Limestone quarry at Podpec near Ljubljana ( Slovenia) and its products

The quarry in Podpec near Ljubljana is considered the main quarry of the Roman colony Iulia Emona (Ljubljana, Slovenia). The existence of an ancient quarry in Podpec has been substantiated based solely on the macroscopic similarity between the Lithiotid Limestone Member outcropping in Podpec and the associated Roman monuments discovered in Ljubljana. In the present work, we have attempted to find tangible archaeological and geoarchaeological evidence for its existence. Archaeological excavations in the form of three trenches were carried out in the northernmost part of the quarry. We determined the lithological composition of limestone discovered in the trenches and the limestone used for the 288 objects found in Ljubljana. The lithological analysis of the monuments from Emona revealed that as many as 182 (or 64%) of the analysed monuments were made of limestone, which is lithologically identical to the types of limestone outcropping in Podpec. Lithologies represented in monuments also spatially group north of the modern quarry. However, the question of the affiliation of some of the varieties of limestone represented remains open. These limestone types lack diagnostic components and could also belong to the slightly older Krka Limestone Member. Reconstruction of the extent of the ancient quarry was enabled using microfacies comparison of lithostratigraphic source units and objects/ products, as well as with the historical analysis of early cartographic and cadastral documents. Studying the forms of the earliest objects (stelae) also suggests that the earliest monuments were produced by stonemasons who came to the area from the quarry in Aurisina (Italy).