Bahla ware from Central Oman: Petrological and chemical information of bodies, chemical information of glazes

[Description of methods used for collection/generation of data] Collection and selection of ceramic samples: More than 6000 sherds were collected from both the excavation and the survey, with approximately 3700 diagnostic sherds coming from the survey and 325 diagnostic sherds from the excavations. The majority of these sherds are medium coarse and coarse ware with lower numbers of comb-impressed pottery, porcelain and as well as more than 500 Bahla ware sherds. From the latter, 32 sherds (10 from excavation contexts, 22 surface material collected during the surveys) were chosen for scientific analyses. Petrography: All 32 samples were subjected to petrographic analysis. Petrographic analysis was used to determine the petrological and mineralogical composition of the ceramic fabrics, as well as their texture. For the analysis of the samples with ceramic petrography, small sherds were taken from each sample and prepared as thin sections in the laboratories of the School of Archaeology and Ancient History at the University of Leicester (UK) . The thin sections were then analysed on a microscope with a polariser, a ZEISS AXIOSCOPE 5 POL, in the same laboratories. Images were collected with a ZEISS AXIOCAM 208. Chemical analysis: The chemical analysis of ceramics aimed to determine the chemical composition of the ceramic bodies of a sub-set of 28 samples. It was determined with wavelength dispersive X-ray fluoresce (WD-XRF) analysis, conducted at the Fitch Laboratory of the British school at Athens. The analysis was carried out on a BRUKER S8 TIGER with a 4kW Rh X-ray tube instrument. All details regarding this instrument can be found in the paper Georgakopoulou, M., Hein, A., Müller, N., & Kiriatzi, E. 2017. Development and calibration of a WDXRF routine applied to provenance studies on archaeological ceramics. X-Ray Spectrometry 46(3): 186–199 SEM-EDS: A subset of 15 samples was subjected to scanning electron microscopy with energy dispersive spectrometry (SEM-EDS). This was used for the chemical analysis of glazes and ceramics as well as and high-resolution imaging. The SEM instrument Zeiss EVO 15 that operates with an attached EDS Oxford Instruments Ultim Max EDS with a 65 SSD detector was used at the Archaeological Science Laboratories of the Cyprus Institute. The analysis was run in high vacuum conditions, at an accelerated voltage of 20 kV, working distance 8.50 mm, process time 4 and acquisition time 30s livetime.