Weathering of monumental Islamic marble in Egypt: a contribution to heritage studies

Abstract

Marble is a metamorphic rock widely used in historical buildings as a structural and decorative stone; also, it is commonly used for sculpture and as a building material; for example, the lower parts of many walls of Mamluk and Turkish buildings are covered with marble tiles of different colors (mainly, white, red, black) as well as many of the columns in these structures. Due to the severe effects of deterioration factors, such as, atmospheric parameters, air pollution, ground water, micro-organisms, the decorative marble slabs and columns are seriously deteriorated. Forty marble specimens were collected from the most deteriorated parts of marbles located inside and outside selected historical buildings, namely the Sultan Qalawun complex in Al-Muizz Al-Deen Allah Street in Cairo (1284 AD) an archaeological architectural group, built in the Mamluk style. The present work focuses on the identification of the mechanism of marble deterioration. In order to carry out this study, different samples were collected from the deteriorated historical marble of the Qalawun; the marble samples collected for study were not from a single building, but from the complex of the Sultan Qalawun Group or the Qalawun Mosque, and included a school and dome, and the Mosque. The mihrab of the dome is considered one of the most luxurious mihrabs of antiquity in Egypt. Each of its sides is surrounded by three marble columns, and its cavity has four layers of gilded recesses supported by marble columns. The marble samples were investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF), polarized light microscope (PLM) and scanning electron microscope with energy dispersive x-ray spectroscopy (SEM-EDS). The obtained results showed that the mineral constituents of the investigated samples were seriously deteriorated, and the physical structure had collapsed.