Pub Date : 2025-12-15DOI: 10.1016/j.chemer.2025.126376
Luís Portela, Maria Rosário Azevedo, Jorge Medina, Beatriz Valle Aguado
The Lusinde fine-grained biotite granite is a small pluton intruded into the metamorphic basement of the Central Iberian Zone during the waning stages of the Variscan Orogeny. LA-ICP-MS zircon UPb ages constrain pluton emplacement to ca. 297–295 Ma. Mineralogical and geochemical data reveals that the intrusion corresponds to a strongly ferroan, peraluminous, reduced A2-type granite (∆FMQ = −3.4 to −1.7, zircon oxybarometry), characterised by a narrow compositional range (SiO2 = 67.7–68.8 wt%), elevated FeOT/FeOT + MgO (0.90–0.92) and 10,000 × Ga/Al (3.1–3.4) ratios, high REE, LILE and HFSE contents and strong depletions in Ba, Sr, Nb, P, Eu and Ti. Decoupling between “mantle-like” Nd and zircon Hf (εNdi = −0.40 to +0.58; TDM2 = 0.81–0.95 Ga; zircon εHfi = −0.41 to +3.01; TDM2-Zrn = 1.08–1.30 Ga) and more “crust-like” Sr (87Sr/86Sri = 0.7097–0.7100) isotopic signatures suggests derivation from small degrees of partial melting of old juvenile mafic/intermediate rocks interlayered in the lower crust, with minor input from more evolved crustal sources. The only studied ferrodioritic enclave shares the A2-type affinity of the host granite and seems to have derived from a mixed source (enriched subcontinental lithospheric mantle and juvenile mafic crust), before injection into the silicic magma chamber. We propose that the generation of the Lusinde A-type granite magma and enclosed enclave occurred in a deep hot zone located at the mantle-lower crust interface, at about 7–10 kb and 850–950 °C, in an extensional post-collisional setting.
{"title":"Petrogenesis of an A2-type intrusion associated with the late-post-collisional calc-alkaline Variscan granites from central-northern Portugal (Central Iberian Zone)","authors":"Luís Portela, Maria Rosário Azevedo, Jorge Medina, Beatriz Valle Aguado","doi":"10.1016/j.chemer.2025.126376","DOIUrl":"10.1016/j.chemer.2025.126376","url":null,"abstract":"<div><div>The Lusinde fine-grained biotite granite is a small pluton intruded into the metamorphic basement of the Central Iberian Zone during the waning stages of the Variscan Orogeny. LA-ICP-MS zircon U<img>Pb ages constrain pluton emplacement to ca. 297–295 Ma. Mineralogical and geochemical data reveals that the intrusion corresponds to a strongly ferroan, peraluminous, reduced A<sub>2</sub>-type granite (∆FMQ = −3.4 to −1.7, zircon oxybarometry), characterised by a narrow compositional range (SiO<sub>2</sub> = 67.7–68.8 wt%), elevated FeO<sub>T</sub>/FeO<sub>T</sub> + MgO (0.90–0.92) and 10,000 × Ga/Al (3.1–3.4) ratios, high REE, LILE and HFSE contents and strong depletions in Ba, Sr, Nb, P, Eu and Ti. Decoupling between “mantle-like” Nd and zircon Hf (εNd<sub>i</sub> = −0.40 to +0.58; T<sub>DM2</sub> = 0.81–0.95 Ga; zircon εHf<sub>i</sub> = −0.41 to +3.01; T<sub>DM2-Zrn</sub> = 1.08–1.30 Ga) and more “crust-like” Sr (<sup>87</sup>Sr/<sup>86</sup>Sr<sub>i</sub> = 0.7097–0.7100) isotopic signatures suggests derivation from small degrees of partial melting of old juvenile mafic/intermediate rocks interlayered in the lower crust, with minor input from more evolved crustal sources. The only studied ferrodioritic enclave shares the A<sub>2</sub>-type affinity of the host granite and seems to have derived from a mixed source (enriched subcontinental lithospheric mantle and juvenile mafic crust), before injection into the silicic magma chamber. We propose that the generation of the Lusinde A-type granite magma and enclosed enclave occurred in a deep hot zone located at the mantle-lower crust interface, at about 7–10 kb and 850–950 °C, in an extensional post-collisional setting.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126376"},"PeriodicalIF":2.9,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-08DOI: 10.1016/j.chemer.2025.126375
Lidong Zhang , Yue Liu , Kewei Zhang , Ziqiang Zha , Jianeng Wu , Wenjun Xuan , Huiyuan Zhang
The Nenjiang–Heihe district, on the eastern margin of the Central Asian Orogenic Belt, hosts porphyry CuMo and epithermal Au systems emplaced through multiple tectonomagmatic episodes. To extract process–diagnostic signals from regional geochemistry and convert them into practical exploration targets, we applied compositional balance analysis (CoBA) and the concentration–area (C–A) fractal model to stream–sediment geochemical data collected from the Nenjiang–Heihe region, China. Compositional hierarchical clustering and a suite of data– and knowledge–driven balances identify three complementary geochemical patterns: (i) Fe–oxide–rich intermediate–mafic domains that define broad NNE–NE corridors coincident with volcanic belts and major faults; (ii) porphyry/base–metal chalcophile behavior (e.g., b01, b02, b03, b08, b7, b26, and b31) that captures Cu anomalies along permeable structures; and (iii) felsic–HFSE/LILE fertility and volatile–rich epithermal overprints, highlighted by b05, b06, b07, b15, and b16, localized over or adjacent to intermediate–felsic intrusions. C–A breakpoints provide objective thresholds that delineate statistically significant targets. Highest–priority prospects occur where b01–b02 highs overlap at fault intersections and locally coincide with b06 anomalies. The results demonstrate that CoBA, coupled with C–A segmentation, offers a low–cost, and interpretable framework for prospectivity mapping in forest–swamp terrain, mitigating closure effects and enhancing weak but geologically meaningful signals for decision–making.
