Advances in Mantle–Crust Interactions for Petrogenesis and Ore-Forming Processes: An Introduction

1. Introduction

Accurately identifying the composition of crust–mantle reservoirs and deciphering the processes governing material exchange between them remain fundamental scientific issues in Earth sciences [1,2,3]. Mantle–crust interactions not only control the composition and evolutionary architecture of the modern lithosphere, but also profoundly influence the long-term habitability of Earth. Moreover, they represent a critical driving mechanism for the mobilization, transport, enrichment, and ultimately ore formation of metallic elements [4,5,6,7,8], thereby providing essential resource foundations for human civilization and societal development. Consequently, unraveling the composition, evolutionary history, and interaction mechanisms of crustal and mantle materials is of great significance for advancing petrology, geochemistry, tectonics, and economic geology.

Over the past decades, studies on crust–mantle material composition and exchange processes have evolved from early qualitative interpretations based mainly on petrographic observations toward increasingly quantitative and process-oriented investigations integrating multidisciplinary approaches. Elemental geochemistry, radiogenic isotope systems, and stable isotopes have become powerful tools for tracing the sources, evolution, and metallogenic implications of crust–mantle interactions [9,10,11,12,13,14]. During crust–mantle recycling processes, aqueous fluids and hydrous melts derived from subducting slabs or lower crustal materials can metasomatize mantle sources, whereas the upward transfer of mantle-derived heat and materials promotes continental crustal growth and reworking [15,16,17,18,19]. These complex crust–mantle interaction processes not only govern magma generation and evolution, but are also commonly accompanied by the activation, transport, and enrichment of critical metals, ultimately leading to the formation of diverse mineralization systems.

Despite extensive investigations into crust–mantle magmatism and fluid activity, the specific mechanisms governing crust–mantle material exchange remain incompletely understood. In particular, how crustal and mantle materials are transported, mixed, and recycled under different geodynamic settings, and how these processes further control the formation and enrichment of specific ore deposits, remain subjects of ongoing debate. Furthermore, the effects of mineral fractionation, melt–fluid evolution, and fluid metasomatism occurring during magma ascent and emplacement within the shallow crust remain insufficiently constrained, especially regarding their roles in elemental redistribution and ore-forming processes. Therefore, systematic investigations integrating geochronology, mineralogy, elemental geochemistry, and isotope geochemistry of magmatic rocks and associated ore deposits derived from different crust–mantle reservoirs are essential for deciphering the coupling relationships among crust–mantle composition, material exchange, and metallogenesis.

This Special Issue, entitled “Advances in Mantle–Crust Interactions for Petrogenesis and Ore-Forming Processes”, focuses on key scientific questions related to crust–mantle composition and evolution, magmatism, and ore-forming processes. It aims to bridge current knowledge gaps and improve our understanding of deep Earth processes and their metallogenic consequences. The collected contributions not only highlight recent advances in petrology, geochemistry, and isotopic tracer techniques applied to igneous petrogenesis and crust–mantle interactions, but also provide important geochemical constraints on the sources of ore-forming materials, geodynamic mechanisms, and metal enrichment processes. Collectively, these studies further deepen our understanding of mantle–crust interaction processes and provide new perspectives and theoretical foundations for future investigations into the intrinsic links between deep Earth dynamics and resource-environmental systems.

2. An Overview of Published Articles

The 16 articles included in this collection address the above scientific issues from four major perspectives.

2.1. Petrogenesis of Igneous Rocks and Mantle–Crust Interactions

Prabha-Mohan et al. (Contribution 1) conducted a detailed investigation of oxygen isotope compositions in zircon, monazite, and quartz from the Higher Himalayan Crystallines of the Sikkim Himalayas. Their study identified source characteristics and equilibrium conditions of the melts involved, revealing the presence of multiple melt sources within the High Himalayan Crystalline Sequence. Although zircon and monazite from the same rocks display similar oxygen isotope compositions, the authors proposed that low-elevation fluid activity may have produced lighter oxygen isotope signatures in these minerals, with such fluids probably derived from metasedimentary country rocks.

Zhao et al. (Contribution 2) performed combined radiogenic Sr–Nd–Pb and stable C–O isotope studies on the Huangshuian carbonatites in central China. The results demonstrate that these carbonatites possess C–O isotope compositions comparable to primary igneous carbonatites but exhibit enriched radiogenic Sr–Nd–Pb isotope signatures. Their study suggests that the Huangshuian carbonatites represent late-stage differentiated products of mantle-derived carbonatitic magmas sourced from carbonated lithospheric mantle, with possible contamination by basement rocks.

