The Geology
of
Longyearbyen
Karsten Piepjohn, Rolf Stange,
Malte Jochmann & Christiaane Hübner
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1
2
Introduction
S
valbard tells a fantastic history through the seemingly unremarkable rocks of the dark-shaded
mountain ranges that lie exposed beside the glaciers and along the cold coasts. Geological
history is excellently presented, as if in a geology textbook, because the ice-free areas are not
covered by vegetation the way they are in Central Europe, for example. A large proportion of Earth’s
history is exposed on the islands of the small archipelago, which makes Svalbard uniquely attractive
to geologists in the Arctic.
The present landscape shows distinct
land forms characteristic of cold climate
conditions on Earth: in Longyearbyen,
the Quaternary Ice Age still has not
ended.
In this booklet, we would like to
take you on an exciting journey through
the ancient past in the surroundings
of Longyearbyen. We will start with a
brief general description of Svalbard’s
geological history, and then zoom in on
the geology and the present landscape
in and around Longyearbyen.
Map: Geology of Svalbard (Hjelle 1993).
Publisher: Longyearbyen feltbiologiske forening (LoFF)
P.O.Box 694, 9171 Longyearbyen
All text, figures, maps and photographs, unless otherwise
specified, are by Karsten Piepjohn, Malte Jochmann,
Rolf Stange and Christiaane Hübner
Illustrations and layout: Trond Haugskott
Translation: Janet Holmén
2012 ©
No. of pages: 36
Issue: 1000
ISBN 978-82-93009-05-4 (printed)
ISBN 978-82-93009-06-1 (PDF)
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1 The geological history of Svalbard
– a journey through time and space
T
he rocks of Svalbard represent a huge archive of information about geological history, the
ancient climate, earlier life forms and the evolution of Svalbard through space and time.
Incredible as it seems, Svalbard was covered by tropical oceans, deserts or subtropical
rain forests eons ago. The current apparently stable geographic position at the north edge of the
European continent is the result of a long journey from the South Pole to the North Pole over the
last 600 million years. How many are aware that Svalbard was situated at the center of a huge ancient
continent (called Laurasia) which unified North America, North Europe and Asia for more than 300
million years? It sounds like science fiction – but, in contrast to H.G. Wells’ novel, geology really is a
kind of a time machine...
Some 600 million years ago, the landscape of Svalbard was dominated by large glaciers of an
ancient Ice Age. The big difference: Svalbard was not located in the northern hemisphere of the
old Earth but in the vicinity of the South Pole! Since then, Svalbard has drifted northward 12,000
kilometers through our planet’s various climate zones, approaching its present position at a «speed»
of 2.5 centimeters per year!
In Devonian times, Svalbard crossed the Equator, and a huge desert
dominated the landscape, which probably looked like the Sahara in
southwest Libya today. It’s almost unbelievable, but rain shower that
took place 400 million years ago in the Devonian desert left imprints
that can still be seen at Woodfjorden!
4
By the end of the Devonian, the climate
became more humid: the oldest forests
on Earth grew along the shores of
ancient rivers in what is now Dickson
Land west of the Russian settlement of
Pyramiden.
At the beginning of the Carboniferous, some
350 million years ago, Svalbard was located in
the northern Tropics. As in Central America
today, huge rain forests covered parts of the
island, which turned later into the coal that was
mined in Pyramiden until 1998.
Fossil corals in life position at
Brøggerhalvøya.
In the middle of the Carboniferous (330 million
years ago), Svalbard was inundated by a shallow,
subtropical sea. Numerous marine fossils such
as corals indicate that Svalbard was situated
at a geographical latitude similar to that of the
Bahamas today. This warm shallow sea covered
wide areas of the present arctic until the end of
the Permian.
5
During the Triassic and Jurassic, 250 to 150
million years before present, Svalbard travelled
continuously northwards into the humid climate
zone of the Earth. It was still covered by a
shallow sea, but the water was colder than in
the sub-tropical seas of the Carboniferous and
Permian. Life was dominated by ammonites
and huge marine dinosaurs such as ichthyosaurs
and plesiosaurs. During Lower Cretaceous
times (150-100 million years ago), the shallow
sea disappeared, and Svalbard emerged as land
where dinosaurs several meters tall, such as
Iguanodon, grazed in the Cretaceous forests.
By the beginning of the Tertiary some 65
million years ago, Svalbard had already reached
its present geographical latitude. The island was
characterized by extensive humid forests similar
to the present forests in Central Europe. If it
were possible to travel back to Svalbard of 65
million years ago, we would find the vegetation
very familiar. How strange to think that the
dinosaurs had just died out at that time! Forty
million years ago, the climate worldwide started
to cool down and about 3 million years ago,
the present Quaternary Ice Age started in the
northern hemisphere. The landscape of Svalbard
became what we see today.
Ichthyosaurus at Kapp Thordsen
(Photo: Dierk Blomeier).
Plesiosaurus
Ammonite from
Ostrogradskij­
fjella, Hornsund.
6
2 The geology of Longyearbyen
2.1 Introduction
T
he geology of Longyearbyen and
its surroundings is dominated by
marine and terrestrial mudstones and
sandstones of the youngest chapters of Earth’s
history. Looking from Longyearbyen across
Adventfjorden at Hiorthfjellet, you can see an
almost horizontal succession of Cretaceous and
Tertiary sedimentary beds with the oldest rock
units at the bottom and the youngest deposits
on top.
The lower and middle parts of Hiorthfjellet
consist of 140-100 million-year-old deposits
of the Early Cretaceous era, whereas the upper
third of Hiorthfjellet is formed of 65-55 millionyear-old Tertiary sediments. The sedimentary
succession is not continuous: deposits from the
time interval between 100 and 65 million years
ago (Late Cretaceous) are not represented in
Svalbard. Either no sediments were deposited
at all or the deposited layers were eroded before
the Tertiary sedimentation began – a time gap of
35 million years (marked by the double dotted
line in the picture of Hiorthfjellet in middle of
the book). However, the whole mountainside of
Hiorthfjellet from the base to the top exhibits a
time span of 85 million years!
