Francesca Bulian

This study presents new evidence for the early use of lime mortar during the Early Iron Age at the Piscina Torta site (Ostia, Italy), situated on the earliest Holocene beach ridges in the southern Tiber delta. The site, which was earlier described as a briquetage site, dates from between the late 8th and 6th century BCE and consists of a large complex of dumps, holding kilns and working floors. Lime mortar‐like materials were abundantly present in these dumps and used in the construction of some kilns and working floors. To assess their nature, truly lime‐based mortars or natural indurated marl, we performed petrographic and geochemical analyses on these materials, and on lime mortars experimentally produced using local marl from the Piscina Torta palaeochannel, which is the only nearby source of high‐carbonate sediment in this part of the Tiber delta. The experiments showed that the marl begins to calcine effectively above 800°C, developing characteristic lime mortar features between 900°C and 1100°C. Some archaeological materials indeed showed diagnostic microscopic features of lime mortar, including micritic binder, lime lumps, reaction rims and lack of birefringence, demonstrating that the marl had undergone the complete lime cycle (calcination, slaking and carbonation). Moreover, the analyses confirmed the origin of the archaeological mortar‐like materials, being these marls. Our study provides the first evidence to date for the intentional production and use of lime mortar in central Italy, predating the widespread use of this technology in the Roman world. The results also imply that the Piscina Torta site was a multifunctional production site with a variety of kilns and activities, underscoring the technological sophistication and multipurpose nature of the site.

Salt played a crucial role in ancient societies, serving both dietary and industrial purposes. Despite its importance, direct quantification of salt demand remains challenging due to limited archaeological evidence and the complexity of variables involved in salt production. This study proposes an indirect approach to estimating salt consumption through a reconstructive model of agropastoral landscape exploitation. By assessing the maximum number of people and animals requiring salt, along with the production of food items such as bread, cheese, and preserved meat, this model allows for a broad estimation of salt needs in each settlement. By reconstructing the territorial system’s agricultural and pastoral economy, this research estimates salt consumption and explores its implications for settlement sustainability. The case study of the Iron Age site of ‘Piscina Torta’ (Rome, Italy)—a production site—is used to test this methodology. The study further assesses the necessary volume of seawater to meet the estimated demand. While the results are estimates, they provide a valuable reference framework for understanding salt consumption trends in early state development. Ultimately, this research highlights the significance of salt as a strategic resource, contributing to broader discussions on ancient economic systems and resource management.

The Messinian salinity crisis (MSC) was a short period of isolation of the Mediterranean Sea that caused the precipitation of a million cubic kilometers of salt. The puzzling sedimentary record that formed after this deposition yields conflicting values of the extent of desiccation. Estimations range from a full exposure of most of the Mediterranean seafloor based on shallow fossil fauna found in the abyss to a nearly full Mediterranean scenario as suggested by similar, fresher-water deposits ubiquitous along the coastline: the so-called Lago-Mare formation. Using a landscape evolution model of the drawdown stage constrained with paleoclimate and sediment budgets, we show that the propagation of an erosional wave into the surrounding continents added a gradual sea level rise superimposed on the climatic oscillations of the Mediterranean. This retrogressive river incision along the spillways of the Paratethys and the Pannonian basins also explains the Mediterranean transition to fresher-water conditions during the last stage of the MSC.

The Messinian salinity crisis and its precursor events have been the greatest environmental perturbation of the Mediterranean Sea to date, offering an opportunity to study the response of marine ecosystems to extreme hydrological change and a large-scale biological invasion. The restriction of the marine connection between the Mediterranean and the Atlantic Ocean resulted in stratification of the water column and high-amplitude variations in seawater temperature and salinity already from the early Messinian. Here, we present a unified and revised marine fossil record of the Mediterranean (https://doi.org/10.5281/zenodo.13358435, Agiadi et al., 2024) that covers the Tortonian stage, the pre-evaporitic Messinian stage, and the Zanclean stage and encompasses 23 032 occurrences of calcareous nannoplankton, dinoflagellates, foraminifera, corals, ostracods, bryozoans, echinoids, mollusks, fishes, and marine mammals. This record adheres to the FAIR principles, is updated in terms of taxonomy, and follows the currently accepted stratigraphic framework. Based on this record, knowledge gaps are identified, which are due to spatiotemporal inconsistencies in sampling effort and the distribution of sedimentary facies, as well as the inherent differences in the preservation potential between the groups. Additionally, sampling bias in old records may have distorted the record in favor of larger, more impressive taxa within groups. This record is now ready to be used to answer both geological and biological questions about the Mediterranean Sea and beyond and is amendable when new fossil data are brought to light.

Understanding deep-time marine biodiversity change under the combined effects of climate and connectivity changes is fundamental for predicting the impacts of modern climate change in semi-enclosed seas. We quantify the Late Miocene–Early Pliocene [11.63 to 3.6 million years (Ma)] taxonomic diversity of the Mediterranean Sea for calcareous nannoplankton, dinocysts, foraminifera, ostracods, corals, molluscs, bryozoans, echinoids, fishes, and marine mammals. During this time, marine biota was affected by global climate cooling and the restriction of the Mediterranean’s connection to the Atlantic Ocean that peaked with the Messinian salinity crisis. Although the net change in species richness from the Tortonian to the Zanclean varies by group, species turnover is greater than 30% in all cases, reflecting a high degree of reorganization of the marine ecosystem after the crisis. The results show a clear perturbation already in the pre-evaporitic Messinian (7.25 to 5.97 Ma), with patterns differing among groups and subbasins.

Massive salt accumulations, or salt giants, have formed in highly restricted marine basins throughout geological history, but their impact on biodiversity has been only patchily studied. The salt giant in the Mediterranean Sea formed as a result of the restriction of its gateway to the Atlantic during the Messinian Salinity Crisis (MSC) 5.97 to 5.33 million years ago. Here, we quantify the biodiversity changes associated with the MSC based on a compilation of the Mediterranean fossil record. We conclude that 86 endemic species of the 2006 pre-MSC marine species survived the crisis, and that the present eastward-decreasing richness gradient in the Mediterranean was established after the MSC.