Porphyry mineral systems formed in volcanic arcs supply most of the world’s copper and constitute major sources of gold and molybdenum, making them central to both resource security and exploration strategy. Despite decades of study, exploration targeting at regional to global scales remains challenging because porphyry formation and preservation are governed by complex, long-lived tectonic and surface processes. In particular, uncertainties persist regarding how evolving subduction regimes, properties of the subducting slab, and post-formational erosion interact to control where porphyry deposits ultimately occur and are preserved in the geologic record.Current prospectivity models typically focus on present-day tectonic configurations or isolated geological proxies, leaving a critical gap in our ability to explicitly link porphyry mineralisation to the full spatio-temporal evolution of subduction systems and landscape processes over hundreds of millions of years. As a result, the relative importance of slab-derived inputs, overriding plate structure, and preservation potential remains poorly constrained at a global scale.Here, we address this gap by developing a global, data-driven prospectivity model for porphyry mineralisation using a machine learning framework trained on a worldwide database of known porphyry occurrences. The model integrates time-dependent features derived from global plate tectonic reconstructions from 540 Ma to the present, including ocean basin evolution, alongside erosion–deposition outputs from a landscape evolution model to explicitly quantify preservation likelihood and the probability of preserved mineralisation.Our results highlight several strong controls on porphyry occurrence. The most influential parameters are crustal thickness of the overriding plate, total sediment thickness, carbonate accumulation on the subducting plate, and distance from the trench. Porphyry deposits are most likely to occur 200–400 km from the trench, preferentially where overriding crust exceeds ~36 km in thickness and the downgoing slab carries more than ~200 m of pelagic sediments. While trench distance likely reflects slab dip and the degree of mantle wedge hydration, our findings suggest that mechanical coupling between plates plays a key role in modulating volatile transfer and deformation. Notably, carbonate thickness emerges as a positive predictor of mineralisation probability, implying that carbon-rich slabs may enhance volatile fluxes into the mantle wedge—an interpretation that challenges the traditional emphasis on silicate-dominated sediment inputs alone.We propose that thickened continental crust promotes magma differentiation and volatile retention, fostering the generation of fertile, chalcophile-metal–rich magmas, while sediment- and carbonate-rich slabs deliver abundant water- and carbon-bearing fluids that metasomatise the mantle wedge and redistribute metals such as Cu and Au. Together, these results demonstrate that porphyry systems are products of tightly coupled tectonic, geochemical, and surface processes operating over geological timescales. This integrated framework provides a new basis for global-scale exploration targeting and underscores the importance of considering both mineral system fertility and long-term preservation in assessing porphyry prospectivity.

During research expedition SO299 with the German RV Sonne, we discovered the first deep-sea hydrothermal vent system along the Tabar-Lihir-Tanga-Feni island chain in northeastern Papua New Guinea. The Karambusel vent field is hosted by a volcanic center on the western flank of Conical Seamount that formed ~ 89 ka ago. Karambusel is remarkable in that it hosts both a fossil high-temperature, gold-rich mineralization and an active low-temperature (< 51 °C) vent system precipitating arsenic-, antimony-, thallium-, and mercury-rich sulfide minerals. Chemosymbiotic fauna is associated with the vent system and we identified more endemic species than in previous studies on nearby seeps. Our study shows that the magmatic event at Karambusel likely triggered the epithermal mineralization at Karambusel and at the central summit of Conical Seamount. The current hydrothermal fluids originate from condensed magmatic vapor or connate fluids. Gas bubbles were observed at some vent sites and the proportion of methane in the gas phase exceeds that of any other hydrothermal vent system. The composition of the light hydrocarbons points towards a thermogenic origin. Karambusel is thus the first hybrid magmatic-hydrothermal vent and hydrocarbon seep system discovered globally which explains the highly endemic vent fauna as a consequence of the unique ecological niche.