Geng et al. (Contribution 3) carried out detailed geochronological, elemental, and isotopic investigations on Early Jurassic hornblende gabbros from northeastern China. Their results indicate that these rocks were generated through metasomatism of the mantle wedge by supercritical fluids and originated from a mixed source involving depleted mantle and approximately 10–20% terrigenous sediments. This study highlights the important role of supercritical fluids in modifying the mantle wedge during westward subduction of the Paleo-Pacific Plate.

Jin et al. (Contribution 4) evaluated diorite porphyrites from southern Xintai area in the western Shandong Peninsula, eastern China, using zircon U–Pb–Hf isotopes together with whole-rock elemental and Sr–Nd isotope geochemistry. The studied rocks exhibit pronounced adakitic geochemical affinities. The authors proposed that rollback of the Paleo-Pacific Plate during the Early Cretaceous triggered localized delamination of the lower crust, and that interaction between lower crust-derived melts and enriched lithospheric mantle ultimately generated these diorite porphyries.

Ouyang et al. (Contribution 5) identified two types of Late Permian–Early Triassic basalts from Hainan Island, South China, characterized respectively by calc-alkaline and alkaline affinities. The early-stage basalts were derived from enriched mantle modified by subduction-related fluids, whereas the later-stage basalts originated mainly from depleted mantle and were likely contaminated by crustal materials during ascent. These basaltic suites record a tectonic transition from an island-arc setting to an intracontinental extensional environment, indicating that subduction of the Paleo-Tethyan oceanic slab persisted until at least the Late Permian and may have evolved into intraplate extension during the Middle Triassic.

Sun et al. (Contribution 6) investigated the formation mechanisms of plagioclase–amphibole and amphibole–spinel symplectites in the Bijigou layered intrusion along the northern margin of the Yangtze Block, South China. Their results demonstrate that the symplectites crystallized during the late stages of magmatic evolution, and that different mineral assemblages may preserve orientational inheritance or pseudomorphic features from earlier-formed minerals. This work refines our understanding of mineralogical evolution in layered intrusions.

Wang et al. (Contribution 7) performed geochronological, elemental, and Sr–Nd–Hf isotopic studies on Middle Jurassic to Early Cretaceous granitoids from southeastern China. Their results reveal distinct crustal and mantle source characteristics for different granitoid types. Combined with regional tectonic evolution, the study demonstrates that the region experienced significant tectonic transformation through time, evolving from a compressional regime related to Paleo-Pacific Plate subduction during the Middle Jurassic to lithospheric extension and intensified crust–mantle interaction induced by slab rollback during the Early Cretaceous.

Kiray and Cengiz (Contribution 8) investigated a complex Oligocene–Miocene volcanic assemblage in northwestern Türkiye and demonstrated that these volcanic rocks formed in a tectonic setting related to continental collision. Although the magmas were primarily derived from enriched lithospheric mantle, subsequent mineral fractional crystallization played a critical role in controlling magmatic evolution, while crustal assimilation also modified their geochemical compositions. This study provides an excellent example of crustal modification of mantle-derived magmas during ascent and emplacement.

2.2. Magmatism Related to Ore Formation

Khedr et al. (Contribution 9) conducted detailed mineralogical and geochemical studies on Neoproterozoic metavolcanic rocks and associated jasperoid veins in southern Eastern Desert of Egypt. Their results suggest that the metavolcanic rocks originated from differentiated melts derived from depleted mantle sources that were influenced by slab-derived fluids and/or melts during formation. The jasperoid veins are enriched in Fe oxides and base metals and display trace-element characteristics indicative of fluid-mobile element enrichment, suggesting formation through metasomatism by silica-rich magmatic-hydrothermal fluids.

de Souza et al. (Contribution 10) examined Fe–Ti–V oxide-bearing clinopyroxenites and magnetitites from the Ponte Nova Massif in southeastern Brazil using detailed mineralogical and geochemical approaches. Their results indicate that these rocks formed during different stages of magma chamber evolution and record distinct open-system processes. Deep magma recharge and shallow-level crustal contamination were identified as the principal controls on geochemical variations, whereas later magmatic events superimposed on these magmatic pulses contributed to sulfide formation.

Yang et al. (Contribution 11) carried out detailed geochronological and geochemical studies on granites genetically related to regolith-hosted rare-earth element (REE) deposits in South China. The granites were interpreted to have originated from sediment-derived sources. Their geochemical characteristics resemble those of granitic parent rocks associated with typical regolith-hosted REE deposits in South China, suggesting that the formation of regolith-hosted REE deposits in the Darongshan–Shiwandashan region was primarily controlled by magmatic differentiation, geomorphology, and weathering processes.

