AG 209 The Tectonic and Sedimentary History of Svalbard
Excursion Report
August 2006
Søren H. Rasmussen
Front picture: Pyramiden Mountain
The Tectonic and Sedimentary History of Svalbard 2 Index
1. Introduction...... 4 2. Festningen ...... 5 3. Botnheia ...... 11 4. Janusfjellet ...... 12 5. Helvetiafjellet Formation ...... 14 6. Basilikafjellet ...... 15 7. Storvola ...... 18 8. Pyramiden Mountain...... 19 9. Billefjorden Basin ...... 20 10. Lövehovden Mountainside...... 22 11. Midterhuken Mountainside...... 23 12. Mediumfjellet Mountainside...... 24 13. Grumantbyen Thrust ...... 25 14. References...... 26
The Tectonic and Sedimentary History of Svalbard 3
1. Introduction This report is based on a field excursion from August the 11th to 20th 2006. The field excursion was a part of the two courses The Quaternary History of Svalbard (AG 210) and The Tectonic and Sedimentary History of Svalbard (AG 209). This report contains all visit locations that was related to the course The Tectonic and Sedimentary History of Svalbard. Guides was: Arvid Nøttvedt and Alvar Braathen. Figure 1 shows a bedrock map of Svalbard on this the visited locations mark.
Figure 1: Stratigraphic map of Svalbard (Norwegian Polar Institute).
The Tectonic and Sedimentary History of Svalbard 4 2. Festningen Visit on August the 11th and 12th.
The profile along the coast from Isfjorden Radio in west to Grønfjorden in east, have one of the most completely bedrock section on Svalbard. In the western end Precambrian metamorphic rock and in east Tertiary sedimentary rock is exposed. This locality lays on the western side of the Central Tertiary Basin, therefore the layer dipping towards east, around 60 % in west and 100 % in east. Figure 3 show a stratiographic log with formations, groups and important member. All of these will by descript below.
Billefjorden Group Orustdals Formation, Lower Carboniferous, is layer of sandstone, conglomerate and some coal. It is deposit alluvial as a fan, floodplain or braided stream. Under the Billefjorden Group is the Basement, between there is an unconformity. Deposit from Devon is missing.
Gipsdalen Group Wordiekammen Formation, Lower Permian, is limestone. Limestone is shells or fragments from marine organisms. There for the depositing environment is at sea, with oxygen riche condition. Gipshuke Formation, Lower Permian, this is limestone and evaporate. Evaporite is precipitated from evaporate of saltwater. This mean that the sea has been shallow and still for some time, so concentration of salt could be high enough to precipitate. These Evaporites has change calcite with dolomite and are there for Dolostones. There are now fossils in this formation, with could be coursed by the high salt concentration, that animals and plants do not like.
Tempelfjorden Group Kapp Starostin Formation, Upper Permian, limestone and shale. These layers contain fossils, and they are intact. This is evidence of climate shift. Figure 2 shows the border between Lower and Upper Permian.
Figure 2: Border between Lower and Upper Permian. At the bottom of the picture is Gipshuke Formation and on top is Kapp Strarostin Fromation.
The water is continuous shallow, with only little movement, otherwise the fossils would have broken. Water depth around 10 m. Fossils is in the first unit only Brachiopod, in the next unit the diversity of fossils becomes lager, example corals, see figure 4. This means that the water was becoming deeper, a transgression. Kapp Strarostin is special from other of the sedimentary rock.
The Tectonic and Sedimentary History of Svalbard 5
Coal Basilika Fm.
Cgl Firkant Fm. Tertiary Lower Cretaceous Mudst + sst Carolinefjellet Fm. Deltaic Mudst + sst Helvetiafjellet Fm. Fluvial sst
Mudst + sst Rurvikfjellet Fm. Lower Cretaceous Upper Jurassic Mudst + sst Agardfjellet Fm. Lower Jurassic Cgl Brentskardhaugen Bed Upper Triassic Mudst + silt De Geerdalen Fm. + sst (Tschermarkfjellet Fm.) Sst Bravaisberget Fm. Middle Triassic Shale (Botnheia Fm.) Sst Tvillingodden Fm. Shale Sst Vardebukta Fm. Triassic Shale Upper Permian Limest Shale Kapp Starostin Fm. cementated
Limest + evap Gipshuken Fm. Lower Permian
Limest Wordiekammen Fm.
