Rate of diffuse carbon dioxide Earth degassing estimated from carbon balance of regional aquifers : The case of central Apennine, Italy

摘要: Central Italy is characterized by an anomalous flux of deeply derived CO2. In the western Tyrrhenian sector central Italy, CO2 degassing occurs mainly from focused emissions (vents and strong diffuse degassing) thermal springs, whereas in eastern Apennine area, deep dissolved “cold” groundwaters regional aquifers hosted Mesozoic carbonate-evaporite formations. Influx into 12 carbonate (12,500 km2) computed through a carbon mass balance that couples aquifer geochemistry with isotopic hydrogeological data. Mass calculations estimate 6.5×1010 mol yr−1 inorganic are studied aquifers. Approximately 23% this amount derives biological sources active during infiltration recharge waters, 36% comes dissolution, while 41% representative common signature (δ13C ≅ −3‰). The calculated influx rate ranges 105 to 107 km−2, increasing regionally east west study area.