At the beginning of the Tertiary era, ancient
swamps led to the formation of the coal seams in
Nordenskiöld Land which became the economic
basis for the foundation of Longyear City more
than 100 years ago. In Longyeardalen and
Adventdalen, it is easy to recognize the bottom
of the Tertiary sediments, because all the mine
entrances lie like pearls on a necklace at the level
of the coal seam.
The pearl necklace of mines in Longyeardalen (from left to right): Gruve 1B at Sverdrupbyen (180 masl),
Gruve 1A above the church (240 masl), the mine at Hiorthfjellet (550 masl), Gruve 2B at Sukkertoppen
(270 masl), Gruve 2B above Nybyen (230 masl) and another mine opening to Gruve 2B close to
Larsbreen. Picture taken from the entrance of Gruve 4 (just below Sarkofagen at 160 masl).
7
2.2 The Early Cretaceous
time period (145-100
million years ago)
T
he oldest deposits in the Longyearbyen
area are Early Cretaceous siltstones at
the base of Hiorthfjellet. During this
era, Spitsbergen was characterized by constant
shifts between marine and terrestrial conditions
due to changes in sea level. Thus, Spitsbergen
was land which was repeatedly inundated by a
shallow shelf sea. Most of the Cretaceous marine
deposits are dark-gray to black mudstones and
siltstones which contain very characteristic
structures called geodes or concretions. They
look like cannonballs and are often perfectly
spherical in shape, with diameters up to 30
centimeters.
When marine animals die, their bodies
– or parts of them – sink to the sea bottom,
where they are deposited in and covered by
mud. Due to the decomposition of this organic
material, chemical processes result in a harder
consolidation within spherical aureoles than in
the surrounding mudstones. Often, remnants
of bones or bivalve shells or ammonites can be
found within the «cannonballs».
During times of low sea level, the shallow
sea retreated and Spitsbergen became land with
large flat, river-crossed plains and deltas along
the coast. Characteristic sediments are green
and gray successions of sandstone and mudstone
with abundant plant remains and dinosaur
footprints. Spitsbergen’s flat landscape must have
been covered by extensive forests: evidence that
supports this is the existence of coal seams at
the base of Adventtoppen, the mountain ridge
opposite Longyearbyen airport. Such coal layers
can only be generated by decomposing organic
material from growing plants under terrestrial
conditions.
Geodes or
«cannonballs»
at Øienbukta,
Bohemanflya.
8
Footprints of an Iguanodon, a dinosaur up to
8 meters long and 5 meters tall and weighing
up to 4.5 tons. These tracks were found close
to Barentsburg. The sediments that make up
the lower slopes of Hiorthfjellet represent the
age when Iguanodon was walking through the
Early Cretaceous forests of Spitsbergen.
2.3 The «missing» Late
Cretaceous time period
(100-65 million years ago)
I
n Svalbard, no sediments of Late Cretaceous
age are preserved: 100 million-year-old Early
Cretaceous sandstones and siltstones are
directly overlain by 65 million-year-old deposits
from the Early Tertiary age. Geologists call such
a break a «hiatus». In Svalbard, the narrow
joint or boundary between the two rock units
represents a time gap of 35 million years!
What happened in this period? Probably
sedimentation continued into the lower part
of the Early Cretaceous while Svalbard was
slowly uplifted. This uplift raised Svalbard over
the water surface of the surrounding oceans
– Svalbard became land, and erosion started
removing the previously deposited sediments
until the uplift stopped 65 million years ago.
Most information about Svalbard’s environment,
climate, plants and animals during the hiatus is
lost together with the eroded sediments.
Worldwide, the Cretaceous – Tertiary
boundary represents a major event in the
evolution of life on Earth. During one of the
most important mass extinctions in Earth’s
history 65 million years ago, a huge number of
plants and animals – entire genera – suddenly
disappeared from Earth’s surface. This was the
time when the dinosaurs died out. As one of
the consequences, the evolution of mammals
exploded after the dinosaurs had died out.
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2.4 The Early Tertiary
time period (65-23
million years ago)
W
hen you look from the center of
Longyearbyen to the slopes on either
side of Longyeardalen, you can see
the cableways of the old coal transportation
system and the buildings and entrances of
several abandoned coal mines, all at the same
altitude at the base of the Tertiary sediments.
Here lie several coal seams which are the most
important productive coal deposits of Svalbard
in Longyearbyen, Barentsburg and Sveagruva.
The landscape of Spitsbergen in the Early
Tertiary was distinctly different from what it is
today: the characteristic topography with the
plateau mountains and vast fjords in central
Spitsbergen and the high mountain ranges along
the west coast of Spitsbergen did not exist!
Sixty-five million years ago, the landscape of
central Spitsbergen was dominated by a large
bay that opened towards a shallow ocean in the
south and was bounded by flat land areas west,
north and east.In the area around Longyearbyen,
geologists have found evidence of sandy beaches,
tidally influenced
lagoons and tidal
flats similar to those
of the wave energydominated shores of
the Wadden Sea along
the Danish and North
German coast. Muddy
deposits with high
organic content, coal
and plant remains are
evidence of coastal plain
swamps which probably
extended from the coast
approximately 10 km
inland. This coastal
plain was protected from
waves and storms by
barrier bars and islands.
Modified from
C.J.Lüthje (2008).
10
Satellite image of the North German Wadden Sea
(Photo: NASA).
The tidally influenced lagoons, swamps and
extensive mires with rich and dense vegetation
must have been attractive for grazing mammals.
Until recently, no fossil of a land animal had
been found in the Early Tertiary deposits to
prove the assumption that grazing animals lived
in the coastal areas around Longyearbyen. So
it was a stroke of luck when the miners Håvard
Dyrkolbotn and Kent Solberg found fossilized
mammal footprints in the roof of Gruve 7 in
Longyearbyen in December 2006. Studying this
find, the scientists C.J. Lüthje, J. Milan and J.
Hurum could reconstruct the tracks of at least
three individuals. The footprints belong to large
mammals called pantodonts, which resembled
the present hippopotamus: they were up to 2
meters long and weighed 500 kilograms. The
new scientific name for the pantodonts in Gruve
7 is Thulitheripus svalbardii: Thulitheri means
«great beast from the north», pus means «foot»,
and svalbardii signifies the location where the
footprints were found.
