Analytical study of the weathering of the Jeronimos Monastery in Lisbon

A variety of samples of the weathering crust and of rain runoff and washdown water were collected from the Jeronimos Monastery, Lisbon. Runoff and leaching samples were taken from upper walls, facing the north, the east and the west. For the crust samples, attention was focused on three points where the decay is more noticeable: the southern portal, the San Vicente portal and the cloister. The samples were analysed by different quantitative trace and micro-analytical techniques. The soluble fraction of the rain, runoff and leaching samples was analysed for major anions by ion chromatography. Multi-elemental analyses of the particles in suspension were carried out by energy-dispersive X-ray fluorescence spectrometry. Electron probe X-ray micro-analysis was applied to make line scans on petrographic sections across the weathered zone, and to analyse and classify individual suspended particles in samples of rain, runoff and washdown. A few thin sections have also been characterised petrographically and by X-ray diffraction analysis. The weathering crust is up to 400 μm thick and is enriched in S, K, Si, Fe and Mg. Large amounts of sulphate, and also phosphate and oxalate are detected in the runoff and leaching water. In the suspended fraction, high amounts of Fe and Ca are measured. The blank and rainwater samples have mainly Si-rich particles from quartz and feldspars in soil dust. The leaching and runoff samples are enriched in Ca-rich particles due to CaCO 3 leached from the stone.