Emona (mod. Ljubljana) was a Roman settlement in Region X in present-day central Slovenia. To date, several source areas have been proposed for the extraction of limestone used by the Romans. Stratigraphically, the source areas extend from the Lower Triassic to the Miocene and geographically include the periphery of the Ljubljana Moor, as well as the area around Medvode, Lake Zbilje, Smlednik Hill, Nabrežina/Aurisina and Moravče. Due to the insufficient resolution of the geological data, it has not yet been possible to assign the provenance of the stone products to source areas for all lithofacies and microfacies types. All sedimentary successions in the proposed Roman quarries were therefore examined in geological detail. To be able to make comparisons, 404 stone products from Emona and the area around Ig were also examined.
The methodology applied includes geological mapping, detailed sedimentological logging of sedimentary successions, macroscopic examination of samples, microfacies analysis using optical microscopy, biostratigraphy, cathodoluminescence analysis, strontium isotope value analysis, stable isotope analysis of carbon and oxygen, and determination of mineral composition and contents of major, minor and trace elements. The methodology focuses on the application of the strontium isotope stratigraphy (SIS) approach, which was applied for the first time to determine the provenance of limestone stone products.
Analyses of the sedimentary successions exposed in the proposed quarry source areas show that all identified units contain both lithofacies and microfacies types, predominantly biogenic limestones, enabling the determination of the provenance of stone products. When lithofacies and microfacies could not be distinguished, I relied on the composition of foraminiferal assemblages or cathodoluminescence analysis. If these latter methods also failed to provide distinction, a stratigraphic approach using strontium isotope stratigraphy was used.
This approach allowed me to distinguish between all lithostratigraphic units considered and to clearly determine the lithostratigraphic affiliation for all stone products studied. The proposed methodology made it possible to investigate the provenance of the natural stone used in Emona and Ig area more reliably.
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