Posters on site: Mon, 28 Apr, 16:15–18:00 | Hall X1
Cobalt, nickel, rare earth elements (REEs) and other critical metals are highly enriched in deep sea supergene mineral deposits such as cobalt-rich crusts, poly-metallic nodules and REEs-rich sediments, which are potential strategic mineral resources in the future. Crusts, nodules, and REEs-rich sediments are distributed on the surface of seamounts, seabed and deep sea sediments respectively, they have similar metallogenic elements, and sea water plays an important role in the mineralization process. The critical metals such as cobalt, nickel, copper and REEs haven’t formed independent mineral state. Previous studies mainly focus on the separate research on each minerals, which limited overall understanding of deep-sea mineralization processes. On the basis of reviewing the progress and existing problems of domestic and foreign scholars on the spatial distribution, occurrence status, enrichment mechanisms, and controlling factors of three deep-sea sedimentary minerals above, guided by the ideas of Earth system science, we focuse on ore-forming elements, to conduct the process of “source-migration-enrichment” of the critical metals under multi sphere interaction and the spatiotemporal coupling mechanism of sedimentary minerals in “sea mountain-basin system”. In addition, expected to guide the deep-sea mineral exploration
How to cite: He, G.: Research on the metallogenic mechanism of deep sea sedimentary mineral resources: review and outlook, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7969, https://doi.org/10.5194/egusphere-egu25-7969, 2025.
Carbonatite-fenite complexes, associated with alkaline or ultra-alkaline magmatism, typically have high concentrations of rare earth elements (REE), niobium (Nb), thorium (Th) and uranium (U). Although most of these complexes form in intra-continental tectonic settings, in contrast to the majority, they can also develop in post-collisional settings. A few examples of such carbonatite intrusions were identified in China, Turkey, Italy and Spain. In Turkey, a few notable carbonatitic intrusions were identified in Central and Western Anatolia. These complexes are relatively young and some of them are covered by volcanic or volcano-sedimentary rocks. The recently identified carbonatite/carbothermalite (late stage metasomatic halo) intrusion is located at Arıklı and Nusratlı Villages in Çanakkale, NW Anatolia within Miocene volcanics. In Arıklı, a 10-meters-thick carbonatite dyke with stockwork veinlets and potassic fenite zone are clearly visible and cross-cutting relationships can be observed between the carbonatite and the host rocks. Two kilometers east of Arıklı, at the entrance of Nusratlı village, also a metasomatic aureole zone can be observed that consists of thin carbonatite veinlets. These veinlets predominantly constituted by subhedral calcite, dolomite, and magnesite, forming a Mg-carbonatite composition and they contain small amounts of uranium (~4 ppm) and thorium (<1 ppm). However, the concentrations of these elements increase significantly in the adjacent fenite zone, reaching up to 372 ppm for U and 109 ppm for Th. An approximately 7% increase in K2O within the fenite zone has been calculated based on a comparison of the current and original composition of the host rock, using immobile elements as a reference. Overall, this carbonatite/carbothermalite system can be evaluated as late-stage phase of a carbonatitic intrusion which is product of Miocene post collisional magmatism in Western Anatolia.
How to cite: Kaplan, E., Yabacı, Ö., Ünal, A., Döner, Z., and Ünlüer, A. T.: Geochemical Features of Miocene Carbonatite/Carbothermalite-Fenite Complex in Western Anatolia: Evidences from Arıklı and Nusratlı Villages, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10081, https://doi.org/10.5194/egusphere-egu25-10081, 2025.
Heavy rare earth elements (HREE) are strategic metals in China, primarily sourced from ion-adsorption type heavy rare earth deposits (iHREE). Granite constitutes an important parent rock for iHREE. Generally, rare earth elements (REE) undergo pre-concentration during the process of rock formation, which is crucial for the mineralization of HREE. However, the mechanisms of migration and concentration of HREE during the magmatic-hydrothermal (alteration) processes remain unclear. The typical iHREE in Lincang, Yunnan Province, exhibits multiple episodes of granite intrusion, and the partial enrichment of HREE in the ore bodies offers a natural research subject. The authors selected the granites in the area as the research subjects. Specifically, the granodiorite (YNlc2-j3) has a zircon shrimp U-Pb age of 214.7 Ma, and the medium-coarse-grained biotite granite (MCGB, YNlc4-j1) has a zircon shrimp U-Pb age of 217.7 Ma. Analysis using back-scattered electron (BSE) imaging, Electron Probe X-ray Micro-Analyzer (EPMA), and TESCAN integrated mineral analyzer (TIMA) revealed that during the magmatic-hydrothermal (alteration) process: (1) the shape of monazite and zircon changes from authomorphic to anhedral. (2) At the magmatic stage, monazite and zircon exist as independent minerals; however, at the hydrothermal (alteration) stage, monazite associates with apatite, and zircon associates with xenotime. (3) HREE-bearing fluorocarbonate minerals from nonexistence to pass into existence. These results indicate that HREE-bearing minerals undergo complex hydrothermal alterations, with a preferential accumulation of HREE in HREE-bearing fluorocarbonate minerals, which are shown to play significant roles in the formation of iHREE.
