Читать книгу Monument Future - Siegfried Siegesmund - Страница 183

In the course of its geological history, immense amounts of volcaniclastic material were deposited in the territory of Armenia. Armenian tuffs show a wide variety of color, grain size, clast content and chemical composition. The two examples presented in this study, Hoktemberyan and Golden Armenia, are frequently used in the past and recent construction in many parts of the country (Figure 1a shows the utilization of Qasakh tuff).

In Mexico, volcanic tuffs were and are widely used in the construction of pre-Hispanic, colonial and 132modern monuments. The type and variety of these tuffs exceed half a hundred. In the present study, five tuffs of Central Mexico (San Luis Potosí, SLP), are presented as examples (Figure 1b). The volcanic tuffs of SLP belong to the Paleogene Silicic Large Igneous Province, the Sierra Madre Occidental, the largest ignimbritic province in the world.

Figure 1: Examples of the historical use of the studied tuffs and relevant geographic locations: a) Hovhannavank Monastery, Ohanavan (Armenia), 5th c.; b) Templo del Carmen, San Luis Potosí (Mexico), 17th–18th c.; c) Eger Castle, Eger (Hungary), 13th–18th c.; d) Porphyry house, Chemnitz (Germany), 1868.

Miocene volcanic activity produced a large amount of welded and unwelded pumiceous tuffs in Hungary. Besides the prevailing rhyolitic composition, dacitic and andesitic tuffs also formed in Eastern Hungary. Rhyolitic tuffs are particularly common in a 50 × 10 km area known as Bükkalja Volcanic Field in Northern Hungary.

Emblematic monuments such as the castle or the minaret of Eger were constructed from this material (Figure 1c).

Significant volcanic tuff deposits in Germany are mainly found in the eastern and western Central part of the country. Permian volcanism led to the deposition of the Hilbersdorf tuffs in eastern Central Germany, near the city of Chemnitz.

The Quaternary Weibern tuff is located in western Central Germany, in the municipality of Weibern.

Prominent examples of its application as building stone are, e. g. the Kaiser Wilhelm Memorial Church in Berlin, the Castle Church of Chemnitz or the porphyry house of master stonemason Findewirth in Chemnitz (Figure 1d).