Zhong et al. (Contribution 12) investigated syenite porphyries associated with the Beiya porphyry Au-polymetallic deposit in southwestern China through geochronological and geochemical analyses. These rocks exhibit adakitic-like geochemical signatures and were interpreted to have originated from ancient thickened lower crust modified and metasomatized by upwelling mantle-derived materials. Their study highlights the significant metallogenic potential of crust–mantle interactions during magmatism and ore formation.

2.3. Geochemistry of Ore-Forming Minerals

Xu et al. (Contribution 13) conducted high-precision Zn, Pb, and S isotope analyses of ore-forming minerals (sphalerite and robinsonite) from the Sanjiang Metallogenic Belt in southwestern China. Their results indicate that Pb and Zn in the ores were derived from mixed sedimentary and crustal basement sources, whereas sulfur was likely sourced from a deep reservoir. Using a multi-isotope approach, this study provides new insights into the genesis and metallogenic processes of sediment-hosted Pb–Zn deposits in the Sanjiang Metallogenic Belt.

Du et al. (Contribution 14) performed detailed mineralogical, in situ geochemical, and sulfur isotope analyses of pyrite closely associated with Sn-polymetallic mineralization in the Jiepailing deposit, southern Hunan Province, China. Five pyrite types with distinct textures and sulfur isotope compositions were identified. Their results demonstrate that various ore bodies in the deposit were products of Late Cretaceous magmatic-hydrothermal activity and reconstruct the distinct mineralization and alteration processes involved.

2.4. Experimental Petrology and Magmatic Ore-Forming Processes

Borisova (Contribution 15) experimentally simulated the dissolution of pyrrhotite in hydrous rhyolitic melts under sulfate–sulfide transition conditions. The results demonstrate that sulfur can achieve the highest chemical diffusion rates in hybrid melts as S²⁻ or S³⁻ species under these conditions. This process may not only contribute to explosive volcanic eruptions in arc settings, but may also promote enrichment of chalcophile metals such as Au, Cu, and Pt associated with dissolved sulfide components, thereby facilitating ore formation.

Thomas and Rericha (Contribution 16) demonstrated that supercritical fluids or melts may be preserved within crustal rocks as critical high-temperature and high-pressure exotic minerals. In particular, typical fluid inclusions hosted by cassiterite are likely products of supercritical fluids. Their study suggests that mantle-derived supercritical fluids may interact with crustal rocks and become trapped within crustal lithologies.

3. Perspectives and Future Directions

The 16 contributions compiled in this collection provide systematic insights into crust–mantle material cycling and ore-forming processes. These studies not only deepen our understanding of crust–mantle compositions and exchange mechanisms under diverse tectonic settings, but also highlight the critical roles of subduction, slab rollback, lower crustal delamination, lithospheric extension, supercritical fluid metasomatism, and magmatic–hydrothermal evolution in magma generation and metallogenesis. Collectively, these studies demonstrate that mantle–crust interaction represents one of the fundamental mechanisms controlling continental magmatic evolution and ore-forming processes. Whether in continental collision zones, active continental margins, post-collisional extensional settings, or intraplate tectonic environments, complex and multi-stage material exchange and energy transfer commonly occur between the mantle and crust [17,20,21,22].

Increasing evidence suggests that magmatic systems rarely originate from a single endmember source, but instead result from contributions from depleted mantle, enriched lithospheric mantle, lower crust-derived melts, sedimentary components, and slab-derived fluids/melts [18,19,23,24]. During magma ascent and storage, these systems commonly undergo fractional crystallization, crustal assimilation, deep magma recharge, and open-system evolution, further increasing their complexity.

From a regional tectonic perspective, several studies in this collection emphasize the profound influence of plate subduction and its subsequent evolution on mantle–crust interactions. For example, subduction and rollback of the Paleo-Pacific Plate are regarded as major driving forces for Mesozoic magmatism and lithospheric thinning in eastern China, whereas prolonged subduction of the Paleo-Tethyan oceanic lithosphere and its later transition into intraplate extension record a major geodynamic transformation from convergence to extension within the Tethyan realm. Meanwhile, lower crustal delamination, lithospheric extension, and asthenospheric upwelling not only modified magma source characteristics, but also facilitated upward transfer of deep heat and metal-bearing materials, thereby creating favorable conditions for mineralization.

