Illustrationes chapter 9.

Illustrations can be downloaded in the gallery further down.

 

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 Chapter 09 - pp. 304-305

In Ebbadalen on Svalbard there are folded yellow and red sandstones, alternating with white evaporites and grey limestones from the Carboniferous and Permian. (Photo: A. Nøttvedt)

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Chapter 09 - p. 308

Map illustrating the major structural elements on the Barents shelf during the Carboniferous and Permian. Elevated highs are shown in green. Subsidence was active in the Nordkapp Basin, which is shown in yellow. Other stippled areas indicate structures that developed later during the Jurassic and Cretaceous.

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Chapter 09 - p. 309a

Reconstruction of Early Carboniferous and Early Permian climate zones. In the Early Carboniferous (upper map), Norway was located in the humid tropical zone, while in the Early Permian (lower map), the climate was hot and arid. (Figures modified from C. Scotese)

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Chapter 09 - p. 309b

Diagram showing the continental drift of Svalbard Since the Carboniferous, Svalbard has drifted progressively northwards over a distance equivalent to about 90 degrees of latitude, or a quarter of the Earth's circumference. (Figure modified from R.J. Steel & D.Worsley)

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Chapter 09 - p. 310a

In the Early Carboniferous, the climate wad humid and characterised by large swamp forests, containing ferns, club mosses and Lepidodendron trees. (Illustration: B. Bocianowski)

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Chapter 09 - p. 310b

In the Late Carboniferous and Permian northern Europe was hot and dry, and reptiles ruled the scorched landmasses. (Illustration: B. Bocianowski)

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Chapter 09 - p. 311a

Stratigraphic dolumns showing Caroniferous and Permian successions on the Barents shelf and in Svalbard. In the Early Carboniferous, we find coal-bearing sandstones and mudstones, while the Late Carboniferous and Permian are dominated by limestines and evaporites. These successions reflect a progressive change from humid to arid climatic regimes.

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Chapter 09 - p. 311b

Diagram showing basin evolution in Central Spitsbergen during the Carboniferous and Permian. The map shows the position of the geological profile and the locations wherethe Carboniferous and Permian rocks crop out.Spitsbergen's evolution is typical of large parts of the Barents shelf. In the Early Carboniferous, sand and mud were deposited in broad basins, while in the Mid-Carboniferous, crustal movements resulted in the formation of narrow and more isolated rift basins. In the Late Carboniferous and Permian, the Barents Sea are developed into a gradualle subsiding, stable platform. BFZ = Billefjorden Fault Zone, LAFZ = Lomfjord–Agardhbukt Fault Zone. (Figure modified from A. Andresen)

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Chapter 09 - p. 311c

Diagram showing basin evolution in Central Spitsbergen during the Carboniferous and Permian. The map shows the position of the geological profile and the locations wherethe Carboniferous and Permian rocks crop out.Spitsbergen's evolution is typical of large parts of the Barents shelf. In the Early Carboniferous, sand and mud were deposited in broad basins, while in the Mid-Carboniferous, crustal movements resulted in the formation of narrow and more isolated rift basins. In the Late Carboniferous and Permian, the Barents Sea are developed into a gradualle subsiding, stable platform. BFZ = Billefjorden Fault Zone, LAFZ = Lomfjord–Agardhbukt Fault Zone. (Figure modified from A. Andresen)

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Chapter 09 - p. 312a

Diagram showing the paleogeography and most important sediment types in the northern areas during the Early Carboniferous. Elongated basins with alluvial plains were developed between Norway and Greenland, while a shallow sea occupied the present Barents shelf area. The locations of Norway, svalbard and Greenland are shown in relation to the Carboniferous plate reconstruction. (Figure modified from H. Brekke)

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Chapter 09 - p. 312b

Paleogeography and depositional environments in Svalbard in the Early Carboniferous. (Figure modified from R.J. Steel and D.Worsley)

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Chapter 09 - p. 313a

From Billefjorden in Svalbard. The photograph shows Lower Carboniferous coal-bearing mudstones and sandstones of  the Hørbyebreen Formation. The yellow sandstone beds were deposited in and along the banks of river channels, while the geyish-black mudstone were deposited on flood plains between the channels. (Photo: A. Nøttvedt)

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Chapter 09 - p. 313b

Fossil stem of the club moss Stigmaria, from Billefjorden in Svalbard. (Photo: E.P. Johannessen)

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Chapter 09 - p. 314a 

Geological map of Billefjorden on Spitsbergen, showing Carboniferous and Permian successions unconformably overlying Devonian strata. (Figure from NPI, W. Dallmann)

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Chapter 09 - p. 314b

Drill core from the Soldogg Formation in well 7128/4-1 on the Finnmark Platform, showing alluvial plain deposits - pale grey sandstones and dark grey mudstones, separated by a coal seam. (Photo: G.B. Larssen et al.)

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Chapter 09 - p. 314c

Diagram of a seismic profile from the Finnmark Platform. Billefjorden Group sequences exhibit a wedge-shaped geometry and were deposited in half-graben basins during the Early Carboniferous. The Gipsdalen Group also varies somewhat in thickness over large areas. These were deposited after crustal movements in the Barents Sea area had abated. (Figure from G.B. Larssen et al.)

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Chapter 09 - p. 315

The remains of the mine railway on Bjørnøya. The wreckage is not the result of the passage of time, but of a shelling attack by the British Navy in 1940! (Archive photo)

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Chapter 09 - p. 316

Paleogeography and the most important sediment types in the northern areas during the Mid-Carboniferous. Shallow marine environments in the Barents Sea area had now expanded to include an elongated gulf extending southwards across Sweden and Finland. The locations of Norway, Svalbard and Greenland are shown in relation to the Carboniferous plate reconstruction. (Figure modified from H. Brekke)

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Chapter 09 - p. 317a

The mountain Pyramiden in Billefjorden on Spitsbergen, with the Russian mining town Pyramiden in the foreground. The pipe-lines on the left lie approximately along the Billefjorden Fault Zone. Dark red Devonian rocks outcrop to the left of the fault. On the  right, and closest to the fault, are the greyish-black, coalbearing Lower Carboniferous deposits of the Hørbyebreen Formatin, and these are overlain by alternating red and yellowish-grey Mid-Carboniferous beds of the Ebbadalen Formation. The grey beds at the top of the mountain belong to the Wordiekammen Formation of Late Carboniferous age. (Foto. A. Strøm)

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Chapter 09 - p. 317b

Mid-Carboniferous palaeogeography and depositional environments in Svalbard. (Figure modified from R.J. Steel og D.Worsley)

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Chapter 09 - p. 317c

Detail of Mid-Caroniferous beds from the Odellfjellet Member of the Ebbadalen Formation at Pyramiden. 
A) Laminated, gravel-bearing sandstone deposited as part of a flood-dominated delta fan. (Photo: E.P. Johannessen) 
B) A sequence comprising bedded red sandstones deposited as flood-dominated delta fans and eolian dunes, overlain by white sandstones deposited in coastal settings, and shallow water dolomites. The sequence marks the gradual flooding of the basin in response to subsidence. (Photo: A. Nøttvedt)

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Chapter 09 - p. 318a

The mountain Trikolorfjellet at the mout of Austfjorden in Svalbard. The photograph shows interbedded red and yellow sandstones, white evaporites, and greyish-black dolomits from the Trikolorfjel Member, Ebbadalen Formationen. (Photo: A. Strøm)

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Chapter 09 - p. 318b

Schematic section through the Billefjorden Trough on Spitsbergen. Note the marked wedge-shaped geometry of the Ebbadalen Formation deposits. These beds are termed "sync-rift" deposits because they were laid down while subsidence of the trough was ongoing. (Figure from E.P. Johannessen)

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Chapter 09 - p. 318c

Diagram of seismic profile from the Loppa High, extended northwards towards the Bjarmeland Platform. The Gipsdalen Group exhibits a wedge-like geometry and was deposited in half-grabens, as in Svalbard. Note that the faults do not penetrate the Bjarmeland and Tempelfjorden Group units, which were deposited after crustal movements in the Barents shelf area had abated. (Figure from G. B. Larssen et al.)

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Chapter 09 - p. 319a

White gypsum and anhydrite from the Minkinfjellet Formation in Billefjorden on Spitsbergen. The gypsum is formed mainly at the surface by the hydration of anhydrite. (Photo: A.Nøttvedt)

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Chapter 09 - p. 319b

Chicken-wire anhydrite formed on vast sabkhas during the Late Carboniferous. Picture is 15 centimetres wide. (Photo: A.Nøttvedt)

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Chapter 09 - p. 320

Palaeogeography and the most important sediment types in the northern areas during the Early Permian. (Figure modified from H. Brekke)

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Chapter 09 - p. 321a

From the area between Austfjorden and Billefjorden in Svalbard. Yellowish-grey limestones of the Upper Carboniferous Wordiekammen Formation directly overlie greyish-black basement rocks of the Hecla Hoek Group. Inset: Geologists examine fine-grained limestones within the Wordiekammen Formation. (Photos: A. Nøttvedt)

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Chapter 09 - p. 321b

Thin section from the Ørn Formation in well 7128/6-1. The photograph shows a coarse-grained, bioclastic limestone containing the remains of planktonic foraminifera. (Photo: G. B. Larssen et al.)

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Chapter 09 - p. 322

Fossils from the Late Carboniferous and Early Permian in Svalbard and Bjørnøya.
A. The bryozoan Fenestella,Wordiekammen Formation – Tyrrellfjellet Member, Grøndalen, Spitsbergen.The photographs's actual size is four centimetres across..
B. The bryozoan Ascoporella,Wordiekammen Formation – Tyrrellfjellet Member, Gipsvika, Spitsbergen. The bryozoans are seven milimetres thick. 
C. Fusulinids, Wordiekammen Formation – Tyrrellfjellet, Billefjorden, Spitsbergen.
D. The brachiopod Neospirifer, Wordiekammen Formation – Tyrrellfjellet, Billefjorden, Spitsbergen. The brachiopod is five centimetres across. 
E. The colonial coral Kleopatrina, Kapp Kåre Formation, Bjørnøya. The photographs's actual size is ten centimetres across.
F. Corals, Kapp Kåre Formation, Bjørnøya. Each coral is 2 cenimetres thick. (All photos: H.A. Nakrem)

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Chapter 09 - p. 323a

Life on the sea floor in the Early Permian. A rich benthic faune inhabited the warm seas, including corals, bryozoans (moss animals), crinoids (sea-lilies), and sponges. From the exhibition ”Life through the ages”, University of Michigan. (Photo: www.palaeos.com/Timescale)

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Chapter 09 - p. 323b

Fossil reef structures from the Wordiekammen Formation near Skansen on Spitsbergen. Inset: The reefs were formed by a single organism, Palaeoaplysina - a plate-like animal resembling the sponges. (Photos: A. Nøttvedt)

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Chapter 09 - p. 324a

The mountain Skansen in Billefjorden on Spitsbergen. The lowermost slope is made up of beds of white and grey gypsum, anhydrite and dolomite of the Gipshuken Formation. The steep uppermost  liffs comprise chert beds of the Kapp Starostin Formation. (Photo: A. Nøttvedt)

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Chapter 09 - p. 324b

Seismic relief display from the Loppa High showing polygonal carbonate reef patterns in the Permian sequence. (Figure from D. Hunt)

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Chapter 09 - p. 324c

Seismic line from the Loppa High showing well-defined reef structures within dipping Permian sequences. (Figure from D. Hunt)

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Chapter 09 - p. 325a

Thin section showing Late Permian bryozoans and fusulinids from shallow borehole 7129/10-U-2 on the Finnmark Platform. (Photo: H.A. Nakrem)

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Chapter 09 - p. 325b

Diagram of seismic profile from the Nordkapp Basin showing Late Carboniferous salt penetrating overlying Mesozoic and Cenozoic sequences and reaching the sea floor. During it ascent the salt has carried with it a large block of Permo-Carboniferous limestone. The Mesozoic sequences have been forced upwards and, at the present day, Triassic sandstone beds that have been truncated by the salt diapir form traps for oil and gas. Well 7228/7- 1A is shown penetrating the "Dumbo" prospect. (Figure from K. Sollid)

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Chapter 09 - p. 325c

Von Buch's drawing of Spirifer keilhavii. The permian brachiopod Spirifer keilhavii was described by Professor Keilhau when he visited Bjørnøya in 1827.

