Mineralogical and Petrographic Investigations on the Tesserae in North Sacred Agora Ground Mosaics from Laodikeia Ancient City (Denizli): First Insights into the Provenance of Raw Materials

Abstract

The ground mosaics of the West Portico of the North Sacred Agora (WPNSA) in Laodicea cover an area of 20x14 meters and are partially deteriorated. There are five different layers at ground mosaic which consist of statumen (schist, marble, quartzite, metagabbro, brick-tile and lisvenite pebbles), rudus (rough mortar in 3-4 cm thickness), nucleus (fine mortar in 2-3 cm thickness), bedding mortar (1-2 mm in thickness) and tessellatum. Transitions between these layers are not obvious. The ground mosaic of the WPNSA were created by using of Opus Regulatum, Opus Tesselatum, and Opus Vermiculatum techniques of 14 different patterns. Tesserae, sizes ranging from 1x1x1, 1x1x2 cm in different color tones, are composed of marble, dolomitic marble, recrystallized limestone, travertine, oolitic sandstone rocks, and brick-tile fragments. In petrographic examinations, the origin rocks of tessera samples, which are called dolomitic marble and white marble, were determined to be dolomite-limestone and limestone, respectively, and the results were supported by XRD studies. It was determined that different colored tessera samples showed similar distribution patterns in the multi-element distribution diagram normalized according to the Upper Continental Crust (UCC) values, however, all elements (except Cs, Ta, and La) showed depletion compared to the UCC values. As a result, it has been evaluated that the minero-petrographic properties of the tessera samples used in the KKABP mosaic flooring are compatible with the geological formation of the region and that possible source areas may be geological units in the vicinity of Laodiekeia. © 2022, Bursa Uludag University. All rights reserved.