Investigations on Limestones used in Historic Monuments in Shahdara, Lahore-Pakistan

Abstract

The weathering of built heritage has always been attributed to the cumulative impact of natural and anthropogenic activities over the centuries. This complex interaction has resulted into the physical, chemical and biological deterioration of historic materials which need examination to understand the weathering factors, mechanisms and products. The conservation and restoration of these historic monuments revealed to be extremely difficult under the present days of activated deterioration, even more in developing countries like Pakistan, where the lack of information and research on historic materials is one of the major reasons for past failures in conservation and restoration efforts in Pakistan. The present investigation concerns the identification of various types of limestone’s used in the historic monuments in Shahdara, Lahore (Pakistan) including Jahangir Tomb, Asif Khan Tomb, Nur Jahan Tomb and Akbari- Serai. Materials and Methods: The sampled limestones were analyzed by optical microscopy and X-ray powder diffraction for the identification of mineralogical phases. Major elemental content in addition to trace elemental analyses were measured by X-ray fluorescence. Results: The analytical study characterized the sampled limestones into seven type’s i-e nummulitic limestone, abri limestone, cloudy limestone, grey carbonaceous limestone, black carbonaceous limestone, cloudy limestone (local) and black limestone. Conclusions: This classification is the first step towards the formulation of effective conservation and restoration framework for the heritage site and hence the insurance for long-term survival of the Pakistani heritage.