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Chapter 09 - p. 326

Palaeogeography and the most important sediment types in northern areas during the Late Permian. Shallow marine conditions persisted in the Barent Sea area, but mud now became the dominant sediment type in preference to carbonate. The locations of Norway, Svalbard and Greenland are shown in relation to the Permian plate reconstruction. (Figure modified from H. Brekke)

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Chapter 09 - p. 327a

Akseløya in Bellsund on Spitsbergen. Akseløya is composed of vertically-bedded cherts of the Kapp Starostin Formation, and forms a prominent ridge almost blockin the entrance to van Mijenfjorden. The chert beds are very hard, and because of this the glaciers that carved out van Mijenfjorden failed to erode these strata to the same degree as the surrounding rocks. (Photo: A. Nøttvedt)

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Chapter 09 - p. 327b

Drill core from well 7128/6-1 on the Finnmark Platform, showing the transition from greyish-blue limestones of the Isbjørn Formation to greyish-black, silica-bearing mudstones of the Røye Formation. (Photo: G.B. Larsen et al.)

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Chapter 09 - p. 327c

Thin section showing a spiculite unit from the Kapp Starostin Formation. The photograph shows sponge spicules mixed with clay. (Photo: T. Hellem)

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Chapter 09 - p. 328a

Thin section from well 7128/4-1 on Finnmark Platform, showing a spiculite unit from the Røye Formation. The blue colour is an epoxy resin that is used to highlight zones of high porosity within the rock. (Photo: G. B. Larssen et al.)

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Chapter 09 - p. 328b

Late Permian fossils from Spitsbergen, Bjørnøya and the Barents Sea.
A. Meekopora magnusi, Svalbard. The photograph's actual size is two centimetres across.
B. The brachiopod Neospirifer, Miseryfjellet Formation, Gravodden Bjørnøya. The brachiopod is five centimetres across. 
C. Crionid stems, Miseryfjellet Formation, Gravodden, Bjørnøya. The stems are one centimetre in diameter.
D. The bryozoan Ramipora,Kapp Stavrostin Formation, Festningen, Spitsbergen. The photograph's actual size is eight centimetres across. 
E. The bryozoan Fenestella, Late Permian, shallow borehole 7129/10-U-1, Finnmark Platform. The drill core is five centimeters in diameter.
F. The bryozoan Tabulipora, Kapp Starostin Formation, Trygghamna, Spitsbergen. The bryozoan is two centimetres across.
(Photo A-C and E-F: H.A. Nakrem. Photo D: A. Nøttvedt)

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Chapter 09 - p. 329

Modelled average annual temperature of the Earth's surface during the Late Permian mass extinction. The calculations assume an average annual sea surface temperature of 30-35 degrees at the equator, and 5-10 degrees near the Poles. The model i based on a simulation conductet at the National Center for Climatic Research, Boulder. (Figure from J. Kiehl, www.ucar.edu/news/releases/2005/permian)

 

 

Dette året har vært spesielt for alle, også for oss som jobber med Geologiens Dag. Til tross for uforutsigbare tider så klarte mange å gjennomføre planlagte arrangement. Det skal sies at de største arrangørene meldte avbud, forståelig nok, da mange av dem bruker å ha flere hundre besøkende på sine arrangement. Med utgangspunkt i årets tema som var «klima og geologi gjennom tidene», ble det laget 54 arrangement rundt i hele Norge. Veldig mange av disse arrangementene ble holdt utendørs.

NGF i Trondheim, med leder Trond Svånå Harstad, laget en familievennlig geologisk rebus i Trondheim sentrum. Det var fem forskjellige poster basert på ulike geologiske tidsperioder. På posten for prekambrium fikk man oppleve magnetismen i en bundet jernformasjon. Jakt på kambro-silur fossiler og funn av ortoceras-blekkspruter engasjerte både voksne og barn i post to, før vulkanisme i perm var tema i post tre. De lokale Kaledonske bergartene som vi ser i veggen på erkebispegården var tema for post fire. Etter siste istid var nesten hele Trondheim under vann, noe som ble tema i post fem. Interesserte foreldre og barn kom tilbake til start for å heve premien sin, og uttrykte samtidig glede og undring over alt man kan se i geologien.

I Stavanger ble det arrangert en geologisk sykkelekskursjon, og i Tromsø ble det arrangert tur til Tromsdalstinden og familieaktiviteter på Tromsøya. På turen opp til "Tinden" ble det stopp ved fem geologiske lokaliteter. På Tromsøya fikk besøkende lære om sedimentkjerner som kan brukes til å forstå fortidens klimaendringer og havstrømmer. De fikk kjenne på kvikkleire og lære om geofarer, se ulike mineraler og prøve gullvasking. Stipendiat ved Universitetet i Tromsø, Sofia Kjellman, ble i tillegg intervjuet av NRK Troms om Geologiens Dag.

NGFs avdeling i Oslo arrangerte to turer. Nicola Møller og Morten Bergan var guider på tur langs Lysakerfjorden. Gråhvite kalksteiner og gråsvarte skifre ligger der i rekkefølge langsmed stranda. Det ble fortalt hvordan de ble til og hvorfor de ligger akkurat der. Det ble en reise nesten 450 millioner år tilbake i tid, med sedimenter avsatt i et hav som ikke lenger er der. Man kan se rester etter den voldsomme påvirkningen fra Den kaledonske fjellkjedefoldingen - da dette havet lukket seg og høye fjell bygget seg opp i vest. Det ble også fortalt om riftingen og vulkanismen i permtiden og dannelsen av et nytt hav.Hans Arne Nakrem inviterte til en geologisk rusletur rundt Malmøya, en av øyene i indre Oslofjord, som har en helt spesiell flott geologi. Kyststrekningen som ble besøkt er fredet som geologisk naturminne, noe som forteller litt om områdets unike status. Fossiler og bergarter ble studert, til stor interesse for deltakerne. Foruten disse arrangementene ble det altså laget mange lærerike arrangement rundt i hele landet. Motgangstider tvinger oss til å tenke nytt, og det kommer ofte noe spennende ut av det. Så også for Geologiens Dag.

 

Illustrations chapter 7.

Illustrations can be downloaded in the gallery further down.

 

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 Chapter 07 - pp. 232-233

The continent of Laurussia, which was formed when Greenland collided with Scandinavian in Silurian to Early Devonian time. The collision zone is marked by the large Caledonian mountain chain. (Small illustration: R. Blakey)

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Chapter 07 - p. 235

The mountain Litjehesten in the outer part of Sognefjorden. The boundary between the Devonian conglomerates in the Solund Basin and their substrate follows the edge of the shadow. (Phto: T.B. Andersen)

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Chapter 07 - p. 236a

After the basement was forced deep down into the crust during the Caledonian collision (a), and the collision forces died away, it was exhumed again and drawn back towards the east (b). By degrees, the crust was stretched out because new extensional shear zones formed (c)

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Chapter 07 - p. 236b

Such folds are common in large parts of the Caledonian nappe pile in southern Norway. They formed when the mylonites, which were produced during the inward thrusting of the nappes, were deformed whn the nappe pile slid back in the earliest Devonian. Bergsdalen Nappe, West Norway. (Photo: H. Fossen)

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Chapter 07 - p. 237a

The backward sliding of the nappes created structures that reflect the movement direction. The arrows show the directions in southern Norway. They swing from northwesternly in the central mountains to more westerly around the Devonian basins. Broken line mark Devonian extensional shear zones formed by segmantation of the crust after the backward sliding took place.

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Chapter 07 - p. 237b

This photograph shows an approximately 400 million-year-old microdiamond from the Møre coast. (Photo: IKU)

 Kap07 print Page 236a  

Chapter 07 - p. 238

Examples of structures that serve to determine shearing movements in deformed rocks - tools for determining movement directions.

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Chapter 07 - p. 239a

Brurestakken on Atløy, west of Askwoll, is a distinct expression of the strong folding experienced by the Caledonian strata after the Caledonian collision had ceased and Devonian extension had begun. The light-coloured beds are quartzite, which is compacted, lithified and metamorphosed sand from the pre-Caledonian continental shelf. (Foto: H. Fossen)

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Chapter 07 - p. 239b

Devonian basement mylonites in the foreground demonstrate westward movement in the Nordfjord-Sogn Detachment. Lihesten, sculpted in Devonian conglomerates, towers in the north. A low-angle fault separates the Devonian rocks from their Cambro-Ordovician substrate. (Photo: H. Fossen)

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Chapter 07 - p. 240

Devonian extensional shear zones as they are mapped today. More will probably show up as mapping of such structures continues.

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Chapter 07 - p. 241a

Warm colours on geomagnetic maps indicate especially magnetic bedrock. The continuation of the Hardangerfjorden Shear Zone south-westwards along the Ling Depression is most distinct. The zone thus affected the Permian to Jurassic development of this part of the North Sea. HSZ - Hardangerfjorden Shear Zone.

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Chapter 09 - p. 241b

The Hardangerfjorden has been excavated along one of the longest shear zones or faults in the mountain chain. Basement rocks crop out high on the south side, whereas on the north side nappe rocks rest in what has been referred to as the fold depression.

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Chapter 07 - p. 242

Simplified block diagram depicting where the extensional shear zones occur in Trøndelag and Nordland, and how they are connected with basement windows.

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Chapter 07 - p. 243

Photograph of a brittle fault in Øygarden, west Norway. The fault is probably Devonian, and the shiny surface has a coating of finely crushed, green epidote. (Photo: H. Fossen)

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Chapter 07 - p. 244

The Devonian deposits in west Norway (yellow), together with Caledonian nappe rocks (violet and brown) have been separated from the basement by the Nordfjord-Sogn Detachment.

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Chapter 07 - p. 245

Death Valley in California is a basin formed between high mountains and faults. Avalanche fans originating at the faults line the foot of the mountains. This landscape probably resembles the original Devonian landscape in Norway. (Photo: H. Fossen)

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Chapter 07 - p. 246a

The first map of the entire Kvamshesten Basin, published by C.F. Kolderup in 1921. The mai aspects are correct, but the contact between the Devonian and its substrate was looked upon as a major thrust fault.

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Chapter 07 - p. 246b

Devonian conglomerate (breccia) in the Håsteinen Basin. Angular boulders imply short transport, perhaps as scree deposits. (Photo: V.V. Vetti)

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Chapter 07 - p. 247

Fish and plant life. (Photo fosil: H. Fossen)

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Chapter 07 - p. 248

A drwaing by Hans Reuschs of the unconformity between folded nappe rocks and Devonian conglomeratesn at Bulandet (Sogn & Fjordane). This unconfomrity is beautifully exposed in many places along the coas of western Norway.

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Chapter 07 - p. 249

Mountains composed of Devonian sandstones and conglomerates viewed from the west towards Kvamshesten.(Photo: P.T. Osmundsen)

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Chapter 07 - p. 250a

Rhythmic rock (Figure modified from R. Steel)

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Chapter 07 - p. 250b

A naked, barren "Devonian landscape" in the mountains near Ålfoten. (Photo: P.T. Osmundsen)

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Chapter 07 - p. 251a

The rhythmic bedding is distinct on the mountainsides near Haukå, east of Florø. (Photo: I. Bryhni)

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Chapter 07 - p. 251b

Simplified model of how enormous thicknesses of Devonian deposits in the Hornelen Basin are envisaged to have been formed. Owing to the curvature of the fault plane, the beds were gradually rotated as they slid down the fault, and new beds were deposited above them.

