Linking mineralogical, geochemical, and textural controls to petrophysical signatures in the Kiruna Mining District, Sweden

Abstract

Discoveries of deposits at shallow depths are becoming scarce, leading exploration efforts to increasingly focus on deeper targets. Traditional exploration techniques for subsurface mapping are often ineffective in terrains obscured by vegetation and glacial sediments, prompting the development of new methods, particularly those centered on geophysics. While geophysical surveys can be valuable for peering beneath the surface cover, reducing initial exploration costs, they are often insufficient to resolve the three-dimensional architecture in structurally complex settings. Integrating geological and geophysical studies ensures that geological characteristics of rock units and structural frameworks are considered, leading to geologically validated results. Merging geological and geophysical models demands a strong understanding of how physical properties are distributed and influenced by geological factors. Our study aims to enhance the understanding of geological factors controlling petrophysical properties in the Kiruna Mining District (Sweden). We conducted an integrated analysis of geochemistry, mineralogy, texture, and petrophysical properties from 35 outcrop locations, including 105 density, magnetic susceptibility, and P-wave velocity measurements from the Kiruna area. The results reveal not only distinct contrasts between lithological units but also significant intraformational variability driven by alteration and fabric, which can obscure lithological boundaries in geophysical surveys. Structural processes such as crustal shortening and basin inversion were found to impose a strong control on the petrophysical properties, contributing to complex and diagnostic signatures. The geological-petrophysical framework presented in this study serves as a foundation for integrated studies in northern Sweden, enabling geophysical methods to serve as a tool for understanding mineral system components and test conceptual models.