How to cite: Lu, L., Liu, Y., Zhao, Z., Zheng, X., He, G., and Wang, C.: Constraints on metallogenic mechanism of ion-adsorption type HREE deposit from hydrothermal alteration and evolution features of minerals in Lincang granite, Yunnan, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14462, https://doi.org/10.5194/egusphere-egu25-14462, 2025.
Lithium demand has grown exponentially over the last decade, driven by the ongoing energy transition, and is expected to increase in the EU by up to 12 times by 2030 (European Commission, 2023). To meet this rising demand, efforts must focus on enhancing recycling and developing new unconventional lithium resources. While Italy does not have records of lithium production from conventional deposits such as pegmatite ores or salars, promising sources have been identified in low-enthalpy, lithium-rich waters originating from sedimentary sequences along the Apennine compressional front (Dini et al., 2022). Lithium content in these waters, up to 164 mg/L in the Salsomaggiore Terme area (Boschetti et al., 2011), is likely influenced by fluids expelled from sediments during diagenesis or by subsequent water-rock interactions. Modern Direct Lithium Extraction (DLE) techniques provide an efficient method for lithium recovery from fluids, highlighting the significant potential of these resources. Despite their scientific and economic potential, limited knowledge exists regarding the genetic processes and chemical and isotopic characteristics of these systems.
To address the existing data gap and explore the sources and processes governing lithium distribution, an extensive sampling campaign was conducted on the main argillite-clay sedimentary formations of the Northern Apennines in the Emilia Romagna region. The sampling also covered sediments from mud volcanoes, which serve as proxies for deeper processes, as well as waters from SPA wells and natural springs to investigate water-rock interaction.
The collected samples were analysed for major and trace elements. Lithium concentrations ranged from 13 to 263 mg/kg in rock samples, with several exhibiting values well above the shale average. The mineralogical composition was identified through XRD analysis, while SEM-EDS imaging revealed micro-scale mineralogical and chemical zonations. Selected samples underwent further investigation using LA-ICP-MS, revealing significant micro-scale lithium variability, with concentrations reaching up to 700 mg/kg in phyllosilicate-rich micro-layers. These enriched layers were strongly associated with boron, potassium, aluminium, and iron, in contrast to bordering carbonate-rich layers, which systematically showed lower lithium contents.
Isotope analysis of boron (δ11B), strontium (87Sr/86Sr), and lithium (δ7Li) provided additional insights into the origin of the formations and suggested the potential involvement of multiple provenances. In this regard, a lithium isotope purification and analysis protocol was developed for MC-ICP-MS at the Radiogenic and Unconventional Stable Isotopes Laboratory at IGG-CNR. Leaching experiments conducted on the most Li-rich sample, using various solutions (deionised water, NaCl, CaCl2, and HCl) and different temperatures, showed the behaviour of Li release from the solid phase, with a significant release occurring during the initial hours of interaction that demonstrated the importance of early-stage water-rock interaction processes.
This research is part of a PhD project funded by the European ITINERIS Project. The results could provide a fundamental basis for understanding the sources and mechanisms influencing lithium distribution in the sedimentary basins of the Northern Apennines and in other similar geological settings. Meeting the goals outlined by the EU in the Critical Raw Materials Act (CRMA 2024), this study could promote interest in the sustainable exploration of lithium resources and DLE techniques.
How to cite: Matteo, S., Maddalena, P., Massimo, D., and Andrea, D.: Lithium distribution in argillite-clay sequences of the Northern Apennines, Italy: investigating a potential source of Li-rich fluids, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4207, https://doi.org/10.5194/egusphere-egu25-4207, 2025.