Drawing of the
Pantodont footprints
in Gruve 7
(C.J. Lüthje (2008)).
11
It is important to know that Thulitheripus
svalbardii is the first pantodont found in Europe,
and that pantodonts had been only known from
the Early Tertiary in North America before the
tracks were discovered in Longyearbyen. So,
this finding is additional evidence that North
America and Svalbard were still attached
together in the Early Tertiary – it was still
possible to walk from Longyearbyen to North
Greenland. Most probably, the small group
of pantodonts came over from Greenland to
Svalbard to graze in the rich vegetation of the
swamps near the coast of the ancient bay near
Longyearbyen. At Hiorthfjellet, the level of the
old coal mine marks the point of time, when
Thulitheripus svalbardii was walking across the
Tertiary swamps of Spitsbergen.
In Early Tertiary times, Svalbard had already
reached the high polar latitudes where it is
situated today. The existence of the coal and very
well preserved imprints of leaves in the Tertiary
sandstones – not only in Spitsbergen but almost
everywhere around the Arctic Ocean – show
that the climate on Earth was much warmer than
it is today. There were no glaciers and there was
probably no sea ice around the North Pole. At
the same time, conditions in southern Germany
were sub-tropical and palm trees were growing in
Paris and London! Sixty-five million years ago,
the climate in Spitsbergen was warm-temperate
with high humidity equally distributed over the
year. The mean annual temperature has been
estimated at +12°C in the Early Tertiary – this
is significantly warmer than the current mean
annual temperature of +8.5°C in Germany!
The sediments that were deposited in the
time span between 55 and 30 million years
ago in central Spitsbergen are monotonous
12
Fossil leaf from Longyearbreen moraine.
and consist mostly of black to dark-gray shale,
mudstones and fine-grained gray and green
sandstones. As in the Early Cretaceous times,
sea level changes led to alternating marine and
terrestrial conditions in the Longyearbyen area,
with flat coastal plains at low sea levels and
shallow inland sea at high sea levels.
2.5 The collision between
Svalbard and Greenland
I
n the Early Tertiary, Svalbard was still
attached to Northeast Greenland. Due to
simultaneous opening of Baffin Bay and
the North Atlantic, Greenland was pushed
northeastwards against Svalbard like a bulldozer.
This collision produced a 300-kilometer long,
folded and thrust-faulted mountain range along
the west coast of Spitsbergen, the so-called
West Spitsbergen Fold-and-Thrust Belt. It
resembles the deformable zones of cars after car
crashes – but is much, much larger! On both
sides of the entrance to Isfjorden, sediments more
than three kilometers thick have been turned
into a vertical position; the folded rock units
are easily recognizable in the mountains. In the
Longyearbyen area, the fold structures at the end
of the steep cliff along the road to the airport
are related to this deformation of the edges of
Svalbard and Northeast Greenland.
13
Folds along the road to Longyearbyen airport: Lower Cretaceous, 100 million-year-old siltstones
which have been deformed, folded and thrust-faulted during the formation of the Tertiary
Fold-and-Thrust Belt some 50 million years ago.
14
After the deformation that formed the West
Spitsbergen Fold-and-Thrust Belt, Svalbard
started to break loose from Northeast
Greenland.
Thirty-five million years ago, the land bridge
between Greenland and Svalbard sank beneath
the waves; North America and Europe were
finally separated, and Svalbard drifted to its
current position.
2.6 The Late Tertiary time period
(23-2.6 million years ago)
N
o deposits younger than 30 million
years are preserved in the area of
Longyearbyen. Like the «missing Late
Cretaceous» they have either been eroded after
deposition or were never deposited at all. In
this period, the global climate started to cool
down and changed to almost cool-temperate
with mean annual temperatures around +8°C in
Svalbard. By the end of the Tertiary the climate
became increasingly colder until the Quaternary
Ice Age started in the Arctic, leading to the
situation we know today.
2.7 Coal
Coal geology
Sixty million years ago, even though Svalbard
was situated north of 70° latitude, vegetation
dominated a landscape that looked very unlike
the one we see today. Due to the high latitude
there was a long polar night just as there is today,
but nonetheless the climate was relatively warm
and offered suitable conditions for blooming
landscapes. There is no comparable place on
earth today!
As parts of the land slowly subsided, ground
water level rose and coastal swamps could grow
thicker and thicker. Where grasses, ferns and
horsetail had created stable ground along lakes
and lagoons, hazelnut bushes and birch trees
moved in and were then followed by trees we
might recognize as elm, beech, plane and giant
redwood – or at least their ancestors. The land
continued subsiding and was flooded while rivers
15
transported mud and sand from inland out into
the sea. Eventually the former wetlands and
mires were covered with several kilometers of
sediments.
How do we know about those forests and
wetlands then? Well, they are still there! The
land was pressed up again, luckily rising to even
a bit higher than it was 60 million years ago. If
we walk inside the coal mines, we can find fossils
and imprints of ancient plants in the roof and
the surrounding rocks. And the coal itself is
nothing else other than peat that has been slowly
roasted for some million years at around 80°C.
What happened exactly? When the peat
was slowly covered by sediments, the water it
contained was pressed out and thus it dried,
turning slowly into brown coal (lignite).
Typically temperature rises by about 30°C per
1000 meters of depth, and at the same time
the pressure increases. More and more water
is pressed out of the coal and at some point
the brown coal changes its chemical structure
and becomes black and lustrous. This point is
called the geochemical gelification and more
or less marks the change from brown coal to
bituminous coal – the stuff which is mined
in Longyearbyen. The whole process is called
coalification and explains how 6-10 meters of
peat can be converted into 1 meter of energy-rich
coal. If this process were to continue, further
increases in temperature, pressure and time
would turn the coal into anthracite, graphite and,
at very high pressure, diamond.
The mine in the old Advent City on the
northern side of Adventfjorden produced
cretaceous coal. All the other mines in
Longyearbyen worked early Tertiary bituminous
coal. We can imagine the coal layers in the
surrounding mountains as the jam in a layer
cake. In an up to 50-meter thick succession of
16
sandstone, mudrock and conglomerate, we can
find five main layers of coal, so-called seams.
