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Draft:Luegibodenblock


link=https://de.wikipedia.org/wiki/Datei:Luegibodenblock_1360.jpg|thumb|Luegibodenblock from southwest The Luegibodenblock near Habkern in the Bernese Oberland is a large granite boulder with a petrographic composition that is unique in the Alpine region. The boulder, which is also shown on the national map, is designated as a geotope and was protected in 1868 as the first natural monument in the canton of Bern, marking the beginning of the Swiss nature and landscape conservation movement. Its immediate surroundings, covering an area of four hectares, form a cantonal nature reserve which, together with the boulder, is listed in the Federal Inventory of Landscapes and Natural Monuments of National Importance (BLN) and also as an IUCN protected area category IV object in both the Federal Inventory of Raised Bogs and Transition Bogs of National Importance and the Federal Inventory of Fens of National Importance.


Before the geological context of its formation could be clarified, the Luegibodenblock was long regarded as the supposedly largest erratic boulder in Switzerland due to its material, which differed from the surrounding rock, meaning that it would have been brought to its location by a glacier in the Ice Age.[1] Efforts to preserve it were based on the then current international discussion about the Ice Age theory.

Geology

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The boulder lies one kilometer south-east of the village of Habkern on a small plateau called Luegibode, at an altitude of 1100 m on the southern slope of the Lombachtal valley below the Roteflue. The municipal boundary between Habkern and Unterseen runs right next to the boulder. The slope rises steeply around the small slope terrace from the 150 meter lower Lombachgraben towards the south up to the Hardergrat. The Luegiwald forest covers the slope around the Luegiboden, on which a peat bog has developed. The part of the boulder made of so-called Habkern granite that is visible above the ground is 14 meters high, 31 meters long and 28 meters wide. Its volume is estimated at around 13,000 cubic meters, more than half of which lies below the surface in the bog soil and moraine debris.

The rock lies on the Habkern flysch bedrock, which forms part of the Bernese Pre-Alps[2] The flysch zone was formed during the folding of the Alps from old deposits in a former deep-sea trench. The rock mass of the Habkern granite originated from an older mountain range, slid down into the depths together with sediments and sank into the surrounding mud, from which the so-called wild flysch later formed. During the formation of the Alps, the rock reached the surface and was exposed again by the erosion of the Lombach valley. In the Quaternary period, marginal gravel and moraines from the Alpine glaciers and slope debris from the Brienzer-Rothorn chain, which is made up of layers of sandstone and limestone, were deposited in the valley and on the mountainside around the Luegiboden block without completely covering it.

 
Photography 1949 (ETH-Bibliothek)

History

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There used to be many of these boulders scattered throughout Habkern. Because the granite, with its unusual yellow-reddish hue and its fine and hard structure, was very popular as an ornamental stone, for example for house facades, most of these boulders were quarried. A gravestone made of Habkern granite was long a status symbol in the Bernese Oberland.

In 1841, Jakob Zimmermann bought the Luegiboden block from Bäuert (Burgergemeinde) Schwendi for 400 francs in order to cut it up. He wanted to sell the granite to the city of Bern, which wanted to use it to decorate the arches, parapets and ledges of the Nydegg Bridge. However, the Bernese building authorities ultimately decided against the purchase due to the color of the granite. Zimmermann sold the Luegiboden block on to five local politicians who also wanted to exploit it, but could not agree with the landowners on the route of the necessary road. Only a small piece of the block was demolished and turned into the base of a monument in Neuchâtel. It was also long believed that a slab of Habkern granite, which Switzerland donated to the United States in 1852 for the construction of the Washington Monument, came from the Luegiboden Block. In fact, however, it had been taken from another stone in the Lombach Valley.

In 1867, the Geneva geologist Alphonse Favre published an appeal on behalf of the Swiss Society for Natural Research, which at the time was concerned with the ice age theory, to protect the erratic blocks as witnesses to the former glaciation of the Swiss Plateau. Following an initiative by Bernhard Studer, the canton of Bern decided in 1868 to protect the erratic blocks in the state forests.[3] In the same year, the Bernese businessman and politician Friedrich Bürki[4] and the geologists Isidor Bachmann and Edmund von Fellenberg, together with the Bernese Natural History Society, were able to buy the Luegiboden block from the owner. They donated it to the Natural History Museum of Bern, which has owned it since 1869 at an official value of 980 francs. In 1868, the Luegibodenblock became the first stone in Switzerland to be placed under state protection. This rescue operation, which is regarded as the birth of nature conservation in Bern, is commemorated by an inscription and a plaque on the stone as well as photographs taken at the time, which can be found in the ETH archives.

In an article published in 1870 on the erratic blocks of the canton of Bern, Isidor Bachmann drew attention to the distinction between the "red granites of Habkern", which were to be regarded as exotic rocks, and the "actual erratic blocks"[5].

Vegetation

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Mosses, lichens, grasses, blueberries and woody plants such as rowanberries and small trees grow on the irregular, rugged surface of the Luegibodenblock.

The raised bog and fen on the Luegiboden have species-rich vegetation. Among the rare plant species in the protected area are the round-leaved sundew, the cottongrass and orchids. Toothwort beech forest and maple-ash forest extend along the mountainside around the moor clearing.

Protection Objectives

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Several protection objectives apply to the nature reserve in accordance with the various protection categories. The BLN summarizes the purpose as follows:[6]

  • Preserve the Luegibodenblock in its size and substance and with its characteristic vegetation.
  • Preserve the bog complex in its quality, ecological function and with its characteristic plant and animal species.
  • Preserve the quality of the forests.
  • Preserve the forest-open land mosaic.
  • Conserve the structurally rich and low-disturbance habitat, especially for the hazel grouse.
  • Preserve the scenic embedding of the Luegibodenblock and the moors.

Literature

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  • Raymond Beutler, Andreas Gerth: Switzerland's natural heritage. Landscapes and natural monuments of national importance. Bern 2015, p. 215.
  • Rudolf Lindt: The stone on the Luegiboden, with woodcut "Erratischer Block". In: Yearbook of the Swiss Alpine Club, 5th year, 1868, pp. 629-635.
  • Sarah Neuhaus: Size is not important. In: Jungfrau Zeitung. April 19, 2016
  • Emanuel Maurer: "In the interest of science and in honor of the country". The protection of erratic blocks in the canton of Bern. In: Communications of the Natural History Society in Bern. Volume 62, 2005, pp. 135-159.
  • List of protected natural monuments in the canton of Bern. In: Mitteilungen der Naturforschenden Gesellschaft in Bern, 10th vol. 1953, pp. 110-126 (Luegibodenblock: p. 119) (digital copy on E-Periodica of the ETH-Bibliothek)
  • Max Weibel: The Luegiboden block near Habkern BE. In: Mineralienfreund, 34. vol. 1996, no. 2, pp. 14-19.
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Individual references

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