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Chapter 07 - p. 252

Folded beds at Grøndalen, at he southern boundary of the Hornelen Basin. The beds that are most resistant to erosion stand out as stripes in the hillside. The light-coloured patches left of centre are the tips of gravel fans stacked on top of one another and derived from the basin margin to the right of the massif. (Photo: H. Fossen)

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Chapter 07 - p. 251

Devonian sandstones near the Ålfotbreen glacier. (Photo: I. Bryhni)

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Chapter 07 - p. 254

The beds forming the transition between the Austfjorden Member (yellow, calcareous sandstone) and the Dicksonfjorden member (red sandstone) in the Wood Bay Formation, here beside the Orsabreen glacier, north of  Ekmanfjorden, James I Land. (Phto: W. Dallmann)

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Chapter 07 - p. 255

Feeder pipe to the Quaternary vulcano in the Wood Bay Formation. The locality is near the Breibogen Fault. (Photo: W. Dallmann)

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Chapter 07 - p. 256a

Geological map of part of Svalbard where Devonian deposits are preserved.

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Chapter 07 - p. 256b

A generalised E-W profile across the above map.

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Chapter 07 - p. 257a

Sedimentary facies associations in the Wood Bay Formation.

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Chapter 07 - p. 257b

Sedimentary facies associations in the Wood Bay Formation.

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Chapter 07 - p. 257c 

Sedimentary facies associations in the Wood Bay Formation.

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Chapter 07 - s. 257d

Part of the head of a Devonian armoured fish (Arctolepis sp.). Its eye cavity is visible at the upper right. A reconstruction of the fish is seen above. (Illustration: H. Fossen, Photo: Norsk Polarinstitutt)

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Chapter 07 - p. 258

Folding av Devonian beds belonging to the Grey Hoek Formation. These westward-facing folds belong to the Gråhuken Fold Zone at Bråvallafjella, Vårfluesjøen. (Photo: W. Dallmann)

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Chapter 07 - p. 259

Quartz vein along one of the faults in the Billefjorden Fault Zonewest of Austfjorden, Dicksons Land. Baryte is found locally in this vein. (Photo: W. Dallmann)

 

 

Illustraiones chapter 6.

Illustrations can be downloaded in the gallery further down.

 

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Chapter 06 - pp. 178-179

Lhotse, Nepal (Photo: P. Zycki, CAMC, Polen)

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Chapter 06 - p. 182

This is how Hans Reusch, one of the pioneers in Norwegian geology, imagined that the Caldeonian mountain chain was formed. The crust was pressed together by folding, but the enormous sheets of rock, or nappes, which we now know were detached, are missing.

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Chapter 06 - p. 183a 

Reconstructions of plate movements when lapetus was closing. (Illustration: T.H. Torsvik)

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Chapter 06 - p. 183b

Pillow lava from Leka, Nord-Trøndelag. Pillow structures are formed when basaltic lava erupts into water. Note the fine-grained rim around the pillows and the gas vesicles further in. (Photo: R.-B. Pedersen)

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Chapter 06 - p. 184

Ophiolite

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Chapter 06 - p. 185a

Periodite on Leka. This is what the very lowest part of the iron-rich oceanic crust looks like after it has been on land for more than 100 million years - thoroughly rusty and weathered. (Photo: R.-B. Pedersen)

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Chapter 06 - p. 185b

Distribution of ophiolite complexes in the Scandinavian Caledonides. The most important ophiolite localities are named.

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Chapter 06 - p. 186

Sulpide ore formation. (Block diagram below from T. Grenne)

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Chapter 06 - p. 187a

Gold is also found in ophiolite complexes in Noway. The largest find has been made on Bømlo, where 137 kg of pure gold were extracted in 1882-1898. Gold can still be found at the site. (Photo: H. Fossen)

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Chapter 06 - s. 187b

Illustration: H. Fossen og R.-B. Pedersen

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Chapter 06 - p. 187c 

Island-arc rocks (quartz diorite with granite dykes) in the Sunnhordland batholith. (Photo: H. Fossen)

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Chapter 06 - p. 188

The Cambro-Silurian rocks of oceanic derivation (Upper Allochthon) range from acid granites that are resistant to weathering to phyllites an other "rotten" rocks. This gives great contrasts in soil and vegetation, as here at Huglo in Sunnhordland where acidic rhyolite forms naked ridges between lush areas of calcareous phyllite. (Photo: H. Sunde)

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Chapter 06 - p. 189

Granite is one of the commonest rocks in Norway. It largely consists of white to reddish feldspar, quartz and a little mica. Many of the granites in the orogenic belt were formed in island-arc complexes or batholiths prior to the main collision between Norway and Greenland. Trondhjemite (lowermost) was firmed first and more ordinary granites (uppermost) later. (Photo: H. Fossen)

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Chapter 06 - p. 190a

Possible evolution of the Caledonian orogenic belt from just after the plates began to converge in the Late Cambrian until the ocean closed and the actual mountain chain really began to rise around the transition from Silurian to Devonian. (Illustration H. Fossen)

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Chapter 06 - p. 190b

Possible evolution of the Caledonian orogenic belt from just after the plates began to converge in the Late Cambrian until the ocean closed and the actual mountain chain really began to rise around the transition from Silurian to Devonian. (Illustration H. Fossen)

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Chapter 06 - p. 191

The granites and associated plutonic rocks in Nordland are remnants of island arcs in the lapetus Ocean. Heilhornet, near the border with Nord-Trøndelag (Photo: H. Fossen)

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Chapter 06 - p. 192

Silurian quartzite conglomerate uppermost in the sedimentary sequence deposited unconformably on the Gullfjellet ophiolite in the Bergen Arcs. (Photo: H. Fossen)

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Chapter 06 - p. 193

The rock problem. (Illustration: H. Fossen, modified after E. Erdtmann, 1896)

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Chapter 06 - p. 194

The simplified stratigraphy on the island of Atløy in Sogn og Fjordane. The Høyvik Group corresponds to the sparagmitic rocks further east, and the Särv rocks in Sweden. It was folded and tilted before the deposition of the Silurian Herland Group which, in turn, was overriden by the Solund-Stavfjord ophiolite when the lapetus Ocean closed late in the Silurian.

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Chapter 06 - p. 195

Anorthosite quarry at Sirevåg, Rogaland. (Photo: T. Heldal)

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Chapter 06 - p. 196

The Caledonian nappes were piled up in a wedge-shaped stack of nappes in front of the Laurentian "bulldozer". (Illustration: H. Fossen)

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Chapter 06 - p. 197 

Eclogite from Nordfjord. (Photo: H. Fossen)

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Chapter 06 - p. 198

The basement along Sognefjorden has been kneaded like dough during the Caledonian orogeny. (Photo: H. Fossen)

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Chapter 06 - p. 199a

Flattening of the basement during the collision: Flattened version of Migmatic gneiss wiht Precambrian structures. (Photo: H. Fossen)

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Chapter 06 - p. 199b

Flattening of the basement during the collision:  Migmatic gneiss wiht Precambrian structures. (Photo: H. Fossen)

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Chapter 06 - p. 200a 

The tectonostratigraphy of the Norwegian Caledonides. (Illustration: H. Fossen, based on maps from NGU)

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Chapter 06 - p. 200a

Mylonitic augen gneiss. (Photo: H. Fossen)

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Chapter 06 - p. 201a

The Jotun Nappe, sparagmitic deposits and phyllitic rocks now lie piled on top of one another (uppermost). If they are drawn out and placed afther one another, the Jotun Nappe proves to have originally been at least 300 km west of its present position, as the lowermost  (split) profile shows. (See next page for location)

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Chapter 06 - p. 201b 

The main Caledonian lineation directions (arrows) suggest predominantly east-southeasterly transport of rock onto the continent, with additional movement in the longitudinal direction of the orogenic belt in the westernmost nappes.

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Chapter 06 - p. 202a

Lineation directions and nappe transport. (Modified from A. Kvale)

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Chapter 06 - p. 202b

Schematic illustration of where the various main units in the nappes may have been located prior to the collision. Profile line A-B refers to the recontrstructed profile on the previous page.

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Chapter 06 - p. 203

Stretched out conglomerate clasts are examples of lineations that may help us to calculate oth the transport direction and the deformation intensity. Rundemanen Formation near Bergen. (Photo: H. Fossen)

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Chapter 06 - p. 204

The sandstones in the Gaissa Nappe here at Austertana in east Finnmark are distinctly folded. One of the worlds's largest quartzite quarries (operated by Elkem Tana) dominates the landscape to the right. (Photo: S. Bergh)

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Chapter 06 - p. 205a

The nappe pile in Finnmark andTroms. (Illustration: H. Fossen and S. Bergh)

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Chapter 06 - p. 205b

Kalak Nappe rocks. The light-couloured quartzitic rock derives from the pre-collision Norwegian continental margin. The dark lenses (boudins) and bands are metamorphosed dolerite dykes which were partialle dismembered during the caledonian orogeny. Porsanger, Finnmark. (Photo: S. Bergh)

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Chapter 06 - p. 206a 

A prelude to the orogeny. (Photo: H. Fossen)

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Chapter 06 - p. 206b 

The Alta flagstone is metamorphosed Late Precambrian sediment that was foliated during the Caledonian orogeny. It has been quarried for use both indoors and outdoors for around 100 years. (Photo: T. Heldal)

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Chapter 06 - p. 207 

Zircons from the island of Seiland are not just beautiful and sought after by mineral collectors, they are ideal for age determinations using the uranium-lead method. They are just over 550 million years old, that is, from the very latest Precambrian. (Photo: H. Fossen)

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Chapter 06 - p. 208a

Windows revealing the substrate of the orogenic belt

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Chapter 06 - p. 208b

Granite slab in Tysfjord. (Photo: E. Rykkelid)

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Chapter 06 - p. 210

The Balsfjord conglomerate in Troms, flattened and foldedt. (Photo: S. Bergh)

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Chapter 06 - p. 211

The Lyngen alps consist mainly of gabbro from the ancient lapetus Ocean between Norway and Greenland. The layering formed when the gabbro magma crystallised, and is an alternation of layers rich in plagioclase and pyroxene and amphibole, respectively. (Photo: S. Bergh)

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Chapter 06 - p. 212

On the summit of Tromsdalstind is eclogite which originated at a depth of 80 km. (Photo: S. Bergh)

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Chapter 06 - p. 213

Tectonostratigraphical map of the allochtons in Nordland and central Norway. (Based on maps from NGU)

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Chapter 06 - p. 214

Fauske marble. (Photo: H. Fossen)

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Chapter 06 - p. 215

Granite rocks in the Rombak window. (Photo: S. Bergh)

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Chapter 06 - p. 216

Caledonian nappes in Nordland. (Photo: H. Fossen)

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Chapter 06 - p. 217a 

The largest deposits of metalimestone in Norway are in the central part of the Caledonides. The map shows localitites where quarrying is taking place for building stone or industrial use.(Based on maps from NGU)

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Chapter 06 - p. 217b

Chalcopyrite and iron pyrites from Sulitjelma, Nordland. (Photo: H. Fossen)

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Chapter 06 - p. 218 

Flagstone - a useful result of the orogeny. (Photo: H. Fossen) Illustration: Locations based on maps from)

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Chapter 06 - p. 220

Thrust fault and folds in Ordovician strata near Fornebu, Oslo, formed when the Caledoian nappes were transported from the northwest. (Photo: B.T. Larsen).

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Chapter 06 - p. 221a

The phyllites in the sole thrust between the nappe pile and the basement here inn Voss testify to the intense deformation which they underwent. (Foto: H.Fossen)

 

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Chapter 06 - p. 221b 

Tectonostratigraphical map of the allochtons in outhern Norway.