The tectonic setting of porphyry systems is influenced by the subduction style and history that impact the distribution and concentration of copper (Cu), gold (Au), and molybdenum mineralisation. Typically linked to the intrusion of arc-related magma into the upper crust along subduction zones, the formation of porphyry ore deposits is currently understood primarily through geological and geophysical observations of the overriding plate, creating a knowledge gap regarding arc metallogenic processes in convergence zones over time. In this study, we address this gap by investigating the connection between the formation of porphyry Cu-Au deposits and the evolution of subduction zones, utilising a range of features derived from a plate motion model and oceanic crust age grids. Incorporating 47 Cenozoic intrusion-related Cu-Au deposits located in Papua New Guinea and the Solomon Islands, we employ a spatiotemporal mineral prospectivity framework that leverages advanced machine learning methods to map prospective arc terranes. The model successfully predicts all known mineral occurrences in the testing set and identifies the most important features for predicting potential areas of porphyry mineralisation.We observe that the obliquity angle of the relative motion vector in subduction zones plays a crucial role in distinguishing between mineralised (highly prospective) and barren areas (low prospective). This feature is recognised for its significant influence on a spectrum of geological processes, encompassing fluid flow dynamics, magmatic processes, and stress regimes. This influence extends to the transport of mineralising elements and the creation of favourable conditions for ore deposition, with the range of 25 to 90 degrees correlating with mineralised zones, suggesting that oblique subduction zones are more likely to be rich in mineralisation in the study area. Additionally, the length and curvature of arcs emerge as important features for identifying mineralised areas, with tightly curved arcs associated with higher compressional stress and fractures facilitating magma ascent and porphyry formation. The orthogonal component of the downgoing absolute plate velocity is also identified as a significant feature, with higher magnitudes associated with mineralisation, indicating that rapid convergence rates are optimal for porphyry system formation due to accelerated metasomatism and partial melting processes in the overriding plate.The seafloor spreading rate of the subducting crust, computed at the time when the crust originally formed, is an additional important feature linked to mineralised areas. This preferentially occurs when crust formed in the range of 25 to 55 mm/yr (half spreading rate) is subducted. At lower spreading rates, there is a higher proportion of serpentinised mantle peridotite, adding water and carbon to the plate, which will be expelled during subduction, contributing to increasing hydrous melting in the mantle wedge and acting as a catalyst for porphyry deposits. In conclusion, the performance of our model underscores the potential of integrating plate motion models and machine learning to advance mineral exploration along subduction zones. This approach holds promise for more efficient, accurate, and sustainable exploration strategies in these geologically active areas.

Mineralogical and geochemical characterization of some of the main lithium-cesium-tantalum (LCT) pegmatite intrusions of the Archaean Yilgarn and Pilbara cratons, Western Australia, was undertaken to establish the key parameters that distinguish these important Li-ion battery resources. The majority of Western Australia pegmatites investigated belong to one of three main complex subtypes: (1) spodumene-Greenbushes, Kathleen Valley, Dome North, Mount Marion; (2) petalite-Londonderry, Dome North; and (3) lepidolite-Sinclair cesium. Examples of less common pegmatite types included Mount Cattlin, Bald Hill, and Pilgangoora (albite-spodumene type) and the Dalgaranga pegmatite (albite type). Spodumene shows a near-stoichiometric LiAlSi2O6 composition with a Li2O content of similar to 8.0 wt %. Impurities of commercial importance, Fe (+ Mn) varied up to 1 to 1.2 wt % with Na (500-1,200 ppm), as the only other trace element of significance detected in spodumene. Structural deficiencies of Li on the M2 site in the pyroxene structure contribute to the susceptibility of spodumene to alteration and to the preferential removal of Li, relative to Al and Si, during postcrystallization, and hydrous alteration resulting in reduced Li contents of 5.50 to 5.84 wt % Li2O. Spodumene is universally affected by two key types of alteration: a less common, postcrystallization, pseudomorphic replacement of spodumene by a massive, dark-green-to-black, fine-grained, Li-bearing mica-chlorite (cookeite) assemblage (Mount Cattlin and Bald Hill pegmatites); and a more widespread alteration characterized by symplectitic assemblages of graphic-textured, spodumene-quartz intergrowth (SQUI) along the crystal margins of spodumene in contact with Na/K-feldspar. Related to the former alteration style is a pervasive, secondary sericite-like vein alteration, developed along internal fractures and cleavage planes of spodumene. In all cases, alteration leads to the loss of Li from spodumene, and, in relation to the pseudomorphic replacement and vein alteration, introduces significant K and lesser trace element impurities such as F, Mn, Fe, Mg, and Rb. Mineral-textural associations revealed a more coarsely textured but unrelated SQUI developed in the upper petalite zone at the Dome North deposit and in the Li zone in the Greenbushes pegmatite formed by the decomposition of precursive petalite (confirmed) and virgilite (inferred), respectively. Changes in mica (muscovite and lepidolite) composition followed well-correlated trends with Li wt % positively correlated with F wt % and Al/Si negatively correlated with the Li content. The K, Rb, and Cs composition systematics of mica in Western Australia and worldwide pegmatites indicate a complex fractionation mechanism than cannot be explained alone by simple Rayleigh fractionation, which may operate during pegmatite crystallization. A new zircon U-Pb age of 2631 +/- 4 Ma for the Greenbushes pegmatite is older than the previously determined age 2527 Ma and suggests that emplacement of the Greenbushes pegmatite was contemporaneous with other pegmatites in the Yilgarn craton with a maximum age range, ca. 2650 to 2620 Ma. Reported Pb-Pb dating of Ta-Nb-Sn oxides in Pilbara craton pegmatites (e.g., Wodgina and Pilgangoora) defines an emplacement window of 2850 to 2830 Ma, establishing the pegmatites as significantly older (ca. 200 m.y.) than the Yilgarn craton pegmatites. The younger 2629 +/- 13 Ma U-Pb zircon age for the Pilgangoora pegmatite of the current study conflicts with the Meso-Archaean age reported for Pilbara craton pegmatites and is attributed to Pb loss associated with regional deformation and metamorphism, resetting zircon to an isotopically younger age. Further geochronology research is merited to establish a regional, temporal framework of pegmatite crystallization in the Pilbara craton.

