![]() ![]() ![]() Thus its structure reminds the coats of an onion. The mural jointing follows the isothermal faces of cooled down magma. You may encounter the trachytic plates also on Milesovka mountain, especially near to its summit. The stony fields consisting of such plates are abundant on phonolitic hills. The phonolites from Milesovka are exhibiting characteristic mural jointing the material is slacking into relatively thin plates having uneven surfaces. By its volume, which represents 60 millions m3 ( only the portion protruding above 600m a.s.l.), the mountain is largest phonolitic body far and wide. It is probable that the mountain has been formed from the subsurface body consisting of very viscous magma squeezed through the fractures in the earth's crust into subsurface layers where it formed dome-shaped formation. In principle, it is a kind of phonolite having higher content of potassium feldspar and soda-lime feldspar. In the geological maps and guides we read that the basic material from which the mountain is formed is sodalitic trachyte. It means that the body of this mountain was formed during the main volcanic stage of the creation of Ceske Stredohori. According to geochronological studies, the age of Milesovka is 27-31,5 millions years. This mountain has almost same geological origin as the rest of phonolite cones of Ceske Stredohori. Since 1903, the meteorological observatory (which is oldest Czech mountain station) is situated on its top reaching 836,5m a.s.l., together with the outlook-tower. ![]()
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