{"title":"Compositional balance analysis for geochemical prospectivity mapping in Nenjiang–Heihe region, China","authors":"Lidong Zhang , Yue Liu , Kewei Zhang , Ziqiang Zha , Jianeng Wu , Wenjun Xuan , Huiyuan Zhang","doi":"10.1016/j.chemer.2025.126375","DOIUrl":"10.1016/j.chemer.2025.126375","url":null,"abstract":"<div><div>The Nenjiang–Heihe district, on the eastern margin of the Central Asian Orogenic Belt, hosts porphyry Cu<img>Mo and epithermal Au systems emplaced through multiple tectonomagmatic episodes. To extract process–diagnostic signals from regional geochemistry and convert them into practical exploration targets, we applied compositional balance analysis (CoBA) and the concentration–area (C–A) fractal model to stream–sediment geochemical data collected from the Nenjiang–Heihe region, China. Compositional hierarchical clustering and a suite of data– and knowledge–driven balances identify three complementary geochemical patterns: (i) Fe–oxide–rich intermediate–mafic domains that define broad NNE–NE corridors coincident with volcanic belts and major faults; (ii) porphyry/base–metal chalcophile behavior (e.g., <em>b01</em>, <em>b02</em>, <em>b03</em>, <em>b08, b7</em>, <em>b26</em>, and <em>b31</em>) that captures Cu anomalies along permeable structures; and (iii) felsic–HFSE/LILE fertility and volatile–rich epithermal overprints, highlighted by <em>b05, b06</em>, <em>b07, b15</em>, and <em>b1</em>6, localized over or adjacent to intermediate–felsic intrusions. C–A breakpoints provide objective thresholds that delineate statistically significant targets. Highest–priority prospects occur where <em>b01–b02</em> highs overlap at fault intersections and locally coincide with <em>b06</em> anomalies. The results demonstrate that CoBA, coupled with C–A segmentation, offers a low–cost, and interpretable framework for prospectivity mapping in forest–swamp terrain, mitigating closure effects and enhancing weak but geologically meaningful signals for decision–making.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126375"},"PeriodicalIF":2.9,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.chemer.2025.126316
Justin Filiberto , Mikhail Yu. Zolotov , Erika Kohler , Piero D'Incecco , Dmitry A. Gorinov , Sriram S. Bhiravarasu , Matthew B. Weller , Jeremy F. Brossier , Iván López , Philippa J. Mason , Jemila A. Edmond , Nicola Mari , Goro Komatsu , Gaetano Di Achille , James B. Garvin
One of the biggest unknowns about Venus is how volcanically active it is today. Venus has a similar size and density to Earth, suggesting it may have a comparable composition, and therefore it is expected to be volcanically active; however, exploring Venus and confirming current volcanic activity is difficult because of the thick omnipresent optically opaque clouds that hamper traditional observations of the lower atmosphere and surface. Further, surface conditions make long-lived missions challenging. Despite the difficulty, there have been tantalizing hints of currently active or very recent volcanism. Here, we review what is known about active volcanism, point out gaps in knowledge to be addressed, and highlight techniques and approaches that need to be developed before the new decade of Venus exploration. It is crucial to constrain the activity and rate of volcanism today and through time to begin to understand the geodynamic state of the planet.
We find that the combination of all evidence strongly indicates that Venus is volcanically active today. The best evidence for active volcanism comes from combining data sets and approaches – specifically at Idunn Mons, Maat Mons, and Aramaiti Corona – in contrast to those from a single study or data set alone. Considering the evidence for activity, observations do not favor so-called “catastrophic” models of resurfacing, instead they are better represented by ongoing regional scale events. To reliably detect and characterize active or recent effusive basaltic volcanism new missions must collect high-resolution imaging, repeat observations, radar polarimetry, evidence of outgassing, and high-resolution topographical data that provide insights into surface changes over time. The ability to capture and interpret these data is vital for understanding Venus's geological activity, particularly in regions where volcanic processes are suspected to be ongoing.