Lithium has been receiving increased attention due to its relevance to the green energy transition and increasing demand. One of the main sources of Li is peraluminous granitoids and pegmatites. Current models for the genesis of such enriched lithologies include the fractional crystallisation of melts derived from sedimentary protoliths (e.g., Linnen et al., 2012); the low-volume melting of Li-rich protoliths (e.g., Shaw et al., 2016); and the subsequent re-melting of S-type orthogneisses (Ballouard et al., 2024; Koopmans et al., 2024). Hence, understanding the behaviour of Li during partial melting is critical, regardless of the preferred model. However, modelling studies have shown contrasting trends in melt Li concentrations during partial melting reactions due to the use of different distribution coefficient sets (Ballouard et al., 2024; Koopmans et al., 2024).
In this study, we coupled existing and newly acquired mineral Li concentration data from high-grade terranes, and phase equilibria and trace element modelling to improve our understanding of Li behaviour during partial melting. Our main results highlight that: (1) when present cordierite is the main mineral host of Li in metapelitic migmatites; and (2) the experimentally observed temperature-dependent variation of cordierite Li concentrations (Evensen and London, 2003) is also observed in natural samples, but – as expected – with different concentrations levels. Moreover, our results show that the mineral distribution coefficients of natural samples do not match experimentally derived Li distribution coefficients for cordierite and biotite. We discuss possible reasons for divergent distribution coefficients based on the comparison of physicochemical parameters associated with these distribution coefficients and typical high-grade metapelites. Our findings also indicate that low-pressure melting with peritectic cordierite will suppress melt Li concentrations, in agreement with Ballouard et al. (2024).
This study highlights how metamorphic minerals and melting conditions affect Li behaviour during partial melting. Moreover, our findings and discussion highlight that further experimental and natural constraints on Li distribution coefficients are necessary for a precise understanding of how Li is mobilised during metapelite melting.
References:
Ballouard et al. (2024) Contrib to Min and Petr 178(11), 75
Evensen and London (2003) Contrib to Min and Petr 144, 739-757
Koopmans et al. (2024) Geology 52(1), 7-11
Linnen et al (2012) Elements 8(4), 275-280
Shaw et al. (2016) Precamb Res 281, 338-362
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 956125.
How to cite: Oliveira da Costa, E., Argles, T., Kriegsman, L., Kunz, B., and Warren, C.: Lithium behaviour during partial melting, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18645, https://doi.org/10.5194/egusphere-egu25-18645, 2025.
Jiaodong and Liaodong peninsulas share similar geological backgrounds for gold mineralization, and there are many similarities between the Jiaodong and Liaodong gold deposits. However, the currently known gold endowment of the Liaodong gold deposit is significantly lower than that of the Jiaodong gold deposit. In this study, we selected the Xiling gold deposit from the Jiaodong and the Xinfang and Xindian gold deposits from the Liaodong as the research objects. Combining the data obtained in this study with previous research results, a comparative study was conducted on the gold mineralization in the Jiaodong and Liaodong gold districts in China.
The ore-forming fluid of the Xiling gold deposit from the Jiaodong is medium temperature, and low salinity CO2-H2O-NaCl hydrothermal fluid system. The mechanism of gold precipitation is interpreted as the fluid immiscibility. The initial sulfur source of the Xiling gold deposit is magmatic origin of sulfur, and the Precambrian basement have provided sufficient sulfur for gold mineralization via intensive water-rock interaction. The ore-forming fluid is a deep-seated magmatic-hydrothermal fluid. As mineralization progressed, abundant ore-forming elements enter the ore-forming fluid from the Precambrian basement via intensive water-rock interaction. The Xindian gold deposit in the Liaodong formed in the Early Cretaceous, between 127.2 and 120.9 Ma. The S-Pb isotopes studies indicate that the ore-forming materials of the Xinfang and Xindian gold deposits in the Liaodong are mainly magmatic origin, and the Gaixian Formation have provided sufficient ore-forming materials for the Xindian gold mineralization. Pyrite trace elements analyses indicate that the initial ore-forming fluids of the Xinfang and Xindian gold deposits are mainly magmatic-hydrothermal fluids. At Xindian, the fluid chemistry was intensively modified by interacting with wall rock (Gaixian Formation) via intensive water-rock interaction. However, the Anshan Group did not play an important role in the Xinfang gold mineralization.
The mineralization age of the Jiaodong gold deposits is mainly clustered at ~120 Ma. The mineralization age of the Liaodong gold deposits mainly includes Triassic, Early Jurassic, and Early Cretaceous. Among them, the Early Cretaceous gold mineralization is extensively distributed in the Liaodong. The ore-forming fluids of the Jiaodong and Liaodong gold deposits were a mixture of crustal-derived and mantle-derived fluids. However, the contribution of mantle-derived fluids to the Jiaodong gold deposit is significantly greater than that of the Liaodong gold deposit. In addition, the Archaean Jiaodong Group and Paleoproterozoic Liaohe Group Gaixian Formation have made great contributions to the gold mineralization in the Jiaodong and Liaodong, respectively.
