World Library  
Flag as Inappropriate
Email this Article
 

Oslo Graben

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 strong 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.

References

  1. ^ Larsen, Bjørn; Olaussen, Snorre; Sundvoll, Bjørn; Heeremans, Michel. "The Permo-Carboniferous Oslo Rift through six stages and 65 million years" (PDF).  

External links

  • Mantle Plume Beneath The Oslo Graben?
  • Evolution of the Arctic-North Atlantic And The Western Tethys

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.