{"title":"Assessing the evidence for active volcanism on Venus: current limitations and prospects for future investigations","authors":"Justin Filiberto , Mikhail Yu. Zolotov , Erika Kohler , Piero D'Incecco , Dmitry A. Gorinov , Sriram S. Bhiravarasu , Matthew B. Weller , Jeremy F. Brossier , Iván López , Philippa J. Mason , Jemila A. Edmond , Nicola Mari , Goro Komatsu , Gaetano Di Achille , James B. Garvin","doi":"10.1016/j.chemer.2025.126316","DOIUrl":"10.1016/j.chemer.2025.126316","url":null,"abstract":"<div><div>One of the biggest unknowns about Venus is how volcanically active it is today. Venus has a similar size and density to Earth, suggesting it may have a comparable composition, and therefore it is expected to be volcanically active; however, exploring Venus and confirming current volcanic activity is difficult because of the thick omnipresent optically opaque clouds that hamper traditional observations of the lower atmosphere and surface. Further, surface conditions make long-lived missions challenging. Despite the difficulty, there have been tantalizing hints of currently active or very recent volcanism. Here, we review what is known about active volcanism, point out gaps in knowledge to be addressed, and highlight techniques and approaches that need to be developed before the new decade of Venus exploration. It is crucial to constrain the activity and rate of volcanism today and through time to begin to understand the geodynamic state of the planet.</div><div>We find that the combination of all evidence strongly indicates that Venus is volcanically active today. The best evidence for active volcanism comes from combining data sets and approaches – specifically at Idunn Mons, Maat Mons, and Aramaiti Corona – in contrast to those from a single study or data set alone. Considering the evidence for activity, observations do not favor so-called “catastrophic” models of resurfacing, instead they are better represented by ongoing regional scale events. To reliably detect and characterize active or recent effusive basaltic volcanism new missions must collect high-resolution imaging, repeat observations, radar polarimetry, evidence of outgassing, and high-resolution topographical data that provide insights into surface changes over time. The ability to capture and interpret these data is vital for understanding Venus's geological activity, particularly in regions where volcanic processes are suspected to be ongoing.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126316"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.chemer.2025.126359
Linna LI , Jiangang JIAO , Yunfei MA
The Niancaowan mafic-ultramafic intrusion is located within the Bayan Obo Rift Zone of central Inner Mongolia. Systematic genetic investigations were conducted in this study to clarify the genetic relationship between the Niancaowan mafic-ultramafic intrusion and known CuNi deposits within the rift zone, as well as to assess the comparability of their mineralization potential. Through integrated petrographic observations, high-precision geochronological dating, whole-rock geochemical analyses, and zircon Hf isotope tracing, the research specifically focused on elucidating the magmatic source characteristics, rock-forming timing, and magmatic evolutionary processes of the intrusion. The Niancaowan mafic-ultramafic intrusion is predominantly composed of hornblende gabbro and gabbro-diabase. LA-ICP-MS zircon UPb dating reveals that the hornblende gabbro crystallized during the Early Permian (273.2 ± 3.5 Ma), which demonstrates temporal synchronicity with the emplacement ages of other mafic-ultramafic intrusions within the central-western Inner Mongolia rift system. Geochemical tracers further disclose significant zircon Hf isotopic heterogeneity, indicating that the parental magma was derived from partial melting of a lithospheric mantle source and underwent contamination by lower crustal materials during its ascent. Comparative analysis indicates that the zircon Hf isotopic compositions of the Niancaowan intrusion (εHf(t) = −17.0 to +1.4) are similar to those of typical regional intrusions such as the Wulantaolegai and Huanghuatan intrusions, revealing that crustal contamination was prevalent during the emplacement of mafic-ultramafic magmatic systems within the Bayan Obo Rift Zone. The incorporation of such crust-derived components may be controlled by the melting or assimilation processes of ancient basement rocks in the extensional setting of the rift zone. The petrological characteristics and quantitative modeling results indicate that the Niancaowan intrusion experienced relatively weak crustal contamination (4 %–8 %). If sulfide mineralization were to occur in this intrusion, it would primarily depend on deep-seated magmatic differentiation. Comparative studies between the Niancaowan intrusion and other intrusive bodies within the Bayan Obo Rift Zone reveal that the mineral exploration potential of mafic-ultramafic intrusions in the Bayan Obo Rift Zone should not be overlooked. Particular attention should be given to highly contaminated mafic-ultramafic intrusion clusters within the rift zone and multi-stage tectonic-magmatic convergence nodes.
{"title":"Petrogenesis of the Niancaowan mafic-ultramafic intrusion: Decoding magmatic evolution in the cuNi Metallogenic Province of the Bayan obo rift zone","authors":"Linna LI , Jiangang JIAO , Yunfei MA","doi":"10.1016/j.chemer.2025.126359","DOIUrl":"10.1016/j.chemer.2025.126359","url":null,"abstract":"<div><div>The Niancaowan mafic-ultramafic intrusion is located within the Bayan Obo Rift Zone of central Inner Mongolia. Systematic genetic investigations were conducted in this study to clarify the genetic relationship between the Niancaowan mafic-ultramafic intrusion and known Cu<img>Ni deposits within the rift zone, as well as to assess the comparability of their mineralization potential. Through integrated petrographic observations, high-precision geochronological dating, whole-rock geochemical analyses, and zircon Hf isotope tracing, the research specifically focused on elucidating the magmatic source characteristics, rock-forming timing, and magmatic evolutionary processes of the intrusion. The Niancaowan mafic-ultramafic intrusion is predominantly composed of hornblende gabbro and gabbro-diabase. LA-ICP-MS zircon U<img>Pb dating reveals that the hornblende gabbro crystallized during the Early Permian (273.2 ± 3.5 Ma), which demonstrates temporal synchronicity with the emplacement ages of other mafic-ultramafic intrusions within the central-western Inner Mongolia rift system. Geochemical tracers further disclose significant zircon Hf isotopic heterogeneity, indicating