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Chapter 06 - p. 222 

Riplle marks preserved in the arkose overlying the sub-Cambrian peneplain, or basement surface, near Finse. The Caledonian nappes at the Hardangerjøkulen ica cap are seen in the background. (Photo: H. Fossen)

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Chapter 06 - p. 223

The Jotun Nappe includes anorthosite, which is typically white as here in Nærøydalen, on the boundary between Hordaland and Sogn & Fjordane. (Photo: I. Bryhni)

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Chapter 06 - p. 224a

Quartz. (Foto: H. Fossen)

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Chapter 06 - p. 224b 

A bird's-eye view of the Bergen Arcs. The arcs stand out as both topographical and lithological features. (Illustration: H. Fossen)

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Chapter 06 - p. 225

Anorthosite - a useful rock (Photo: I. Bryhni)

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Chapter 06 - p. 226a

An offshoot of the Olaberget trondhjemite pluton cutting through deformed mafic and felsic volcanites of the Hersjø Formation, Meråker Nappe. From the quarry at Olaberget, 7 km north-northeast of Vingelen, Hedmark county. The trondhjemite is the Early Silurian age, dated isotopically to 43 Ma. (Photo: D.Roberst)

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Chapter 06 - p. 226b

The eastern thrust contact of the Meråker Nappe, Trondheim Nappe Complex, just below Steinfjellet (909 m a.s.l.) about 1 km west of the Swedish border, close to Storlien; looking southwest. A thin slice of Seve Nappe rocks below the cliff, mostly covered by scree, overlies rhyolites and quartzites of the Lower Allochton. (Photo: D. Roberts)

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Chapter 06 - p. 227a

A map of the Løkken mine produced in 1718 looking towards the north.  Only the whallow part of the deposit, dominated by copper-rich sulphide stockwork ore, was mined. Subsezuent extraction of the main, massive pyritic ore body continued alont the westward extension to a depth of more than 1,000 m below the surface. (Illustration: Orkla Industrimueseum)

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Chapter 06 - p. 227b

Massiv pyritic ore in contact with jasper bed, Løkken. The deposition of both the ore and jasper was related to hydrothermal ventng at the sea floor. (Photo: T.Grenne)

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Chapter 06 - p. 228

Bedrock map of Svalbard

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Chapter 06 - p. 229

The three terranes of Caledonian-deformed rocks in Svalbard. The division is based on differences and similarities in both rock type and structural development.

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Chapter 06 - p. 229b

Marbel, mica schist and amphibolite, recombently folded during the Caledonian orogeny; Sigurdfjellet, northern Spitsbergen. Red Devonian sandstones in the background are separated from the basement by a major fault (the Breibogen Fault). (Photo: NPI, W. Dallmann)

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Chapter 06 - p. 230

The terrane model for Svalbard proposed by Brian Harland, where enormous lateral movements explain geological differences across substantial lineaments. This map shows the three terranes schematically replaced in their positions at the beginning of the Silurian, as Harland envisaged.

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Chapter 06 - p. 231

Folded and disrupted layers in a marble-gneiss unit at Liefdefjorden, Svalbard. The severe deformation is Caledonian and the strata belong to the Proterozoic Generalfjella Formation. (Photo: NPI, W.Dallmann)

 

 

Illustraiones chapter 5.

Illustrations can be downloaded in the gallery further down.

 

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Chapter 05 - p. 148-149

Limestone boulder from Langøya, off Holmestrand, showing a rich variety of Silurian fossils, including corals, brachiopods and bryozoans. (Photo: H.A. Nakrem)

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Chapter 05 - p.153a

Folding of the Cambro-Silurian strata is a result of the collision between Baltica and the American Plate, Laurentia, when the Caledonides were formed in the west. This deformation was quite strong in places, as here in Ordovidian shales at Bygdøy in Oslo. (Photo: D. Worlsey)

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Chapter 05 - p. 153b

Simplified geological map of the Oslo region showing the distribution of Cambro-Silurian sedimentary rocks and Permo-Carboniferous magmatic rocks, as well as the most importen faults. 

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Chapter 05 - p. 154a

Life in the Cambrian. Trilobites which crawled on the bottom and swam in the sea are typical representatives of organisms in the Early Cambrian marine environment on Baltica. In other parts of the world, reefs dominated by sponges (in the foreground) have been found, but no such reefs are known in Norway. (Reproduced by permission of the Natural History Muesum, University of Oslo. Illustration: B. Bocianowski)

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Chapter 05 - p. 154b

Trilobites were among the first organisms to evolve a hard shell (exoskeloton)

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Chapter 05 - p. 155-1

Holmia kjerulfi, a trilobite from the Lower Cambrian (Holmlia shale), Ringsaker (2 cm long). (Photo: H.A. Nakrem)

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Chapter 05 - p. 155-2

Fossils from Cambrian deposits in the Oslo region
A. The mikrofossil Torellella, Hadeland (Photo: H.A. Nakrem)
B. The mikrofossil Lapworthellide, Hadeland. (Photo: H.A. Nakrem)
C. The mikrofossil Lapworthellide, Hadeland (Photo: H.A. Nakrem)
D.The trilobite Ptychagnostus gibbus, Slemmestad. (Photo D: M. Høyberget/ D.L. Bruton)

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Chapter 05 - p. 155a

The mikrofossil Torellella, Hadeland (Photo: H.A. Nakrem)

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Chapter 05 - p. 155b

The mikrofossil Lapworthellide, Hadeland. (Photo: H.A. Nakrem)

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Chapter 05 - p. 155c

The mikrofossil Lapworthellide, Hadeland (Photo: H.A. Nakrem)

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Chapter 05 - p. 155d

The trilobite Ptychagnostus gibbus, Slemmestad. (Photo D: M. Høyberget/ D.L. Bruton)

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Chapter 05 - p. 156a

Life in the Ordovician was characterised by cephalopods and graptolites in the water masses and sea lilies, trilobites and corals on the sebaed. (Reproduced by permission of the Natural History Muesum, University of Oslo. Illustration: B. Bocianowski)

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Chapter 05 - p. 156b

Asaphus expansus, the trilobite which W.C. Brøgger illustrated in his work: "Die silurischen Etagen 2 und 3" from 1882. From the Hukf Formation, Tøyen, Oslo. 8 cm long. (Photo: H.A. Nakrem)

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Chapter 05 - p. 157

Fossils from Ordovician deposits in the Oslo region 
A. The graptolite Rhabdinopora, Tøyen Formation, Tøyen (Oslo) (Photo: H.A. Nakrem)
B. The graptolite Phyllograptus, Tøyen Formation, Slemmestad (Photo: H.A. Nakrem)
C. The starfish Cnemidactis osloensis, Elnesformasjonen, Djuptrekkodden (Asker), ca. 4 cm in diameter (Foto C: D.L. Bruton / T. Hansen)
D. The trilobite Pseudomegalaspis, Elnes Formation, Fiskum (Photo: H.A. Nakrem)
E. The cephalopod Endoceras (upside down on the bedding plane), Hukformasjonen, Krekling i Buskerud, 4 cm in diameter. (Photo: H.A. Nakrem)
F. The cephalopod Discoceras, Bønsnes Formation (Upper Ordovician), Stavnestangen (Ringerike), 12 cm in diameter. (Photo: H.A. Nakrem)

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Chapter 05 - p. 157a

The graptolite Rhabdinopora, Tøyen Formation, Tøyen (Oslo) (Photo: H.A. Nakrem)

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Chapter 05 - p. 157b

The graptolite Phyllograptus, Tøyen Formation, Slemmestad (Photo: H.A. Nakrem)

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Chapter 05 - p. 157c

The starfish Cnemidactis osloensis, Elnesformasjonen, Djuptrekkodden (Asker), ca. 4 cm in diameter (Foto C: D.L. Bruton / T. Hansen)

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Chapter 05 - p. 157d

The trilobite Pseudomegalaspis, Elnes Formation, Fiskum (Photo: H.A. Nakrem)

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Chapter 05 - p. 157e

The cephalopod Endoceras (upside down on the bedding plane), Hukformasjonen, Krekling i Buskerud, 4 cm in diameter. (Photo: H.A. Nakrem)

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Chapter 05 - p. 157f

The cephalopod Discoceras, Bønsnes Formation (Upper Ordovician), Stavnestangen (Ringerike), 12 cm in diameter. (Photo: H.A. Nakrem)

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Chapter. 05 - p. 158

A. Crinoids (1.5 m in diameter) curled on a bedding plane, Vik Formation, Malmøya. (Photo: H.A. Nakrem)
B. Crinoid, holdfast ("root"), ca. 20 cm i diameter, Rytteråker Formation, Malmøya. (Photo: H.A. Nakrem)
C. Favosites, honeycomb coral (arrow) in cross section (field of view is 25 cm wide), Vik Formation, Malmøya. (Photo: H.A. Nakrem) 
D. Bedding plane with several corals, Steinsfjorden Formation, Langøya near Holmestrand. (Photo: H.A. Nakrem)
E. Monograptus, a graptolite, Skinnerbukt Formation, Malmøya. (Photo: H.A. Nakrem)
F. Bedding plane with various brachiopods, including Eoplectodonta, Isorthis and Coolina, Solvik Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158a

Crinoids (1.5 m in diameter) curled on a bedding plane, Vik Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158b

Crinoid, holdfast ("root"), ca. 20 cm i diameter, Rytteråker Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158c

Favosites, honeycomb coral (arrow) in cross section (field of view is 25 cm wide), Vik Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158d

Bedding plane with several corals, Steinsfjorden Formation, Langøya near Holmestrand. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158e

Monograptus, a graptolite, Skinnerbukt Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158f

Bedding plane with various brachiopods, including Eoplectodonta, Isorthis and Coolina, Solvik Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 159

The graptolite Didymograptus from the Tøyen Formation, Lower Ordovician, Slemmestad, 4 cm long. This type of graptolite is very common in Ordovcian lihologies over large areas, and is therefore a valuable zone fossil. (Photo: H.A. Nakrem)

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Chapter 05 - p. 160

Thalassinoides, burrows probably excavated by a crustacean or similar articulated animal living in the sea bottom.  (Illustration: G. Pemberton)

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Chapter 05 - p. 161a

A landscape from the end of the Silurian, when the first plants began to grow on land. Sea scorpions soon began to creep out of the sea too, and land scorpions, millipedes and mites settled on land, where the plants gave food and protection from the sun. (Reproduced by permission of the Natural History Muesum, University of Oslo. Illustration: B. Bocianowski)

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Chapter 05 - p. 161b

Pharyngolepis, one of the jawless fish found as a fossil in Ringerike. (Illustrasjon: NHM, UiO)

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Chapter 05 - p. 162

One of the finest fossils found in Norway, the 75 cm long sea scorpion, Mixopterus kiaeri, found in red sandstone near Kroksund, Ringerike. When Johan A. Kiær described the discovery in 1924 he wrote: "I'll never forget the moment when we found this new scorpion. My assistants had just turned over a large flat stone when we saw the big creature with its outstretched flippers. It looked so natural we almost expected it to get up from the spot where it had been resting for so many millions of years and creep down to the lake below us.". (Foto: P. Aas, NHM, UiO)

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Chapter 05 - p. 163

Nodules and trace fossils
A. Calcareous nodules in dark shale from Hovedøya (Skogerholmen Formation, Ordovicioan). (Photo: H.A.Nakrem)
B. Cross section of nodules and some fossil fragments, a coral and some crinoid stems in and around the nodules (Rytteråker Formation, Silurian, Malmøya), field of view is 30 cm (Photo: H.A.Nakrem)
C. Nodules in the form of burrows (Rytteråker Formation, Silurian, Malmøya), the burrows are 10–20 mm in diameter. (Photo: H.A.Nakrem)
D. Cambrian cannonballs (Alum Shale Formation, Slemmestad). (Photo: H.A.Nakrem)
E. Bedding plane with fine grazing burrows (Chondrites type) (Solvik Formation, Sillurian, Malmøya), the burrows are about 2 mm in diameter. (Photo: H.A.Nakrem)
F. Weathered bedding plane which shows a maze of coarse burrows (Vik Formation, Silurian, Malmøya), the burrows are 10–20 mm in diameter. (Photo: H.A.Nakrem)

