## 3 Results and Discussion
### Results of the Measurements of Radon Radiation and Gas Permeability  
The radon radiation in the soil air in the area of the Chidvinskaya pipe varies in the range from 123 to 4650 Bq\(\cdot\)m\({}^{-3}\), with an average value of 1010 Bq\(\cdot\)m\({}^{-3}\). The spatial distribution of radon over the pipe area is uneven. The highest values of radon radiation, exceeding 1600 Bq\(\cdot\)m\({}^{-3}\), are observed at the border of the pipe with the host sediments. The western, eastern, and northern borders are characterised by increased radon radiation (Figure 2). This may be due to the fact that, at the contacts of the Chidvinskaya pipe with the host Ediacaran rocks, fractured fault zones with increased gas permeability are developed, leading to the formation of the observed positive anomalous radon radiation in the soil air. The general orientation of the Ediacaran sedimentary rocks is near-horizontal; however, on the border of the kimberlite pipe and host rocks, there are local tectonic elements, namely, zones of mylonites, steep cracks, and low-amplitude thrusts. Fracturing is associated with the diatreme formation process, which influenced the tectonic structure of the adjacent sediments. As a result of this disturbance, a system of radial and concentric fracture zones was formed, with crushing and weak vertical movement of blocks of the country rocks. This affected the radiation parameters of the host rock, including the formation of radon and its vertical migration to the surface. The study of the deep structure of the Chidvinskaya pipe using microseismic measurements confirmed the presence of fault zones and fractures at the contact of the pipe with the host Ediacaran sedimentary rocks, which were distinguished in the microseismic field studies by reduced velocities [49]. The southern border of the pipe has no radon anomalies. This is due to the large thickness of the overlying sediments in this part of the pipe. Above the pipe, the variations in radon activity are insignificant and do not exceed 1200 Bq\(\cdot\)m\({}^{-3}\). The gas permeability of rocks in the area of the Chidvinskaya pipe vary from 0.1 \(\times\) 10\({}^{-13}\) to 110 \(\times\) 10\({}^{-13}\) m\({}^{2}\), with an average value of 6.2 \(\times\) 10\({}^{-13}\) m\({}^{2}\). A comparison of the distribution of radon radiation with the distribution of the gas permeability parameter showed that areas with increased values of radon radiation and gas permeability coincided partially (Figure 2). However, areas with the highest radon radiation do not reflect the distribution field of the gas permeability parameter. This is likely due to the fact that an increase in the thickness and composition of the overlying sediments can reduce the permeability of soils and does not allow the gas permeability parameter for a pipe using the RADON-JOK system to be determined reliably.  
The results of the correlation analysis show no relationship between radon radiation and permeability (Figure 3). The correlation coefficient is 0.024 and the regression coefficient is 0.0006. If abnormally high values of permeability (over \(10^{-12}\) m\({}^{2}\)) are excluded, a weak relationship between these parameters is observed, with a correlation coefficient of 0.41 and a regression coefficient of 0.17 (Figure 4). These results show the need to consider multiple environmental factors (moisture and temperature, density and porosity along the soil profile, atmospheric parameters in the case of a non-stationary observation mode) in statistical analyses and the search for more complex relationships between these. The RADON-JOK system revealed the possibility of its application in assessing the radon potential in general for the territory of the kimberlite pipe, but only as an additional method and only in the case of a low thickness of the overlying Quaternary layer.