Lower Sst + Carboniferous coal/shale Billefjorden Group + cgl
Basement
Figure 3: Strationgraphic log of Festningen Profil.
The Tectonic and Sedimentary History of Svalbard 6 The rock is cementatede by silicate; the silicate comes from silicate riche sponge. The silicate makes the rock very strong, therefore Kapp Strarostin often is on top of mountains see figure 5.
Figure 4: Brachiopod, Lower Kapp Strarostin sandstone, picture 2 cm high. Corals, Middle Kapp Strarostin limestone, picture around 4 cm high.
Kapp Strarostin
Vardebukta Formation
Figure 5: Top of Kapp Strarostin, Upper Permian. Kapp Strarostin is harder therefore it makes the top. Vardekukta Formation is not as hard, there for this has been eroded more.
90 % of all living spices death at the end of Permian. This could be courts by a huge volcanic eruption from Siberia, that raise the CO2 level in the air and the water temperature in the sea. Or it could be meteor strikes in Antarctica.
Sassendalen Group Vardebukta Formation, Lower Triassic. This sediment are softer, there is now cementation. Therefore deformations go into this formation, instead of example Kapp Strarostin. Sediments from Greenland were at this time transported to Svalbard, which still is under the sea. The basin gets filled with sediment, this result in a coarsening-upward of the sediments from mud/silt to sand. After a transgression it starts again. Tree times this goes on, this and the next two formations. In this formation there is to sills, one is seen on figure 6. Sills is intrusive igneous rock horizontal with the beds. Unlike dikes there goes through the layers. This Basaltic intrusive comes from volcanic activities at the end of Jurassic, when the Atlantic Ocean starts to open.
The Tectonic and Sedimentary History of Svalbard 7
Shale
Basalt
Shale
Figure 6: Sill, intrusive of igneous rock along the layers.
Tvillingodden Formation, Lower Triassic, black shale. The black colour is from dead organisms. The total organic contain (TOC) is 6-8 %, with is high. Most of the organisms were algae. The condition at this time was anoxic, otherwise the carbon would have oxidised and not deposit. Anoxic condition only contains where the water is still, like an inlet. The rock is a source rock for oil, is has high carbon contain and has been heated, so there is kerogen in it. This rock contain kerogen type tree, because it is marine carbon. Bravaisberget Formation, Middle Triassic. Like Tvillingodden Formation. In this formation there is beginning to be biotutbation, disturbance of sediment by animals and plants. This is signs of oxygen at sea floor.
Kapp Toscana Group De Geerdalen Formation, Upper Triassic, shale and some places red colour. The red colour comes from cementation with Siderite (Iron Carbonate). There is symmetric ripples, see figure 7. Symmetric ripples is from waves, when they move forward and backward. Ripples from stream, where the water flows in one direction are asymmetric. The ripples are a sign of shallow water, where the waves reach the seafloor, example near the shore.
Figure 7: Symmetric ripples in De Geerdalen Formation.
The Tectonic and Sedimentary History of Svalbard 8
Brentskardhaugen Bed, border between Triassic and Jurassic, this layer is around 10 cm thick. It is orange conglomerate with brown nods. The nods are fish bones there has rolled in mud and thereby getting bigger. The condition must have been low supply of sediments, otherwise the bones have been buried, and sill water so the nodes do not break or carry away. There is doubt about the bed belongs to Triassic or Jurassic. Between this to period there is an unconformity.
Adventdalen Group Agardfjellet Formation, Upper Jurassic, layer of black shale and mudstone. Some mudstone layer contain vertical hole from animals, see figure 8. The energy level in the sea is higher in contrast to where we find horizontal holes. In vertical holes the animal waits for food to come by. In horizontal holes they live of what there is on the seafloor. The formation is mudstone and shale, deep water.
Figure 8: Vertical holes from animals at seafloor, Agardfjellet Formation.