Determining the maximum temperature or burial depth where liquid hydrocarbon is preserved (i.e., oil preservation window) is a critical scientific problem. However, large discrepancy remains in the documented oil preservation window (e.g., 150-175 degrees C versus >240 degrees C), significantly influencing our understanding of the distribution of oil in deep earth. In this study, complete diagenesis and fluid inclusion records of oil charging and cracking were discovered in a Permian carbonate reservoir from the eastern Sichuan Basin (South China). Reconstructions of the diagenesis and petroleum evolution history reveal dynamic temperature-pressure controls on oil stability. Specifically, oil can be cracked to form methane-dominated gas after heating at <= 192 degrees C (sigma = 4) and in a hydrostatic pressure regime for similar to 20 m.y. Extreme overpressure formed postdating oil cracking due to intense calcite cementation, which resulted in isolated system and favored generation and accumulation of abnormally high pressure (up to 199 MPa) hydrocarbon fluids. The new oil preservation window can be applied to normal pressure or weak overpressure reservoirs, predicting the distribution of liquid hydrocarbon in deep earth.

A suite of spodumene samples from albite-spodumene type pegmatites, mined for their lithium content, in the Archaean North Pilbara and Yilgarn Cratons regions of Western Australia, were examined to assess the influence of trace element impurities in spodumene and associated gangue phases on the thermal transformation of spodumene. Calcination of spodumene is required to convert the natural, monoclinic alpha-spodumene form into the tetragonal beta-spodumene form, which is more amenable to recovering lithium during hydrometallurgy processing. Spodumene contains minor concentrations of Fe (500-10,000 mg/kg), Mn (200-1400 mg/kg) and other trace element impurities incorporated within the crystal structure. Primary gangue mineralogy comprises quartz, Na/ K-feldspar and mica, with secondary alteration predominantly as 'sericitic' phyllosilicates (muscovite-lepidolite, chlorite/cookeite mixtures) variably enriched in Fe, Mn, Mg and K relative to spodumene. Primary and secondary mica undergo thermal dehydroxylation at temperatures (<950 degrees C) below the spodumene transformation temperature (970-1100 degrees C). Decomposed micas form melts that coat the surface and partially encapsulate the calcined spodumene grain surfaces. Feldspar decomposition at 1060 to 1200 degrees C, coincides with spodumene transformation, and can also result in melt formation, depending upon the composition of the feldspars (K-feldspar, albite). The thermal degradation of other mineral contaminants, such as biotite, pyroxene and amphibole from the presence of country rock (mafic, ultramafic) in the concentrate also coincides with the alpha to beta-spodumene phase transformation. The generated melts that coat grains can reduce the rate of alpha-beta spodumene conversion and the subsequent ability to extract lithium from calcined spodumene. Primary Fe and Mn impurities in spodumene, and those hosted by mica impurities within spodumene have a marked effect in decreasing the temperature of the alpha gamma-beta spodumene conversion. Spodumene is not a strong conductor of heat, and the highly exothermic reaction of Fe and Mn oxidation within both mica and spodumene during thermal alteration affects thermal conductivity, leading to increased heat transfer within spodumene particles, which promotes the thermal transformation of spodumene at a lower temperature. However, calcined spodumene particles with high Fe and Mn contents (> similar to 0.5 wt%) showed black, open sintered regions, accompanied by the generation of fine (<5 mu m) particles, and exsolution of Fe/Mn-oxides particles. The sintering and the generation of fines in the calciner will lead to reduced lithium recovery from calcined products. This study illustrates the importance of minimising micaceous and feldspar components in the concentrate during the beneficiation stage, which can potentially lead to a decrease in lithium recovery during the extraction process. However, the fine-integrated nature of micas associated with spodumene alteration and those associated with fine fractures within spodumene are unlikely to be liberated without costly fine grinding and cleaning processes before the calcination process. Alternative calcination processes that target reducing the effect of gangue materials on clinker formation and encapsulation of spodumene particles are available and discussed.

