Making of a Land - Chapter 6

Illustraiones chapter 6.

Illustrations can be downloaded in the gallery further down.

 

Kap06 print Page 178179     

Chapter 06 - pp. 178-179

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

Kap06 print Page 182  

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.

Kap06 print Page 183a  

Chapter 06 - p. 183a 

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

Kap06 print Page 183b  

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)

Kap06 print Page 184    

Chapter 06 - p. 184

Ophiolite

Kap06 print Page 185a  

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)

Kap06 print Page 185b  

Chapter 06 - p. 185b

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

Kap06 print Page 186a  

Chapter 06 - p. 186

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

Kap06 print Page 187a  

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)

Kap06 print Page 187b  

Chapter 06 - s. 187b

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

Kap06 print Page 187c  

Chapter 06 - p. 187c 

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

Kap06 print Page 188  

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)

Kap06 print Page 189  

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)

Kap06 print Page 190a  

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)

Kap06 print Page 190b  

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)

 Kap06 print Page 191  

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)

 Kap06 print Page 192  

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)

Kap06 print Page 193  

Chapter 06 - p. 193

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

 Kap06 print Page 194  

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.

Kap06 print Page 195  

Chapter 06 - p. 195

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

Kap06 print Page 196  

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)

 Kap06 print Page 197  

Chapter 06 - p. 197 

Eclogite from Nordfjord. (Photo: H. Fossen)

Kap06 print Page 198  

Chapter 06 - p. 198

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

Kap06 print Page 199a  

Chapter 06 - p. 199a

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

Kap06 print Page 199b  

Chapter 06 - p. 199b

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

 Kap06 print Page 200a  

Chapter 06 - p. 200a 

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

 Kap06 print Page 200b  

Chapter 06 - p. 200a

Mylonitic augen gneiss. (Photo: H. Fossen)

Kap06 print Page 201a  

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)

 Kap06 print Page 201b  

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.

Kap06 print Page 202a  

Chapter 06 - p. 202a

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

 Kap06 print Page 202b  

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.

Kap06 print Page 203  

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)

Kap06 print Page 204  

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)

Kap06 print Page 205a  

Chapter 06 - p. 205a

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

Kap06 print Page 205b  

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)

Kap06 print Page 206a  

Chapter 06 - p. 206a 

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

Kap06 print Page 206b  

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)

 Kap06 print Page 207  

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)

 Kap06 print Page 208a  

Chapter 06 - p. 208a

Windows revealing the substrate of the orogenic belt

 Kap06 print Page 208b  

Chapter 06 - p. 208b

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

Kap06 print Page 210   

Chapter 06 - p. 210

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

 Kap06 print Page 211  

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)

 Kap06 print Page 212  

Chapter 06 - p. 212

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

 Kap06 print Page 213  

Chapter 06 - p. 213

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

 Kap06 print Page 214  

Chapter 06 - p. 214

Fauske marble. (Photo: H. Fossen)

Kap06 print Page 215  

Chapter 06 - p. 215

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

 Kap06 print Page 216  

Chapter 06 - p. 216

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

 Kap06 print Page 217a  

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)

 Kap06 print Page 217b  

Chapter 06 - p. 217b

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

 Kap06 print Page 218  

Chapter 06 - p. 218 

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

Kap06 print Page 220  

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).

Kap06 print Page 221a  

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)

 

 Kap06 print Page 221b  

Chapter 06 - p. 221b 

Tectonostratigraphical map of the allochtons in outhern Norway.

 Kap06 print Page 222  

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)

Kap06 print Page 223  

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)

Kap06 print Page 224a  

Chapter 06 - p. 224a

Quartz. (Foto: H. Fossen)

 Kap06 print Page 224b  

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)

 Kap06 print Page 225  

Chapter 06 - p. 225

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

2 utgave s 228a  

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)

2 utgave s 228b  

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)

 2 utgave s 229a  

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)

2 utgave s 229b  

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)

 Kap06 print Page 226  

Chapter 06 - p. 228

Bedrock map of Svalbard

 Kap06 print Page 227a  

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.

 Kap06 print Page 227b  

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)

 Kap06 print Page 228  

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.

 Kap06 print Page 229                                                                                                              

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)

 

 

Bildegalleri

View the embedded image gallery online at:
https://www.geologi.no/item/1087-mol-ch6#sigProIda6a9ba2403
AkerBPsvarthvit1 NGUlitenfarge ngi logo svarthvit Equinor PRIMARY logo RGB BLACK sandvik-logo svarthvit
Lundin svarthvit od svarthvit
logo visneskalk ranagruber svarthvit

 

AkerBPsvarthvit NGUlitenfarge
ngi logo svarthvit statoillogo svarthvit
sandvik-logo svarthvit dongenergy
Lundin svarthvit ranagruber svarthvit
 
od svarthvit logo visneskalk