Rurvikfjellet Formation, Lower Cretaceous. Beds of sandstone with lamination and siltstone with no lamination were repeating, see figure 9. In bed with no lamination animals lived at the seafloor, bioturbation. The sandstone is storm events with deposit sand fast, may be 24 hours. Water depth around 40 m. The storm was powerful enough to infect the entire water column. This deposit of big storm events is call hummocky cross-stratification.
Silt Sand Sand Silt Sand Sand
Figure 9: Hummocky cross-stratification, Rurvikfjellet Formation.
Helvetiafjellet Formation, Lower Cretaceous, the base is Festningen sandstone, this is fluvial deposit of a braided river. Above there is beds shale and some sandstone. The island Festningen is the hard sandstone. In the formation there is footprint of dinosaur, the dinosaur have walk on moist sand near the coast, see figure 10. Climate was mild at that time and rich of vegetation, allow dinosaur to live. Svalbard was about 60-70oN and still a part of Greenland.
The Tectonic and Sedimentary History of Svalbard 9
Figure 10: Dinosaur footprint, Helvetiafjellet Formation.
Carolinefjellet Formation, Lower Cretaceous, at the base sandstone deposit in a delta. Over mud and sandstone, marine deposit.
Van Mijenfjord Group Firkant Formation, Tertiary, is a conglomerate of round stones in sand matrix, deposit by rivers or on beach. At the border from Lower Cretaceous to Tertiary there is an unconformity, see figure 11. In Tertiary the North Atlantic Ocean begins to open.
Figure 11: Border between Lower Cretaceous and Tertiary. Tertiary conglomerate to left and Cretaceous shale to right.
The Tectonic and Sedimentary History of Svalbard 10 3. Botnheia Visit on August the 19th.
Botnheia is on the eastern side of the Central Tertiary Basin, the beds are dipping toward west, the centre of the basin. The first formation, from bottom and up, is Vikinghøgda Formationen, see figure 12. This is the same unit as Vardebukta and Tvillingodden Formation together at Festningen Profile. It is black shale. Generally the formation is coarsening-upward. The sediments are here general finer, then with Festningen Profile. This mean that the sediments getting finer from west to east. This fit with Greenland in west at that time sending material to the sea that was deposit over Svalbard. The fine sediment is transported longer then the coarse. Like at Festningen Profile there are sills. Botnheia Formation is the same unit as Bravaisberget at Festningen Profile. Like at Festningen Profile it contains 6-8 % of organic material, and is source rock for oil. The upper part of Botnheia Formation there is fossils, see figure 13, nearly all of these species dead at end of this formation depositing period. Botnheiafjellet Janusfjellet
E W De Geer- dalen Caroline- fjellet
Tscher- Helvetia- mark- fjellet fjellet
Botnheia Rurvikfjellet Agardfjellet Vikinghøgda
Figure 12: Formations at Botnheia- and Janusfjellet.
Figure 13: Fossils, Upper Botnheia Formation. Picture height 5 cm.
The Tectonic and Sedimentary History of Svalbard 11
Tschermarkfjellet Formation, this formation is not present at Festningen Profile, it is underlying De Geerdalen Formation. The rock is shale, purple in colour, and is bioturbatede, this mean oxidation of water at the seafloor. Animals and plants are again living on the seafloor. De Geerdalen For- mation, silt/sandstone, with wave ripple and hummocky cross-stratification. In this depositing period the water is shallower, with some fluctuation in the sea level. 4. Janusfjellet Visit on August the 19th.
Janusfjellet is lies side by side with Botnheiafjellet, see figure 12. Therefore the stratigraphic section is continuing. Agardfjellet Formation, again there is black shale, because of organic content. The condition at this time is anoxic for a long period, no circulation in the water. Maybe there was no cold north pole to drag the circulation like today, with the Gulf Stream. An anoxic condition like this is found in North America and Siberia, therefore it is a more global condition at that time. Many algae could have used the oxygen and thereby making the anoxic condition worse. The lamination of the shale is thin, and is called paper lamination, see figure 14. This tine lamination again tells about still water. Upward the grains are getting finer, from sand/silt to mud, this mean that the sea getting deeper.
Figure 14: Shale with paper lamination, Janusfjellet, Agardfjellet Formation.
