A 22 m sediment core was collected from the unsaturated zone (USZ) in the dunes south of Ashdod, Israel, in a low rainfall year, following an even lower-rainfall year. The mineralogy of was quartz with some clay and carbonate. The local climate is semi-arid. The roots of the sparse vegetation can reach ~8 m. The porosity was ~40–55%. The DIC ranged from 2 to 13 mmole C/L. Large variability is noted in the soil moisture, with a maximum at the high clay region at ~8 m. Oxygen isotopes enter the USZ with rain falling on the surface. There is 18O enrichment in the top of the section due to evaporation during the summer. Below this depth δ18O values of ~ –5‰ prevail as in the local aquifer. CO2 and the carbon isotopes enter the USZ laterally by exhalation from roots. The δ13C varies from –5‰ to –23‰, representing stages in carbon isotopic fractionation: CO2gas becomes dissolved CO2aqueous which then forms carbonic acid and HCO3– . The high δ13C, Δ14C, and DIC are found at the 8 m depth. These values along with high humidity are replicated at ~22m depth. They most probably represent recharge water from the previous rainy season at 8 m depth subsequently pushed down 12.8±0.8 m during the last winter.

Secondary carbonate deposits (similar to speleothems) in urban undergrounds, have been recently highlighted as powerful archives for reconstruction of the historical anthropogenic imprint on the environment. The precise chronology of these secondary carbonate deposits is a key issue for the accurate time reconstruction of environmental conditions. We present three 14C data sets for urban speleothem-like deposits that developed in contrasted man made environments. The first one was sampled in an underground technical gallery of the Palace of Versailles (France), and the other two in a manhole (Saint-Martin spring) of a historical underground aqueduct in Paris (France). The comparison of these records with the bomb peak and relative chronology (laminae counting) allowed us to identify: i) fast carbon transfer from the atmosphere to the urban underground; ii) a high proportion of dead carbon and a high damping effect in relation to possible old carbon stored within urban soils and/or the influence of local fossil carbon burning. This study also shows that the lamination of these deposits is bi-annual in these highly urbanized sites.