The seams have been given names: the
main seam here is called Longyear seam. At
the bottom we find the Svea seam (which is
more than 5 meters thick at the active mine
Svea Nord, 45 km southeast of Longyearbyen),
overlain by the thin Todalen seam. Above are the
Svarteper and Askeladden seams.
Between the seams, layers of mudrock,
sandstone and conglomerate tell geologists a
story about tidal flats, beaches and rivers 60
million years ago.
To find out if a seam is worth mining in a specific
area, a many analyses and evaluations must
be done. Factors such as coal seam thickness,
content of inorganic material (so called ash),
sulfur content, energetic value and the location of
the coal field decide whether mining can be done
economically or not.
Mining operation inside Gruve 7
(Photo: Tommy Dahl Markussen; SNSK).
Coal mining
All the mines in the vicinity of Longyearbyen are
underground coal mines. In 1906 the American
«Arctic Coal Company» started mining in
the valley that is now named after the founder
John Munro Longyear. In 1916 the Norwegian
«Store Norske Spitsbergen Kulkompani»
(SNSK) bought Longyear City and has been
mining in the Longyearbyen area ever since
(apart from two years during the Second World
War). SNSK is Norway’s only coal mine, the
northernmost active mine in the world and
produces without subsidies.
SNSK’s mines are numbered, Gruve 7 (Mine
7) is active today. Though the old mines have
been abandoned, most of the installations are
preserved and visible on the mountainsides (see
2.1). Most of the coal was transported to the
harbors by cableway.
SNSK’s main office is situated in
Longyearbyen. The main activity, however, is
in Sveagruva: the mine «Svea Nord» started
production in 2002 and is the most productive
mine ever in Svalbard. At its peak, the annual
production was more than 4 million tons! For
comparison, all the other mines worked by
SNSK have produced about 27 million tons
since 1916. Today (2012), SNSK is opening up
a new mine, called Lunckefjellet.
Compared to Svea Nord, Gruve 7 is a small
mine with just over 20 employees and an annual
production of 90 000 tons. It works the Longyear
seam with a thickness between 1 and 2 meters,
typically 1.6 meters. The coal is extracted using
the technique called «room and pillar»mining;
this production method allows 70-80% of the
coal to be exploited. The rest of the coal is left in
place as pillars that maintain stability in the mine.
The bulk of the coal from Gruve 7 is shipped
to Germany where it is used in the metallurgic
industry as an important factor in the production
of car engines, among other things. The coal is of
very good quality and requires no washing. The
rest of the coal (about 25,000 tons/year) is used
in the local power plant to generate electricity
and community heating for Longyearbyen.
The coal is transported by truck through
Longyearbyen to the harbor and the power
plant. Sometimes the trucks lose lumps of coal.
If you are lucky enough to find a specimen beside
the road, pick it up. Look at the luster and the
layered structure; maybe you will even find a leaf
imprint. Can you imagine the plants this black
lump is made of? Close your eyes and imagine
the warm wind, the smell of the swamps and the
rustling of the leaves of the giant trees that grew
here in the Arctic 60 million years ago!
17
18
19
3 Quaternary – the present landscape
around Longyearbyen
3.1 Remnants of the pre-ice age landscape:
peneplains, isolated mountains and valleys
During the ice age, Svalbard was repeatedly
covered by huge ice sheets with formidable
destructive power. Nevertheless, the most
important large-scale landscape features around
Longyearbyen have survived from times far more
ancient than the last ice age.
The best examples are the wide mountain
plateaus that are characteristic of Longyearbyen’s
surroundings. If you were to connect the plateaus
across today’s valleys, you would essentially
get the landscape as it would have been many
million years ago: a wide, rolling peneplain near
sea level, with low hills and muddy rivers. The
wide, shallow valleys of these rivers probably
created today’s system of fjords and valleys such
as Isfjorden and Adventdalen. A few isolated
mountains had resisted erosion while the
surrounding bedrock was worn down through
many million years and towered 500 meters or
more above the plain, just as they do today (e.g.
Nordenskiöldfjellet).
Over the next millions of years, uplift raised
the plains to higher elevations, creating the
mountain plateaus. Uplift also led to increased
erosion, thus turning the wide, shallow river
valleys into deep valleys with steep slopes.
With the onset of the ice age, these valleys were
repeatedly filled with glaciers that created typical
glacial U-shaped valleys with steep slopes and
wide bottoms (Longyeardalen, Bjørndalen).
Nordenskiöldfjellet towering over Plateaufjellet.
Bjørndalen, a glacial valley with U-shaped cross
section, incised into a pre-glacial, uplifted plain.
3.2 The ice age: continental ice sheets come and go
During the past two million years, northern
Europe has time and again been covered by
vast ice sheets stretching from Svalbard to the
southern Baltic Sea area. Twelve thousand years
ago, Isfjorden was completely filled by a huge
glacier extending well beyond its present-day
mouth. This glacier later retreated even beyond
the margins of today’s glaciers. Plant remains
that were found under Longyearbreen turned
out to be at least 1,100 years old. This shows
that for a long time, Longyearbreen was much
smaller than it is today and had to grow by two
20
thirds to assume its modern appearance! During
the Little Ice Age around 1850, it advanced
markedly to reach its maximum size. Since then,
Longyearbreen – like many other glaciers both
in Svalbard and worldwide – has been shrinking
due to the global warming that followed the
Little Ice Age, a trend that has recently been
accentuated owing to emission of artificial
greenhouse gases. Thanks to the moraine
cover at its lower terminus, Longyearbreen has
essentially kept its length, but it has become up
to 30 meters thinner over much of its area.
Larsbreen.
Old beach ridges at Revneset highlighted by snow patches.
The volume changes of the large Quarternary ice
sheet left quite obvious traces in the landscape.
The more than 1000 m thick ice mass pressed
the Earth’s crust down by about 200 m. Once
most of this ice had disappeared, the crust
reacted elastically and started to pop up again,
returning to its original position.
This uplift resulted in retreating shorelines.
