Research on some effective properties in nomination of Urfa Limestone to the “Global Heritage Stone Resource” designation

Abstract

Extracted from Şanliurfa Province in Turkey, Urfa limestone is one of the limestone types that can be nominated to Global Heritage Stone Resource (GHSR). It has been used since the Neolithic Period (i.e., approximately 12,000 years ago) in world-renowned Gobekli Tepe Cultural Center in Urfa. In this study, a research has been conducted on the candidacy potential of Urfa limestone for Global Heritage Stone Resource (GHSR). Urfa limestone, which was used as a building block as of the Neolithic Period and in the first temple built in Anatolia, was also the building block of Gobekli Tepe. The use of Urfa limestone in Sogmatar Ancient City (second century AD), Şuayb City, Harran Ulu Mosque, Urfa Ulu Mosque (St. Stephan Church), Reji Church, sculptures, and Şanliurfa’s traditional city texture in houses, inns, castles, walls, gates, and bridge structures was investigated along with the use in Gobekli Tepe. The use of Urfa limestone in historical buildings and today’s buildings was investigated along with the use in Gobekli Tepe. The engineering characteristics of the building blocks in which Gobekli Tepe was built were examined. A series of engineering characterization tests and analyses were made on the building block samples regarding mineralogical and petrographic properties (polarize microscope, XRD, and SEM), and chemical (XRF), physico-mechanical, petrophysical, and insulation properties (TG and DTA analysis). Urfa limestone is in crystallized form and has a sparite texture containing 55.86% CaO and 0.36% SiO2. The Δ (change of characteristics in percentages) values in petrophysical characteristics were between 1.23 and 18.72%, and the Δ values after salt crystallization test were between 3.78 and 31.67%. According to this characteristics change (Δ%), it is more resistant to degradation compared with other natural stones originating from calcium carbonate. According to SEM Analysis, it was determined that it has a high insulation characteristic in the structure of Urfa limestone because it is contactless among pores. The usage performance of Urfa limestone in Gobekli Tepe, and in historical buildings and today’s buildings has been proven to be good according to engineering characterization tests. Urfa limestone fulfills all requirements for Global Heritage Stone Resource (GHSR) designation.