Spatio-Temporal Data Mining of Craton Edge-Related Mineralisation: Unveiling the Dynamics of Sediment-Hosted and IOCG Deposits

Most sediment-hosted mineral deposits occur in marine sedimentary rocks along intracratonic or epicratonic rift basins at the edges of the thick continental lithosphere. Craton thickness, typically 150–200 km, was analysed using the Full-Waveform Seismic Tomography (REVEAL model) to extract horizontal shear wave velocity (Vsh), vertical shear wave velocity (Vsv), and isotropic P-wave velocity (Vp). Principal component analysis and k-means clustering revealed that Vsh effectively defines craton boundaries and similarly thick lithospheric features, aligning well with mineral deposits. IOCG and sediment-hosted deposits are found within ~125 km of these boundaries (based on total metal content) and ~100 km (based on ore tonnage). These deposits form along internal and external craton boundaries, separating Archean nuclei from Proterozoic terranes and along Phanerozoic orogens and accreted passive margins. Thermal and lithospheric models were used to differentiate cratons from other thick lithospheric features, isolating ~85% of all deposits related to the edge of cratons. Additionally, we found that more than ~85% of craton edge deposits are formed within 90 km of craton boundaries. A consistent gradient of increasing metal content with proximity to craton boundaries underscores the significance of these craton boundaries. In fact, more than 85% of known target craton edge deposits are concentrated within just 16% of continental areas, significantly enhancing exploration efficiency and resource discovery by reducing exploration areas.

Building on this foundation, we conducted a temporal analysis to explore why some craton boundaries are fertile while others are not, aiming to reduce exploration areas more. By analysing over 20 kinematic features using the latest reconstruction model spanning 1,800 Ma for craton deposits and uniformly generated random points within 180 km of craton boundaries, we reconstructed craton boundaries, deposits, and random points to identify key patterns. Lower craton velocities (<5 cm/year) emerged as a critical factor in mineralisation compared to random points, which can reach velocities up to 20 cm/year. This is likely driven by prolonged hydrothermal fluid circulation, enhanced fluid-rock interactions, sustained structural pathways, and extended thermal anomalies that support mineralisation. Similarly, lower Convergence rates (<4 cm/year) were associated with deposits, in contrast to random points with velocities up to 30 cm/year. The interplay between slower rifting and Convergence rates reflects the interconnected dynamics of tectonic and mantle processes, where reduced rifting rates weaken ridge push and slab pull forces, slowing subduction. In turn, slower subduction impacts mantle convection and lithospheric recycling, further reducing rifting rates in a complex feedback system. Additionally, we found that most deposits cluster within 400–1,800 km of subduction trenches at the time of formation, indicating a spatial relationship between tectonic activity and deposit formation. Deposits also tend to cluster around specific subduction lengths (~2,500 km and ~5,000 km), suggesting these tectonic settings provide more favourable conditions for mineralisation in contrast to the broader distribution of random points.