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Chapter 05 - p. 163a

Calcareous nodules in dark shale from Hovedøya (Skogerholmen Formation, Ordovicioan). (Photo: H.A.Nakrem)

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Chapter 05 - p. 163b

Cross section of nodules and some fossil fragments, a coral and some crinoid stems in and around the nodules (Rytteråker Formation, Silurian, Malmøya), field of view is 30 cm (Photo: H.A.Nakrem)

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Chapter 05 - p. 163c

Nodules in the form of burrows (Rytteråker Formation, Silurian, Malmøya), the burrows are 10–20 mm in diameter. (Photo: H.A.Nakrem)

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Chapter 05 - p. 163d

Cambrian cannonballs (Alum Shale Formation, Slemmestad). (Photo: H.A.Nakrem)

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Chapter 05 - p. 163e

Bedding plane with fine grazing burrows (Chondrites type) (Solvik Formation, Sillurian, Malmøya), the burrows are about 2 mm in diameter. (Photo: H.A.Nakrem)

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Chapter 05 - p. 163f

Weathered bedding plane which shows a maze of coarse burrows (Vik Formation, Silurian, Malmøya), the burrows are 10–20 mm in diameter. (Photo: H.A.Nakrem)

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Chapter 05 - p. 164

Generalised stratigraphical table showing the division of the Cambro-Silurian succession and characteristic aspects in the central part of the Oslo region (Oslo-Asker)

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Chapter 05 - p. 165

Black Middle Cambrian shales lie directly on Precambrian basement and are overlain by a horizontal intrusive sill og light maenaite at Slemmstad, in the centre of the Oslo region. (Photo: H.A. Nakrem)

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Chapter 05 - p. 166

Large Lower Ordovician carbonate "cannonballs" are exposed in the Alum Shale at Nærsnes, Near Slemmestad. (Photo: B.T. Larsen)

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Chapter 05 - p. 167a

Schematic block diagrams showing the Cambrian and Ordovician depositional development of the Oslo region
Early Cambrian ( ca. 540 million years ago).

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Chapter 05 - p. 167b

Schematic block diagrams showing the Cambrian and Ordovician depositional development of the Oslo region
Middle Cambrian (ca. 500–510 million years ago).

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Chapter 05 - p. 167c

Schematic block diagrams showing the Cambrian and Ordovician depositional development of the Oslo region
Early-middle Ordovician (ca. 470–480 million years ago). 

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Chapter 05 - p. 167d

Schematic block diagrams showing the Cambrian and Ordovician depositional development of the Oslo region
Late Ordovician (ca. 443–445 million years ago). 

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Chapter 06 - p. 169

A greenish, readily weatering layer of bentonite (fossil volcanic ash), approximately 1 m thick, is found withhin dark Odovician shales of the Arnestad Formation in Asker. (Photo: H.A. Nakrem)

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Chapter 05 - P. 170

Tidal channel filled with boulders of calcareous sandstone uppermost in the Ordovician (the Langøyene Formation) on Kalvøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 171a

The Ordovician Tromsdal limestone is quarried in Verdal, Nord- Trøndelag. (Photo: H.A. Nakrem)

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Chapter 05 - p. 171b

The cliff of Tsjebysjovfjellet on the south side of Hornsund, Svalbard. The rocks are almost unmetamorphosed carbonates in Nørdstetind Formation, which is part of the Ordovician Sørkapp Land Group. The recumbent isoclinal fold is of Caledonian age and is probably a folded nappe. (Photo:W. Dallmann)

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Chapter 05 - p. 171c

Distribution of Cambro-Silurian rocks (black) in Norway and adjacent part of western Sweden. (From: H. Fossen)

 

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Chapter 05 - p. 172

Cambro-Silurian fossils from localities outside the Oslo region
A. Rhabdinopora, an Ordovician graptolite, Digermul Peninsula, Finnmark (field of view is 6 mm wide). (Photo: H.A. Nakrem)
B. Syringophyllum, a coral in metamorphosed and deformed Silurian limestone (marble), Bergen (the coral is 3 mm in diameter). (Photo: H.A. Nakrem)
C. Peltocare compactum, an Ordovician trilobite, Digermul Peninsula, Finnmark (ca. 12 mm long). (Photo: H.A. Nakrem)
D. Drill core showing brachiopods and corals, from the Farsund Basin (Lower Silurian), Skagerrak (the core is 5 cm in diameter). (Photo: H.A. Nakrem)
E. Deformed trilobite Calymene, Silurian, Bergen (Reusch's original specimen), (the trilobite is 1 cm across). (Photo: H.A. Nakrem)
F. Solidary corals ("Cyathophyllum") in metamorphosed and deformed Silurian limestone (marble), Bergen (The corals are 1 cm in diameter). (Photo: H.A. Nakrem)
G. Colonial corals ("Syringophyllum") in metamorphosed and deformed Silurian limestone (marble), Bergen (The coral is 3 mm in diameter). (Photo: H.A. Nakrem)
H. Gonioceras, a cephalopod from the Ordovician on Bjørnøya (25 cm long) (Photo: H.A. Nakrem)

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Chapter 05 - p. 172a

Rhabdinopora, an Ordovician graptolite, Digermul Peninsula, Finnmark (field of view is 6 mm wide). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172b

Syringophyllum, a coral in metamorphosed and deformed Silurian limestone (marble), Bergen (the coral is 3 mm in diameter). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172c

Peltocare compactum, an Ordovician trilobite, Digermul Peninsula, Finnmark (ca. 12 mm long). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172d

Drill core showing brachiopods and corals, from the Farsund Basin (Lower Silurian), Skagerrak (the core is 5 cm in diameter). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172e

Deformed trilobite Calymene, Silurian, Bergen (Reusch's original specimen), (the trilobite is 1 cm across). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172f

Solidary corals ("Cyathophyllum") in metamorphosed and deformed Silurian limestone (marble), Bergen (The corals are 1 cm in diameter). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172g

Colonial corals ("Syringophyllum") in metamorphosed and deformed Silurian limestone (marble), Bergen (The coral is 3 mm in diameter). (Photo: H.A. Nakrem)

Kap05 side172h Gonioceras  

Chapter 05 - p. 172h

Gonioceras, a cephalopod from the Ordovician on Bjørnøya (25 cm long) (Photo: H.A. Nakrem)

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Chapter 05 - p. 173a

Schematic block diagrams showing the Silurian depositional development of the Oslo region.
Early Silurian (ca. 435–440 million years ago). 

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Chapter 05 - p. 173b

Schematic block diagrams showing the Silurian depositional development of the Oslo region.
Early Silurian (ca. 430 million years ago). 

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Chapter 05 - p. 173c

Schematic block diagrams showing the Silurian depositional development of the Oslo region.
Middle Silurian (ca. 430–425 million years ago).

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Chapter 05 - p. 173d

Schematic block diagrams showing the Silurian depositional development of the Oslo region.
Late Silurian (ca. 420 million years ago). 

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Chapter 05 - p. 174

A. Relatively flat reef structure (1 m thick) in the upper part of the Rytteråker Formation at Limovnstangen, Ringerike. The yellow broken line denote the reef surface, the red one its base and the blue one the reef flank. 
B. Reef-building coral: Halysites (chain coral)
C. Reef-building coral: Favosites (honeycomb coral)
(Photos: H.A. Nakrem)

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Chapter 05 - p. 174b

Reef-building coral: Halysites (chain coral) (Photo: H.A. Nakrem)

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Chapter 05 - p. 174c

Reef-building coral: Favosites (honeycomb coral) (Photo: H.A. Nakrem)

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Chapter 05 - p. 175

Sediments and reconstructed depositional environment from the end of the Silurian period

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Chapter 05 - p. 175a

The shift from green, coastal sandstone to red, continental sandstone in Ringerike, with wave ripples in the red beds, probably formed in a lake or lagoon with fresh or brackish water. Kroksund, Ringerike. (Photo: H.A. Nakrem)

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Chapter 05 - p. 175b

A river channel has cut down into more fine-grained fluvial sediment. Ringerike Sandstone, Sundvollen, Ringerike. (Photo: D. Worsley)

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Chapter 05 - p. 175c

Model of the sea scorpion, Mixopterus kiaeri, in its natural habitat in these lakes. (Natural History Museum, University of Oslo. Foto: H.A. Nakrem)

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Chapter. 05 - p. 175d

Model of the primitive fish, Aceraspis, which lived with the sea scorpions. (Natural History Museum, University of Oslo. Photo: H.A. Nakrem)

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Chapter. 05 - p. 176 

Paleogeographical map of Baltica at the transition from Early to Late Silurian: the Caledonides were rising in the north and west, while the southern margin of Baltica formed a deep foreland basin towards the Palaeotethys Ocean. (Illustration: T. Torsvik)

 

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Chapter 05 - p. 177a 

Life in a fossil reef reconstructed and modellen on the basis of the reef at Limovnstangen, Ringerike. The reef was primarily built up of corals (B,D,I,K,L) and calcareous sponges (stromatoporoids) (A), but brachiopods (F), bryozoans (G), gastropods (C), algae and sea lillies (H) were all important components in this environment. Trilobites crawled among the sedentary organisms, while cephalopods (J) swam in the sea surronding the reef. (NHM, UiO. foto H.A. Nakrem)

 

 

Illustrations chapter 4.

Illustrations can be downloaded in the gallery further down.

 

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Chapter 04 - p. 120-121 

Giemašfjellet, on the east side of Tanafjorden, consists of folded sandstones of Neoproterozoic age. The pure quartz rocks are quarried at Austertana to use the quartz for industrial purposes. The successions from the last part of the Precambrian are very well exposed and thoroughly studied in the Tanafjord–Varangerfjorden region. (Photo: A. Siedlecka)

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Chapter 04 - p. 122 

Simplified map of the Baltica continent as it may have looked when it separated from the supercontinent, Rodinia. The north-eastern and north-western margins, the Timanian and Baltoscandian margins, respectively, delimited the "Norwegian" part of the continent.

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Chapter 04 - p. 123

Map of the north-western part of Baltica showing the present distribution of Neoproterozoic sedimentary rocks (yellow) in Norway and along the Caledonian thrust front. The Neoproterozoic Gardnos Crater and the Fen volcano are situated at Gardnos and Fen, respectively. Other Caledonian rocks are indicated with pale grey colour. 

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Chapter 04 - p. 124

Geological map of Finnmark showing the most important divisions of the bedrock. Compiled from various sources.

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Chapter 04 - p. 125

The Neoproterozoic to Cambrian successions in the Tanafjorden – Varangerfjorden and Barents Sea regions. (Adapted from several works by A. Siedlecka)

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Chapter 04 - p. 126a

Podolina minuta, a star-shaped acritarch, a microfossil, just a few micromillimeter in size, from the lower part of the Vadsø Group beside Varangerfjorden, on av the oldest fossils in Norway, found, prepared and photographed by Gonzalo Vidal.

