Radiological characterization of granitoid outcrops and dimension stones of the Variscan Corsica-Sardinia Batholith

This study focuses on the radiological characterization
of granitoid outcrops and dimension stones using
in situ gamma-ray spectrometry. Extensive measurements
were performed on 210 granitoid outcrops of the Corsica-
Sardinia Batholith. The large statistical sample allowed us
to improve the analysis by considering a log-normal distribution
of radioelements and propagating the uncertainties
using Monte Carlo method. The activity concentrations
of 40K, 226Ra (238U) and 232Th in C-SB area were
1,177-304
?408, 60-23
?36 and 69-25
?38 Bq/kg (at 1r uncertainty). The
median abundance of K, U and Th on the Variscan C-SB
was higher than the average values of the upper continental
crust and was comparable with Variscan belt. This
corresponds to an outdoor absorbed dose rate of
124-26
?33 nGy/h at 1r uncertainty which is 3r higher than the
population-weighted average absorbed dose rate (60 nGy/
h). Seven commercial granites (Rosa Beta, Ghiandone,
Giallo San Giacomo, Rosa Cinzia, Grigio Malaga, Bianco
Sardo and Grigio Perla) were investigated to characterize
their radiological hazard through 147 measurements taken
in 73 extractive quarries. All of the commercial granites
were categorized as A2 material based on their activity
concentration indices, excluding (at the 3r level) any
restriction on their utilization as superficial materials. Rosa
Beta, Grigio Malaga, Grigio Perla and Bianco Sardo can
also be used as bulk materials as they can be included in
the A1 category. In the case of Ghiandone, Giallo San
Giacomo and Rosa Cinzia, we are confident of an A1
classification only at the 1r level.