Table 4 Parameters of bulk-rock chemistry interpolation by ordinary kriging of the Kovdor phoscorite-carbonatite complex.

From: Approach of automatic 3D geological mapping: the case of the Kovdor phoscorite-carbonatite complex, NW Russia

Component Distribution of raw data Additive constant for lognormal transformation* Nugget-effect Range, m Sill Semivariogram type
Femagnetic Normal No transformation 6.9 131 91.1 Spherical
SiO2 Lognormal 0 0 150 0.436 Spherical
P2O5 Normal No transformation 0 111 10.55 Exponential
CO2 Lognormal 0 0.079 139 0.515 Spherical
  1. *In case of lognormal distribution of raw data, i.e. SiO2 and CO2.