The manuscript delivers a predictive, integrated model for fractures in truly deep/ultra-deep tight sandstones combining cores, thin sections, acoustic-emission tests, and well logs, linking micro- to reservoir-scale fracture evidence. It quantifies sedimentary controls, brindging rock mechanics, structural geology and stratigraphy/sedimentology. It also delivers clear rules and implementation, ensuring transferability, which is rather important for such a rare case study.

The presented seismic exploration experiment exhibits the potential of using a low-cost survey design for 3-D imaging of the subsurface. In this case study, a deep layered intrusion and its feeder system are investigated. The new insights into the tectonic evolution and mineralization potential of the studied region in Finland evidences a complex, layered system rather than a simple magma channel. Furthermore, a major fault is identified that may influence how the development of mineral deposits in the area are interpreted. In summary, this work offers new tools and insights for exploring valuable underground resources in hard rock environments. This is a timely scientific result not only for Europe but has influence on people's sustainable living worldwide.