The Amtjärnsberget was declared as a nature reservation in 2002
§ At the natural reservation it is unlawful
-
to dig, break loose or alter the exposed bedrock and the surface of the ground with tools,
-
damage any trees, wheather living or dead, standing or fallen,
-
to dig up herbs and to pick mosses, fungi and lichens
-
drive motor vehicle in the area,
-
make a fire
500 - 400 million years ago during the Ordovicium-Silurian period, Sweden was located at a tropical latitude and was covered by a warm and shallow sea. A multitude of lifeforms existed, such as algae, corals, crustaceans (trilobites), cuttle-fishes (nautoloids), sealiles (crinoides) and graptolites. Many of these organisms had shells and skeletons. Dead organisms and layer upon layer of silt and sand were deposited on the bottom of the sea. With time loose deposits became compressed into sedimentary rocks as limestone, sandstone and shale. These disposed organisms petrified into fossils. Most of the area of the Nordic countries was covered by sedimentary rocks. Since then these rocks have been eroding, except for a few places where the rocks are protected from wind, water and ice. One of these places is in Dalarna, in the so-called Siljan Ring Structure.
The Siljan Ring Structure originates from the crash of an enormous meteorite some 360 millions years ago. Inside this crater remains of the sedimentary rocks have been preserved, often in a vertical position. Amtjärnsbrottet is one of these places where organisms from Ordovcium and Silurian periods are preserved as fossils.
Armfoting (brachipod)
Sett framifrån och från sidan
Sjölilja
(crinoidé)
Graptolitkoloni
The northern part of the guarry has been left intact. At the entrance to the guarry and on the east side of the guarry you can see vertical layers of clay (shale). In the shale you can see fossils of graptolites and the small trilobite named Tretaspis. The southern part of the guarry has been protected from vegetation, to make it easier to study the walls. The vertical layer of limestone at the base of the western wall is called Kullsbergskalksten and exposes a wealth of fossils from sealilies (crinoides). The cigarette-like fossils you can see here are pieces of the stems. Sealilie was an animal closely related to sea urchin. It was anchored to the bottom of the sea by a long, swaying stem and had a mouth facing upwards and arms which it used to catch food that sank down from the surface ot the water. Here you can also see brachiopods, cystoids and bryozes.
Further information on the natural and geological history of the Siljan Structure can be found at Rättvik´s Museum at the Rättviks Cultural Center.
Kristalläpple
(cystoidé)
Sett i genomskärning
Before the 19th century farmers from the villages around dug for limestone in the Amtjärnsberget. The limestone was burned in stonemade ovens located beside the guarry and sold as an ancillary occupation to farming. Remains of the ovens can be seen east of the quarry. From the middle of 1800´s until 1900, Nittsjö Brick- and Stoneware factory dug for limestone in the southern part of the Amtjärnsberget. The limestone was burned in a brickmade oven and used as a ingredient in brick and stoneware production. Beside the oven there was a brickmade cabin . Remains of the oven and cabin can be seen south of the quarry. Horses transported the lime and clay to Nittsjö along a narrowgauged railroad. Kullsbergs Lime Processing Factory was founded in 1898. The company bought Amtjärnsberget from the farmers and the Nittsjö Brick- and Stoneware factory including the southern part of the quarry.
From 1929 until 1948 the company removed all valuable limestone from the guarry. A comparatively small, limestone mine was built inside of the Amtjärnsberget. The mine measures 260 m x 35 m. Digging only took place above ground. Underground digging would have caused water to come inside. The mine was 15 meters high. In the beginning the company was drilling by hand when blasting. In 1936 the company bought a mobile compressor driven by diesel. The compressor was kept to the building whose remains are to be seen by the entrence to the guarry. The lime was transported along the narrowgauged railroad which extended from Kullsbergs to the beach of Siljan.
Further information of the history of the treatment of limestone in Rättvik can be found at Skålberget limestone quarry and Dalhalla .
Kräftdjur (trilobit) Tretapsis
