Lehr R (2022)
Publication Type: Journal article
Publication year: 2022
Book Volume: 81
Article Number: 219
Journal Issue: 7
Sandy-marly siltstones, sandy-silty marlstones, silicified marlstones and marly silicites are the characteristic cyclically deposited sediments in large areas of the Bohemian–Saxonian and Münsterland Cretaceous Basins. In the German-speaking area, these typical sedimentary rocks are called Pläner. In the Czech Republic they are called opuka, in Poland/Lithuania opoka and in France/Wallonia gaize. They can be easily quarried as managable dimensional stones, which can be formatted with little effort and were therefore the preferred material for use as a masonry stone. In the Middle Ages, Pläner was therefore the dominant stone used for exterior architecture. Harder Pläner was used as floor slabs and for paving. In Prague, a local Pläner is exposed with beds reaching a thickness of 1.3 m. This local variety is called the Golden Pläner/zlatá opuka, where it was also used for high-quality sculptural work. The Golden Pläner is therefore a stone with a wide variety of uses. Prague also owes its title as the "Golden City" to this rock. The Golden Pläner is well studied. Its mineral composition, important petrophysical characteristics and weathering behavior have been published in several geoscientific papers. Publications dealing with the other Pläner stones of the Czech Republic, those in Saxony or exposed in the Münsterland are still lacking. The aim of this paper is to illustrate the similarities and differences of the Pläner stones used as a building material from the Cretaceous basins considered here. Four different types of Pläners can be classified based on their primary facies and early diagenetic characteristics, but also the limestones that are called Pläners, which occur within the Pläner sequences and the residuals of these Pläners are considered. The high proportion of very fine-grained constituents requires the combination of several analytical and observational methods such as optical microscopy, microanalysis, powder X-ray diffraction and textural analysis of pore space by mercury porosimetry. To be able to classify the weathering resistance, and thus the possibility of using Pläners as a natural stone, the structural parameters of compressive strength, porosity, water absorption, freeze–thaw resistance and hygric dilatation were also determined.
Lehr, R. (2022). Pläner: a traditional building stone in Saxo-Bohemian Cretaceous and Münsterland Cretaceous Basin. Environmental Earth Sciences, 81(7). https://dx.doi.org/10.1007/s12665-022-10218-x
Lehr, Ralf. "Pläner: a traditional building stone in Saxo-Bohemian Cretaceous and Münsterland Cretaceous Basin." Environmental Earth Sciences 81.7 (2022).