Sedimentation at the Jurassic–Triassic boundary, south-west Barents Sea: indication of climate change - From Depositional Systems to Sedimentary Successions on the Norwegian Continental Margin - page 212

the Barents Sea basins. This climatic change is
apparently very widespread and is referred to
from basins as far to the south as Spain and
Hungary.

Badley, M.E., Price, J.D., Rambech Dahl, C. and Agdestein, T.
(1988) The structural evolution of the northern Viking
Graben and its bearing upon extensional modes of basin
formation. J. Geol. Soc. London , 145 , 455-472.
Bergan, M. and Knarud, R. (1993) Apparent changes in
clastic mineralogy of the Triassic to Jurassic succession,
Norwegian Barents Sea: possible implications for pale-
odrainage and subsidence. In: Arctic Geology and
Petroleum Potential (Eds T.O Vorren, E. Bergsager, Ø.A.
Dahl-Stamnes, E. Holter, B. Johansen, E. Lie and T.B.
Lund), Norw. Petrol. Soc. Spec. Publ ., 2 , Elsevier,
Amsterdam, 481-493.
Berglund, L.T., Augustson, J., Færseth, R., Gjelberg, J. and
Ramberg-Moe, H. (1986) The evolution of the
Hammerfest Basin. In: Habitat of Hydrocarbons on the
Norwegian Continental Shelf (Eds A.M. Spencer, C.J.
Campbell, S.H. Hanslien, P.H. Nelson, E. Nysaether and
E.G. Ormaasen), Proc. Norw. Petrol. Soc., Graham and
Trotman, London, 319-338.
Besly, B.M. and Fielding, C.R. (1989) Palaeosols in
Westphalian coal-bearing and red-bed sequences, cen-
tral and northern England. Palaeogeogr. Palaeoclimatol.
Palaeoecol. , 70 , 303-330.
Blystad, P. , Brekke, H., Færseth, R., Larsen, B.T., Skogseid,
J. and Tørudbakken, B. (1995) Structural elements of
the Norwegian continental shelf. Part II: The Norwegian
Sea region. Norw. Petrol. Direct. Bull. , 8 , 1-45.
Breivik, A.J., Faleide, J.I. and Gudlaugsson, S.T. (1998)
South-western Barents Sea margin: late Mesozoic sedi-
mentary basins and crustal extension. Tectonophysics ,
293 , 21-44.
Bridge, J.S. and Leeder, M.R. (1979) A simulation model of
alluvial stratigraphy. Sedimentology , 26 , 617-644.
Bridge, J.S. and Mackey, S.D. (1993) A revised alluvial
stratigraphy model. In: Alluvial Sedimentation (Eds C.
Puigdefabregas and M. Marzo), Int. Assoc. Sedimentol.
Spec. Publ. , 17 , 319-336.
Bugge, T., Elvebakk, G., Fanavoll, S., Mangerud, G.,
Smelror, M., Weiss, H.M., Gjelberg, J., Kristesen, S.E.
and Nilsen, K. (2002) Shallow stratigraphic drilling
applied in hydrocarbon exploration of the Nordkapp
Basin, Barents Sea. Mar. Petrol. Geol. , 19 , 13-37.
Charnock, M., Kristiansen, I.L , Ryseth, A. and Fenton, J.
(2001) Sequence stratigraphy of the Dunlin Group,
northern North Sea. In: Sedimentary Environments off-
shore Norway: Palaeozoic to Recent (Eds O.J. Martinsen
and T. Dreyer), Norw. Petrol. Soc. Spec. Publ ., 10 ,
Elsevier, Amsterdam, 145-174.
Collinson, J.D. (1996) Alluvial sediments. In: Sedimentary
Environments: Processes, Facies and Stratigraphy (Ed.
H.G Reading), pp 37-82. Blackwell.
Dalland, A., Worsley, D. and Ofstad, K. (1988) A lithostrati -
graphical scheme for the Mesozoic and Cenozoic suc-
cession offshore Mid- and Northern Norway. Norw.
Petrol. Direct. Bull. , 4 , 1-65.
Dallmann, W.K. (Ed) (1999) Lithostratigraphic Lexicon of
Svalbard: Upper Paleozoic to Quaternary Bedrock .
Review and Recommendation for Nomenclature Use .
Norwegian Polar Institute, Tromsø, 318 pp.
Doré, A.G. ( 1992) Synoptic palaeogeography of the North-
east Atlantic Seaway: late Permian - Cretaceous. In:
Basins on the Atlantic Seaboard: Petroleum Geology,
Sedimentology and Basin Evolution (Ed. J. Parnell),
Geol. Soc. London Spec. Publ ., 62 , 421-446.

Whereas sub-regional factors such as changing
subsidence rates and rejuvenation/reconfigura-
tion of hinterlands can explain the very sandy and
coarse-grained nature of the Tubåen Formation, as
opposed to (for example) the generally finer-
grained Snadd Formation with its more sporadic
occurrence of channel sandstones, these effects
would clearly be amplified by a wetter climate. In
relative terms, the coarser sandstones in the
Tubåen Formation would require more powerful
streams to form than the finer grained sandstones
in the Snadd Formation. This can clearly be
accomplished if the river discharge increased due
to higher annual precipitation in the rejuvenated
hinterland.
Although not entirely conclusive, the data and
interpretations presented here accord with other
studies indicating increased climatic humidity
across the Triassic to Jurassic boundary in many
European basins. A direct climatic relationship
with the Triassic to Jurassic volcanism to the south
can only be speculated on, although the very
regional nature of the change to a more humid cli-
mate in the Early Jurassic supports a global (vol-
canic) cause.

ACKNOWLEDGEMENTS

I wish to thank Statoil for the permission to publish
this paper. Also, the partners in the Snøhvit
Production unit, Petoro AS, Total E&P Norge AS,
RWE DEA Norge AS and GDF SUEZ E&P Norge AS,
are thanked for the permission to publish data from
well 7121/4-F-2H. Reviewers William Helland-
Hansen and Atle Folkestad provided many useful
comments to the manuscript. Geir Samuelsen is
thanked for his careful drafting and many good
ideas to improve the graphic work.

REFERENCES

Ahlberg, A., Arndorrf, L. and Guy-Ohlson, D. (2002)
Onshore climatic change during the Late Triassic marine
inundation of the Central European Basin. Terra Nova ,
14 , 241-248.
Allen, J.R.L. (1978) Studies in fluviatile sedimentation:
an exploratory quantitative model for the architecture
of avulsion-controlled alluvial suites. Sed. Geol. , 21 ,
129-147.