that the parental magma was derived from partial melting of a lithospheric mantle source and underwent contamination by lower crustal materials during its ascent. Comparative analysis indicates that the zircon Hf isotopic compositions of the Niancaowan intrusion (ε<sub>Hf</sub>(t) = −17.0 to +1.4) are similar to those of typical regional intrusions such as the Wulantaolegai and Huanghuatan intrusions, revealing that crustal contamination was prevalent during the emplacement of mafic-ultramafic magmatic systems within the Bayan Obo Rift Zone. The incorporation of such crust-derived components may be controlled by the melting or assimilation processes of ancient basement rocks in the extensional setting of the rift zone. The petrological characteristics and quantitative modeling results indicate that the Niancaowan intrusion experienced relatively weak crustal contamination (4 %–8 %). If sulfide mineralization were to occur in this intrusion, it would primarily depend on deep-seated magmatic differentiation. Comparative studies between the Niancaowan intrusion and other intrusive bodies within the Bayan Obo Rift Zone reveal that the mineral exploration potential of mafic-ultramafic intrusions in the Bayan Obo Rift Zone should not be overlooked. Particular attention should be given to highly contaminated mafic-ultramafic intrusion clusters within the rift zone and multi-stage tectonic-magmatic convergence nodes.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126359"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.chemer.2025.126363
Abdelmadjid Seddiki , Bertrand Moine , Jérôme Bascou , Ratiba Kared , Jean Yves Cottin , Marguerite Godard , François Faure , Richard C. Greenwood , Ian A. Franchi
Northwest Africa (NWA) 4269 is an anomalous monomict eucrite that is characterized by a very high content of metallic iron (~ 3 %). It shows various textures (relict magmatic sub-ophitic, granulitic areas as coarse and fine-grained). NWA 4269 also shows petrographic evidence of secondary sub-solidus reheating events. Pyroxenes have homogeneous compositions and are iron-rich. NWA 4269 is metamorphosed type 5. It has a normal HED oxygen isotope composition. The chemical composition of NWA 4269 has characteristics similar to that of Nuevo-Laredo trend eucrites. Metal is extremely abundant in the fine-grained areas (~ 10 %). Metal also has a very low Ni content (Ni < 0.1 %) that excludes a direct origin from a chondrite-like impactor. Origin of the pure-Fe groundmass metal remains enigmatic. The high metal content in NWA 4269 can be interpreted as having formed via the reduction of FeO and probably also by desulfidation of pre-existing troilite. Iron metal could have formed by deposition from a Fe-rich fluid that, probably after an event that triggered sudden reduction. NWA 4269 has normal HED oxygen isotope compositions and interpreted as belonging to the 4-Vesta asteroid.
{"title":"Northwest Africa 4269: a metal-rich eucrite from the Algerian Sahara","authors":"Abdelmadjid Seddiki , Bertrand Moine , Jérôme Bascou , Ratiba Kared , Jean Yves Cottin , Marguerite Godard , François Faure , Richard C. Greenwood , Ian A. Franchi","doi":"10.1016/j.chemer.2025.126363","DOIUrl":"10.1016/j.chemer.2025.126363","url":null,"abstract":"<div><div>Northwest Africa (NWA) 4269 is an anomalous monomict eucrite that is characterized by a very high content of metallic iron (~ 3 %). It shows various textures (relict magmatic sub-ophitic, granulitic areas as coarse and fine-grained). NWA 4269 also shows petrographic evidence of secondary sub-solidus reheating events. Pyroxenes have homogeneous compositions and are iron-rich. NWA 4269 is metamorphosed type 5. It has a normal HED oxygen isotope composition. The chemical composition of NWA 4269 has characteristics similar to that of Nuevo-Laredo trend eucrites. Metal is extremely abundant in the fine-grained areas (~ 10 %). Metal also has a very low Ni content (Ni < 0.1 %) that excludes a direct origin from a chondrite-like impactor. Origin of the pure-Fe groundmass metal remains enigmatic. The high metal content in NWA 4269 can be interpreted as having formed via the reduction of FeO and probably also by desulfidation of pre-existing troilite. Iron metal could have formed by deposition from a Fe-rich fluid that, probably after an event that triggered sudden reduction. NWA 4269 has normal HED oxygen isotope compositions and interpreted as belonging to the 4-Vesta asteroid.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126363"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phoscorites (fluorapatite dominated rocks) from the Beldih carbonatite-alkaline complex of the South Purulia Shear Zone in eastern India were studied to investigate how the presence P in melt determines the fate of rare earth elements (REEs) enrichment in carbonatite during its magmatic and hydrothermal evolutionary stages through detailed petrographic and geochemical analyses. The study suggests that P-saturation at an early stage of magma evolution at Beldih facilitated early fluorapatite formation through fractional crystallization or exsolution of phosphorus-rich melt from the carbonatite counterpart led to phoscorite formation. The early fluorapatite fractionated almost all the REEs from melt, preventing direct REE crystallization.
Study of the associated calcite-bearing ultramafic silicate rocks, together with the phoscorites, revealed the occurrence of both magmatic (Fap1a and Fap1b) and hydrothermal or secondary (Fap2) varieties of fluorapatite with monazite, allanite, crandallite, and minor baddeleyite and betafite in the vicinity. The ΣREE2O3 contents in Fap1a > Fap1b > Fap2 with up to 1.50 wt% in Fap1a and Fap1b. They exhibit higher Z-contrast in BSE images than Fap2 alongside indications of hydrothermal dissolution-reprecipitation and REE redistribution manifested as intricate associations of secondary Fap2, crandallite, monazite, and allanite with both magmatic and hydrothermal variants of fluorapatite. The geochemical and textural evidence suggests that REE precipitation happened through two mutually compatible, low-mobility pathways (i.e., dissolution-reprecipitation and in-situ conversion) with only a few micrometers to essentially no REE mobilization. These pathways formed monazite in phoscorite and allanite in ultramafic rocks with Fe, Al, and Si after fluorapatite dissolution and fast REE immobilization by phosphorous at the reaction front. Aluminium-bearing fluid influx caused crandallite precipitation in phoscorite during fluorapatite dissolution. These findings demonstrate that the hydrothermal processes are only capable of localized REE redistribution rather than large-scale mobilization.