Boulders from Festningen sandstone, Helvetiafjellet Formation, have been brought to lower places by glacier. Under the stone wind erode the light shale and leaving the stones, see figure 15. In this layer there is found skeletons from big fish. At the top of Agardfjellet Formation there is many fossil preserved in orange shale, cemented by Siderite, see figure 16.
The Tectonic and Sedimentary History of Svalbard 12
Figure 15: Wind is eroding the shale and sandstones are left back. In the right side a big boulder is undermined be the wind. Janusfjellet, Agardfjellet Formation.
Figure 16: Seashells to the left and Ammonite to the right.
On border between Jurassic and Cretaceous there is 2 m of pure clay. Under there is silty mudstone with thin beds of sandstone. Over continues beds of shale. There has been a long time with only supply of clay and still water, to deposit the clay. Under this unit there has been found higher concentration of glass and different minerals, with could have come from a meteor crash. In the Barents Sea a crater, called Mjolnercrater, is found, this is about the same age, and there could be a connection. Rurvikfjellet Formation is generally an up coarsening. Agardfjellet and Rurikfjellet Formations is together call Janusfjellet Subgroup. On the top are Helvetiafjellet and Carolinefjellet Formation.
The Tectonic and Sedimentary History of Svalbard 13
5. Helvetiafjellet Formation Visit on August the 12th.
At Festningen a part of the Helvetiafjellet Formation was logged, se figure 17. The log starts above the layer of sandstone there continue out to the island Festningen. The log part is a part of the Festningen sandstone with is deposit by braided river systems and in near coast deltas (Hjelle, 1993). The first two log unit is deltaic, it is sandstone with some cross stratification. The next unit is not so often flooded, finer materials can be deposit. Lenses of sand are from storm events. The coarsening upward are coursed be often and more energy filled water flooding. In a time there has been a lake on this place, this is the unit of black shale. In a lake there is still water and time to deposit clay. A river has overrun the lake and deposit coarser material. Cross bedding is from different energy levels in the river, which change over time. The last unit is a braided river system, the unit is more massive then the others, with is coursed be more compact depositing.
Figure 17: Log of a part of Helvetiafjellet Formation, Festningen.
The Tectonic and Sedimentary History of Svalbard 14 6. Basilikafjellet Visit on August the 17th.
On the top of Basilikafjellet are Carolinefjeller and Firkant Formation exposed. Carolinefjellet Formation is from Lower Cretaceous and the overlying Firkant Formation is from Tertiary. In the Firkant Formation there is hummocky cross-stratification, see figure 18. There is also fossils of holes from sea worms, see figure 19. The walls in the hols were covered with clay, and therefore stronger. Today the walls is often seen as outcrop and darker then the surrounding rock.
Figure 18: Hummocky cross-stratification, Firkant Formation, Basilikafjellet.
Figure 19: Wormhole, Firkant Formation, Basilikafjellet.
The Tectonic and Sedimentary History of Svalbard 15
We were logging from the border between Lower Cretaceous and Tertiary and up, the log is seen on figure 20. General it is a transgression from Lower Tertiary and up. We only have the first part of Tertiary. The deposit goes from marine, beach to land.
Figure 20: Log of Lower Tertiary, Basilikafjellet. Size reduces to 90 % of original.
Our first layer is a diamicton, underlying of mudstone from Carolinefjellet Formation. This part of Carolinefjellet Formation is marine with some biotutbation, the upper border is eroded. The diamicton is fluvial or beach deposit (Braathen, 2006). There were white spots on the stones in the diamicton, this is from compression from the overlaying layers. There was also press marks in the underlying layer, see figure 21. Above the diamicton there is shale with fossils of leafs, with documents on land deposit, see figure 22.
The Tectonic and Sedimentary History of Svalbard 16
Figure 21: Pressed diamiction and press mark in to the underlying layer. Basilikafjellet.
Figure 22: Leaf from Tertiary.
The border to the next unit was not exposed, because of overlaying boulders. The last log layer was marine coarsening-upward, with means a transgression.
Our log showing a regression it is going from marine sediments, to beach and on land. Our last unit is a transgression marine unit and this is the start of the general transgression up through the next units, there were logged be other groups. Some of the youngest units there was logged at this site contain wormholes, like on figure 19.
