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The World's Coasts
8. Europe
8.1.1. SVALBARD AND JAN MAYEN
©Geostudies Pty Ltd.
Compiled by: Tormod Klemsdal (Department of Geosciences, University of Oslo, Norway).
Last revised: September 2008
Svalbard
The Svalbard archipelago lies approximately 700 km north of Norway between 74°N
and 81°N and between 10° E and 35° E (Figure 1). It consist of six large islands Spitsbergen (39,043 sq. km), Nordaustlandet (14,210 sq. km), Edgeøya (5,030 sq. km),
Barentsøya (1,330 sq. km), Prins Karls Forland (640 sq. km) and Kong Karls Land (326
sq. km) - and a great number of smaller islands. It also includes Bjørnøya (Bear Island)
(178 sq. km)(Figure 4), 440 km north of the mainland of Norway and 250 km south of
Svalbard. The Svalbard Treaty (1925) gave custody of these islands to Norway.
The geology of Svalbard and Bjørnøya (Winsnes 1988) includes the Hecla Hoek
Complex, found in the northern part of the Nordaustlandet, in the northeast and along
the western coast of Spitsbergen, on Prins Karls Forland and in the southern part of
Bjørnøya (Figure 1). The Hecla Hoek Complex consists of mainly Pre-Cambrian
metamorphic rocks with some Cambrian and Ordovician sedimentary formations. The
rocks of the Hecla Hoek Complex were metamorphosed during the Caledonian orogeny
in late Silurian - early Devonian, and varies from highly metamorphosed gneisses and
migmatites to marble and schists, quartzites and limestone/marble. North of
Kongsfjorden the Complex consists of gneisses and migmatites with Caledonian
granites and basic intrusives, which are also found, together with igneous rocks like
quartz porphyry lava, on the north eastern parts of Nordaustlandet.
The younger sedimentary rocks vary. The Devonian rocks are shale and sandstone,
while Carboniferous and Permian rocks consist of continental sandstones, beneath
limestone and chert with seams of coal. Clay, shale and siltstone, and younger sandstone
of Triassic age are followed by Jurassic shale and conglomerates. Cretaceous sandstone
and shale underlie the sandstone, and there are Tertiary shales and seams of coal.
The Devonian rocks are found in a rectangular area in the central, northern parts of
Spitsbergen (Figure 1). The Carboniferous and Permian rocks occur in the southern
parts of Nordaustlandet, in the north-eastern and central parts of Spitsbergen and in
small areas in the western parts of Spitsbergen, from west of Ny Ålesund in the north to
the area of Hornsund in the south. The Tertiary rocks constitute the rocks of the central
parts of southern Spitsbergen, south from Isfjorden. Around these Mesozoic rocks are
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found in the central and southern parts of Svalbard. The islands of Barentsøya, Edgeøya,
Svenskøya, Kongsøya and Hopen all have Triassic sedimentary rocks intruded by
dolerite of Mesozoic age.
The Caledonian Orogeny caused folding, thrusting and faulting of the bedrock. The
opening of the North Atlantic Ocean in Tertiary times, with faulting and flexuring of the
bedrock produced the present geological setting.
Meteorological stations on Svalbard (Figure 1) are at Ny-Ålesund, Isfjord Radio,
Longyearbyen, Sveagruva, Hopen and Bjørnøya. Mean annual precipitation varies
between 300 mm and 500 mm along the coast, and the average annual temperature is
close to -6° C. The mean monthly temperature ranges from -15° C to 6° C, and is above
freezing between the beginning of June and the end of September. As frost weathering is
most active with temperature variations around 0° C to -5° C frost weathering along the
coast is most active from April to June and from September to December.
Wind-generated waves strongly affect the shore. The strongest winds are from SW,
across open sea with a large fetch from the North Atlantic Ocean. Autumn is when the
strongest winds produce the largest waves attacking the coast.