Notably, increasing attention has been paid to the role of supercritical fluids in mantle–crust interactions within subduction zones [25,26]. Owing to their hybrid fluid–melt properties, supercritical fluids are highly efficient agents for transporting elements and isotopic signatures, and their metasomatic effects on mantle wedges may represent an important mechanism for generating unusual magmatic assemblages and metal enrichment [27,28,29]. Studies included in this collection concerning mantle wedge metasomatism by supercritical fluids, sulfide diffusion in melts, and supercritical fluid inclusions provide new experimental and theoretical constraints on the relationship between deep fluid activity and ore formation. These findings imply that the traditional binary distinction between “fluid metasomatism” and “melt metasomatism” may require further refinement, and that the role of deep supercritical systems in element transport and metal enrichment deserves much greater attention.

In terms of metallogenesis, the studies presented here further highlight the fundamental role of mantle–crust material exchange in controlling metal enrichment and ore formation. Whether involving adakitic magma-related Au–Cu polymetallic mineralization, regolith-hosted REE deposits, Fe–Ti–V oxide mineralization, Sn-polymetallic systems, or sediment-hosted Pb–Zn deposits, these ore-forming processes are closely associated with deep magmatic activity, mantle–crust interactions, and subsequent hydrothermal evolution. In particular, lower crustal melting coupled with interaction between crustal and mantle-derived materials is increasingly recognized as a key mechanism for generating metal-rich magmas, whereas the addition of deep volatile components and sulfur may significantly enhance metal transport and precipitation efficiency [30,31,32]. Collectively, these studies suggest that metallogenesis fundamentally represents the shallow crustal response to deep geodynamic processes.

This collection also demonstrates the importance of multidisciplinary and multi-scale approaches in modern geological research. The integration of high-precision geochronology, multi-isotope systems (e.g., Sr–Nd–Hf–Pb–C-O-S-Zn isotopes), in situ mineral-scale analyses, experimental petrology, and thermodynamic modeling is driving geological research from traditional lithological description toward dynamic and process-oriented interpretations. In particular, trace-element and stable isotope records preserved at the mineral scale provide increasingly refined temporal and spatial constraints on magma evolution, fluid activity, and ore-forming processes.

Despite significant progress in recent years, several key scientific issues concerning mantle–crust interactions remain unresolved.

First, accurately distinguishing the relative contributions of different endmembers during crust–mantle material exchange remains highly challenging. In complex systems affected by multi-stage magmatic evolution and late hydrothermal overprinting, it is still difficult to quantitatively resolve the respective contributions from depleted mantle, enriched lithospheric mantle, lower crust-derived melts, sediment melts, and slab-derived fluids. Future research, therefore, requires the development of more sensitive isotopic tracers and more robust quantitative models.

Second, the mechanisms by which supercritical fluids transport deep elements remain incompletely understood. Future studies integrating high-temperature and high-pressure experiments, fluid inclusion analyses, and numerical simulations are necessary to constrain the transport and partitioning behaviors of metals, volatiles, and sulfur under supercritical conditions, thereby clarifying their actual contributions to subduction-related magmatism and ore formation.

Third, the coupling relationships between mantle–crust interactions and metallogenesis require further investigation. At present, questions such as which types of mantle–crust interactions are most favorable for the formation of giant ore deposits and how deep geodynamic processes control metal enrichment efficiency remain poorly constrained. Future work should therefore emphasize integrated studies linking deep sources with shallow ore systems to establish cross-scale metallogenic geodynamic frameworks.

Fourth, mineral-scale investigations are expected to become a major future research direction. Increasing evidence indicates that minerals not only record magma and fluid evolution, but also preserve short-timescale dynamic processes. Greater application of in situ isotopic microanalysis, atomic-scale mineralogy, and machine learning-assisted data interpretation will enable higher-resolution reconstructions of magma–fluid system evolution.

Finally, global comparative studies should be further strengthened. Many current studies remain restricted to individual regions or tectonic systems. Future research should place greater emphasis on comparisons among different continental margins, collisional orogenic belts, and intraplate settings in order to understand mantle–crust cycling and metallogenic processes from a global geodynamic perspective, and to further explore their intrinsic links with Earth’s long-term habitability, atmospheric evolution, and resource formation.

Overall, this collection highlights recent advances in the study of mantle–crust interactions and their metallogenic consequences, while also reflecting a broader transition in deep Earth research from static compositional characterization toward dynamic process-oriented interpretations. With continued advances in high-precision analytical techniques, multi-isotope systems, experimental simulations, and big-data approaches, future studies will provide increasingly comprehensive insights into the coupling relationships among deep Earth material cycling, magmatism, and ore-forming systems, thereby establishing a stronger theoretical framework for understanding continental evolution and resource formation.