{"title":"Phosphorus-induced REE enrichment and hydrothermal alteration in the Beldih fluorapatite-bearing rock, Purulia, West Bengal: Implications for REE mineralization","authors":"Reeya Ghosh , Ashim Kumar Patel , Manoj Kumar Ozha , Sakthi Saravanan Chinnasamy","doi":"10.1016/j.chemer.2025.126352","DOIUrl":"10.1016/j.chemer.2025.126352","url":null,"abstract":"<div><div>Phoscorites (fluorapatite dominated rocks) from the Beldih carbonatite-alkaline complex of the South Purulia Shear Zone in eastern India were studied to investigate how the presence P in melt determines the fate of rare earth elements (REEs) enrichment in carbonatite during its magmatic and hydrothermal evolutionary stages through detailed petrographic and geochemical analyses. The study suggests that P-saturation at an early stage of magma evolution at Beldih facilitated early fluorapatite formation through fractional crystallization or exsolution of phosphorus-rich melt from the carbonatite counterpart led to phoscorite formation. The early fluorapatite fractionated almost all the REEs from melt, preventing direct REE crystallization.</div><div>Study of the associated calcite-bearing ultramafic silicate rocks, together with the phoscorites, revealed the occurrence of both magmatic (Fap1a and Fap1b) and hydrothermal or secondary (Fap2) varieties of fluorapatite with monazite, allanite, crandallite, and minor baddeleyite and betafite in the vicinity. The ΣREE<sub>2</sub>O<sub>3</sub> contents in Fap1a > Fap1b > Fap2 with up to 1.50 wt% in Fap1a and Fap1b. They exhibit higher <em>Z</em>-contrast in BSE images than Fap2 alongside indications of hydrothermal dissolution-reprecipitation and REE redistribution manifested as intricate associations of secondary Fap2, crandallite, monazite, and allanite with both magmatic and hydrothermal variants of fluorapatite. The geochemical and textural evidence suggests that REE precipitation happened through two mutually compatible, low-mobility pathways (i.e., dissolution-reprecipitation and in-situ conversion) with only a few micrometers to essentially no REE mobilization. These pathways formed monazite in phoscorite and allanite in ultramafic rocks with Fe, Al, and Si after fluorapatite dissolution and fast REE immobilization by phosphorous at the reaction front. Aluminium-bearing fluid influx caused crandallite precipitation in phoscorite during fluorapatite dissolution. These findings demonstrate that the hydrothermal processes are only capable of localized REE redistribution rather than large-scale mobilization.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126352"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.chemer.2025.126354
Aleš Šoster , Matej Dolenec , Luna Grum-Verdinek , Janez Zavašnik
The evaporites in the Karawanke Mountains (northwestern Slovenia) are hosted in a structurally complex lithological sequence, intercalated between Carboniferous-Permian and Permo-Triassic rocks. These evaporites are primarily composed of gypsum, with minor amounts of anhydrite, dolomite, and barite-celestine. Geochemically, the evaporites are characterized by elevated Sr (2000–2700 mg kg−1) and low Ba (210–400 mg kg−1) contents, reflecting the contrasting solubility behaviors of these elements in low-temperature syngenetic environments. Thermal dehydration, induced by peak burial temperatures ranging from 190 to 260 °C facilitated the transformation of gypsum to anhydrite. Subsequent cooling below the anhydrite stability threshold enabled gradual rehydration, accounting for the coexistence of both minerals. Thermal alteration also mobilized trace elements from the evaporites, which precipitated as secondary celestine and barite through dissolution-reprecipitation mechanisms, producing compositionally zoned fracture infills. The observed zoning, transitioning from Ba-rich to Sr-rich endmembers, likely reflects shifts in temperature, solubility and the chemical reactivity of evaporite-derived brine. Sulfur isotope analyses reveal δ34S values of +11.8 to +13.7 ‰ for the evaporitic sulfates, showing minimal variation and only a small difference relative to coexisting sulfides. This small isotopic offset indicates nearly complete sulfate reduction under high-temperature conditions, consistent with thermal alteration inferred from burial temperatures. These geochemical and isotopic results put forward not only the thermal and diagenetic evolution of the Karawanke evaporites but also their broader significance as minor reservoirs of strontium, a critical element with growing industrial and technological importance.
