Fractal dimension and its translation into a model of gold spatial proxy

Abstract

Unraveling the spatial distribution of mineral deposits is an essential part of exploration and important for developing a better understanding of ore-forming processes. In this study, gold assay results (in g/t) of twelve boreholes completed from Mysore Block and eleven boreholes completed from Nabhapur North Block, Central Lode System, Gadag Gold Field (GGF), India, were analyzed using fractal analysis. Both the fractal correlation integral and rescaled range analysis were used to measure the fractal dimension from the gold-concentration values. The fractal dimension values obtained from the fractal correlation integral were used to better constrain the possible auriferous fluid-flow pathways, whilst results obtained from the rescaled range analysis were used to describe the behavior of auriferous veins across the boreholes. The fractal dimension values were found to vary from 0.014 to 3.0, with the higher values taken to indicate the presence of well-developed interconnected fault-fracture networks representing steep permeable fluid-flow pathways. The lower fractal dimension values were taken to indicate unfavorable fluid-flow pathways. In other words, higher-grade gold ores were deposited along the structures represented by steep fractal gradients. Hurst exponent (H) values obtained from the rescaled range analysis were found to vary from 0.50 to 0.96, satisfying the condition 0.5 < H < 1. In summation, the mineralized veins displaying fractal behavior are persistent across the boreholes from both the Mysore and Nabhapur gold deposits, which suggests these deposits are targets for gold exploration.