Gold mineralization and deep prospecting methods

Gold, a strategic and critical mineral resource, poses substantial challenges in deep exploration. This study systematically reviews and analyzes the geochemical behavior of gold mineralization, the mechanisms of gold mineralization, and the technical systems for deep exploration. Gold concentrations in crust-mantle layers remain at low levels (10-9). Through diverse fluid mineralization processes, gold achieves enrichment over a thousand-fold to form industrial-scale ore bodies. The geological characteristics, genetic models, and spatiotemporal distribution of various mineralization types-including orogenic, Jiaodong-type, porphyry-skarn, epithermal, intrusion-related gold deposits (IRGD), Carlin-type, iron oxide copper-gold (IOCG), and volcanogenic massive sulfide (VMS) deposits-indicate extensive gold mineralization processes involving the transportation and enrichment of gold by mantle-derived fluids, magmatic hydrothermal fluids, meteoric water, and other media. A tectono-dynamic model for gold mineralization is established to show diverse deposits demonstrate genetic relationships with convergent plate margin dynamics, implying their temporal distribution has correlation with supercontinent cycles. Gold mineralization in China occurs primarily in four tectonic settings: accretionary orogenesis, cratonic destruction, continental collision, and intracontinental reactivation. Research on orogenic gold deposits has advanced beyond traditional models emphasizing purely crustal metamorphic fluids in compressional settings. Current understanding recognizes that these deposits frequently form in transextensional tectonic regimes with significant contributions from mantle-derived fluids. Gold-rich porphyry deposit is considered to be formed in the middle crust thickness. Ore-forming fluid release has evolved from a model of shallow, near-ore magma exsolution to one involving exsolution from deeper magma chambers. Concurrently, the conceptual framework for magmatic evolution has shifted from the traditional "magma chamber" paradigm toward the modern "crystal mush" model. Mineralization exhibits hierarchical structural control spanning lithospheric-scale deep faults and mantle upwelling zones down to ore-field-scale features such as fault bends, fold hinges, and intrusive contacts. These multi-scale structures collectively provide essential conduits and depositional sites for fluid focusing and gold precipitation. Based on the analysis of the mineralization system, the exploration of magma and hydrothermal channels at different scales and depths, as well as the occurrence space of ore bodies, through multi-scale and multi-depth geophysical methods is a crucial approach in gold exploration. Geophysical methods, including magnetotellurics and dense nodal array, delineate deep geological structures, while wide-field electromagnetic method, spectral induced polarization, and surface-borehole transient electromagnetic method identify ore-related anomalies. Deep-penetrating geochemistry (nanoparticle tracing) is employed to detect the vertical migration patterns of elements within concealed ore bodies. Mineral spectroscopy incorporating short-wave and thermal infrared analysis enables precise targeting of hydrothermal centers and mineralized zones. Designing tailored exploration methods based on the metallogenic factors of different gold deposits, and utilize three-dimensional modeling and artificial intelligence further support multi-source data integration and intelligent prospect analysis. The establishment of genetic models, the combination of diverse prospecting techniques, and a tripartite "knowledge-data-simulation" driven prediction approach represents a critical direction for future exploration of concealed gold deposits.