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Chapter 04 - p. 126b

Shallow-water marine sandstone beds in the Dakkovarre Formation of the Tanafjorden group at Skallnes on the south coast of the Varanger Peninsula. (Photo: A. Siedlecka)

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Chapter 04 - p. 126c

Dark-red mudstone and light-red sandstone in the Fugleberget Formation on the south side of the island of Vadsø. The beds were deposited as sandbanks in rivers. One sand bed was folded by the force of strongly flowing water during a flood. (Photo: A. Siedlecka)

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Chapter 04 - p. 127

Examples of columnar and branching stromatolites in the Porsanger dolomite on the west side of Porsangen, near Trollsundet. (Photo: A. Siedlecka)

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Chapter 04 - p. 128

The Bigganjarga tillite at Oibacšanjarga in Varangerbotn, is fossilised moraine from the approximately 600 million-year-old Varangerian Ice Age. This world-famous deposit is protected. (Photo: J.P. Nystuen)

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Chapter 04 - p. 129a

Thick, grey, turbiditic sandstones of the Kongsfjord Formation beside the Barents Sea in Kongsøyfjorden, Varanger Peninsula. The beds were deposited as huge submarine sand fans more than 700 million years ago. (Photo: J.P. Nystuen)

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Chapter 04 - p. 129b

Multicoloured beds of shales, sandstones and dolomites in the upper part of the Båtsfjord Formation in the Barents Sea Group in inner Persjorden, Varanger Peninsula. (Photo: A. Siedlecka)

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Chapter 04 - p. 130

Ediacaran fossils from the Stáhpogieddi Formation at the Precambrian-Cambrian boundary on the south coast of the Digermulen Peninsula. The imprints are of round, jellyfish-like organisms, a few centimetres in diameter. (Photo: A. Siedlecka)

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Chapter 04 - p. 131

The geological development of the Tanafjorden-Farangerfjorden region southwest of the Trollfjorden-Komagelva Fault Zone (TKFZ) and the Barents Sea region northeast of the fault zone. a) Deep-water and, later, shallow -water marine sediments were deposited in a basin northwest of the Varanger Peninsula. b) and c) Sediments were deposited on fluvial plains and in shallow sea in the Tanafjord-Varangerfjord region. d) The successions of the Barents Sea Group and the Løkvikfjellet Group slide from northest to southeast along the TKFZ and form the Barents Sea region on the northeast side of the Varanger Peninsula.

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Chapter 04 - p.132

Chalk-white Porsanger dolomite in 30 °C and a heat haze near Børselv in Porsangen casts our minds back to the hot areas in southern latitudes where this carbonate deposit was formed some 650 million years ago. The snow on the mountains in the background reminds us of the great climatic changes in the i Neoproterozoic. (Photo: J.P. Nystuen)

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Chapter 04 - p. 133

Sparagmite, feldspar-rich sandstone (arkose), sometimes containing large, angular clasts, was named by Jens Esmark in 1829. (Photo: I. Bryhni)

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Chapter 04 - p. 134

Igneous rocks in the Seiland Province, Reinfjorden, on the Øksfjord Peninsula. Gneiss on the lower slope of the mountainside is intruded by layered igneous rocks which occupy the upper part of the cliff. Black ultramafic rocks occur in two series separated by an older, light-grey gabbro. The nearly 600 m high mountainside provides a section thourgh a huge magma chamber. (Photo: B. Robins)

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Chapter 04 - p. 135

Light-coloured metasandstone in the Kalak Nappe Complex cut by dolerite dykes metamorphosed to amphibolite. The rocks probably derive from a basin on the outer side of Baltica and were moved several hundred kilometers during the Caledonian orogeny. Road cut south of Hammerfest on Kvaløya. (Photo: J.P. Nystuen)

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Chapter 04 - p. 136

The Sparagmite Region in south Norway.

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Chapter 04 - p. 137

The Rondane Mountains consist of hard, Late Precambrian metasanstones that are approximately 650-750 million years old. During the Caledonian orogeny, these sandstones were thrust several hundred kilometres eastwards from basins along the Baltoscandian margin of Baltica. (Photo: C. Harbitz)

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Chapter 04 - p. 138

The succession in the Hedmark Basin, the Hedmark Group; the western part to the left and the eastern to the right.

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Chapter 04 - p. 139a

Rendalssølen (1754 m) is a landmark in the sparagmite region of eastern Norway. The mountain is composed of the Rendalen Formation, sandstones deposited by rivers in the eastern part of the Hedmark Basin 700–750 million years ago. (Photo: J.P. Nystuen)

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Chapter 04 - p. 139b

Cross-bedded sandstone from an infilled river channel in the Rendalen Formation on the summit of Rendalssølen. (Photo: J.P. Nystuen)

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Chapter 04 - p. 139c

Limestone breccia in the Biri Formation in a road cut on E6 at Kremmerodden, Biri. Up to 50 cm long fragments of the limestone were broken up by tidal currents or powerful waves. (Photo: J.P. Nystuen)

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Chapter 04 - P. 140a

The Brøttum Formation in Maihaugvegen, Lillehammer. Beds of turbiditic sandstones and shales were deposited on the floor of hte Hedmark Basin and raised into a vertical position during the orogenic movements at the end of the Silurian. The shaley beds contain acritarchs, the oldest fossils found in southern Norway. (Photo: J.P. Nystuen)

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Chapter 04 - p. 140b

Beds of conglomerate and sandstone in the Biskopåsen Formation in a road cut near Havik on the east side of Lake Mjøsa. The beds are vertical due to thrusting during the Silurian-Devonian Caledonian orogeny.. (Photo: J.P. Nystuen)

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Chapter 04 - p. 141

Evolution of the Hedmark Basin through six phases from its initial formation by rifting until Baltica was covered by the sea at the beginning of the Cambrian 542 million years ago.

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Chapter 04 - p. 141a- b

a) 750 mill. yrs
b) 750-680 mill. yrs

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Chapter 04 - p. 141c-d

c) 680-650 mill. yrs
d) 630-590 mill.yrs - Varangerian Ice Age

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Chapter 04 - p. 141e-f

e) 570-550 mill.yrs - Ediacaran time
f) 542 mill. yrs - early Cambrian

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Chapter 04 - p. 142a

Papillomembrana compta, the first Precambrian fossil found in Norway. The fossil, of unknown affinity and just over 1 mm long, was found by Nils Spjeldnæs i 1959 in a phosphorite clast in the Biskopåsen Formation near Havik, beside Mjøsa. (Photo: N. Spjelndæs)

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Chapter 04 - p. 142b

A rock core (4 cm in diameter) from Østre Æra, between Rena and Ossjøen in Østerdalen. Basalt lava (dark) flowed over unconsolidated sand (light coloured), some of which was rolled into the base of the lava. The lava extrusions took place during an active rifting phase in the Hedmark Basin. (Photo: J.P. Nystuen)

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Chapter 04 - p. 143a 

Moelv tillite from the approximately 600 million-year old Varangerian Ice Age exposed as ice-polished rock from the last Ice Age, about 10 000 years ago. The tillite has large and small clasts of basement rocks and limestone. Bruvollhagan, Moelv. (Photo: J.P. Nystuen)

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Chapter 04 - p. 143b 

The Ringsake quartzite from the very base of the Cambrian, the youngest part of the Hedmark Group, Steinsodden on the east side of Mjøsa in Ringsaker. Looking northwards towards Mjøsa Bridge. Lundehøgda and Biskopåsen in the background are also in the type are for the Hedmark Group. (Photo: J.P. Nystuen)

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Chapter 04 - p. 143c 

The Ringsaker quartzite, with vertical burrows excavated by a lugworm-like mollusc. Langodden, on the east bank of Lake Mjøsa.  (Foto: J.P. Nystuen)

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Chapter 04 - p. 144

Old source rock for oil: black shale in the Brøttum Formation in Maihaugvegen in Lillehammer. Black shale with a high content of organic carbon (black) is overlain by a thin layer of silt with light-coloured quartz grains. The silt has sunk into the clay, forming the boot-shaped structure. (Foto: M.K.M. Skaten)

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Chapter 04 - p. 145a

The Gardnos Crater.

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Chapter 04 - p. 145b

The Gardnos Crater. Cross section through the Gardnos Crater.

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Chapter 04 - p. 145c

The Gardnos Crater. Core from Branden.

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Chapter 04 - p 146

Geological map of the Fen area. The rocks were formed by many different magmatic processes far below the summit of the Fen volcano.  (Modified after E. Sæther)

 

 

Illustrations chapter 3.

Illustrations can be downloaded in the gallery further down.

 

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 Chapter 03 - p. 62-63

(Illustration:Bogdan Bocianowski. Photo:P.Aas, both NHM, Univ. of Oslo)

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Chapter 03 - p.64 

Photograph of a polished surface of 2800 million-yeard-old gneiss from Grasbakken on the south side of Varangerfjorden, Finnmar. The rock has a tonalitic composition and contains reddish veins of quartz and feldspar which have given the rock its commercial name of "Barents red". (Foto: NGU)

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Chapter 03 - p. 67

Cores of Archaen crust are preserved in all the major continents on the Earth. The earliest rocks that were formed may have been destroyed by meteorite impacts, tectonic prosesses, surface weathering and erosion, or they may be covered by younger strata. Rocks that are older than 3500 million years are only preserved in a few areas.

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Chapter 03 - p. 68

Simplified geological map of the Fennoscandian Shield. The map shows the broad divisions of the bedrock according to its age and the types of rock.

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Chapter 03 - p. 69

Dickinsonia from the White Sean. The fossil is 75 mm across. Museum of Natural History, Tøyen. (Photo: J.H. Hurum)

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Chapter 03 - p. 70

The principle of age determination. The ratio between mother and daughter isotopes in a mineral or rock is measured. Their known half-life is then used to calculate the length of time that has ensued since the process started from the original state, and this gives the age of the mineral or rock.

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Chapter 03 - p. 72

Geological map of the Kola Peninsula and eastern Finnmark showing the distribution of the most imprtant geological units and how they correlate with adjacent areas on the Kola Peninsula and in Finland. On Finnmarksvidda, Neoproterozoic to Cambrian strata rest with an angular unconformity on the basement. These deposits are overlain by nappes belonging to the Caledonian mountain chain which conceal the ancient basement rocks in the fjord districts of Troms and Finnmark.

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Chapter 03 - p. 74

Monozonitic plutonic rock inruded the gneisses in Sør-Varanger 2750 million years ago. The monozite has angular fragments of dark rocks and is transected by a pale-pink pegmatite dyke. Skallvåg, Sør-Varanger. (Foto: Ø. Nordgulen)

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Chapter 03 - p. 75

Unconformity at Skrukkebukt in Pasvik. Conglomerate has filled in an uneven surface where eroision has cut down into foliated ARchaean gneiss. (Foto:V.Melezhik)

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Chapter 03 - p. 77

The figures illustrate the geological evolution of the north-eastern part of the Fennoscandian Shield in the Early Proterozoic.

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Chapter 03 - p. 78a

Schematic drawing showing how the quartz-banded iron ore in Sør-Varanger probably formed. Free oxygen (O2) and iron ions formed the iron oxides, magnetite (Fe3O4) or haematite (Fe2O3) (dark bands in the figure). These are seperated by layers of precipitated jasper (yellow bands). Each band may be from one milimetre up to a few centimetres thick.

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Chapter 03 - p. 78b

The iron ore, which consists of alternating bands of quartz and magnetite that are 2-10 mm thick, occurs in the middle of the Bjørnevann Group. (Photo: Ø. Nordgulen)

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Chapter 03 - p. 79a

A geophysical map shoing the total magnetic field of part of Finnmarksvidda (the Kautokeino Greenstone Belt). (Figures: O.Olesen and J.S. Sandstad)

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Chapter 03 - p. 79b

The bedrock map illustrates part (framed) of the geophysical map. It shows how the geophysical properties of the bedrock can be used as a valuable aid when mapping areas covered by superficial deposits. (Figures: O.Olesen and J.S. Sandstad)

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Chapter 03 - p. 80a

Searching for gold in the bedrock beneath a thick cover of till requires heavy-duty equipment. Sáotgejohka 1990. (Photo:M. Often)

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Chapter 03 - p. 80b

Washing gold in the Goššjohka i 1901. (NGU's photo archive)

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Chapter 03 - p. 80c

Gold from Finnmark. The largest grain is about 2 mm. (Photo: B.M. Messel)

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Chapter 03 - p. 82a

The rocks of the Raipas Group tell an exciting geological story. Fluid basalt lava (brown) poured out of joint systems in a marine rift basin (a) and was followed by explosive volcanic eruptions (b) which gave rise to tuffs (light green). At the same time, the rift zone sank in fits and starts, resulting in the formation of a thick volcanic sequence (Kvenvik Greenstone), C). The basin was subsequently filled, initially by carbonate sediments (Storviknes dolomite) and finally by thick continental sandstones (Skoadduvarri sandstoene).