Evidence from satellite images (1970-1984) has enabled the Norwegian Meteorological
Institute to make maps of the average monthly extent of sea ice along the coast of
Svalbard. Sea ice starts to form along the northern and northeastern coast of Svalbard in
October and by December the archipelago is surrounded. The sea ice breaks up
sufficiently for waves to attack the shore again in late May or early June on the
southwestern coast of Spitsbergen. On the west coast of Spitsbergen sea ice is melted by
the warm North Atlantic current before the rest of the coast is free. The west coast of
Spitsbergen is ice free for an average of 5 months, while the coasts of Edgeøya and
Barentsøya have a 3 month period free of ice from mid-July to the end of October.
However, drifting sea ice can make it impossible for ships to sail around the archipelago
during the summer, and when it is driven onshore it erodes cliffs and rocky outcrops and
moves beach material, including large boulders.
Permafrost also affects the shore. During the summer months the upper part of the
permafrost thaws, forming a layer of unfrozen ground that can be attacked by waves.
When the temperature falls below zero and the ground freezes again the freezing of the
water in the zone between the permafrost and the overlying frozen layer causes frost
weathering on the shore, particularly where the bedrock has many fissures or joints that
are widened by freeze and thaw processes. Frost weathering produces loose material for
the waves to mobilise and use to erode the shore (Nansen 1920, 1922).
Although periglacial processes and wave action are dominant processes now, coastal
landforms have features inherited from earlier phases, such as the plateaux and
escarpments produced by glacial and pre-glacial denudation. The northern, central,
southern and western parts of Spitsbergen have wide, open valleys between hills and
more or less rounded mountains.
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There are five main types of coastal landform in Svalbard: strandflats, fjords, cliffs,
composite cliffs, and concave slopes (Figure 2). Reference should be made to the map
of glacial geology and geomorphology of Svalbard by Kristiansen and Sollid (1986).
The term strandflat was introduced into the Norwegian language by Reusch (1894). In
his 1912 expedition Nansen described the strandflat along the coast of Spitsbergen, and
later he advocated frost weathering and wave action as the processes responsible for the
development of the strandflats. There are strandflats along the north coast of
Nordaustlandet, on the islands of Hinlopenstretet and on the islands of Kongsøya,
Svenskøya, Barentsøya and Edgeøya (Klemsdal 1989). The islands of Hinlopenstretet,
Kongsøya, Svenskøya, Barentsøya and Edgeøya are situated east of Spitsbergen and
consist mainly of Triassic sedimentary rocks with some Carboniferous and Permian
formations. The strandflat on these islands may be the result long-continued postTriassic denudation in a warm and humid climate. The denudation formed a gently,
undulating topography with low relief in the eastern parts of Svalbard and on the
surrounding Barents Sea floor, including a coastal plain which is the strandflat.
Geomorphological activity during Quaternary, especially glacial erosion, was of minor
importance in this area and did not destroy the preglacial landforms.
The fjord coasts of northern and western Spitsbergen and Nordaustlandet also had their
origin in preglacial topography, which was here an upland in contrast with the lower
relief further east. Long-continued weathering in a warm climate, accompanied by mass
movements, shaped rounded mountains and hills dissected by river valleys. Zones of
weakness in the bedrock guided the incision of valleys. Some preglacial valleys in
central Spitsbergen developed an open form with a steep upper slope on the valley sides
and gently declining slopes towards a broad valley floor. In Quaternary times valley
glaciers at the beginning and end of the glacial periods and ice currents during
maximum ice cover, further deepened these valleys. The short valleys along the west
coast were transformed by valley glaciers into U-shaped valleys, and ice currents may
have overdeepened the larger Isfjorden during maximum extent of glaciation. When the
glaciers retreated and the sea entered the lowest parts of the valleys the fjords were
formed. The slopes along a fjord may fall steeply into the sea, as in Magdalenafjord or
the slope may change from a steep upper slope to a gentler lower slope down to the
shore, as on the western and eastern sides of Billefjord (Photo 1).
