leve l. In conclusion, both the microfauna and nannoplank­

ton assemblages support a latest Turonian age below

59 m, and a possible Coniacian-Santonian age above

58.43 m.

Seismic interpretation and sequence stratigraphy Seismic units and reflections

At site 3 we can define two seismic units within the penetrated section on seismic line IKU-201-88 ( Fig. 2).

These correspond to lithostratigraphic Units A and B,

respectively. Both bedrock units have chaotic acoustic

signatures with discontinuous reflections. The frequency of reflections is lower in Unit A, but this might be

explained by the processing causing lower energy return

from around 0.5 s. The reflection amplitudes are high in

Unit B, and low below the strong and nearly continuous

reflection separating the two units. This reflection has a

large-scale hummocky appearance in the upper part, but

is difficult to interpret confidently below 0.5 s.

The reflections in the upper part of Unit B at site 3 are

apparently truncated at a nearly horizontal and partly

continuous west of the site, approximately 20 ms below the base Quaternary. A possible explanation could be that this represents a weathering boundary within the

upper unit, stratigraphically above the cored section. At site 2, two seismic units corresponding to litho­

stratigraphic Units B and C are defined (Fig. 2). The lower seismic unit was also defined in the upper part of

core 3. The lower unit ( B) has a chaotic seismic signa­ture, with discontinuous high amplitude reflections. The

upper unit (C) has high amplitude reflections which

become more continuous higher up. Also the amplitude

and frequency of reflections increase upwards in this

unit.

At site l three seismic units corresponding to litho­

stratigraphic Unit C and the Cretaceous Lange and

Kvitnos formations are defined (Fig. 2). The oldest com­

prises partly continuous high amplitude reflections as

described above. The onlapping reflectors in the seismic unit above corresponding to the Lange formation have

lower amplitude and are truncated by the uppermost

NORSK GEOLOGISK TIDSSKRIFT 74 (1994)

sequence boundary, i.e. the boundary between the Lange and Kvitnos formations. The middle seismic unit is prob­ably pinching out immediately eastwards of the coring site. The uppermost seismic unit corresponding to the Kvitnos formation has a chaotic seismic signature at the coring site, but upwards nearly parallel continuous reflec­tions can be seen.

Seismic and depositional sequences

The large-scale hummocky appearance of the reflection at the interface indicates that Unit A has been subject to erosion, and the boundary between Unit A and Unit B represents a major sequence boundary. This corresponds

to seismic reflection IJ 1 on Figs. 2 and 3. The poor biostratigraphic resolution makes it difficult to estimate the tempora! magnitude of the hiatus separating these two units, but the stratigraphic gap may be in the order of 20 My, implying that at !east the Sinemurian and Pliensbachian are missing at this site.

The boundary between Unit B and Unit C in core 2 is defined at 85 m by the transition to a unit comprising poorly sorted sandstones and mudstones with coal frag­ments. This boundary corresponds to the IJ 1 seismic reflection. The boundary between Units B and C in core 2 is also recognized by a distinct shift in the petrophysi­cal logs, and by the high amplitude seismic reflection, which has a distinctive 'wavy' appearance, possibly rep­

resenting an inundated topography. The erosional lag deposits at the base of Unit C are

interpreted here as a transgressive surface. Following this interpretation the proximal fan-delta deposits of Unit B would comprise low stand deposits, while Unit C would represent the lower part of a transgressive unit.

This transgressive unit is also represented by core 8, which penetrated the same seismic unit as the upper part

of core 2. The seismic unit recovered in core 8 contains high amplitude reflections which are partly continuous at the coring site and to the west of it. The high frequency of reflections which correlates with the observation of numerous cemented layers in the sandstone sequence encountered at this site.

Within the penetrated bedrock at si te l , three seismic units are defined (Fig. 2). These units correspond to the Lower Jurassic Unit C, and to the Cretaceous Lange Formation and the Kvitnos Formation, respectively.