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Chapter 03 - p. 83b

The rocks of the Raipas Group tell an exciting geological story. Fluid basalt lava (brown) poured out of joint systems in a marine rift basin (a) and was followed by explosive volcanic eruptions (b) which gave rise to tuffs (light green). At the same time, the rift zone sank in fits and starts, resulting in the formation of a thick volcanic sequence (Kvenvik Greenstone), C). The basin was subsequently filled, initially by carbonate sediments (Storviknes dolomite) and finally by thick continental sandstones (Skoadduvarri sandstoene).

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Chapter 03 - p. 82c

The rocks of the Raipas Group tell an exciting geological story. Fluid basalt lava (brown) poured out of joint systems in a marine rift basin (a) and was followed by explosive volcanic eruptions (b) which gave rise to tuffs (light green). At the same time, the rift zone sank in fits and starts, resulting in the formation of a thick volcanic sequence (Kvenvik Greenstone), C). The basin was subsequently filled, initially by carbonate sediments (Storviknes dolomite) and finally by thick continental sandstones (Skoadduvarri sandstoene).

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Chapter 03 - p. 82d

Kvenvika greenstone with pillow structures. (Photo:S.Bergh)

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Chapter 03 - p. 82e

Storviknes dolomite with stromatolite structures. (Photo:S.Bergh)

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Chapter 03 - p. 83

The figure shows a scematic section illustrating the geological evolution in Nordaustlandet. Two unconformities separate three important stratigraphical units, the Helvetesflya Formation, the Svartrabbana Formation and the Murchisonfjorden Supergroup. An unconformable surface is an expression of a fundamental time interval - a milestone in the geological evolution of an area. It marks the end of a cycle of mountain chain formation and folding (F1 and F2 in the figure) followed by breakdown and erosion. The basal conglomerates record the onset of a new period of deposition of strata on an erosion surface. The youngest folds (F3) are Caledonian. The age of igneous rocks (granites and volcanic rocks) helps to time the various events.

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Chapter 03 - p. 85

The mountains north of Ersfjorden on Kvaløya, Troms, from Skamtinden in the west to Blåmannen and Orvasstinden in the east (right), consist of 1800 million-year-old granite. (Photo: K. Kullerud)

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Chapter 03 - p. 86

Geological map depicting the main features of the bedrock from Senja in the southwest to Vanna in the northeast. The Precambrian rocks along the coast underlie the Caledonian nappes that were thrust from the northwest. At Mauken, there is a tectonic window where Precambrian rocks show through the nappes.

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Chapter 03 - p. 87

Sandstone from Jøvik, Vanna. The sanstone, which is between 2400 and 2220 million years old, has crossbedding which shows that it was deposited as sand in a large, deep river, a delta or along a shore beside a sea or a large lake. (Photo: K. Kullerud)

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Chapter 03 - p. 88a

Photomicrograph of a thin section of the graphite ore from Senja; everything black is graphite.(Photo: H. Gautneb)

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Kap. 03 - s. 88b

The finished product, Silvershine from Skaland Graphite Mine. (Photo: H. Gautneb)

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Chapter 03 - p. 89

Geological map of Lofoten and Vesterålen.

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Chapter 03 - p. 90

Geological map showing the distribution of Precambrian rocks and Caledonian nappes in Nordland and western Troms. Archaean rocks occur furthest north. The basement windows in Nordland are mainly composed of Early Proterozoic granitic gneisses. Similar rocks also occur in Nord-Trøndelag.

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Chapter 03 - p. 92

The basement is mostly composed of crustal blocks. Geologists have referred to these blocks by a variety of terms over the years, including sectors and terranes. The amount of lateral and vertical movement that has taken place along the various shear zones that separate the blocks is not known. It is also uncertain how the various blocks have been situated in relation to one another 1600-1700 million years ago and subsequently.

Kap03 print Page 093  

Chapter 03 - p. 93

Basement composed of Precambrian banded gneiss (in the foreground) beneath flat-lying Cambro-Silurian deposits (dark, in the background). The photograph is taken at Rognestranda in Bamble, Telemark. This locality is situated in an area in the counties of Vestfold and Telemark which was designated as a European geopark in autumn 2006, the first in the Nordic countries. The geoparks are approved by UNESCO and their intention is to display the most important geological environments on the Earth. (Photo: S. Dahlgren)

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Chapter 03 - p. 94a

A simplified geological map of south-western Scandinavia. The map focuses on the oldest rocks in the basement. Several parts of southern Norway (not differentiated on the map) have rocks which are at least as old.

Kap03 print Page 094b  

Chapter 03 - s. 94b

Ignimbrite from Flendalen in Trysil, scanned on a polished stone. This volcanic rock was formed by the welding together of dark pumice fragments and ash. (Photo: J. P. Nystuen)

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Chapter 03 - p. 95

Gneiss-forming processes deep in the crust.

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Chapter 03 - p. 95a

The photographs show three rocks that occur together in the Western Gneiss Region. The uppermost photograph shows a granulite with alternating dark and light bands formed during the Sveconorwegian orogeny. (Photo: A. Engvik)

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Chapter 03 - p. 95b

The dark layers in the middle photograph were transformed into eclogite and mixed with light-coloured quartzite at a depth of 60 km in the root of the Caledonian mountain chain. (Photo: A. Engvik)

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Chapter 03 - p. 95c

The lowermost photograph illustrates the banded gneiss that formed during the subsequent uplift, folding, flattening and metamorphism of the eclogite and quartzite. (Photo: A. Engvik)

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Chapter 03 - p. 96a

Mylonite from Mjøsa–Magnor mylonite zone east of Lake Mjøsa. (Photo: G. Viola)

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Chapter 03 - p. 96b

Metasedimentary rock composed of light-coloured layers of metasandstone alternating with darker layers of mica schist. The vertical beds were originally horizontal and were depostited in a marine basin near the Fennoscandian Shield 1600-1500 milion years ago. Photograph taken at Veme, west of Hønefoss. (Foto: Ø. Nordgulen)

Kap03 print Page 097  

Chapter 03 - p. 97

Crustal factories along subduction zones. 

Kap03 print Page 098  

Chapter 03 - p. 98

Geological map of parts of Telemark and Numedal. The stratified supracrustal rocks have been folded one or more times, which explains why the boundaries between the various rock types are  arcuate on the map. The youngest granites cut the boundaries between the older strata.

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Chapter 03 - p. 99

Rhyolite from the Rjukan Group north of Heddersvatn. The original layering is distinct. (Photo: S. Dahlgren)

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Chapter 03 - p. 100

V.M. Goldschmidt (right) and assistants in 1915. (NGUs Photo archive)

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 Chapter 03 - p. 101

Towering to a height of 1883 m a.s.l.,Gaustatoppen is the highest mountain in southeast Norway. The bare upper slopes of the mountain consist of hard quartzite that is poor in nutrients and is metamorphosed ripple-marked sandstone, originally deposited in basins close to sea level. (Photo:S.Dahlgren)

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Chapter 03 - p. 102

Quartzite with ripple marks formed on a sandy shore more than 1200–1300 million years ago. Vindsjåen,Telemark.(Photo:S.Dahlgren)

 Kap03 print Page 103  

Chapter 03 - p. 103

Erosion boundary (unconformity) between coarse conglomerate (Kalhovd Formation) with large, angular clasts (uppermost) and banded gneiss with severalt senerations of granite and pegmatite veins (below). (Photo: E.Sigmond)

 Kap03 print Page 104  

Chapter 03 - p. 104

Simplified map of southern Norway focusing on the Sveconorwegian mountain chain. The most important types of plutonic rocks are grouped according to their age. The blank areas on land indicate bedrock older than 1300 million years; e.g. older than the Sveconorwegian orogeny. Black lines indicate major faults.

 Kap03 print Page 105  

Chapter 03 - s. 105

The Monolith in the Vigeland Sculpture Park, Oslo. (Photo: T. Heldal)

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Chapter 03 - p. 106

From stone axes to kitchen benches: 9000 years of quarrying. (Photo: T. Heldal)

 

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Chapter 03 - p. 107a

Anorthosite landscape in Rogaland. (Photo:G.Meyer)

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Chapter 03 - p. 107b

The Rogaland Anorthosite Province consists of two large and several smaller anorthosite bodies. The western part of the Egersund-Ogna anorthosite consists entirely of anorthosite, but some light-coloured norite bodies occur further south-east. The Åna-Sira anorhosite consists mostly of light-coloured norite and anorthosite. In addition, there are small instrusions, mostly comprised of jotunite, mangerite and charnokite.

Kap03 print Page 108a  

Chapter 03 - p. 108a

Storeknuten sør for Helleland. Legg merke til den skråstilte skarpe grensen mellom bergarter med apatitt nederst til venstre, og bergarter uten apatittsom stikker opp som nakne knauser.(Foto:L.-P.Nilsson)

Kap03 print Page 108b  

Chapter 03 - p. 108b

The trough-shaped Bjerkreim–Sokndal intrusion near Bjerkreim is composed of six units which correspond to repeated injections of new magma from depth. Together, these units make up a several thousand-metre-thick succession in which economically valuable minerals like apatite and ilmeite are conentrated in specific layers. Younger jutonite dykes cut the layering in the intrusion. (Drawn by G.Meyer)

Kap03 print Page 109  

Chapter 03 - p. 109

Opencast mine at Tellnes i Sokndal kommune, Rogaland, where Titania AS works ilmenite ore. (Photo: L.-P. Nilsson)

Kap03 print Page 113  

Chapter 03 - p. 113

Map showing the general distribution of rocks in the Western Gneiss Religion. The Jotun Nappe Complex and other Caledonian nappes overlie the gneisses. (Map drawn by A.Solli)

Kap03 print Page 114  

Chapter 03 - p. 114

Ålesund Church is built of variegated marble with some amphibolite, which often occurs with the marble. Here, the builders have returnend to the building practice used in the 12th-century stone churces in the northern part of west Norway. (Photo: I. Bryhni)

Kap03 print Page 115  

Chapter 03 - p. 115

Inrusion breccia with angular blocks of the Precambrian bedrock carried up from depth in a dark plutonic rock nicely presented on a wave-washed shore at Farstad. (Photo: I. Bryhni)

Kap03 print Page 116  

Chapter 03 - p. 116

The jagged peaks between Molladalen and Hjørundfjorden consists of charnockitic rocks, which have produced the dramatic, characteristic erosion forms. (Photo:I.Bryhni)

Kap03 print Page 117  

Chapter 03 - p. 117

View from Litjegrønova (south of Lunde in Jølster) towards the mountains along Nordfjord, west of the Jostedalsbreen ice cap. In the foreground is deformed granite (now augen gneiss) with layers of aplite and a small pegmatite dyke. (Foto:I.Bryhni)

Kap03 print Page 118                                                                                                                   

Chapter 03 - p 118

Garnet pyroxenite with orhopyroxene (grey), clinopyroxene (green) and garnet (violet) from Nordøyane, Sunnmøre. The rock contains mineral grains that are partitioned from the high-pressure mineral, majoritic garnet. (Photo: I. Bryhni)

 

 

Illustrations chapter 2.

The illustrations can be downloaded in the gallery further down.