How to cite: Yu, B.: A comparative study on the gold mineralization in the Jiaodong and Liaodong gold districts in China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2232, https://doi.org/10.5194/egusphere-egu25-2232, 2025.
The role of bi- and poly-metallic melts (i.e., Pb, Bi, Se, Sb, Te, etc.) is increasingly gaining attraction as highly efficient carriers for the precious metals Au and Ag in ore-deposit genesis. These melts have been reported in several types of ore deposits (e.g., orogenic, intrusion-related, volcanogenic massive sulfide) at different temperature ranges. Nevertheless, their occurrence and evolution in low-temperature (<400 °C) hydrothermal ore deposits (e.g., epithermal) is poorly understood. In this communication, we report a micro-to-nanoscale investigation of electrum (Au-Ag alloy) from two epithermal deposits with a very similar ore mineralogy dominated by Cu-Pb-Bi minerals from. In specific bands within a colloform-banded vein at the Switchback epithermal deposit in southern Mexico, electrum (Au-Ag alloy) form intergrowths with chalcopyrite (CuFeS2) and minerals of the galena (PbS)-matildite (AgBiS2) solid solution (ss) and ourayite (Ag3Pb4Bi5S13). These minerals show a telescoping of their intergrowth and textures from the nano- to micron-sized scales, characterized by curvilinear boundaries, bleb-like morphologies, and rounded nanoparticles (~100 nm) within the gangue minerals (quartz, fluorite, and calcite) or pyrite. A similar telescoped transition from nano to micron-sized scales is observed in ore minerals of the epithermal gold-rich base metal prospect of Svishti Plaz in central Bulgaria. Here, electrum grains (~100 nm to 1 mm) are also intimately associated with Cu-Pb-Bi minerals, including: (1) chalcopyrite, bismuthite [Bi2S3]-pekoite (CuPbBi11S18), (2) aikinite (CuPbBiS3)-friedrichite (Cu5Pb5Bi7S8), or (3) bismuthiferous galena hosting exslutions of berryite (Cu3Ag2Pb3Bi7S16) and benjaminite (Ag3Bi7S12). All these minerals also exhibit mutual curved outlines but are exclusively found filling cracks of high porosity zones of pyrite. Collectively, all these observations are consistent with transport in a molten state of a precursor Pb-Bi melt containing Au, Ag, and Cu. Our nanoscale study suggest that that nano Cu-Pb-Bi melts in epithermal fluids are highly efficient collectors of Au and Ag, while acting as transient agents for the formation of larger pools of melt precursors for the crystallization of ore minerals. The intervention of these melts in the hydrothermal fluids parental to epithermal ores satisfactorily explains the abnormally high Au-Ag enrichments (i.e., bonanzas) observed in the deposits targeted in this study and elsewhere.
How to cite: González-Jiménez, J. M., Cano, N. A., Yesares, L., Kerestedjian, T. N., Camprubí, A., and Gervilla, F.: Nano Cu-Pb-Bi melts as highly efficient agents for Au-Ag enrichment in epithermal ore systems , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21114, https://doi.org/10.5194/egusphere-egu25-21114, 2025.
Posters virtual: Thu, 1 May, 14:00–15:45 | vPoster spot 1
EGU25-2960 | ECS | Posters virtual | VPS23
Enrichment Factors of Alkali and Key Metal Mineral Resources in Fengcheng Formation of Mahu Sag, the Junggar BasinThu, 01 May, 14:00–15:45 (CEST) | vP1.7
The second member of the Fengcheng Formation in the early Permian of the Mahu Depression has a rock series with interbedded alkali mineral layers and tuffaceous layers. The dark layer contains a large amount of associated metal minerals, which are closely related to the volcanic hydrothermal material at the Fengnan fault nose. However, due to the presence of detrital rock deposits on the west side of the Mahu Depression, this area is jointly controlled by volcanoes and terrestrial sources to form alkali mineralization. There are also a large number of dark hydrocarbon source rocks developed in the region, which are also one of the reasons for the mineralization of alkali minerals and associated metal minerals. Therefore, a mineralization model is established.
How to cite: Liu, X. Y., Longwei, Q., and Yongqiang, Y.: Enrichment Factors of Alkali and Key Metal Mineral Resources in Fengcheng Formation of Mahu Sag, the Junggar Basin, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2960, https://doi.org/10.5194/egusphere-egu25-2960, 2025.
