Читать книгу Monument Future - Siegfried Siegesmund - Страница 396

The basalt rock used for the construction of the architecture outside the rockface also shows 259varieties of different quality (Fig. 2a and 2b). It is noteworthy, that the foundation of the church building consists of a much harder basalt variety (BF) than the rising masonry (BW). The BF variety shows a macroporosity characterised by a distinctive lamination (Fig. 2a), while the basalt ashlars of the walls (BW) show a finely homogeneous porous structure (Fig. 2b).

The rock cut architecture is carved into the soft rock that can be divided into different varieties. A clear distinguishing feature is the clastic material. The sample material in this study distinguishes between a rock variety that is largely free of clasts (RF) and another that contains a high proportion of clasts (RC) shown in figure 2c and 2d. This clastic material may constitute up to 40 % of the rock and can display a diameter up to about 5 cm (Fig. 2c). The fine matrix has an ocher tone and shows a variety of brownish traces of oxidation (Fig. 1a, 1c, 2c and 3d).

It can be characterised as an ash-rich, welded tuff with a fine matrix containing a large percentage of microlites, more or less uniform in size from idiomorphic feldspar crystals (Fig. 2e and 2f). Some of these can be identified as plagioclase.

In this study two types of this tuff rock were investigated further: the clast-rich (RC) and a clast free material (RF), (Fig. 2c–2f).

Figure 2: Different building materials used for the monastery. a) The basalt of the foundation (BF) and b) the basalt of the walls (BW). c) The rock variety with clasts (RC) and d) the variety without clasts (RF). e) Thin section of RC and f) of RF under polarised light. The pore size distribution of RC (left) and RF variety (right) is shown below.