Botond PAPP^1,*, Alexandru SZAKÁCS², Tamás NÉDA², Nicolae FRUNZETI¹, Kinga SZACSVAI² & Constantin COSMA^1
1Faculty of Environmental Science and Engineering, Babeş-Bolyai University, Fântânele street, no. 30, RO-400294, Cluj-Napoca, Romania, Email: papp.botond@ubbcluj.ro
²Department of Environmental Science, Sapientia University, Deva street, no.19, Cluj-Napoca, Romania

SOIL RADON AND THORON ACTIVITY CONCENTRATIONS AND CO2 FLUX MEASUREMENTS IN THE NEOGENE VOLCANIC REGION OF THE EASTERN CARPATHIANS (ROMANIA)

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Our study is based on soil radon and thoron activity concentration measurements along with CO₂ flux measurements, performed in the area of the mofettes and mineral water springs occurrences in two locations: Bálványos-Bai (Bodoc Mts.) and Sugás-Bai (Baraolt Mts.) of the Eastern Carpathians (Romania). During the fieldwork, the existence of presumed fault systems was examined (which controls the occurrence of the mofettes and water springs), across selected profiles (normal to the assumed fault direction). Soil radon and thoron activity-concentration measurements were performed by the LUK3C radon and thoron detector (with Lucas cells), and the CO₂ flux measurements at soil surface were performed by using a closed chamber technique. Results of radon and thoron concentrations were in the range from several kBq⋅m^-3 to tens of kBq⋅m^-3, having distributions with maximum values for both cases (up to 25 kBq⋅m^-3 for radon and up to 40 kBq⋅m^-3 for thoron). Results of the CO₂ fluxes were in the order of thousands of g⋅m^-2⋅day^-1 in case of Bálványos-Bai (at Turia) and of tens of g⋅m^-2⋅day^-1 in case of Sugás-Bai, having distributions with maximum values up to 9300 g⋅m^-2⋅day^-1 in case of Bálványos-Bai, and up to 20 g⋅m^-2⋅day^-1 in case of Sugás-Bai. The distributions of ²²²Rn, ²²⁰Rn and CO₂ are consistent with the hypothesis that the gas migration occurs along the fault system, and consequently, the maximum values indicate a more precise location and direction of the fault line.