The Tectonic and Sedimentary History of Svalbard 17
7. Storvola Visit on August the 17th.
Storvola is located in Van Keulenfjorden in the Central Tertiary Basin on the western side. The clinoforms on Storvola is deposits of sediment coming from west, where the fold and thrust belt is and pushing up mountains. Sediments were transported by rivers over land to the sea, on the coastal shelf and at the end as deepwater turbidites, see figure 23. In west erosion of the mountains gets to older and older rock, therefore sediments in the turbidites gets older. At figure 23 turbidite 1 is made of younger sediments then turbidite 2, and so on.
Present day mountain
Fold Alluvial and deposit Shelf thrust 234 belt 1
Deepwater turbidites
Figure 23: Depositing of clinoforms. Material is transport from left to right. The dash line is approx what is seen on Storvola.
Figure 24 is a picture of Storvola, on the left side deposit on the coastal shelf is seen, and on the right side deepwater turbidites are seen, where the layer dips.
Figure 24: Storvola (Rafaelsen, 2001).
The Tectonic and Sedimentary History of Svalbard 18 8. Pyramiden Mountain Visit on August the 18th.
The western side of Pyramiden Mountain is Devonian, and the eastern side is Carboniferous, respectively is dark red and light red, see figure 25. Pyramiden Mountain is located in the Billefjorden Fault Zone, one of the major fault lines on Svalbard. Between the Devonian and the Carboniferous there is a normal fault. The Devonian on west side is footwall block and the east of the fault is the hanging-wall block, there has dropped down and is a part of the Billefjorden Basin. In the basin there is Hultberget Formation, Lower Carboniferous, with layer of coal, Ebbadal Formation, Middle Carboniferous, and Minkinfjellet Formation, Upper Carboniferous. The top of the mountain is Wordiekammen Formation from Upper Carboniferous, and it is also on top of Devonian on the surrounding mountains. When Wordiekammen Formation was deposit the fault is inactive, and therefore on top of the mountains in the area.
Wordiekammen Formation Minkinfjellet Formation W
Ebbadalen Formation Coal Devonian
Hultberget Formation
Figure 25: Pyramiden Mountain.
The Devonian rocks are called the Old Red Sandstone. At the time of deposit Svalbard was a part of the Old Red Continent, located around equator. Today Devonian deposit is mainly only present in a basin in northern Spitsbergen. The Devonian rock is deposit be big river systems. Pyramiden Mountain is located on the south-east corner of the basin, see figure 1.
The Tectonic and Sedimentary History of Svalbard 19
9. Billefjorden Basin Visit on August the 18th.
The Billefjorden Basin was filled in by Devonian sediments from west. First deposit of alluvial fan, then beaches, open water and on the eastern side is sabkha, see figure 26. The fault in west is active bulling up a mountain, coarse materials form the mountain is deposit as an alluvial fan out in the basin. On the east side off the basin there was sabkha, flat arid shoreline zone. These serials of deposit are found across the Billefjorden Basin, from Pyramiden Mountain in west to Lövehoveden Mountainside in east. These serials are overlaying each other, with some variation in distribution. In a period the alluvial fan is bulling out. With the time of erosion the sediments getting finer, therefore the sand beach and fine grain dolostone. The fault is active again and a new alluvial fan bulling out. This deposited serial can be seen on figure 27.
Alluvial fan Beach Marine Sabkha Devonian
E
Billefjorden fault zone
Figure 26: Sketch of deposit in Billefjorden Basin.
5 Alluvial fan bulling out
4 Fault is active 3 Marine, dolostone
2 Coastal and beach
1 Alluvial fan bulling out
Figure 27: Stratigraphic section, west side of the Billefjorden Basin, Pyramiden Mountain.
The Tectonic and Sedimentary History of Svalbard 20
On the eastern side of the Billefjorden Basin there is mainly evaporate, see figure 28. Ebbadalen Formation are here white of evaporate, with some bed of dolomite, dark grey.
Figure 28: Ebbadalen Formation overlaying by Minkinfjellet Formation, Lövehovden Mountain. Picture taken from Ebbadalen, east is toward right.
