『Abstract
　Slightly weathered white and pink tuffs of Midas monument have deterioration problems. In this study, depths of the weathering zones developed in the tuffs are investigated through optical microscopy, XRD, chemical analyses, SEM and some index parameters. By examining quantitative weathering indices and comparing them with thin section studies, it is found that thin section analyses of the phenocrysts, LoI and WPI are good indicators to quantify the depth of weathering for the tuffs. However, thin section studies have limited value for fine-grained tuffaceous matrix. The chemical weathering of the tuffs produces weathered zones that are 4.5 cm thick within the white tuff and 2.5 cm thick within the pink tuff. Physical weathering causes fracturing of feldspars along their cleavage planes. Variations of the index properties of the tuffs caused by weathering are not significant enough to quantify the weathering depths in the tuffs.

Keywords: Chemical weathering; Midas monument; Physical weathering; Tuff; Weathering indices』

Introduction
Geological setting of the tuffs
Climate and common weathering processes in central Anatolia
Quantification of weathering depths
　Mineralogical properties of the weathered tuffs
　Chemical properties and quantitative chemical indices of the weathered tuffs
　Index properties of the weathered tuffs
Conclusions
Acknowledgements
References