Major, minor and trace geochemistry is perhaps the most commonly collected form of analytical data within the Earth sciences, either as the sole approach to a research question or to supplement other methods such as geochronology, thermochronology or isotopic studies. With increasing access to instrumentation and diversification of research applications, inorganic geochemistry data is being produced in volumes which exceed the capacity of existing data management systems, reducing the ability of data to be found, accessed and reused as part of the data lifecycle, thus consigning much data as ‘single use’. Lack of visibility additionally removes the ability to critically assess data quality and validity of interpretations, which is vital for maintaining a healthy research ecosystem. Here we propose a new, flexible inorganic geochemistry reporting schema available within the open access EarthBank platform, as a service to store, interpret, disseminate and explore geochemistry data. The application of this data structure, augmented by purpose-built data interrogation tools, is demonstrated using real-world case studies, including volcanic evolution and magma genesis, mineralisation prospectivity, and catchment provenance and contamination through stream sediment geochemistry. The combination of data schema and integrated data analytics through EarthBank offers a service beyond a basic repository, and allows for active exploration and interpretation of in-house and community geochemistry data, providing a resource beneficial across the entire data lifespan, from generation to publication and reuse.

Banded iron formations (BIFs) archive the relationship between Earth's lithosphere, hydrosphere, and atmosphere through time. However, constraints on the origin of Earth's largest ore deposits, hosted by BIFs, are limited by the absence of direct geochronology. Without this temporal context, genetic models cannot be correlated with tectono-thermal and atmospheric drivers responsible for BIF upgrading through time. Utilizing in situ iron oxide U-Pb geochronology, we provide a direct timeline of events tracing development of all the giant BIF-hosted hematite deposits of the Hamersley Province (Pilbara Craton, Western Australia). Direct dating demonstrates that the major iron ore deposits in the region formed during 1.4 to 1.1 Ga. This is one billion to hundreds of millions of years later than previous age constraints based upon 1) the presence of hematite ore clasts in conglomerate beds deposited before ~1.84 Ga, and 2) phosphate mineral dating, which placed the onset of iron mineralization in the Province at ~2.2 to 2.0 Ga during the great oxidation event. Dating of the hematite clasts verified the occurrence of a ~2.2 to 2.0 Ga event, reflecting widespread, but now largely eroded iron mineralization occurring when the Pilbara and Kaapvaal cratons were proximal. No existing phosphate mineral dates overlap with obtained hematite dates and therefore cannot be related to hematite crystallization and ore formation. New geochronology conclusively links all major preserved hematite deposits to a far younger (1.4 to 1.1 Ga) formation period, correlated with the amalgamation of Australia following breakup of the Columbia supercontinent.

The Tabei uplift in the Tarim Basin is one of the deepest and most important petroleum-producing areas in China, with more than 3 billion t (21 billion bbl) of oil equivalent discovered in the Paleozoic carbonate reservoirs. Further petroleum exploration and development in the Tabei and neighboring areas will greatly bene fit from an in-depth understanding of the hydrocarbon charge and accumulation history of these deeply buried carbonate reservoirs. The molecular correlation of reservoir oils indicates that oils from major accumulations in the area share similar geochemical characteristics and were presumably derived from the same source rocks deposited in a marine environment. The Shunbei reservoir oil has the highest thermal maturity, followed by the Yuecan reservoir oil, whereas the Tahe reservoir oil has the lowest thermal maturity. Six generations of calcite cementation spanning over 130 m.y. have been delineated in calcite veins, with U-Pb ages ranging from ca. 446 Ma to ca. 316 Ma. The second and fifth generations of calcite cementation were accompanied by oil charge events, as indicated by the occurrence of bitumen and primary oil inclusions. Fluid inclusion analysis coupled with basin modeling results reveal that the Tabei area experienced two major oil charges, with the first charge occurring during the late Caledonian Orogeny, at 426 to 415 Ma, and the second charge during the middle-late Hercynian Orogeny, at 339 to 278 Ma. The Shunbei and Yuecan reservoirs contain well-preserved oils accumulated during the two charge events, whereas the Tahe reservoir oil has been partially biodegraded.

