Characterization of Historic Mortar from the Architectural Decoration and Plaster of Rocky Temple of Verjuy in Maragheh, Iran

Temple of Verjuy or Mehr Temple is one of the particular monuments in the type of regional architecture, in the slope of Sahand volcano; has been located in Verjuy village in the suburbs of the Maragheh city, East Azerbaijan province, Iran. The Verjuy researchers believe that this building belongs to the Mithraism religion which is an Iranian ancient religion (248 BCE-224 CE). But, new excavation around the temple demonstrated that this building is a part of underground rocky architecture with an unclear date and history. Underground Verjuy temple has seven spaces with a number of holes which are connected to each other. According to the literature, the temple was a worshiping place before Islam, but since then, the evidence show that it was used as a mosque. The architectural decorations of the temple have not been taken into consideration and in general, a lot of references, repeat the first information related to the history, usage and stone carving of this temple. As the specific architectural decorations of this monument have not yet been scientifically studied, the exploring variety of architectural decorations as well as the characterization of materials used for making the decorations of this building would be one of the main objectives of this research. Based on the results obtained, the main decorations of temple are including: carving of Islamic Arabesque and Quranic inscriptions as well as Moqarnas decoration inside the dome of the main space of the building. The results also showed the application of mortar on architectural decoration as a plaster inside the building and also on the surface of Moqarnas as a very thin layer in Islamic era. Moreover, the field work (redrawing the plan of temple and describe of architectural spaces as a documentation of architectural decorations with photography) and sampling of plaster along with XRPD, XRF and thin section petrography analysis were done. The results of this research show that, except for stone decoration, there is another decoration with lime base mortar in cover of Muqarnas work and some other places of the building, that this new finding is reported for the first time. This finding showed the application of the building during different periods and it is possible to attribute the earliest works and shreds of evidence of the use of the original dome in its new use in the Islamic era, to the Ilkhanid period.