Caratterizzazione a Fini Archeometrici del Travertino di una Cava Antica nel Settore Estrattivo di Cisterna di Latina (Lazio, Italia)

The aim of this archaeometric work was to study the extensive travertine outcrop near Cisterna di Latina (Latium, Italy), exploited as far back as Imperial Roman times, when the area was marshy and malarial. The site is located below the Monti Lepini, between the Latium volcanic nappe and the flat Pontine plain. The deposit lies under the Alban “Pozzolane Superiori”, which contains a calcareous layer called “Travertino Inferiore” with rare continental molluscs at the base. The outcropping travertine, to which the quarry studied here belongs (S. Biagio), is always of “sottostante” (underlying) type, which is the basal part of the “Travertino Superiore” and is the result of the action of the upper phreatic aquifer accumulating in the valley depression of Paleoteppia and Campomaggiore, currently buried. This study presents all the parameters (minero-petrographical, chemical, geochemical) necessary for comparisons with the travertine used in many artistic and historical works of art and decoration, with the aim of identifying its provenance. Macro- and microscopic observations of samples emphasize sedimentary structures (spathic and micritic laminae of various thicknesses), fossils (ostracods), mineralogical composition, and bacterial inclusions in minerals, in order to establish a lithofacies typical of a river-lake depositional environment. The mineralogical composition shows the presence of calcite and lacking of dolomite, also when compared with the action of diagenetic processes. The chemical elements found, mainly Ca, Sr and Mg, and their mineral ratios yielded the mineralogical identity of travertine and defined the composition of the water from which they came or the rate of diagenetic processes. The isotopic compositions of δ18O and δ13C revealed ranges of values typically belonging to meteoric and magmatic CO2, and were comparable, in our case, with the action of vadose water passing through the volcanic and karstic complexes in the same deposit. Oxygen isotope values also identified the temperature of the water at the moment of deposition, which was close to environmental temperature, as shown by the low dispersion values.