FRACTAL PROPERTIES OF MULTI-ORDER FOLDING AS A TOOL FOR EXPLORATION OF LOW-GRADE BANDED IRON ORES IN THE KRIVOY ROG BASIN (UKRAINE)

Abstract

The low-grade Palaeoproterozoic stratabound banded iron ores of the Krivoy Rog basin (Ukraine) underwent strong tectonometamorphic deformation into superimposed folds of several orders, with amplitudes from centimetres to hundreds of metres. The across-strike sections of bed surfaces defining the low-grade ore bodies resemble self-similar fractal curves; hence, a fractal geometrical model was developed in order to quantify the complexity and sinuosity of bed contours. Two different methods of measurement (polygonal approximation and two-dimensional grid cell counting) were used for 5–8 different scales. Factual similarity dimension D and other model parameters have been estimated by means of linear regression and compared for both measurement methods. From the fractal model a sinuosity coefficient of contours of the folded bed surfaces K s and a coefficient of degree of exploration of iron ore bodies K e were constructed. It is pointed out that parameters of the model can be used for determination of the optimal exploration length scales.