Traces of this process remain in the form
of beach ridges and occasionally driftwood,
whalebones and seashells well inland. Near
Longyearbyen, the highest traces of former
coastlines are 60-70 m above sea level and date
back 10,000-11,000 years.
You can find quite
obvious fossil beach ridges at
Hotellneset, Revneset and the
entrance to Bolterdalen, where
even whalebones and seashells
have been found in the marine
sediment, kilometers away from
the modern day coastline.
Fossile seashell in Bolterdalen.
3.3 Water erosion
Svalbard’s rivers are frozen for most of the year.
In late spring, the snow cover is able to store
meltwater for some time, but when its storage
capacity is exceeded, huge meltwater floods
will rush down the river beds. These floods
can last for a couple of hours or even days. The
meltwater, which is mixed with snow, ice, mud
and stones, can cause dangerous slush torrents
(«avalanches»). This happens especially when
there is a lot of snow in the catchment area,
combined with a warm period to saturate the
snow with meltwater and finally another warm
spell and rain to trigger the event.
3.4 Vannledningsdalen: hazardous slush torrents
On 11 June 1953, parts of Haugen were
destroyed when a slush torrent rushed down
Vannledningsdalen. Several houses were ruined,
three people lost their lives and 30 were injured
On 14 June 1989 and 30 January 2012, other slush
torrents caused damage in the same area, both
times without harming any people. To prevent
further damage, endangered houses have been
protected with avalanche fences and the river has
been channeled with dams.
In steep, narrow river beds such as Vann­
ledningsdalen, meltwater can transport huge
volumes of sediment that are deposited again as
soon as the river has left the steep and narrow
section, and entered flat terrain. Over time, the
deposits will gradually form an alluvial fan.
Historical picture of Vannledningsdalen and its
avalanche sediments/alluvial fan
(Photo: Vestby; SNSK).
21
3.5 One tamed and one wild arctic river:
Longyearelva and Adventelva
Longyearelva in its artificial bed.
Multiple channels of Janssonelva north of
Janssonhaugen in Adventdalen.
The estuary of Adventelva. In the upper left, the
large alluvial fan from Mälardalen can be seen.
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During the snow-melt period in early summer,
the brown, muddy water in Longyearelva can rise
to impressive levels. You may hear large stones
rumble along on the river bed.
When a valley bottom is flat and wide as
in Longyeardalen, the river will develop many
channels: Large volumes of sediment from
frost-shattered rocks and glacial erosion in the
catchment area overload the river, which has only
the short summer to transport all sediments into
the sea. At the end of the summer, as water levels
are fall, stones, gravel and sand will remain where
they are, blocking the river channel with a new
gravel bank, forcing the river to move sideways or
split into two smaller channels the following year.
Arctic rivers that carry a huge sediment
load and have plenty of space on the wide valley
bottoms usually split up into a multitude of
channels (braided river system). Longyearelva
has been forced artificially into one channel
to gain space for the settlement. In contrast,
Adventelva in the lower, wide part of
Adventdalen, has many intertwined channels.
The river mouth of Adventelva is an estuary,
influenced by tides and waves. There is no sharp
boundary between land and sea or between river
and fjord. Instead, there is a large, very shallow
area that falls partly dry at low tide.
The muddy freshwater of Adventelva
provides a strong contrast to the clear saltwater
of the fjord. The freshwater has lower density
than the seawater and remains as a thin layer at
the surface before it eventually mixes with the
seawater.
3.6 Islands on the rocks: Glaciers
Due to the relatively dry and mild climate, only
18% of the land area around Longyearbyen
is covered by glaciers. That is little compared
to the rest of Svalbard, where glaciers cover
about 60% of the land area. Most glaciers near
Longyearbyen are small isolated valley glaciers,
and there are only few ice caps. One is on top of
the mountain Bassen. Another one is Foxfonna,
southeast of Gruve 7 in Adventdalen. Both ice
caps are thin and move only slowly.
Glaciers can move in different ways. The ice
mass can slide as a whole block. This happens
in «warm» (temperate) glaciers where the
temperature is at the pressure melting point
near 0°C. These glaciers are kept «warm» by
meltwater that penetrates into the glacier ice and
then re-freezes at the bottom, emitting melting
heat and thus warming up the surrounding ice.
The resulting thin water layer between the ice
and the underlying bedrock serves as a lubricant.
The glacier can slide. This type of movement,
called basal gliding, is quite efficient and can
result in velocities of several hundred meters
per year. Huge ice masses sliding across a rock
surface can cause strong erosion.
The glaciers near Longyearbyen are mainly
cold glaciers. Cold glaciers have a temperature
Bassen with ice cap and the famous snow field
shaped like a champagne glass.
below the pressure melting point and are frozen
solid to the underlying ground. They can only
move by means of internal deformation under
the influence of gravity. This movement is
much slower than basal gliding – amounting
to only a few meters per year – and does not
cause much erosion: cold glaciers can even
preserve pre-glacial landscapes. Below the ice of
Longyearbreen, there is still a V-shaped cross
section, created by a river in pre-glacial times and
similar to Vannledningsdalen, a typical rivercreated valley. Longyearbreen has a maximum
thickness of 115 meters and is moving at a speed
of 2 to 4 meters per year.
3.7 Landscapes created by glaciers:
moraines and valleys
From the surrounding slopes, frost-shattered
rocks fall on a glacier surface and will move
together with the ice until they finally reach
the lower end of the glacier, where they form
a moraine. There is usually a core of glacier
ice under the rocks, which can make up more
than 90% of the total volume of the moraine.
Mudslides, mudholes and slippery, instable
terrain are common on ice-cored moraines.
Moraine of Longyearbreen showing some collapse
structures.
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3.8 Steep and active: slopes
The steep slopes surrounding Longyearbyen
are areas where important landscape-shaping
processes take place.
The huge volume of broken rocks that covers
the lower slopes is provided by frost shatter,
which can attack porous sedimentary rocks
quite efficiently. Meltwater penetrates into
pores and cracks; in autumn it will freeze and
expand, thereby breaking the rock. The ice serves
as mortar during the winter and it is not until
spring, when melting starts again, that the rock
will actually fall apart. At this time, many rocks
fall and avalanches occur and large volumes of
rock accumulate on the lower slopes, forming
either continuous scree slopes or distinct talus
cones, if they fall down along discrete channels.