The lowermost Unit C, below the reflections defining

the lowermost sequence boundary at 98.3 m in core l ( i.e. the Jurassic/Cretaceous boundary), shows partly continuous high amplitude reflections. The lowermost

part of this seismic unit represents a further continuation of the transgressive deposits recognized in the upper co re 2 and core 8.

The upward decrease in beach rock horizons and an

increase in signs of subaerial exposure indicate a regres­sive development in the upper part of the unit.

The evidence is vague, but, based on the distribution of marine microplankton and the interpretation of the

NORSK GEOLOGISK TIDSSKRIFT 74 (I994)

petrophysicial logs, we have interpreted the peak in the

gamma readings at � 1 35 m, tentatively to coincide with

the maximum flooding surface of the sequence compris­

ing lithostratigraphic Units B and C. The transgressive deposits of this sequence would thus comprise the succes­

si on covered by the upper part of core 2, core 8 and the

lower part of core l (i .e. below 135 m), and the high stand system tract of the sequence would comprise the

middle part of core l (i .e. from 1 35 m up to the sequence boundary at 98.3 m).

The sequence boundary recognized at 98.3 m in core l represents a major hiatus with a tempora} magnitude of 80 My (i .e. spanning the earliest Aalenian to the Late

Albian time interval). This boundary corresponds to the BC seismic reflection. The overlying 43.4 m thick Creta­

ceous succession in core l can be divided into two

sequences by the sequence boundary at 98.3 m and an

intra-Cretaceous sequence boundary at 76.0 m. These

Jurassic to Cretaceous stratigraphy, Møre basin 105

two sequence boundaries show evidence of both trunca­

tion and onlap.

The oldest of the two sequences, which lithostrati­graphically can be related to the Lange Formation, has

lower amplitude reflections than the underlying Lower­Middle Jurassic sequence. It possibly pinches out imme­

diately east of the coring site. Poor seismic resolution

allows no detailed interpretation at the site.

The sequence corresponding to the Lange Formation

comprises three sub-units. The lowermost unit (98 .3-90 m) is interpreted as representing partly mass-gravity

flows, and partly sedimentation from suspension in an inner shelf/prodelta depositional environment. These

may represent low-stand deposits.

The overlying sub-unit (90.0-97.5 m) comprises

marine coastal sand at the base, gradually evolving into

outer shelf deposits during a transgressive event (i .e.

representing a transgressive system fract).

Lit ho log y Gamma Sonic Neutron Density TOC % Stratigraphical significant first/last occurrences of fossil taxa

cl s1 f m � qd CORE 6206/02-U-0 1

� • • i \

( �

o , ' ( , ,

H. delrioensis H. hoelzli

50

S. coronatum 60

P. lundegrani

w. baltica 70

�: =�era H. difficile

L. siphoniphorum L. jarzevae 80

L. jarzevae A. grande

N. minimus

C. thiergartii

N. ambonis

90

1 00

1 1 0

1 20

1 30

1 40

1 50

1 60

1 70

1 80

1 85 m

Fig. 17. Lithostratigraphy, petrophysical logs, TOC - data and first/last occurrences of biostratigraphic key fossils in core 6206/02-U-01 .

l 06 M. Smelror et al.

LEGE ND --.- Fault

6"00'

Seismic boundary l nterpreted seismic u nits (supposed ages)

CJ CJ CJ

Tertiary (un its A,C'1 .c '2 l

63°00'

NW Mere Bas in

Cretaceous (unit D ')

Ju rassic (unit E/ F )

Basement (unit l )

2.5 km

6°20'

Age l l ithology '(from cores )

� Late Cretaceous Mudstone

IJitm:::fl Earl y Ju rass ic Sandstone

Early Jurass ic Conglomerate

NORSK GEOLOGISK TIDSSKRIFT 74 ( 1 994)

06/02 -U-03 6206/02 -U -02

6206/02 -U -08 · 6206/02 -U -01

l

SE 6206/02-U-01 08 02 03

I KU -201 -88

Fig. 18. Seismic interpretation of subcropping units at the Møre Basin Margin. A schematic profile is drawn from seismic line IKU-201-88 (see also Fig. 2).

