Search Results (2)

This study is addressed at the cultural heritage of the UNESCO historical centre of Urbino (Italy) through the focus on a very peculiar building and ornamental carbonate porous (spongy) stone also found in the opus quadratum Roman dry walls. For these rocks, the mathematician and historian Bernardino Baldi (16th century AD) and the mineralogist Francesco Rodolico (middle of the 20th century AD) introduced, respectively, the popular terms of Tufo spugnoso or Pietra Spugna. Physical observations and stable isotope data (δ¹³C and δ¹⁸O) of these rocks allowed, for the first time, their classification as calcareous tufas, thus contributing to the valorization of the stone heritage of the city. This carbonate lithotype was formed by the chemical precipitation of CaCO₃, driven by the CO₂ degassing of supersaturated calcium-bicarbonate-rich waters, coupled with the passive encrustations of organic material in continental environments. Radiocarbon analyses dated these stones mostly between 9100 and 4700 yr. BP when a maximum growth of these carbonate continental deposits occurred in Mediterranean regions and northern Europe, i.e., during the Holocene Atlantic climatic optimum. Work is still in progress on a perched springline of calcareous tufas found along the Metauro Valley (a few km from Urbino), being good candidates for provenance, at least for those blocks exploited by the Romans and successively reused in the architectural framework of Urbino. Full article

In this work we assessed the shallow geothermal heat-exchange potential of a fluvial plain of the Central Apennines, the lower Metauro Valley, where about 90,000 people live. Publicly available geognostic drilling data from the Italian Seismic Microzonation studies have been exploited together with hydrogeological and thermophysical properties of the main geological formations of the area. These data have been averaged over the firsts 100 m of subsoil to define the thermal conductivity, the specific heat extraction rates of the ground and to establish the geothermal potential of the area (expressed in MWh y⁻¹). The investigation revealed that the heat-exchange potential is mainly controlled by the bedrock lithotypes and the saturated conditions of the sedimentary infill. A general increase in thermal conductivity, specific heat extraction and geothermal potential have been mapped moving from the coast, where higher sedimentary infill thicknesses have been found, towards the inland where the carbonate bedrock approaches the surface. The geothermal potential of the investigated lower Metauro Valley is mostly between ~9.0 and ~10 MWh y⁻¹ and the average depth to be drilled to supply a standard domestic power demand of 4.0 kW is ~96 m (ranging from 82 to 125 m all over the valley). This investigation emphasizes that the Seismic Microzonation studies represent a huge database to be exploited for the best assessment of the shallow geothermal potential throughout the Italian regions, which can be addressed by the implementation of heating and cooling through vertical closed-loop borehole heat exchanger systems coupled with geothermal heat pumps. Full article