3.9 Rock towers and avalanche funnels
Frost will attack any rock surface, but is
more efficient in some places than in others.
Avalanches often create funnels that will be
retraced and enlarged by future avalanches.
These funnels have individual catchment areas
of a certain size depending on the rock type
and how easily it is eroded. The funnels are
separated by protruding rock towers. If the
rock type is similar over a large horizontal area,
the catchment area sizes will also be similar. In
these cases a very regular pattern of rock towers
separated by incised funnels can be found,
reminiscent of gothic cathedrals or fortresses.
3.10 Debris flows
During heavy rain events in
summer and during the snow
melting season, impressive
mixtures of water, mud, and
rocks can rush down the steep
funnels with velocities of up to
60 km/h. The tracks of such
debris flows are only a few
meters wide but can be several
hundred meters long.
Rock towers and debris flow track at Vestpynten.
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3.11 Rock glaciers
A rock glacier is a solid body of rocks and
ice that develops when meltwater percolates
between the rocks and freezes in the permafrost
area. It remains frozen for a long time and fills
the hollows between the rocks completely. The
whole mixture can deform under the influence of
gravity and move slowly downhill at a speed of a
few centimeters per year. Avalanches contribute
significantly to supplying rock glaciers with
debris and ice. There are several nice examples of
rock glaciers around Longyearbyen.
The rock glacier on Hiorthfjellet.
3.12 Permafrost and climate
Active rock glaciers depend on permafrost.
In Svalbard, almost all of the unglaciated
land surface is permanently frozen except the
uppermost «active layer» that thaws during
each summer. The thickness of the active layer
depends on the substrate, exposure, moisture,
vegetation cover and on the thickness and
duration of the snow cover. The thickness of the
active layer has increased in recent years due to
a warming climate, and the temperature of the
underlying permafrost has increased.
A deep and long-lasting snow cover protects
the ground effectively from the severe cold of
the winter, but wherever the snow is blown away
by wind, the surface is exposed. As a result, the
greatest permafrost thicknesses have been found
on exposed mountain plateaus and ridges such
as Sarkofagen, where the ground is permanently
frozen down to a depth of 450 meters.
In valleys the permafrost layer may be only
100 meters «thin».
The ski jump competition «Svalbardkollen» in
1932 was held on a rock glacier in Longyeardalen
(Photo: SNSK).
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3.13 Pingos
Pingos are little hills that can be between 10 and
over 30 meters high and have a diameter of more
than 100 meters at their base. Pingos have a thin
outer layer of soft sediment but most of their
volume consists of solid ice. Most pingos can be
found on the bottom of large valleys.
The formation of a pingo can start when
groundwater flows from the catchment area
of a temperate glacier into the layer under the
permafrost. There it is under pressure but
cannot easily escape through the permafrost. The
groundwater will have to find weak zones within
the permafrost to reach the surface. Such zones
are often found in valleys with big rivers. Their
water helps to keep the permafrost weak.
During summer, groundwater can reach the
surface in these areas, but as soon as the surface
is frozen, the water is captured below the surface.
There it will re-freeze to form an ice body that
can grow and survive for many years. During the
summer, there is usually a small artesian spring
somewhere on the pingo, which can create a
large ice-covered area on and around the pingo
in autumn.
The pingo nearest to Longyearbyen is
at Moskuslaguna on the northern side of
Adventfjorden, but there are more pingos in
Adventdalen.
Pingo on the northern side of Adventdalen at the
opening of Mälardalen.
Polygons in Adventdalen beside the road to
Todalen. See cabin for scale.
3.14 Polygons of ice wedges
Ice wedges are wedge-shaped bodies of solid
ice and can be found mainly on even surfaces.
The visible part usually consists of quite
inconspicuous, elongated depressions only a few
centimeters deep and wide. These depressions
run many meters through the tundra and several
ice wedges form a network of polygons, mostly
pentagons and hexagons, with 10-25 meters
across. Occasionally, small rivers can enlarge the
depressions into trenches of more than a meter in
depth and width.
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The development of an ice wedge starts with
frost cracks that form in the soil during winter.
The cavity will be filled with ice crystals or
re-freezing meltwater that may survive the
following summer within the permafrost layer.
This process is repeated over a long time span
whenever the winter temperature drops to about
-15°C or lower.
Over centuries, ice wedges can become up
to a meter thick and extend 10 meters into the
ground, depending on how far down the ground
temperature varies over the year.
Geological excursions
We suggest three excursions, depending on your schedule and circumstances:
Family excursion in Longyeardalen
This is a geological excursion for families with children or just anyone who wants
to get some exercise but doesn’t want to emulate a mountain goat. It can be done as
a round trip in the Longyear valley and takes 1-3 hours. It follows roads all the way
but can also be extended with short excursions off-road.
Trollstein - excursion for mountain goats
This excursion takes 4-7 hours and requires good shoes and mountaineering clothes.
Be sure to take along a proper map, compass or GPS, walking sticks, rifle and signal
pistol. Orientation can be very difficult on the plateau-mountains when the visibility
is poor. The glaciers are normally fine to walk on without crampons but it won’t hurt
to bring crampons. Be careful on the glaciers! The meltwater channels on a glacier’s
surface can be hard to cross – and they can be covered by snow!
Excursion by car to Adventdalen
If you have a car available or are a sporty cyclist you can take this excursion into
Bjørn- and Adventdalen. This jaunt also requires good shoes, a rifle and a signal
pistol with you if you want to see the stops that lie some distance away from the
road.
What a real geologist brings along:
Hammer
Proper
clothes!
Ruler
Helmet
Hand lens
GPS
Camera
Safety goggles
Field book
& pencil
Map
Geological
compass
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Family excursion in Longyeardalen
(1) Soil creep: Beside the road you see tilted wooden stumps. These are the piles
the houses of old Longyear City were built on. The houses burned down during the
Second World War. The stakes were vertical at the beginning of the 20th century. The
tilt is a sign of movement of the active layer, which slowly creeps downslope. At the
same time the piles are pushed up due to frost heave. See chapter 3.12.
