The Oslo Graben or Oslo Rift is a graben formed during a geologic rifting event in Permian time, the last phase of the Variscan orogeny.[1] The main graben forming period began in the late Carboniferous, which culminated with rift formation and volcanism, with associated rhomb porphyrylava flows. This activity was followed by uplifting, and ended with intrusions about 65 million years after the onset of the formation. It is located in the area around the Norwegian capital Oslo.
The lava production was high when the rhomb porphyry lavas were deposited. The lavas reflect a period of abundant earthquake-related movements, when tectonic forces tore the crust apart.
In the Vestfold district, one lava flow was deposited on average every 250,000 years, resulting in a 3000-metre thick sequence of mainly volcanic material. In the Oslo area, lavas were deposited on average every 800,000 years. Only a few plant remains have been found between these lavas. The bedrock in this area, roughly from Skien to Oslo and Mjøsa, results in soil rich in nutrients important for plant growth.
Since the Permian, erosion has removed the volcanic peaks and indeed most of the lava layer and laid bare the magma chambers and volcanic pipes deep below, allowing scientist a rare view of what goes on beneath a rift valley. Several of the old magma plumes are now quarried, the rich black larvikite (named from Larvik, a town south of Oslo) being one.
The Särna alkaline complex in western Sweden, also of Late Carboniferous age, is thought to be related to the Oslo Graben as it is aligned to it.[2]
^Larsen, Bjørn; Olaussen, Snorre; Sundvoll, Bjørn; Heeremans, Michel. (PDF). Episodes (March 2008): 52–58. Archived from the original (PDF) on 2011-09-28. Retrieved 2009-03-19.
^Bylund, G.; Patchett, P.J. (1977), Palaeomagnetic and Rb-Sr isotopic evidence for the age of the Särna alkaline complex, western central Sweden, vol. 10, Lithos, pp. 73–79
External linksedit
Mantle Plume Beneath The Oslo Graben?
Evolution of the Arctic-North Atlantic And The Western Tethys
oslo, graben, oslo, rift, graben, formed, during, geologic, rifting, event, permian, time, last, phase, variscan, orogeny, main, graben, forming, period, began, late, carboniferous, which, culminated, with, rift, formation, volcanism, with, associated, rhomb, . The Oslo Graben or Oslo Rift is a graben formed during a geologic rifting event in Permian time the last phase of the Variscan orogeny 1 The main graben forming period began in the late Carboniferous which culminated with rift formation and volcanism with associated rhomb porphyry lava flows This activity was followed by uplifting and ended with intrusions about 65 million years after the onset of the formation It is located in the area around the Norwegian capital Oslo The lava production was high when the rhomb porphyry lavas were deposited The lavas reflect a period of abundant earthquake related movements when tectonic forces tore the crust apart In the Vestfold district one lava flow was deposited on average every 250 000 years resulting in a 3000 metre thick sequence of mainly volcanic material In the Oslo area lavas were deposited on average every 800 000 years Only a few plant remains have been found between these lavas The bedrock in this area roughly from Skien to Oslo and Mjosa results in soil rich in nutrients important for plant growth Since the Permian erosion has removed the volcanic peaks and indeed most of the lava layer and laid bare the magma chambers and volcanic pipes deep below allowing scientist a rare view of what goes on beneath a rift valley Several of the old magma plumes are now quarried the rich black larvikite named from Larvik a town south of Oslo being one The Sarna alkaline complex in western Sweden also of Late Carboniferous age is thought to be related to the Oslo Graben as it is aligned to it 2 See also editKattsund Koster dyke swarmReferences edit Larsen Bjorn Olaussen Snorre Sundvoll Bjorn Heeremans Michel The Permo Carboniferous Oslo Rift through six stages and 65 million years PDF Episodes March 2008 52 58 Archived from the original PDF on 2011 09 28 Retrieved 2009 03 19 Bylund G Patchett P J 1977 Palaeomagnetic and Rb Sr isotopic evidence for the age of the Sarna alkaline complex western central Sweden vol 10 Lithos pp 73 79External links editMantle Plume Beneath The Oslo Graben Evolution of the Arctic North Atlantic And The Western Tethys59 48 04 N 10 33 23 E 59 8011 N 10 5564 E 59 8011 10 5564 nbsp This Norway location article is a stub You can help Wikipedia by expanding it vte nbsp This plate tectonics article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Oslo Graben amp oldid 1166647405, wikipedia, wiki, book, books, library,
