Rapid technological advancements and growing environmental consciousness created a shifting dynamic of metal demand within the context of contemporary global challenges. The metals play a pivotal role in this transformation and remarkable surge in demand is expected. Mining districts such as the Kiruna area in northern Sweden, provide access to raw materials, assuring supply chain security, sustainability, and an environmentally friendly future. The district is part of the northern Norrbotten ore province, Sweden and is known for hosting the Kiruna-type iron oxide-apatite (IOA) deposits with associated magnetite-hematite-REE ores such as the Per Geijer deposits, and a range of other deposits, including the Viscaria Cu-(Fe-Zn), Pahtohavare Cu-Au and the Rakkurijärvi iron oxide-copper-gold (IOCG) deposits. 

As the discoveries of significant near-surface deposits are declining, mining companies face a pivotal choice between pursuing resource extraction from lower-grade reserves or to focus on deeper exploration targets. The geological understanding of the subsurface decreases with increasing depth, and the reliance on geophysical techniques becomes more important in reducing the search space. Using geophysics to locate and understand elements of a mineral system requires a good understanding of the physical and chemical properties of the rocks that can be translated into geological implications. Mineral system knowledge and geological concepts can be translated into geological models that can be further used in geophysical inversions with the aim of improving targeting by iterative modeling. A geophysical inversion is in fact a realization of a physical property model, therefore the value added by the geophysical model is dependent of how well the relationship between the geology and its petrophysical signature is understood. The petrophysical characterization of geological environments offers the possibility to improve the understanding of geophysical responses, serving as a link in iterative geological-geophysical modeling. 

The approach presented in the current study includes the building of three-dimensional lithological and structural framework models, and investigating the petrophysical footprint in connection with lithology, alteration, and rock fabric from the Kiruna mining district. Geological modeling and petrophysical characterization are important components within the comprehensive mineral system modeling framework and enhance geophysical investigations aimed at detecting and assessing iron oxide mineral systems. A rule-based hybrid implicit-explicit geological modeling technique proved to be useful in the integration of surface and subsurface data of the Kiruna mining district, and a structural framework and geological model was produced that provides insights into the relationship between lithological units and structures. Drill core observations indicate a competency contrast between lithological units confirming previous surface-based observations. Deposit scale structural analysis in connection with the geological models indicated the proximity of NW-SE to SW-NE trending brittle conjugate fault networks with iron-oxide apatite ore lenses, revealing juxtaposition of individual ore lenses. Complementing structural analysis and geological modeling, petrophysical characterization in connection with lithogeochemical, mineralogical, and textural investigations revealed that density and p-wave seismic velocity can be used as a general lithological indicator, while magnetic susceptibility is influenced by secondary processes. Heterogeneous strain accommodation by lithological units indicates a strong influence on density, seismic properties, and the ferromagnetic properties of the samples. Metasomatic processes alter the intrinsic properties of the samples by increasing or decreasing the physical properties of the rocks from the Kiruna area, by controlling the feldspar, mica, magnetite, and ferromagnesian mineral content. Nevertheless, an extensive sample population must be investigated to understand the large-scale effects. The present work serves as a foundation for quantitatively integrated exploration models that use geological models and petrophysical characterization as calibration tools to model mineral systems. 