The Tectonic and Sedimentary History of Svalbard 21
10. Lövehovden Mountainside Visit on August the 18th.
Lövehovden Mountainside is on the eastern side of the Billefjord Basin, and can be seen from Ebbadalen, see figure 29. On the right side of figure 29 Basement is seen, black rock. The fault in that side is a normal fault, because of the view angle it look like a reverse fault, on the left side of the fault another part of Basement is seen, drop down. In the middle of the figure the formations that filled the Billefjorden Basin is seen. Left in the figure to small fault is seen. The soft evaporite is fold, with faults. In the underground there is a big fault, that have coursed the exposed fold and faults. There are discussion between geologist about this is a reveres or a normal fault. To the left is Billefjorden Basin, and the faults on the figure could have been from sinking down the basin, therefore all normal faults. But there could have been compressional stress make a reverse fault.
Lövehovden ENE Wordiekammen Fm. Minkinfjellet Fm.
Ebbadalen Fm. Basement Hultbjerget Fm. Basement
Figure 29: Lövenhovden Mountainside.
The Tectonic and Sedimentary History of Svalbard 22 11. Midterhuken Mountainside Visit on August the 16th.
Midterhuken Mountain is on the southern side of mouth of Van Mijenfjorden. In the mouth of Van Mijenfjorden is a flat island, this is the Kapp Starostin Formation. Kapp Starostin is strong because of cementation with silicate, and therefore hard to erode. The same formation like the start of Festningen Profile is exposed here, from Basement to Vardebukta Formation, see figure 30. At this mountainside two faults are seen, to west there is a fault in Billefjorden Group, at the east end there is a detachment. Detachment is folding of on layer, with out the other. Vardebukta Formation has been fold as result of compressional stress, the underlying Kapp Starostin is strong and did not fold. The folds in Vardebukta Formation are lager, at the sketch one fold going out of the mountain, this is gone by eroding. After this the whole block is tilt, as it is today. The whole complex is a part of the early Tertiary fold and thrust belt, with the opening of the North Atlantic Ocean.
E W
Figure 30: Picture and sketch of Midterhuken Mountainside, with formation name etc.
The Tectonic and Sedimentary History of Svalbard 23
12. Mediumfjellet Mountainside Visit on August the 20th.
Mediumfjellet is located at the northern side of Isfjorden, north of Festningen Profile. At the mountainside fold and thrust of the strong Kapp Strarostion is exposed. This type of thrust is a foreland breaking sequences, also call piggy-back. Compressional stress folds up the layer, and break them with a thrust. On the footwall of the first thrust another fold and thrust, like the first one, is created, and so on, see figure 31.
W 1 2 3 4
Stress Stress
Figure 31: Sketch of creation of a foreland breaking sequences.
At the Mediumfjellet Mountainside tree thrust is seen, see figure 32. The last thrust and fold, the one to right (east), the fold is exposed. The fault in the middle starts as a fault, but upwards the degree of deformation, getting smaller and stops.
Fold W
Figure 32: Mediumfjellet Mountainside.
The Tectonic and Sedimentary History of Svalbard 24 13. Grumantbyen Thrust Visit on August the 20th.
Grumantbyen is located in the middle of the northern end of the Central Tertiary Basin. Here the tree youngest formation from Festningen Profile is exposed, listed from down/oldest and up Carolinefjellet, Firkant and Basilika Formation. On top is Grumant Formationen. Carolinefjellet Formation is from Cretaceous, the others are Tertiary. At the mountainside to thrust is exposed, witch is related to shortening of the Tertiary section, see figure 33. These thrust is cutting through all formations, therefore the thrust is younger then this formation.
Figure 33: Grumantbyen Thrust.
The Tectonic and Sedimentary History of Svalbard 25
14. References Braathen, Alvar (2006), The Tectonic and Sedimentary History of Svalbard, Field Excursion August 2006, UNIS
Hjelle, Audun (1993), Svalbards Geologi, Norsk Polarinstitutt
Norwegian Polar Institute, Topographic maps 1:100.000, Norwegian Polar Institute.
Rafaelsen, Bjarne (2001), Storvola, www.ig.uit.no/~bjarne/storvola.html
The Tectonic and Sedimentary History of Svalbard 26