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Skały w architekturze podkrakowskich kościołów romańskich

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Bromowicz J. , Magiera J.

Przegląd Geologiczny

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2019

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tom Vol. 67, nr 9

728--735

EN

There are a few Romanesque churches (12th to mid of 13th century) located iin the close suburbs north ofKrakow which are not well known nor described, in contrast to the churches of this age located within the city. Three of them were the subject to the present study. All three churches are located close to each other, but the local geology and available building stones are different. The Romanesque walls of the Church in Prandocin are built of calcareous sandstone of light grayish shade (Neogene). Their exposures and probable past mining sites are located a few kilometers to the north of the church. Stone blocks are very neatly shaped and fitted, so the joints are smooth and very narrow. The church in Wysocice is built mainly of a local compact, white to grayish limestone with cherts (Upper Jurassic), with horizontal stripes made of a porous gray travertine (Quaternary?) adapted to retaining the wall. Sculptures are carved of a soft lithotamnium limestone (Pińczów, Leithakalk; Neogene). Both the compact Jurassic limestone and the soft Pińczów limestone are applied in the church of Kościelec Proszowicki. Decorative sculptures and carvings are made exclusively of the Pińczów limestone. The works in all three places were performed by masonry guilds, which searched for and quarried an appropriate stone material and treated it. Stonemasons had apparently high qualifications for selecting an appropriate material which, on one hand, fulfilled aesthetical requirements of the founder and, on the other, guaranteed durability of the whole structure.

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Historia zapisana w kamieniu romańskiej kolegiaty pw. św. Marcina w Opatowie

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Magiera J. , Bromowicz J.

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tom Vol. 71, nr 1

12--18

EN

Romanesque collegiate church in Opatów (south-eastern Poland) belongs to the best-preserved Early Mediaeval edifices in Poland. Its date of origin, founder, architects and history are still unclear despite numerous investigations carried out since the beginning of the 19 th century. It is clear that local sandstones were used in the construction of the impressive church. Present investigations resulted in the inventory of the stones used as a building material: their petrography, size of blocks and strange holes and striae on some of their surfaces. Dominant sandstones have different colours: white-greyish or grey-brownish. They are built of very fine-grained, well sorted quartz with siliceous-clayey binder. All sandstone blocks have similar heights (most frequent average 34–38 cm), but different lengths. Longer (up to 62 cm) are placed in the oldest parts of the edifice, shorter (up to 48 cm) form younger fragments and might have been reused after destruction of previous undefined buildups. The sandstones represent Lower Jurassic sediments exposed currently on the slopes of the Opatówka River valley in Podole, some 5 km NE of Opatów. Only a few sherry (reddish) sandstone blocks found in various parts of the walls are probably replacements during post-Romanesque reconstructions. They represent Lower Triassic sandstone from Lipowa, 3 km NE of Opatów. Lancetoidal grooves, 5–20 cm long, and hemispherical holes of 1–4 cm in diameter are apparently of anthropogenic origin (apotropaic marks); however, their purpose is unclear. It is supposed that the grooves are traces of tool sharpening or grinding, while the holes are places where sandy or dusty material was acquired for magical or medical purposes.

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Problemy konserwacji obiektów architektonicznych z dolomitu na przykładzie barokowych bram w ogrodzeniu Katedry Wawelskiej

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Stępień P. , Kozłowski R. , Magiera J.

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nr 4

338-346

EN

Dolomite has been rarely studied by conservation scientists. The authors’ research has been carried out during the conservation (1992-1993) of three Baroque gates in the wall enclosing the Royal Cathedral at the Wawel Castle, Cracow, Poland. The gates were built between l6l7 and 1619, probably according to the design of an Italian architect Giovanni Battista Trevano from Lugano. Dolomite is the principal material used in these gates. The research has identified in the object several types of dolomite, showing varying resistance to weathering. The mechanism of decay involves acidic corrosion due by sulphur dioxide contained in the polluted air. In contrast to the corrosion of limestone, the corrosion of dolomite yields two reaction products: calcium sulphate (gypsum) and magnesium sulphate (epsomite). Magnesium sulphate is extremely soluble in water. It dissolves and migrates easily in the object and crystallises when the stone dries. Repeated dissolution crystallisation cycles of this salt are the main cause of the decay of dolomite. Symptoms of this decay are deep alveoli, pulverisation and flaking. Furthermore thick black crusts containing gypsum are formed in the non-washed areas. The described process of destruction proceeds differently in different types of dolomite. The porous types and/or those containing many of fine-grained components are much affected. An important damaging factor is exposure to rain water and rising dampness - the corrosion zones in the object are clearly linked to a high moisture content. Conservation of dolomitic architectural objects must involve extraction of soluble salts, specially of magnesium sulphate. Poulticing (cellulose + water) proved an efficient method, but the poultices had to be applied 5-6 times to obtain the reduction of the salt content to levels below 1 weight %. Another important point of the conservation is protection from water. In the case of the gates, new proper roofing of copper leaf and injections at the base of the gate (to obtain insulation against rising damp) were made. The whole surface of the stone was impregnated to obtain water-repellency. A solution of silicone resin (Polish product Ahydrosil Z) was used, both for water-repellency and consolidation. Another possibility is a mixture of acrylic and silicone resins (the method of O. Nonfarmale). Acrylic resins were found insufficiently resistant in Polish climate and silica esters ineffective in the consolidation of relatively large „nodules” of dolomite. It is important also to choose properly the material for repairs, avoiding the „bad” types of dolomite mentioned above. Lime mortars (with some hydraulic additions) and stone powders with a silicone preparation (Adhesil Kl) were used as filling mortars.