Basalt cone
A basalt cone is a science-historical term that is still used colloquially. He describes with weathering exposed, resistant basalt rock inside an extinct volcano that as Härtling towers over the surrounding countryside. In the geosciences will basalt no longer used as a technical term. This also applies to similar terms such as phonolite cone or porphyry cone .
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Such cone mountains formed when magma rose from the interior of the earth and solidified near the surface of the earth. Mostly it is rock that solidified in the chimney of a volcano at the end of the extraction activity. The original cone mountain was over time by the removal of the surrounding softer materials by erosion destroyed, and the upper part of the rock core was exposed in this way.
They are particularly common in low mountain ranges, such as basalt cones in the Steinwald , the Hohe Rhön , and in the Bohemian low mountain range , but also individually, e.g. B. at Desenberg (near Warburg ) or the Druidenstein (near Kirchen an der Sieg ).
term
The term is mainly used colloquially as a proper name and surname, especially when it is a landmark , a landmark or a geotope , such as B. the Hohen Parkstein , the Rauhen Kulm or the Badacsony at Lake Balaton . Such terms are still often used in the tourist-oriented representation of landscapes.
In the geosciences today, the term cone mountain is used, possibly with an addition that refers to the type of rock or a reference to its volcanic origin. The term is usually replaced by a term that more precisely describes the formation or the rock, such as a spring tip , stick or chimney filling. In addition to basalt, other volcanic rocks also form conical and dome-shaped elevations, such as phonolite and porphyry .
Generalization of the term "basalt cone"
The colloquial generalization can be considered necessary because the layperson can hardly distinguish between eruptive rocks and “basalt” is a commonly known word. Bernhard von Cotta provides a prominent example of the abstract use of the term “basalt cone” . This led to the explanation of solidification and igneous rocks in 1867 a. a. from: " Nothing could be more obvious than to take such mostly isolated basalt and trachyte cones as the flushed inner cores of volcanoes ". This historical reference can be understood as an indication of this, although the specific petrographic distinction between volcanic rocks was so pronounced at that time that basalt was used as an umbrella term in common applications.
history
Bohemian geologists of the 19th and 20th centuries often preferred specific terms such as B. phonolite cone . The leading basalt researcher in Bohemia in the 19th century, Emanuel Bořický, used the term basalt cone specifically for eruption cores with pillars . In 1873 he explains:
“ Mountain cones, consisting of vertical or less inclined pillars reaching into the depths, are to be regarded as protrusions ... ... form the usual tectonic shape for those in the edge zones of the left bank of the Elbe and near the right bank of the Elbe Basalt varieties, while in the basalt mountains and basalt cone chains of the north and south-eastern edge zones further away from the Elbe bank, the wall-like corridors made up of horizontal columns appear as a continuation into the depths. Basalt cones of the latter type are partly connected by a wall-like, jagged elevation of the ground with protrusions of small basalt hills ... "
Based on his observations in the Siebengebirge, Goethe describes the basalt cone as a “ typical mountain shape of basalt ”. The historical meaning of this term goes back to the Neptunist dispute , at the center of which was the origin of the basalt. After Nicolas Desmarest scientifically described the volcanic origin of basalt for the first time in 1771, well-known geoscientists of the time turned against it and argued in favor of a sediment theory ( Neptunism / Plutonism ). There was a sharp public controversy between Abraham Gottlob Werner on the one hand and Johann Carl Wilhelm Voigt , Johann Friedrich Wilhelm Widenmann and other naturalists. Werner argued in 1788 in the mining Journal of Alexander William Koehler in direct controversy with a printed there reply by Voigt as follows:
“ The first mineralogists who declared basalt to be a product of fire took their evidence for this from the conical shape and the free standing of the basalt mountains. And in order to support their assertion even more, they worked diligently to find pits all over the tops of these mountains, which they accepted for craters so quickly, easily and for the rest of the world, and presented them as fearfully looking for them beforehand. "
In some standard works on mineralogy and geology in the course of the Neptunist-Plutonist dispute, striking conical mountains are interpreted as a result of their basaltic structure. In 1794, Johann Friedrich Wilhelm Widenmann wrote in his handbook of the oryktognostic part of mineralogy : The basalt mountains are characterized by their conical shape, and by the sometimes more sometimes less regular columns, and sometimes also by spherical separated pieces into which they are often divided, out. He does not comment on the origin of the basalt and only names the various positions. This view persisted for a relatively long time and was carried on within the geoscientific literature of the 19th century. The manual of mineralogy by Christian August Siegfried Hoffmann , continued by August Breithaupt , gives the following description:
“ According to the time of its origin, the basalt belongs entirely to the seam mountains, namely the seam trap, [...]. It must be regarded as the main link of the Settlements, and it is found either in partly pointed, partly flattened, conical mountains and individual peaks, partly in individual camps and nests, with other types of mountain belonging to this mountain range. […] Generally speaking, the basalt mountains and peaks form certain families, which are lined up in rows or are connected to one another through individual sections. If these families are very closely grouped, they form their own kind of mountains, the cone mountains. "
Some tried to find a compromise. a. Alexander von Humboldt and Johann Wolfgang von Goethe . The controversy temporarily drew the attention of scientifically oriented circles to this rock and its manifestations in the landscape. The assumption of a Neptunistic origin of basalt was finally and recognized refuted by the trips of Leopold von Buch to the Auvergne in the years 1802 and 1815.
See also
Individual evidence
- ↑ a b Basalt Cone High Park Stone. Bavarian State Office for the Environment.
- ↑ Guido Bauernschmitt: Thoughts on the expansion of the Rhön Biosphere Reserve. ( Memento of the original from October 1st, 2008 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 66 kB) In: The Rhön Biosphere Reserve is changing. Contributions to the region and sustainability, 4/2007.
- ↑ Anja Bretzler: Excursion “ Hydrogeology and Environmental Geology of Central Europe”. (PDF; 1.1 MB) Excursion report TU Bergakademie Freiberg.
- ^ Berthold Weber: The Rough Kulm. Association of the Friends of Mineralogy and Geology, Weiden district group.
- ↑ The basalt cone "Druidenstein" near Kirchen / Sieg. ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. .
- ↑ Bernhard von Cotta: The geology of the present . Leipzig (JJ Weber) 1867, p. 49.
- ↑ Emanuel Bořický: The work of the geological department of the regional exploration of Bohemia, Part II, Petrographic studies on the basalt rocks of Bohemia . Prague (Řivnač) 1873, pp. 212–213.
- ↑ JWvGoethe. About science in general. Mineralogy and geology . I. Part. In: Goethe's works, Weimar edition, Abth. II, Vol. 9. Weimar (Herm. Böhlau Nachf) 1892 pp. 1–306.
- ↑ Abraham Gottlob Werner: Final note, which contains the further elaboration of my answer above . In: Bergmännisches Journal vol. 1 (1788), vol. 2, p. 887.
- ^ Johann Friedrich Wilhelm Widenmann: Handbook of the oryktognostischen part of the mineralogy . Leipzig 1794. p. 1024.
- ^ CAS Hoffmann, August Breithaupt: Handbook of Mineralogy. Second volume, second division . Freiberg 1815. pp. 169, 170.
- ^ Otfried Wagenbreth: History of Geology in Germany . Stuttgart (Enke) 1999 pp. 36-39.