Cliffs are vertical or steep coastal slopes cut in bedrock. In Svalbard there are high sea
cliffs and the low sea cliffs (Figure 2). Some cliffs are steep formerly glaciated slopes
bordering fjords (Photo 1), but on the open coast waves attack the cliff base and frost
weathering and mass movement keep the cliff vertical or steep (Photo 2). Often there is
an abrasion shore platform in bedrock or an intertidal gravelly area in front of the cliff,
but where the land has been raised by postglacial isostatic rebound the cliffs emerge and
become degraded to bluffs by frost weathering and mass movement. They are fronted by
emerged shore platforms and shingle beaches. Such fossil cliffs are found on the
northwest coast of Spitsbergen and the north coast of Nordaustlandet, all in the Hecla
Hoek Complex.
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On some steep coasts a slope descends from a plateau and is undercut by a vertical cliff,
which may be up to 30 m high (Photo 2). Such slope-over-wall profiles are found in the
sedimentary bedrock of island of Hopen, at Edgeøya, Barentsøya, and on parts of the
southwest coast of Nordaustlandet.
Some steep coasts have a concave upper slope which descends to a gently declining
concave slope towards the sea. This gently declining slope may meet the sea either in a
low sea cliff, up to 20 meters high or on a shore that slopes down into the sea.
Landforms of this type are found along the east coast of Spitsbergen, mostly in
sedimentary rocks younger than Carboniferous and along many of the fjords. In addition
to these five coastal types there are ice coasts where glaciers reach the sea, often
forming a vertical ice wall (Photo 3).
The shores of Svalbard are either rocky, beneath cliffs or coastal slopes, or beaches of
shingle and boulders. Sandy beaches are few, but some of the spits sealing lagoons are
composed of sand and shingle. Along the coast are many pocket beaches, some sandy
beaches others shingle beaches (Photo 4).
Beach ridges consist of pebbles and cobbles of different sizes (Photo 4) and are still
forming on prograding shores. There are also fossil beach ridges that developed during
Postglacial time as the land emerged from the sea due to the isostatic rebound (Figure
3).
Coastal lagoons of are varying size, close to and separated from the sea by a beach ridge
barrier or spits of sand and shingle. Examples are Brandalspynten by Ny-Ålesund
(Photo 5) and Sarstangen, an elongated, sharply pointed arrow spit on the west side of
the Forlandsundet Strait between Spitsbergen and Kong Karls Forland. Most of the
lagoons are found on the west and north coast of Spitsbergen, but lagoons are also
present alongside fjords and on the islands of Barentsøya and Edgeøya (Figure 3)
Klemsdal 1986).
Deltaic fans of fluvial material have been deposited near the coast or protruding into the
sea along the coast of Svalbard. There are many small deltas, which show triangular
fans extending out into the sea.
Bjørnøya
The bedrock of the coast of Bjørnøya consists of a small area of the Hecla Hoek
Complex in the southernmost part, with Carboniferous and Permian sedimentary rocks
in the rest of the island and only a narrow band of Devonian formations. Small areas of
Triassic rocks are found on the highest parts of the island at Miseryfjellet Mountain and
Hamberg - Fuglefjellet Mountain in the south.
These sedimentary rocks are gently folded and lie beneath a gently undulating plain 20
to 35 m above sea level. Frost weathering, mass movement and the action of the waves
and sea ice have formed a low cliff along most of the coast (Figure 4), as on the north
coast at Bjørnøya Radio, where the cliff is between 10 and 20 m high and there is an
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abrasion platform in front of the headlands. Along most of the coast the abrasion
platform is submerged. Headlands and bays are bordered by low cliffs, and in a few of
the bays there is a shingle beach. Otherwise the shore is rocky with features produced by
wave abrasion and locally ice scouring.
There is a high cliff (more than 400 m) around Hambergfjellet Mountain in the
southwest and the coast of the southern tip of the island. The southeastern coast from
Hambergfjellet Mountain and Fuglfjellet Mountain in the south to Miseryfjellet
Mountain has a low cliff coast. The eastern coast along the Miseryfjellet Mountain has a
slope-over-wall profile with is a low basal cliff, which is under attack by the waves and
an upper slope formed by frost weathering and mass movement. Cliffs have been cut
into the tow of a large landslide.