(2) Rock towers: The yellowish cliff two-thirds of the way up the slope are part of
a sandstone layer. This more or less horizontal layer resists erosion better than the
overlying siltstones and therefore forms cliffs. See chapter 3.9.
(3) Mud flows: Most of the mud flows in this area are from the same extreme rain event which occurred
in August 1972. During this event 31 mm of rain fell in 48 hours. As a result, the active layer became
oversaturated with water and was destablized. The wet mud ran downslope and formed channels. Typical
for such mud flows are the levees on either side of the channels and the fans at the lower end. Some of the
channels even crossed the road. See chapter 3.10.
Rolling stones: Blocks break loose from the cliffs of the sandstone layers and tumble down the slope,
especially in the early winter when temperatures change a lot and in early summer when temperatures rise.
Sometimes the boulders roll all the way to the river bed. See chapter 3.8.
(4) Rock glacier: The terrace at the foot of the slope behind Huset was used as a ski-jump in the old
days. Those terraces are rock glaciers. See chapter 3.11.
(5) Level of the coal seam: The installations of Gruve 1A (the American mine) are clearly visible
high above the church. The opening of Gruve 1B is just above Sverdrupbyen; Gruve 4 is at the foot of
Sarkofagen. On the other side of Longyeardalen you see Gruve 2B and the leavings from Gruve 2B at
Sukkertoppen. Look across to Hiorthfjellet and you may discern the installations of the mine far up on
the mountainside. All these mines exploited the same geological coal level, namely the Longyear coal seam.
Imagine the coal as the jam in a layer cake. The cake is tilted slightly towards you and the big erosion
monster (i.e. ancient glaciers) has «eaten» (eroded) the part of the cake where the valleys Longyeardalen
and Adventdalen are today. Before erosion, these too were filled with coal and rock. See chapter 2.1, 2.4
and 2.7.
(6) Alternative: Longyearbreen and fossilized forests: See (20).
Walk back to Huset and cross the valley.
(7) Alternative: Larsbreen: Walk up to Nybyen and continue along the river to Larsbreen. Bring a
rifle! At the end of the valley you see the river coming out of the meltwater channel of Larsbreen’s ice-cored
moraine. In winter it is possible to enter this «moraine cave». See chapter 3.6. and 3.7.
(8) Alternative: Gruve 2B, Santa Claus’ home: climb up the steep slope to Gruve 2B. This
mine entrance was established in 1937. In 1943 the mine caught fire during the German attacks and
burned until 1962. In 1959 the leavings outside the mine entrance started burning spontaneously: selfcombustion. The red, oxidized rock material outside Gruve 2B bears witness to those fires. Gruve 2 was
finally closed in winter 1967/68. SNSK maintains the installations and it is possible to enter some of the
buildings. Every year in Advent season, Santa Claus moves in here. The children of Longyearbyen deliver
their Christmas wish-lists to the mailbox he sets up at the road in Nybyen. See chapter 2.7.
(9) Avalanches: behind Spitsbergen Hotel you see the artificial ridge that was built after the
catastrophic avalanche in 1953, when three people lost their lives. The avalanche was a slush avalanche
that came down Vannledningsdalen with destructive power. (9b) The little footbridge «Perleporten» (The
Pearly Gate) was partly destroyed during a slush avalanche in late January 2012. See chapter 3.4.
(10) Longyearelva, a tamed arctic river: Before humans came here the river bed covered the entire
width of the valley. Today, diligent work with earth-moving equipment keeps the river in its artificial bed –
and away from houses and roads. In winter the river dries out completely. See chapter 3.5.
(11) A rising island, raised beaches: It is not easy to see anymore, but several of the rows of houses
are built on raised beach terraces. If you walk to the end of Vei 236, you can clearly trace the line of the old
beach. See chapter 3.2.
You can end your excursion with a visit to Svalbard Museum and learn more about Svalbard’s
fascinating geology.
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29
Excursion to Trollstein – for mountain goats
(12) Tidal flat: The innermost shoreline of Adventfjord is a big tidal flat. At low tide
you can walk out on the tidal flat and look for traces of benthic marine animals such as
worms and shellfish. You might also be able to see nice sedimentary structures such as
ripplemarks, created by water currents. At high tide the whole area is flooded. See chapter
3.5.
Pass the dog pen and follow the road upwards into the valley.
(13) Svalbard in Cretaceous times: Pass the dam on the grassy ridge to the left and descend into the
valley. The steep rock walls are composed of sedimentary rocks. See (27). You might find embedded
structures that resemble those from the last stop at the tidal flat.
(14) Svalbard in the Tertiary: As you walk up the valley, look for changes in the rocks – very
observant geologists might discover a conglomerate layer that marks the “missing” late Cretaceous time
period as described in chapter 2.3. When you reach the level of the mine entrance (which is to the right)
and if the valley is not filled with snow, you can see the best example of an outcropping coal seam in the
vicinity of Longyearbyen. The well laminated coal is overlain by thick sandstone beds. You are in the
Tertiary Firkanten Formation. See chapter 2.4. and 2.7.
(15) Frost weathering: Walking is difficult on the plateau mountain. Due to freezing and thawing
processes many of the sandstone rocks are standing vertically. You might also see frost separation processes
as patterned ground. See chapter 3.12.
(16) Svalbard in the Tertiary, sea level changes: Sandstones resist erosion quite well and it is thus
the thick sandstone layers that form the plateau mountains in this area. Where the Trollstein ridge starts
you walk upwards onto dark mudrock. The landscape formations get smoother because mudrock is easily
weathered. You walk upwards with geological time: after deposition of the sands close to the beach some
58 million years ago, sea level rose and the shoreline moved inland. The former beach was suddenly 100200 meters below sea level. The sand from the coast did not reach that deep into the marine basin and
was deposited elsewhere. Where you are standing, only the muddy particles were deposited. Remnants of
plants and animals also sank to the bottom and contributed to the high organic content that is responsible
for the dark colors of the rocks.