Karawanke山脉（斯洛文尼亚西北部）的蒸发岩赋存于石炭-二叠纪和二叠-三叠纪岩石之间的构造复杂的岩性层序中。这些蒸发岩主要由石膏组成，少量有硬石膏、白云石和重晶石天青石。在地球化学上，蒸发岩具有Sr含量高（2000 ~ 2700 mg kg - 1）和Ba含量低（210 ~ 400 mg kg - 1）的特征，反映了这两种元素在低温同生环境中溶解度的差异。190 ~ 260℃的峰值埋藏温度引起的热脱水促进了石膏向硬石膏的转变。随后冷却到硬石膏稳定阈值以下，使其逐渐再水化，这是两种矿物共存的原因。热蚀变还调动了蒸发岩中的微量元素，这些元素通过溶蚀-再沉淀机制沉淀为次生天青石和重晶石，形成了成分分带的裂缝充填体。观察到的分带，从富ba到富sr的端元转变，可能反映了蒸发岩衍生盐水的温度、溶解度和化学反应性的变化。硫同位素分析表明，蒸发硫酸盐的δ34S值为+11.8 ~ +13.7‰，变化不大，与共存的硫化物相比差异不大。这种小的同位素偏移表明在高温条件下硫酸盐几乎完全还原，与从埋藏温度推断的热蚀变相一致。这些地球化学和同位素结果不仅表明了卡拉万克蒸发岩的热演化和成岩演化，而且表明了其作为锶小型储层的广泛意义。锶是一种具有日益重要的工业和技术重要性的关键元素。
{"title":"Mineralogical and geochemical significance of secondary burial-related barite and celestine: Evidence from Late Paleozoic evaporites in the Karawanke Mountains (Slovenia)","authors":"Aleš Šoster , Matej Dolenec , Luna Grum-Verdinek , Janez Zavašnik","doi":"10.1016/j.chemer.2025.126354","DOIUrl":"10.1016/j.chemer.2025.126354","url":null,"abstract":"<div><div>The evaporites in the Karawanke Mountains (northwestern Slovenia) are hosted in a structurally complex lithological sequence, intercalated between Carboniferous-Permian and Permo-Triassic rocks. These evaporites are primarily composed of gypsum, with minor amounts of anhydrite, dolomite, and barite-celestine. Geochemically, the evaporites are characterized by elevated Sr (2000–2700 mg kg<sup>−1</sup>) and low Ba (210–400 mg kg<sup>−1</sup>) contents, reflecting the contrasting solubility behaviors of these elements in low-temperature syngenetic environments. Thermal dehydration, induced by peak burial temperatures ranging from 190 to 260 °C facilitated the transformation of gypsum to anhydrite. Subsequent cooling below the anhydrite stability threshold enabled gradual rehydration, accounting for the coexistence of both minerals. Thermal alteration also mobilized trace elements from the evaporites, which precipitated as secondary celestine and barite through dissolution-reprecipitation mechanisms, producing compositionally zoned fracture infills. The observed zoning, transitioning from Ba-rich to Sr-rich endmembers, likely reflects shifts in temperature, solubility and the chemical reactivity of evaporite-derived brine. Sulfur isotope analyses reveal δ<sup>34</sup>S values of +11.8 to +13.7 ‰ for the evaporitic sulfates, showing minimal variation and only a small difference relative to coexisting sulfides. This small isotopic offset indicates nearly complete sulfate reduction under high-temperature conditions, consistent with thermal alteration inferred from burial temperatures. These geochemical and isotopic results put forward not only the thermal and diagenetic evolution of the Karawanke evaporites but also their broader significance as minor reservoirs of strontium, a critical element with growing industrial and technological importance.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126354"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.chemer.2025.126355
Karla R. Hernández Martínez , Sanjeet K. Verma , Darío Torres-Sánchez , Erik Emmanuel M. Torres , José R. Torres Hernández , Sonia A. Torres-Sánchez , Hector Hernández-Mendoza , Juan Antonio Moreno , José Manuel Fuenlabrada , Beatriz A. Rivera-Escoto
The Ventura Espiritu Santo Volcanic Field (VESVF), located in the central part of the Mesa Central (MC), Mexico, is a monogenetic volcanic field dominated by Late Pleistocene mafic volcanism. It covers an area of approximately 100 km between the localities of Cúcamo and Santa Lucia and is emplaced on a basement composed of metamorphic rocks of the Sierra de Salinas and Triassic marine sequences that are tectonically overlain by the Guerrero Terrane. This study presents new petrographic observations, whole-rock major-and trace-element geochemistry, and Sr-Nd isotopic data for mafic rocks from the Cúcamo, El Rosario, and Santa Lucía areas to constrain the magmatic processes involved in the origin and evolution. Chondrite-normalized REE patterns display moderate enrichment in Light Rare Earth Elements (LREE) accompanied by slight depletion in Heavy Rare Earth Elements (HREE) and absence of an Eu anomaly. Primitive mantle-normalized diagrams show prominent positive anomalies in K, P, and Ti, together with negative anomalies in Pb. The absence of Nb-Ta troughs, together with multidimensional discrimination diagrams, could indicate an affinity to intraplate geochemical signature. Isotopic composition (87Sr/86Sri = [0.70307–0.70353, εNd = +5.8 to +6.3] suggests derivation from an enriched mantle source. The trace-element behavior, supported by geochemical modeling, further indicates that the mafic rocks were generated by low degree of partial melting of the enriched lherzolite upper lithospheric mantle source, pointing to a tectonic environment dominated by lithospheric extension and asthenospheric upwelling.
