Open AccessRate of diffuse carbon dioxide Earth degassing estimated from carbon balance of regional aquifers: The case of central Apennine, Italy
Author(s) -
Chiodini G.,
Frondini F.,
Cardellini C.,
Parello F.,
Peruzzi L.
Publication year - 2000
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/1999jb900355
Subject(s) - aquifer , geology , carbonate , evaporite , groundwater recharge , carbon dioxide , geochemistry , isotopes of carbon , dissolved organic carbon , carbonate minerals , hydrogeology , groundwater , isotopic signature , total organic carbon , stable isotope ratio , sedimentary rock , calcite , environmental chemistry , chemistry , oceanography , geotechnical engineering , organic chemistry , physics , quantum mechanics
Central Italy is characterized by an anomalous flux of deeply derived CO 2 . In the western Tyrrhenian sector of central Italy, CO 2 degassing occurs mainly from focused emissions (vents and strong diffuse degassing) and thermal springs, whereas in the eastern Apennine area, deep CO 2 is dissolved in “cold” groundwaters of regional aquifers hosted by Mesozoic carbonate‐evaporite formations. Influx of deep CO 2 into 12 carbonate aquifers (12,500 km 2 ) of the central Apennine is computed through a carbon mass balance that couples aquifer geochemistry with isotopic and hydrogeological data. Mass balance calculations estimate that 6.5×10 10 mol yr −1 of inorganic carbon are dissolved in the studied aquifers. Approximately 23% of this amount derives from biological sources active during the infiltration of the recharge waters, 36% comes from carbonate dissolution, while 41% is representative of deep carbon sources characterized by a common isotopic signature (δ 13 C ≅ −3‰). The calculated deep CO 2 influx rate ranges from 10 5 to 10 7 mol yr −1 km −2 , increasing regionally from east to west in the study area.