Rauk
A rauk is a column-like landform in Sweden, often equivalent to a stack. Rauks often occur in groups called raukfält 'rauk fields'. The limestone rauks of Gotland in the Baltic Sea are among the best known examples.
Sweden
[edit]Rauks are common on the island of Gotland, Sweden and on the smaller islands belonging to Gotland County.[1] Fårö island in Gotland, is particularly rich in rauks.[2] While Fårö is on the northern end of Gotland Holmhällars raukfält at Vamlingbo in the southern end of Gotland is also rich in rauks.[3] Rauks in Gotland often occur in groups or fields, so-called raukfält.[4] Rauks can be found both near Gotland's many cliffs or far away from these.[5]
Other localities with rauks include Byrum on northwestern Öland neighboring Blå Jungfrun island, Hovs Hallar and Kullaberg in northwestern Scania and Härnön in northern Sweden's High Coast.[2] Rauks on Öland are made up of limestone.[2] A few rauks are located in the Scandinavian Mountains in northern Sweden's Sarek[6] and Padjelanta[7] national parks.
Norway
[edit]
In Norway, there are rauks in Trollholmssund where, according to local lore, the rauks are petrified trolls.[8] In Trollholmsund, rauks are made up of dolomite rock. Varanger Peninsula in northern Norway is rich in rauks and they also occur elsewhere along the Finnmark coastline.[8]
In Norway the term rauk is also applied to isolated residual mountains in the flat strandflat landscape along the coast.[9]
Geology
[edit]Rauks are usually formed by wave erosion.[1][5] On Öland and Gotland, rauks are chiefly formed along or near the escarpment known as the Baltic Klint.[4] Gotland rauks consist of limestone representing reefs that existed in the Silurian period.[4][5][10] As waves batter against limestone cliffs, pre-existing vertical fractures begin to erode and widen. Eventually this leads to the formation of caves that merge, and the remaining central rock has now become rauks.[4]
The rauks of Gotland formed after the last ice age. It is unclear to which extent different rauks in Gotland started to form from a cliffed coast, a dissected coast or from glacial landforms.[5] A comparison of photographs from 1900 and from 1966 has shown that some rauks had been destroyed during that period.[5]
Carl Linnaeus, who visited Gotland in 1741, was the first scientist to describe rauks.[4] He called them stenjättar (stone giants) while also noting the ruiniform shape of same rauks.[4]
In Sarek National Park rauks originate as aeolian landforms, thus, contrary to other rauks, they are shaped more by wind than by water.[6] These rauks are made of sandstone that belongs to the Sierggavággenappe (Swedish: Sierggavággeskollan) of the Scandinavian Caledonides.[6]
See also
[edit]References
[edit]- ^ a b Linge, Henriette (2018-02-20). "rauk". Store norske leksikon (in Norwegian). Oslo: Kunnskapsforlaget.
- ^ a b c van Luik, Colette (August 5, 2018). "Glöm Gotland – här är okända svenska platserna som har raukar". Expressen (in Swedish). Retrieved February 19, 2019.
- ^ Enderborg, Bernt. "Holmhällars raukfält". guteinfo.com (in Swedish). Retrieved March 20, 2019.
- ^ a b c d e f Larsson, Kent (September 1, 2001). "Så stiger rauken ur havet". Forskning & Framsteg (in Swedish). Retrieved February 28, 2019.
- ^ a b c d e Rudberg, Sten (1967). "The cliff coast of Gotland and the rate of cliff retreat". Geografiska Annaler. 49 (2): 283–298. doi:10.2307/520895. JSTOR 520895.
- ^ a b c Norris (2014). "Sällsamheter i Sarek". utsidan.se (in Swedish). Retrieved February 12, 2019.
- ^ Wallin, Göran. "Vandra i Padjelanta, det högre landet". swedishlapland.com (in Swedish). Retrieved March 10, 2019.
- ^ a b Dahl, Rolv Magne (July 23, 2015). "Reis til en rauk". www.ngu.no (in Norwegian). Norges geologiske undersøkelse. Retrieved February 23, 2019.
- ^ Motrøen, Terje (2000). Strandflatens dannelse – kystlandskapet som spiser seg inn i landblokken (PDF) (Report) (in Norwegian). Høgskolen i Hedmark. ISBN 82-7671-104-9. Retrieved September 6, 2017.
- ^ Nose, Martin; Schmid, Dieter U.; Leinfelder, Reinhold R. (2006). "Significance of microbialites, calcimicrobes, and calcareous algae in reefal framework formation from the Silurian of Gotland, Sweden". Sedimentary Geology. 192 (3–4): 243–265. Bibcode:2006SedG..192..243N. doi:10.1016/j.sedgeo.2006.04.009.
At the Digerhuvud rauk field (rauk: erosional rock remnant) in the northwestern part of Fårö (Fig. 1), rauks appear to represent erosional remnants of larger patch reef complexes
External links
[edit]The dictionary definition of Rauk at Wiktionary