At 79.5 m there is a marked change in lithofacies, and

the sandstone is replaced by heterogeneous mudstone

with abundant clasts. This lower Cenomanian unit is .

interpreted as inner shelfjprodelta deposits, representing

the high stand system tract of the Late Albian- Middle

Cenomanian depositional sequence.

The Turonian-Santonian sequence referred to as the Kvitnos Formation is interpreted as representing open

NORSK GEOLOGISK TIDSSKRIFT 74 (1994)

marine outer shelf sediments deposited during a relative sea-level high stand period.

The Late Albian to Early Cenomanian sand body within the Lange Formation rnight possess potential reservoir qualities in marginal positions, and deserves some consideration with respect to its possible areal distribution. The sand may have been deposited in re­sponse to a distinct short-term sea level fall dose to 97 My. According to Hastings ( 1 987), the ( ?)Aptian to Cenomanian sands in the northem Haltenbanken area represent regional mappable seismic units, whereas the Turonian and younger sands have the seisrnic character of a submarine fan with local sand bodies. This may support the assumption that the Late Albian (at base) sand is caused by sea level ftuctuations. Our sedimento­logical model (ioner shelfjcoastal) is in agreement with the observation by Hastings ( 1 987). Brekke & Riis ( 1987) indicate that the clastic input is probably derived through erosion from the Trøndelag Platform and Frøya High, which represented stable elements at that time.

Bedrock map of the Møre Basin Margin

A series of westward tilted horst blocks separates the deep Møre Basin from a nearshore basin within the Møre Basin Margin in the southem area. Several sub­cropping units have been mapped in the nearshore area, but owing to the offshore horst only units of late Creta­ceous or younger age can confidently be tied from the nearshore basin into the Møre Basin.

The subcrop map in Fig. 1 7 is modified from the map presented by Haugane et al. (unpublished), partly based on information from cores. As data from new seis­mic surveys have not been avai1able, a comp1ete reinter­pretation of the subcropping units has not been carried out.

Units C� and C2 (Fig. 1 7) were previously interpreted to be of Cretaceous age, but TuronianjSantonian age in the uppermost part of core 6206/02-U-01 now indicates that the Cretaceous-Tertiary boundary subcrops further to the east. The reflection between units C2 and D ' is a possible candidate for this boundary.

Core l shows that the Cretaceous-Jurassic boundary subcrops further to the west than previously interpreted. As this boundary does not subcrop on line IKU-203-88, the subcrops of the sequences seen on line IKU-20 1-88 ( IKU- 141 -87) are cut off by the basement fault to the south somewhere between the two lines.

The seismic tie to the subcropping Jurassic units en­countered at the coring sites southwest of the area around 62°50 ' is uncertain, and the sedimentary unit subcropping near the basement in this area has a seismic signature different from that seen on line IKU-20 1-88. Based on the existing data we cannot, however, exclude a possible Jurassic age of the oldest subcropping strata.

Jurassic to Cretaceous stratigraphy, Møre basin 107

Acknow/edgements. - This pa per presents some of the results obtained in the IK U project 'Shallow drilling off Møre-Trøndelag 1987 /88'. The project was sup­ported by BP Norway Ltd. U.A., Elf Petroleum Norge a.s., Esso Norge a.s., Mobil Exploration Norway Inc., Norsk Agip A/S, Norsk Hydro a.s., Statoil, Amoco Norway Oil Co., Conoco Norway Inc., A/S Norske Shell, Saga Petroleum a.s. and Total Marine Norsk A/S. Their participation and cooperation are gratefully acknowledged. We thank H. Brekke, K. Dybkjaer, D. Renshaw and A. M. Spencer for their reviews, which helped to improve the paper.

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