Petrographic and geochemical investigations of the late antiquity unguentaria from the archaeological site of Tripolis, Denizli (southwestern Turkey)

Abstract

Petrographic and geochemical analyses were performed on unguentarium samples from Tripolis, Denizli, which was in the crossroads of the Phrygia, Caria and Lydia region during the late Antique period. In particular, optical microscopy, X-ray diffraction (XRD), X-Ray Fluorescence (XRF) and Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM-EDS) were used for the determination of the morphological, mineralogical and chemical characteristics of the unguentaria. Thin section and XRD analyses show that unguentaria are composed of an amorphous matrix with various minerals and rock fragments and/or voids and were categorized into three petrographic groups. Group 1 samples consist of abundant quartz, plagioclase (anorthite), gehlenite, clinopyroxene (diopside), rarely calcite and iron minerals. Group 2 samples have similar mineralogical compositions but they have lesser quartz and further calcite than group 1. Group 3 samples have porous matrix and rarely quartz, plagioclase (anorthite), gehlenite. Petrographic differences between groups are further supported by the chemical compositions. The presence of Ca-silicate minerals and bloating pores in the sample matrix indicated higher firing temperatures (approximately 900 or 1000 degrees C) in a reducing atmosphere. The coexistence of calcite and gehlenite can be practically interpreted as a secondary calcite, which has formed in samples as a result of post-burial deposition processes. Results further showed that illitic clays were used for the production and the unguentaria were manufactured by using Baskarci clays from Denizli region.