Alteration parameters affecting the Luxor Avenue of the Sphinxes-Egypt

Stone alteration in the environment is caused by various extrinsic disintegration agents, besides, their intrinsic properties "mineralogical composition, textures and internal structure". Therefore, the purpose of the current study was to evaluate the weathering state affecting the Luxor Avenue of the Sphinxes by studying its chemical, mineralogical and physio-mechanical characteristics, in addition to morphological features. Scientific techniques, such as X-ray fluorescence (XRF), X-ray diffraction (XRD), Petrographical microscopy (PM), Cathodoluminescence (CL), Environmental Scanning Electron Microscope (ESEM) and micro energy-dispersive X-ray fluorescence (μ-EDXRF) were used. The results showed that quartz represents more than 96% of the sandstones and the main cement of the grains is quartz overgrowth. Alteration and formation of kaolinite was clearly observed. Halite, sylvite and bischofite were the main salts that affected the statues representing approx. 78.40%. The study also provided information about the different deterioration factors affected the Avenue of the Sphinxes namely; burial environment, solar effects, soil moisture and groundwater. These caused some deterioration forms such as soiling & crusting, breaking down most of the statues heads, saturation forms, salt crystallizations and stone abrasion. Cleaning, desalination and consolidation using different materials and techniques, in addition to reducing the human anthropogenic impacts are recommended for future conservation of the Luxor Avenue of the Sphinxes.