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Earth of fire

Actualité volcanique, Article de fond sur étude de volcan, tectonique, récits et photos de voyage

Publié par Bernard Duyck
Publié dans : #Excursions et voyages

Near Nidda, the Vulkan dorf (volcanic village) of Michelnau houses the quarry of red tuff of the same name.

Vogelsberg massif produced mainly basalt, but also the red tuff. It is a cluster of slag produced during explosive eruptions, of phreatomagmatic type.

The red tuff of Michelnau contains 64% glass matrix, 32% zeolite and indefinite materials, 2% pyroxene, and other accessory minerals including olivine. Zeolites are found in the pores, forming half of the tuff. The red color of the tuff from its iron content.

Vogelsberg - the red tuff of Michelnau - photo © Bernard Duyck 05.2014

Vogelsberg - the red tuff of Michelnau - photo © Bernard Duyck 05.2014

Vogelsberg - Michelnau - Explanatory panel of the observation deck - photo © Bernard Duyck 05.2014

Vogelsberg - Michelnau - Explanatory panel of the observation deck - photo © Bernard Duyck 05.2014

Vogelsberg - tuff blocks to the parking entrance - Photo © Bernard Duyck 05.2014

Vogelsberg - tuff blocks to the parking entrance - Photo © Bernard Duyck 05.2014

The explotation :

Johann Weisel, a German farmer and innkeeper, began the extraction of stones in 1863. Due soft features of this tuff, he could not use explosives ... the very physical work is done with a saw , with the advantage of being able to choose the size of the extracted block, function of his application. Wholesale bullion rectangular shape are found in the rock wall, released by several sides. Tuff deposit is about 100 m wide on 30, and was operated on several levels.

An old machine hints at the hard work necessary to break these blocks, and carry them out of the quarry.

The extraction was stopped in the middle of the 1990s. Since 2010, the career has become a "GeoTop" accessible only on guided tours. An observation deck is happily accessible to all, starting from a well-marked parking, and offers a breathtaking view of the face.

GPS position: 50 ° 25'18 - 9 ° 2'23.
 

Vogelsberg - access to the quarry of red tuff Michelnau - photo © Bernard Duyck 05.2014

Vogelsberg - access to the quarry of red tuff Michelnau - photo © Bernard Duyck 05.2014

Vogelsberg - Michelnau's quarry - to the observation deck: operating on several levels, notched walls - photo © Bernard Duyck 05.2014

Vogelsberg - Michelnau's quarry - to the observation deck: operating on several levels, notched walls - photo © Bernard Duyck 05.2014

Vogelsberg - Michelnau's quarry - photo © Bernard Duyck 05.2014

Vogelsberg - Michelnau's quarry - photo © Bernard Duyck 05.2014

Vogelsberg - career Michelnau - blocks were transported by trucks before being cut to measure - photo © Bernard Duyck 05.2014

Vogelsberg - career Michelnau - blocks were transported by trucks before being cut to measure - photo © Bernard Duyck 05.2014

This tuff has been used for the construction of bridges, churches, gravestones.

Previously, the tuff was used for making stone ovens, because of its heat resistance and good preservation thereof. It is still prized by sculptors and landscape architects.
 

Career Michelnau - block tuff with traces of saw - photo © Bernard Duyck 05.2014

Career Michelnau - block tuff with traces of saw - photo © Bernard Duyck 05.2014

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