(17) Svalbard in the Tertiary, the filling of a marine basin: As you walk up the beautiful ridge, note
how more and more sandstone layers intercalate the mudrock. The top of Trollstein consists again of pure
sandstones which form manifold sedimentary structures such as dunes and ripples. You might see heavily
folded structures that developed when an earthquake triggered a submarine sand slump around 50 million
years ago. The change from the lower mudrocks to the overlying sandstones tells us the story of a basin that
slowly filled up with sediments: the ancient shoreline was much closer here on top of the mountain than in
the layers further down where we only find mudrock. Nordenskiöldfjellet is even higher. There we can find
coal and plant fossils at the summit, a sure sign of terrestrial deposition. The basin was totally filled up with
sediments at the place and time when the coal was deposited as peat. There were originally coal-bearing
layers also above Trollsteinen, but these have been eroded by glaciers, wind and weather.
(18) A changing glacier, Larsbreen: Many signs that show us that Larsbreen is not as thick as it
has been. These moraine cones were once covered by ice. Careful study of the moraines also shows that
Larsbreen once hung over towards Longyearbreen. See chapter 3.6.
Alternative at (18): walk down the moraine of Larsbreen instead of walking to Longyearbreen.
(19) Meltwater channels: In winter it is possible to enter the glacier by following the channels. A
fascinating experience!
(20) Longyearbreen and fossilized forests: When you come to the rocky moraine of Longyearbreen,
lift up some rocks. Do you see that there is mainly ice below them? See chapter 3.2 and 3.7. Stroll around
and look for hints of a warmer climate in Svalbard once upon a time – you can find amazing imprints of
fossilized leaves and trees, remnants of the huge forests that covered Svalbard some 45 million years ago!
The leaves are from the Tertiary deposits at Nordenskiöldfjellet. See chapter 2.4.
(21) to (25): see (5) to (1)
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31
Excursion by car to Adventdalen
(27) Svalbard in Cretaceous times: Walk along the cliffs at the shore. Pay
attention to the different rock types you encounter: mudrock, silt- and sandstone
from the Cretaceous Carolinefjellet Formation. These sediments were deposited
on the sea floor around 100 million years ago. You can find beautiful sedimentary
structures and trace fossils. You can also find marine fossils such as shells and
(rarely) ammonites. Look for cannon-balls! With a lot of luck you can find
fossilized wood here. See chapter 2.2.
(28) Rockfall and mudflows: see excursion stop (3).
(29) Raised beaches: Between the road and the end of the runway you can see differences in the
vegetation, arranged like horizontal stripes. Those differences represent different ancient shore lines from
the time since the last Ice Age. See chapter 3.2.
(30) Island collision, folding. In the cliffs beside the road you can see how the sedimentary rocks are
folded. See chapter 2.5. The layers are part of the Cretaceous Carolinefjellet Formation, see excursion stop
(27).
(31) Longyearelva, a tamed arctic river: See (10).
(32) Adventelva, a wild arctic river: Adventelva is still wild and changes his braided river beds every
year. See chapter 3.5.
(33) Longyearbyen CO2-lab: Store Norske Spitsbergen Kulkompani and UNIS started a project to
realize the dream of storing CO2 from the coal-fired power plant in the rocks deep under Adventdalen.
Most of the drill holes from this scientific project are here, and a visitors’ center is planned.
(34) Coal mines: On the western side of Endalen you see the mine openings of Gruve 2, which goes
through the mountain all the way to Longyearbyen. Gruve 2 has been the most productive mine in the
Longyearbyen area. On the eastern side of Endalen the mine constructions of Gruve 5 are clearly visible.
See also (5).
(35) Permafrost and frost creep: UNIS has a measuring station that registers frost creep and
temperature. At www.unis.no you will find online temperature data down to 19 meters. See chapter 3.12.
(36) Ice wedges and frost polygons: Beside the road can you see large polygons and lines. In the
depressions that form these patterns, massive ice wedges are hidden. See chapter 3.14.
(37) Whale bones and mummified shells on an ancient shore terrace: Where the road makes a sharp
left turn stop the car and continue a bit into the small valley. Here you can find shells in their living position
(even the mummified body is preserved!) and whale bones that have been dated to an age of 10,000 years.
You will also find typical foreshore sediments and marinoglacial sediments. You are standing exactly where
the shore was 10,000 years ago when the land was still much lower. See chapter 3.2.
(38) Gas below the permafrost: North of the Bolterdalen bridge you can see a metal pipe sticking out
of the ground. This is a coal exploration drill hole, drilled in 1967. From below the permafrost at a depth of
105 meters, gas came up the hole and continued for more than one decade until the hole was sealed. Even
today there is gas pressure in the well. The gas burns well and consists mainly of methane generated by the
coal. The permafrost forms the top seal for the gas.
(39) Mine 7: The only active coal mine in Longyearbyen. See chapter 2.7.
(40) Enjoy the fantastic view over Adventdalen. Imagine the valley filled with water, as a big fjord,
just as it was 10,000 years ago. Try also to imagine the ancient landscape before the deep valleys were cut in
by erosion (see chapter 3.1). From here you can see:
(40a) The ice cap at Bassen. See chapter 3.6.
(40b) The pingos in Adventdalen. See chapter 3.13.
(40c) The braided river system and the estuary of Adventelva. See chapter 3.5.
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33
34
35
10,000-year-old whale bones (to the left) in the river bed of Bolterdalen.
Hiorthfjellet in the background.
In this booklet, we want to take you on an exciting journey through
the ancient past in the surroundings of Longyearbyen. To put things
in context, we start with a short description of the geological history
of Svalbard. Then we zoom in on the geology and the landscape you
can see in and around Longyearbyen today. As an example, we will
use Hiorthfjellet, the prominent mountain that greets the people of
Longyearbyen from the other side of Adventfjorden. Its mountain
slope exhibits 85 million years of Svalbard’s history.
Acknowledgements
We are very grateful to the Svalbard Environmental Protection Fund
and Store Norske Spitsbergen Kulkompani for funding this booklet.
Thanks also to Elke Morgner for comments, Bjørn Frantzen and
Karin Stensson for encouraging us along the way and Tiril Varpe, the
youngest geologist model in Longyearbyen.
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