Kolsås (), sometimes called Kolsaas, is a

hill A hill is a landform that extends above the surrounding terrain. It often has a distinct summit, and is usually applied to peaks which are above elevation compared to the relative landmass, though not as prominent as Mountain, mountains. Hills ...

in the municipality of

Bærum Bærum () is a list of municipalities of Norway, municipality in the Greater Oslo Region in Akershus County, Norway. It forms an affluent suburb of Oslo on the west coast of the city. Bærum is Norway's fifth largest municipality with a populatio ...

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

. Geologically, Kolsås belongs to the Oslo Graben area. Its two peaks consist of hard rhomb porphyric

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

covering softer rocks, forming steep cliffs to the east, south and west.

The name

An old farm beneath the mountain has the name ''Kolsberg''. The first element in this name is the genitive case of the old male name ''Kolr'', and the last element is ''berg'' n 'mountain'. The parish and municipality of Bærum (

Old Norse Old Norse, also referred to as Old Nordic or Old Scandinavian, was a stage of development of North Germanic languages, North Germanic dialects before their final divergence into separate Nordic languages. Old Norse was spoken by inhabitants ...

''Bergheimr'') is probably named after this prominent mountain. The last element in the name of the mountain was later changed to ''ås'' m 'mountain ridge' to distinguish it from the name of the farm.

Protected landscape area

The area from Kolsås to Dælivannet is a protected landscape area from 1978 (five square kilometers), with four

nature reserve A nature reserve (also known as a wildlife refuge, wildlife sanctuary, biosphere reserve or bioreserve, natural or nature preserve, or nature conservation area) is a protected area of importance for flora, fauna, funga, or features of geologic ...

s: ''Skotta'', ''Dalbo'', ''Kolsåsstupene'' and ''Kolsåstoppen nature reserve''."Naturvernområder i Bærum"
– ''Bærum kommune'' (Retrieved on March 30, 2008)"Snelle-askeskog i Dalbo naturreservat"
(Retrieved on March 30, 2008)

Climbing

Kolsås has been a training area for climbers since beginning of the 20th century. Today it is the largest

rock climbing Rock climbing is a climbing sports discipline that involves ascending climbing routes, routes consisting of natural rock in an outdoor environment, or on artificial resin climbing walls in a mostly indoor environment. Routes are documented in c ...

area in the Oslo region. The wall ''Øvre Sydstup'' on the southern wall has more than 200 climbing routes."Klatring på Kolsås i hundre år"
(Retrieved on March 30, 2008)"Kolsås klatreklubb: Klatrefører for Oslo og omegn"
(Retrieved on March 30, 2008)

Winter sports

The northern hillside of Kolsås has alpine skiing facilities.

Kolsåsbanen

Kolsåsbanen is part of the subway rail system Oslo T-bane, running from downtown Oslo to Kolsås station, via Gjettum station and Hauger station.

NATO base

The military base ''Kolsås leir'', partly located inside the mountain, was home of NATO's Allied Forces Northern Europe (AFNORTH) until 1994."NATO handbook07 uploaded March 25, 1993"
(Retrieved on March 30, 2008)

Culture

The area has occurrences of old

petroglyph A petroglyph is an image created by removing part of a rock surface by incising, picking, carving, or abrading, as a form of rock art. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions ...

tumuli A tumulus (: tumuli) is a mound of Soil, earth and Rock (geology), stones raised over a grave or graves. Tumuli are also known as barrows, burial mounds, mounds, howes, or in Siberia and Central Asia as ''kurgans'', and may be found through ...

and

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

quarries A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to manage their safet ...

. The French painter

Claude Monet Oscar-Claude Monet (, ; ; 14 November 1840 – 5 December 1926) was a French painter and founder of Impressionism painting who is seen as a key precursor to modernism, especially in his attempts to paint nature as he perceived it. During his ...

painted ''Mont Kolsaas'' in 1895."Claude Monet: Mont Kolsaas (1895)"
(Retrieved on March 30, 2008)

References

Bærum Landforms of Akershus Ridges of Europe Mountains of Oslo {{Akershus-geo-stub