{"title":"Major and trace element geochemistry and Sr–Nd isotopic constraints on mafic volcanic rocks from the Ventura-Espiritu Santo Volcanic Field, San Luis Potosi, Mexico: Petrogenesis and tectonic implications of Cenozoic volcanism in the Basin and Range Province","authors":"Karla R. Hernández Martínez , Sanjeet K. Verma , Darío Torres-Sánchez , Erik Emmanuel M. Torres , José R. Torres Hernández , Sonia A. Torres-Sánchez , Hector Hernández-Mendoza , Juan Antonio Moreno , José Manuel Fuenlabrada , Beatriz A. Rivera-Escoto","doi":"10.1016/j.chemer.2025.126355","DOIUrl":"10.1016/j.chemer.2025.126355","url":null,"abstract":"<div><div>The Ventura Espiritu Santo Volcanic Field (VESVF), located in the central part of the Mesa Central (MC), Mexico, is a monogenetic volcanic field dominated by Late Pleistocene mafic volcanism. It covers an area of approximately 100 km between the localities of Cúcamo and Santa Lucia and is emplaced on a basement composed of metamorphic rocks of the Sierra de Salinas and Triassic marine sequences that are tectonically overlain by the Guerrero Terrane. This study presents new petrographic observations, whole-rock major-and trace-element geochemistry, and Sr-Nd isotopic data for mafic rocks from the Cúcamo, El Rosario, and Santa Lucía areas to constrain the magmatic processes involved in the origin and evolution. Chondrite-normalized REE patterns display moderate enrichment in Light Rare Earth Elements (LREE) accompanied by slight depletion in Heavy Rare Earth Elements (HREE) and absence of an Eu anomaly. Primitive mantle-normalized diagrams show prominent positive anomalies in K, P, and Ti, together with negative anomalies in Pb. The absence of Nb-Ta troughs, together with multidimensional discrimination diagrams, could indicate an affinity to intraplate geochemical signature. Isotopic composition (<sup>87</sup>Sr/<sup>86</sup>Sr<sub>i</sub> = [0.70307–0.70353, εNd = +5.8 to +6.3] suggests derivation from an enriched mantle source. The trace-element behavior, supported by geochemical modeling, further indicates that the mafic rocks were generated by low degree of partial melting of the enriched lherzolite upper lithospheric mantle source, pointing to a tectonic environment dominated by lithospheric extension and asthenospheric upwelling.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126355"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.chemer.2025.126365
Xuanchi Deng , Xiaofeng Li , Yiting Zhu , Heng Xu , Yong Yu
Li-Rb-Cs rare metal mineralization is closely linked to highly fractionated granites. However, the origin of Li-Rb-Cs rare metal mineralization during the shear-deformation remains unclear. The Gaoligong Shear Zone (GSZ) is situated along the eastern margin of Tibetan in southwestern China. It is a dextral strike-slip shear zone formed by the northward movement of the India Plate to relative to the Eurasia Plate during Oligocene-Miocene. Bulk mineral composition, together with EMPA and LA-ICP-MS data, reveal that Li-Rb-Cs-rich phlogopite occurs in Carboniferous metamorphic rocks of the GSZ. This phlogopite is enriched in F (4.29–5.06 wt%), Li (1281–1849 ppm), Rb (2550–3242 ppm), and Cs (386–1575 ppm), but depleted in Be (<1 ppm). In contrast, scapolite (marialite) intergrown with the Li-Rb-Cs-rich phlogopites is enriched in Be (31.31–91.34 ppm), and Ga (38.92–48.83 ppm), but poor in Li (1.86–18.71 ppm). Two phlogopite samples yield 40Ar39Ar plateau ages of 15.64 ± 0.36 Ma, and 14.44 ± 0.23 Ma, indicating Miocene formation. These ages coincide with major shearing and regional metamorphism in the Gaoligong area. This suggests the formation of Li-Rb-Cs-rich phlogopite may have been related to intense shearing and intracrustal melting. Magma-derived metasomatic hydrothermal fluids may have contributed to the formation of the Li-Rb-Cs-rich phlogopite and the Be-rich scapolite. The study suggests that the Li-Rb-Cs rare metal mineralization can form during the shear deformation and that F-rich phlogopite is a promising indicator for rare-metal exploration in the shear deformation zone.
{"title":"Shear-deformation related Li-Rb-Cs mineralization: The case study from mineral chemistry and 40Ar39Ar ages of phlogopite in the Gaoligong Shear Zone, eastern Tibetan","authors":"Xuanchi Deng , Xiaofeng Li , Yiting Zhu , Heng Xu , Yong Yu","doi":"10.1016/j.chemer.2025.126365","DOIUrl":"10.1016/j.chemer.2025.126365","url":null,"abstract":"<div><div>Li-Rb-Cs rare metal mineralization is closely linked to highly fractionated granites. However, the origin of Li-Rb-Cs rare metal mineralization during the shear-deformation remains unclear. The Gaoligong Shear Zone (GSZ) is situated along the eastern margin of Tibetan in southwestern China. It is a dextral strike-slip shear zone formed by the northward movement of the India Plate to relative to the Eurasia Plate during Oligocene-Miocene. Bulk mineral composition, together with EMPA and LA-ICP-MS data, reveal that Li-Rb-Cs-rich phlogopite occurs in Carboniferous metamorphic rocks of the GSZ. This phlogopite is enriched in F (4.29–5.06 wt%), Li (1281–1849 ppm), Rb (2550–3242 ppm), and Cs (386–1575 ppm), but depleted in Be (<1 ppm). In contrast, scapolite (marialite) intergrown with the Li-Rb-Cs-rich phlogopites is enriched in Be (31.31–91.34 ppm), and Ga (38.92–48.83 ppm), but poor in Li (1.86–18.71 ppm). Two phlogopite samples yield <sup>40</sup>Ar<img><sup>39</sup>Ar plateau ages of 15.64 ± 0.36 Ma, and 14.44 ± 0.23 Ma, indicating Miocene formation. These ages coincide with major shearing and regional metamorphism in the Gaoligong area. This suggests the formation of Li-Rb-Cs-rich phlogopite may have been related to intense shearing and intracrustal melting. Magma-derived metasomatic hydrothermal fluids may have contributed to the formation of the Li-Rb-Cs-rich phlogopite and the Be-rich scapolite. The study suggests that the Li-Rb-Cs rare metal mineralization can form during the shear deformation and that F-rich phlogopite is a promising indicator for rare-metal exploration in the shear deformation zone.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"86 1","pages":"Article 126365"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145658899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.chemer.2025.126357
Ayşe Orhan
The newly discovered Gülkonak Fe-skarn deposit is located in Central Anatolia and lies at the contact zone between the late Cretaceous Behrekdağ granitoid and the late Permian Bozçaldağ marble. The Behrekdağ granitoid is quartz-monzonite – monzonite in composition and contains abundant MMEs of monzonite – monzodiorite composition. Whole-rock and mineral chemistry data suggest that the pluton was associated with subduction in a continental arc setting and derived from crust, mantle, and/or mixed sources. A couple of phases representing different physicochemical conditions in the continental crust for iron mineralization have been identified based on amphibole mineral chemistry. The first phase, which indicates the mixing of mafic-felsic magmas, exhibits relatively high pressure (132–203 MPa), depth (5.0–7.7 km), and temperature (804–871 °C), and moderate-high ƒO2 (ΔNNO: −0.01 to +0.50) and H2O content (3.5–4.9 wt%) in the melt. The second phase is the dissolution of Fe-rich liquid, characterized by decreasing pressure (44–45 MPa), depth (1.7 km), temperature (732–736 °C), and H2O content (3.6–3.9 wt%) and increasing ƒO2 (ΔNNO: +1.1 to +1.2) conditions.