The subsurface has long supplied raw materials, yet with most giant surface-exposed deposits already discovered, exploration increasingly focuses on deeply buried mineral systems in frontier terrains. Collaborations across and beyond traditional geoscience disciplines are becoming increasingly important as deeper discoveries require multidisciplinary and integrated exploration tools. These multidisciplinary exploration tools aim to integrate the mineral system paradigm with existing geological and geophysical models and interrogate and characterize the spatial and temporal relationships of its components. This doctoral thesis employs geological modeling and integration with existing geophysical models within a multiscale framework to investigate the expression of the iron oxide-apatite mineral system in northern Norrbotten (Sweden). The region is regarded as a major metallogenic province hosting more than 40 iron oxide-apatite (IOA) deposits, including the giant Kiirunavaara deposit. More than a century of mining, exploration, and geological surveying in the area has led to an outstanding repository of geoscientific data, encompassing geological mapping, large drill core archives, and high resolution geophysical dataset, providing a solid foundation for integrated, multiscale modeling of the mineral system. At the deposit scale within the Kiruna mining district, integration of surface and drill-core structural measurements with geotechnical, structural, and lithological logging results in models that highlight how the interplay between ore-parallel and orthogonal structures controls mineralization. Low rock quality designation (RQD) values and coreorientation data systematically indicate weak rock mass at ore contacts, whereas orthogonal conjugate faults accommodated heterogeneous strain across adjacent blocks. Within the district, petrophysical measurements of major stratigraphic units establish diagnostic contrasts but also reveal pronounced intraformational variability controlled by alteration intensity and fabric development. Although stratigraphic formations can be discriminated geophysically, this heterogeneity complicates direct local-scale interpretations. The dataset provides a calibrated petrophysical reference, linking field-based geological observations and measurements with ground and airborne geophysical surveys. At the province scale, an integrated 3D model synthesizing deposit- and district-scale geological models with province- wide lithological and structural models and inversions of magnetic and gravity surveys constrain the crustal architecture of the northern Norrbotten ore province (NNOP; here defined as the area between Gällivare and Kiruna). Mafic-ultramafic intrusions occur as dense, magnetically heterogeneous domains systematically proximal to vertically extensive conductors imaged by magnetotellurics (MT), interpreted as the upper-crustal expression of transcrustal magmatic-hydrothermal conduits. IOA deposits are typically situated along second-order oblique structures that intersect or splay from major shear zones at the margin of dense and magnetic bodies, rather than within the firstorder shear zones themselves or directly coincident with MT conductors. Across deposits and prospects, diagnostic total magnetic intensity (TMI) responses, characterized by steep gradients with localized highs flanked by negative lobes constitute repeatable proximal indicators of IOA mineralization. The magmatic character of the intrusions is further constrained by petrography, whole-rock geochemistry, petrophysical characterization, and SIMS U-Pb zircon and titanite geochronology of mafic to intermediate intrusions. Two intrusive groups are distinguished, a cumulate set marked by olivine-pyroxene-plagioclase-rich assemblages, positive Eu/Eu*, elevated Sr/Yb, high density (>3.0 g/cm3) and variable magnetic susceptibilities, and another melt-proxy set of non-cumulates further subdivided into calc-alkaline and tholeiitic lineages with lower densities (2.84-3.00 g/cm3) and more uniform susceptibilities. Cumulate intrusions coincide with MT conductors, gravity highs, and concentric magnetic anomalies, supporting their interpretation as upper-crustal expressions of a deeper magmatic feeder zone. Their association with IOA deposits and complementary geochemical signatures indicates that early Svecokarelian intrusions supplied heat and likely magmatic input to the mineral system. Zircon U-Pb data place both cumulate and non-cumulate intrusions within the early Svecokarelian magmatic pulse, while titanite U-Pb results record both near-magmatic crystallization and later tectonothermal resetting events. At multiple scales, the analyses converge to show that IOA mineral systems in northern Norrbotten emerged from a dynamic interplay of magmatism, structural, and subsequent tectonothermal processes, recorded from deposit scale to province-wide crustal architecture. Embedding field-based geological observations and supporting analysis, mineral system concepts, and geophysical inversion results into integrated multiscale modeling, this thesis establishes a systematic link across scales and a coherent basis for interrogating the spatial and temporal organization of mineral system components. While the approach inevitably simplifies the complexity of a long-lived Paleoproterozoic terrain, it underscores the value of integrated geological modeling in reconciling diverse datasets into consistent frameworks. In doing so, the study refines current interpretations of IOA mineralization in northern Norrbotten and contributes to a more rigorous geological understanding of this major metallogenic province.