Jan Mayen Island
Jan Mayen Island is situated between 8° and 9° W and 71° N, 500 km east of Greenland
and 550 km northeast of Iceland (Figure 1). The island is 53 km long and covers an area
of 373 sq. km. The highest point is Mount Beerenberg, a Quaternary volcano rising
2,277 m above sea level. The island has an arctic, maritime climate with mean monthly
temperature of 5° C in August and -6° C in February and March. Average annual
precipitation at the meteorological station is about 700 mm, but there are large
variations with height above sea level. There are many day with fog and very few clear
days. On the northwest coast of the island the cold East-Greenland Ocean current flows
SW, while on the southeastern coast the warmer North-Atlantic Ocean current travels
northward. Drifting sea ice normally surrounds the island from February to April, but is
more persistent in the north. As the ocean currents meet around the island, air masses
and air currents also converge, producing strong winds and a high wave energy along
the coast of the island. The geomorphology has been studied by Dallmann et al. (1997)
and mapped by Klemsdal (1989) and Høvgard (1996).
From Iceland the North-Atlantic Midoceanic Ridge stretches NE as the Jan Mayen
Ridge. The ridges rises from ocean depths of 1,500 to 2,000 m and north of Jan Mayen
is a fracture zone, running NW-SE, where the sea floor is spreading about 2 cm a year.
The ridge started to form on the sea floor in the Eocene, but the oldest rocks above sea
level only go back 500,000 years. The island is thus relatively young, composed of
basaltic lavas and tephra. There are many minor craters on the southwestern part of the
island, but the Beerenberg volcano dominates the island, the lower part (up to 1,500 m
above sea level) a shield volcano with a slope of 15°, while the upper part is a
stratovolcano with slopes of 30°.
In September 1970 there was a three week eruption on the lower northeastern flank of
the mountain. Lava flowed out from craters along a 5 km long fissure zone and down
towards the sea to add an area of 4 sq. km of new land. During the following winter
more than half of this land was eroded away by waves. Further eruptions in 1985
produced salients of lava extending into the sea.
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There are many days with stormy weather, and Jan Mayen is exposed to strong wave
action from all directions: from the North Atlantic, the Greenland Sea and the Arctic
Ocean. Generally basaltic lava is resistant towards erosion while volcanic gravel and ash
are and more easily eroded by the waves, transported along the coast and accumulated
as sand and shingle beaches.
There are high sea cliffs (10 m to more than 200 m), low cliffs (< 10 m), steeply sloping
rocky shores, shingle beaches and four stretches where glaciers meet the sea (Figure 5).
The longest continuous high sea cliffs are south and east of Beerenberg and on the SE
and SW coasts. Cliff erosion has produced stacks, arches, caves and notches. In front of
the high cliffs there is either a rocky shore where wave abrasion has cut an abrasion
shore platform or a stony beach covering this platform. Extensive low cliffs fronted by
rocky shores are found in the southwest between Kraterflya and Guineabukta and along
the northernmost coast of the island. On the west coast (west of Kronprins Olavs bre),
the land surface slopes gently into the sea, by way of a rocky shore or abrasion platform.
At Kokssletta a 4,000 year old glacial moraine extending on to an emerged (6-10 m)
shore platform is overlain by a more recent lava flow.
There are alternations of rocky shores and shingle beaches in front of these cliffs.
Beaches are derived from cliffs of weathered lava and volcanic sand and gravel by frost
action, slumping and wave scour. Shingle beach ridges have formed in the bays of
Rekvedbukta and Engelskbukta, in places enclosing lagoons, as at Sørlaguna, which
dries out during the summer, and Nordlaguna, which is 40 m deep. A barrier beach 11
km long encloses Lagunevallen on the south coast, and a similar barrier fronts
Stajonsbukta on the north coast, where there is a sandy beach north of Sørlaguna.
Emerged beaches occur in several places along the coast of Jan Mayen.