 

Kap02 Page 24 m           

 Chapter 02 - p. 24

The contours of the coastline on both sides of the Atlantic Ocean and the geological structures in Africa, South America, Europe and North America suggest that these continents once formed a single supercontinent. (Figur adapted from A. Marshak, 2005)

Kap02 Page 25a m  

Chapter 02 - p.25a 

A section through the Earths's interior, showing important boundaries and the distribution of density (d) and temperature. The Moho is a discontinuity where the density increases rapidly from the crust to the mantle. The crust is thickest beneath mountain chains on the continents because the rocks there are lighter than beneath the oceans.

Kap02 Page 25b m  

Chapter 02 - p. 25b

The Earth's interior, its shell-shaped structure and its main elements. mantle plumes are upwellings of molten rock from hot domains in the mantle which end in volcanoes on the Earth's surface. Cold plates of lithosphere which sink beneath lighter plates may go all the way down to the base of the mantle before they disintegrate.

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Chapter 02 - p. 26a

Peeping into the centre of the Earth. The Mid-Atlantic Ridge with its longitudinal fissures and canyons crosses Iceland from south to the north. At Thingvellir in southern Iceland, the site of the former Icelandic Althing, the Earth's crust is still spreading along deep canyons that cut the terrain. Lake Thingvalla, in the background, contains active volcanoes. (Phtot: J.P. Nystuen)

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Chapter 02 - p. 26b

The magnetic anomaly stripes reflect the orientation of the Earth's magnetic field when the rocks solidify along the mid-ocean ridges. Grey stripes show normal orientation and white stripes reverse orientation.

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Chapter 02 - p. 26c

The magnetic anomaly stripes reflect the orientation of the Earth's magnetic field when the rocks solidify along the mid-ocean ridges. Grey stripes show normal orientation and white stripes reverse orientation.

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Chapter 02 - p. 27a

The main features of plate tectonics. New oceanic crust is formed along mid-ocean ridges, while old, heavy crust sinks beneath lighter crust in subduction zones where mountain chains form. Ocean-floor sediments are subducted together with the oceanic plate or are scraped off in accretionary wedges. Crustal stresses trigger earthquakes along the plate boundaries.

Kap02 Page 27b m  

Chapter 02 - p. 27b

Present-day lithospheric plates. The plates drift apart along divergent boundaries where new ocean-floor crust forms, and meet each other along convergent boundaries where mountains form. Transform faults are transverse fractures along divergent boundaries where the mid-ocean ridges are apparantly fragmented and pushed aside.

Kap02 Page 28a m  

Chapter 02 - p. 28a

The Earth as a magnet. In our  time, when polarisation is normal, the magnetic dipole points south, whereas it points north in periods with reverse polarisation (lowermost left). Basalts of known age have preserved the print of the magnetic dipoles from the named times with normal and reverse polarity (middle left). A magnetic time scale (right) is used to determine the age of corresponding magnetic anomalies in ocean-floor crust (uppermost left). (Figur adapted from S. Marshak)

Kap02 Page 28b m  

Chapter 02 - p. 28b

The Earth as a magnet. In our  time, when polarisation is normal, the magnetic dipole points south, whereas it points north in periods with reverse polarisation (lowermost left). Basalts of known age have preserved the print of the magnetic dipoles from the named times with normal and reverse polarity (middle left). A magnetic time scale (right) is used to determine the age of corresponding magnetic anomalies in ocean-floor crust (uppermost left). (Figur adapted from S. Marshak)

Kap02 Page 28c m  

Chapter 02 - p. 28c

Magnetisation of lava. When the temperature in a lava rock drops below about 450oC, the dipoles in all magnetised minerals become oriented parallel with the Earth's magnetic dipole. An internal print is preserved of the polarity, direction and angle of the magnetic lines at the place where the lava was formed relative to the Earth's surface. (Figur adapted from P.J. Wyllie)

Kap02 Page 28d m  

Chapter 02 - p. 28d

The Earth as a magnet. In our  time, when polarisation is normal, the magnetic dipole points south, whereas it points north in periods with reverse polarisation (lowermost left). Basalts of known age have preserved the print of the magnetic dipoles from the named times with normal and reverse polarity (middle left). A magnetic time scale (right) is used to determine the age of corresponding magnetic anomalies in ocean-floor crust (uppermost left). (Figur adapted from S. Marshak)

Kap02 Page 29 m  

Chapter 02 - p. 29

The plate tectonic cycle from the break-up of an old continent to the formation of a new one.

Kap02 Page 30 m  

Chapter 02 - p. 30

At Bitihorn in the outer part of the Jotunheimen Mountains in  Valdres, south-central Norway, Precambrian gabbro was thrust over younger Precambrian sandstones that form the bedrock in the ridge in the foreground. The thrusting took place when two plates collided during the Caledonian orogeny at the end of the Silurian about 145 million years ago.  (Photo: I.Bryhni)

Kap02 Page 32 m  

Chapter 02 - p. 32

Two quartz crystals (rock crystals) coated with antase crystals. Hardangervidda. (Natural History Museum Collection, photo: P. Aas)

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Chapter 02 - p. 33

Classification of plutonic rocks. (Adapted from A.L. Streckeiesen and R.W. Le Maitre)

Kap02 Page 34 m  

Chapter 02 - p. 34

(Photo1 og 2: I. Bryhni. Photo 3: B.T. Larsen)

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Chapter 02 - p. 35

Plutonic, hypabyssal and volcanic igneous rocks.

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Chapter 02 - p. 36a

Faults are fractures in the Earth's crust along which displacement has occurred. The relative movement between the crustal blocks forms the basis for distinguishing different kinds of faults, as shown in a) to g).

Kap02 Page 36b m  

Chapter 02 - s. 36b

Faults are fractures in the Earth's crust along which displacement has occurred. The relative movement between the crustal blocks forms the basis for distinguishing different kinds of faults, as shown in a) to g).

Kap02 Page 36c m  

Chapter 02 - s. 36c

Faults are fractures in the Earth's crust along which displacement has occurred. The relative movement between the crustal blocks forms the basis for distinguishing different kinds of faults, as shown in a) to g).

Kap02 Page 36d m  

Chapter 02 - s. 36d

Faults are fractures in the Earth's crust along which displacement has occurred. The relative movement between the crustal blocks forms the basis for distinguishing different kinds of faults, as shown in a) to g).

Kap02 Page 36e m  

Chapter 02 - s. 36e

Faults are fractures in the Earth's crust along which displacement has occurred. The relative movement between the crustal blocks forms the basis for distinguishing different kinds of faults, as shown in a) to g).

Kap02 Page 36f m  

Chapter 02 - s. 36f

Faults are fractures in the Earth's crust along which displacement has occurred. The relative movement between the crustal blocks forms the basis for distinguishing different kinds of faults, as shown in a) to g).

Kap02 Page 36g m  

Chapter 02 - s. 36g

Faults are fractures in the Earth's crust along which displacement has occurred. The relative movement between the crustal blocks forms the basis for distinguishing different kinds of faults, as shown in a) to g).

Kap02 Page 37 m  

Chapter 02 - p. 37

A. Anticlines are folds that bend the beds upwards; synclines bend them downwards.
B. A folded succession shows a characteristic pattern on the geological map. The orientation of the beds is indicated by symbols for strike and dip and the direction of the fold axes.

Kap02 Page 38 m  

Chapter 02 - p. 38

Nappes and thrusts sheets in a mountain chain. Beyond the mountain chain, a sediementary succession remains undisturbed on its original basement. Towards the mountain chain, the strata are folded and thrust together in thrust sheets and nappes, the further into the chain you come, the further the nappe rocks have been thrust.

Kap02 Page 39a m  

Chapter 02 - p. 39

Climbing Besseggen, a well-known ridge in the Jotunheimen Mountains in south-central Norway. Gjende is the lake on the left and Bessvatnet that on the right. Gjende was excavated by a glacier following a fault zone in easily eroded bedrock. The Gabbro on Besseggen is traversed by bands of hard crush rock called mylonite, which have fortified the ridge, preventing it from being completely worn down by the glacial erosion that otherwise marks the landforms in the Jotunheimen Mountains. (Photo: J.P. Nystuen)

Kap02 Page 39b m  

Chapter 02 - p. 39

The small picture shows the appearance of the mylonite at close quarters. The layer with thin, dark and light bands is a result of locally intense shearing and recrystallisation under plastic conditions to produce a very fine-grained, extremely deformed rock. (Photo: J.P. Nystuen)

Kap02 Page 41 m  

Chapter 02 - p. 41

Acidic water flowing over marble has produced deep flutes because the carbonate minerals in the rock have dissolved. Fræna, Møre og Romsdalen. (Photo: I.Bryhni)

Kap02 Page 45 m  

Chapter 02 - p. 45

The main types of sedimentary basins, as they are formed in a plate tectonic context.

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Chapter 02 - p. 48

This sandstone originated as sand in a shallow Early Cretaceous sea on Spitsbergen. The geologist is filling in a log recording observations on the thickness, grain size and sedimentary struktures. The compass is used to measure the orientation and directions in the sandstone beds and the geology hammer to collect samples. (Photo:E.Tallaksen)

Kap02 Page 49 m  

Chapter 02 - p. 49

Classification of sediments and sedimentary rocks according to grain size. (Figure from S. Gjelle and E. Sigmond)

Kap02 Page 51 m  

Chapter 02 - p. 51

Pale rose-coloured gneiss and black amphibolite, both transected by granitic veins, were formed deep in the crust in a fold belt about 1000 million years ago. The Precambrian basement near Drøbak, east of Oslofjorden. (Photo: J.P. Nystuen)

Kap02 Page 55 m  

Chapter 02 - p. 55

Geological map, part ov the Asker sheet, 1814 I, scale1:50 000. (J. Naterstad et.al., NGU)

Kap02 Page 56a m  

Chapter 02 - p. 56a

Relative age in a succession.
a) A succession is deposited, in part as delta sand and silty clay in the sea,
b) the succession is folded and eroded; valleys and ridges reflect the varying hardness of the beds,
c) the mountains are worn down to a peneplain over which the sea has flooded, and
d) a new succession is deposited.

Kap02 Page 56b m  

Chapter 02 - p. 56b

Stratigraphical division.

Kap02 Page 57 m  

Chapter 02 - p. 57

Relative age in part of the Earth's crust. Order of age is shown by boundary relations between rocks, deposits, struktures and landforms. Younger layers are deposited above older ones, folds are formed after the beds are deposited, younger intrusive rocks cut through older rocks, erosion surfaces cut down into underlying beds, and so on. Find the order of the geological development!

Kap02 Page 58a m  

Chapter 02 - p. 58a

Baltazar Mathias Keilhau (1797-1858), Founder of geology in Norway.

Kap02 Page 58b m  

Chapter 02 - p. 58b

Theodor Kjerulf (1825-1888)

Kap02 Page 59 m  

Chapter 02 - p. 59

Division of successions into two types of sequences, between two erosion surfaces formed by a fall in sea level and between two surfaces formed when the sea transgressed the land. Surfaces with the same age cut through the boundaries of the various sedimentary strata. It is important to correlate - establish a mutual connection between - the successions in the wells that have been drilled through succession.

Kap02 Page 60 m  

Chapter 02 - p. 60

The geological time scale of the Earth. 2008 versieon of ICS's International stratigraphic chart. (Adapted from F.Gradstein et.al.)

Kap02 Page 61 m  

Chap. 02 - s. 61

Permafrost is widespread in Svalbard right down to sea level. The ring-shaped accumulations of stones on Vardeborgsletta on the south side of outer Isfjord on Spitsbergen are formed by stoned being pressed up from the permafrost in the ground beneath, and sorted (patterned ground). The stones were originally shore pebbles, and are clean and light coloured because they have been buried in the ground. (Photo:O.Salvigsen)

 

 

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