Magnetites in Gülkonak Fe deposits occur as massive, irregular lenses and disseminated in the proximal and distal zones. Different types of magnetites were characterized by skarn-type deposit with Ca, Al, Ti, and V contents. Five main stages for skarn formation and mineralization were distinguished in the region: (1) Na-(Ca) alterations consisting mainly of albite (Ab98) and actinolite; (2) prograde stage representing of early-andradite (Grs0.0–28And72–100) and diopside (Di66–95Hed4–31Joh0–3) genetically related to mineralization and late-grossular-andradite (Grs0.00–99.9And0.1–99.6); (3) retrograde stage consisting of epidote (Ep57–72Cli28–43), magnetite, quartz, calcite, and less sulfide (pyrite, chalcopyrite) and chlorite (Mg-chlorite); (4, 5) quartz‑carbonate and supergene stage characterized by quartz, calcite, hematite, goethite, and less siderite, bornite, chalcocite, covellite and malachite.
These findings suggest that skarn and Fe mineralization are genetically related to the Behrekdağ granitoid. It is suggested that the sudden uplift of Fe-Mg-enriched melt into the shallow continental crust through magma-mixing processes may have promoted extensive dissolution of magmatic fluids. The metasomatic reaction of high-ƒO2 and Fe3+-rich ore-forming fluids with carbonate rocks produced andradite and diopside. It can be stated that the primary mechanisms responsible for the precipitation of metals in Gülkonak skarn deposits are increased pH and decreased temperatures, resulting from the reaction of metals transported as metal chlorides with carbonate rocks.
{"title":"Mineral chemistry of the Gülkonak Fe-Skarn Deposit, Central Anatolia, Türkiye: Implications for ore genesis and mineralization process","authors":"Ayşe Orhan","doi":"10.1016/j.chemer.2025.126357","DOIUrl":"10.1016/j.chemer.2025.126357","url":null,"abstract":"<div><div>The newly discovered Gülkonak Fe-skarn deposit is located in Central Anatolia and lies at the contact zone between the late Cretaceous Behrekdağ granitoid and the late Permian Bozçaldağ marble. The Behrekdağ granitoid is quartz-monzonite – monzonite in composition and contains abundant MMEs of monzonite – monzodiorite composition. Whole-rock and mineral chemistry data suggest that the pluton was associated with subduction in a continental arc setting and derived from crust, mantle, and/or mixed sources. A couple of phases representing different physicochemical conditions in the continental crust for iron mineralization have been identified based on amphibole mineral chemistry. The first phase, which indicates the mixing of mafic-felsic magmas, exhibits relatively high pressure (132–203 MPa), depth (5.0–7.7 km), and temperature (804–871 °C), and moderate-high ƒO<sub>2</sub> (ΔNNO: −0.01 to +0.50) and H<sub>2</sub>O content (3.5–4.9 wt%) in the melt. The second phase is the dissolution of Fe-rich liquid, characterized by decreasing pressure (44–45 MPa), depth (1.7 km), temperature (732–736 °C), and H<sub>2</sub>O content (3.6–3.9 wt%) and increasing ƒO<sub>2</sub> (ΔNNO: +1.1 to +1.2) conditions.</div><div>Magnetites in Gülkonak Fe deposits occur as massive, irregular lenses and disseminated in the proximal and distal zones. Different types of magnetites were characterized by skarn-type deposit with Ca, Al, Ti, and V contents. Five main stages for skarn formation and mineralization were distinguished in the region: (1) Na-(Ca) alterations consisting mainly of albite (Ab<sub>98</sub>) and actinolite; (2) prograde stage representing of early-andradite (Grs<sub>0.0–28</sub>And<sub>72–100</sub>) and diopside (Di<sub>66–95</sub>Hed<sub>4–31</sub>Joh<sub>0–3</sub>) genetically related to mineralization and late-grossular-andradite (Grs<sub>0.00–99.9</sub>And<sub>0.1–99.6</sub>); (3) retrograde stage consisting of epidote (Ep<sub>57–72</sub>Cli<sub>28–43)</sub>, magnetite, quartz, calcite, and less sulfide (pyrite, chalcopyrite) and chlorite (Mg-chlorite); (4, 5) quartz‑carbonate and supergene stage characterized by quartz, calcite, hematite, goethite, and less siderite, bornite, chalcocite, covellite and malachite.</div><div>These findings suggest that skarn and Fe mineralization are genetically related to the Behrekdağ granitoid. It is suggested that the sudden uplift of Fe-Mg-enriched melt into the shallow continental crust through magma-mixing processes may have promoted extensive dissolution of magmatic fluids. The metasomatic reaction of high-ƒO<sub>2</sub> and Fe<sup>3+</sup>-rich ore-forming fluids with carbonate rocks produced andradite and diopside. It can be stated that the primary mechanisms responsible for the precipitation of metals in Gülkonak skarn deposits are increased pH and decreased temperatures, resulting from the reaction of metals transported as metal chlorides with carbonate rocks.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 4","pages":"Article 126357"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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