The Heavy Mineral Map of Australia (HMMA) is the world’s first project aiming to define acontinental heavy mineral baseline. It utilises a novel sample processing workflow andautomated mineralogy techniques to rapidly generate and analyse mineralogical data from1315 archived samples of catchment outlet sediments collected from 1186 catchmentsacross the Australian continent.Heavy minerals were extracted and concentrated from the 75–425 μm fraction of eachsample via an optimised workflow to accelerate output while maintaining integrity and quality of produced heavy mineral concentrates. Automated mineralogy facilitated rapid and consistent collection of mineral data from each heavy mineral concentrate, and anassociated bespoke mineral library incorporates more than 160 unique mineral phases,including minerals that will be of interest to both researchers and mineral explorers. Apublicly accessible mineral network analysis application has been developed in parallel with the HMMA project to facilitate exploration and interpretation of the resulting >140 million mineral grain identifications dataset.Upon completion in late 2023 the HMMA will provide a heavy mineral baseline acrossapproximately 80% of Australia, with processing of samples and data acquisition undertaken in a standardised and uniform manner enabling easy replication of techniques and both internal and external comparability.

Constraining the age of many types of ore deposits remains challenging because of the lack of radiogenic isotopes incorporated into common ore-forming minerals. The timing of pre-Caledonian-hosted Cu mineralization along the entire c. 1200 km long East Greenland Caledonides remains virtually unknown, hampering our knowledge of ore deposit timing and genesis in a frontier exploration region. Here, automated mineral analysis of a series of nodular, disseminated and vein-hosted Cu- ± Pb-mineralized metasedimentary rocks in central East Greenland reveals detrital zircon and hydrothermal xenotime, both amenable to U–Pb geochronology. Detrital zircon geochronology of a co-deposited quartzite reveals an age distribution highly similar to the Cryogenian ( c. 700 Ma) upper Eleanore Bay Supergroup. Hydrothermal xenotime U–Pb analyses adjacent to nodular and disseminated chalcocite across three proximal samples have variable amounts of common Pb that together yield a well-defined single discordia with a lower concordia intercept of 438 ± 13 Ma (2 σ ). This age is within uncertainty of the onset of Caledonian regional metamorphism and granitoid production and clearly post-dates deposition of the upper Eleanore Bay Supergroup by several hundred million years. Considering a published chalcocite Pb–Pb isochron age of 680 ± 65 Ma, the hydrothermal xenotime U–Pb ages imply that Caledonian-driven fluid activity, sourced from metamorphic reactions or from granitoids, remobilized diagenetic Cu and Pb mineralization. Chalcocite Pb–Pb isotopes show that dissolved and reprecipitated portions are volumetrically minor, radiogenic and Pb-poor, implying that fluids stripped most of the Pb from the system. Thus, it is likely that remobilization was localized on the grain scale, although some Cu and Pb was transported away from diagenetic sites, perhaps into veins. Although Caledonian metamorphism and granitoid emplacement is widespread in central East Greenland, the full extent of their roles in upgrading Cu mineralization remains to be ascertained. Supplementary material: Supplementary figures and tables are available at https://doi.org/10.6084/m9.figshare.c.6675384 Thematic collection: This article is part of the Caledonian Wilson cycle collection available at: https://www.lyellcollection.org/topic/collections/the-caledonian-wilson-cycle

Argyle is the world’s largest source of natural diamonds, yet one of only a few economic deposits hosted in a Paleoproterozoic orogen. The geodynamic triggers responsible for its alkaline ultramafic volcanic host are unknown. Here we show, using U-Pb and (U-Th)/He geochronology of detrital apatite and detrital zircon, and U-Pb dating of hydrothermal titanite, that emplacement of the Argyle lamproite is bracketed between 1311 ± 9 Ma and 1257 ± 15 Ma (2σ), older than previously known. To form the Argyle lamproite diatreme complex, emplacement was likely driven by lithospheric extension related to the breakup of the supercontinent Nuna. Extension facilitated production of low-degree partial melts and their migration through transcrustal corridors in the Paleoproterozoic Halls Creek Orogen, a rheologically-weak rift zone adjacent to the Kimberley Craton. Diamondiferous diatreme emplacement during (super)continental breakup may be prevalent but hitherto under-recognized in rift zones at the edges of ancient continental blocks.