Chemie Der Erde-Geochemistry最新文献

{"title":"The role of fluid overpressure in Cu-Au porphyry mineralization: Evidence from the Oubulage deposit, Inner Mongolia, China","authors":"Xuegen Chen ,&nbsp;Shangguo Su ,&nbsp;M. Santosh ,&nbsp;Yanan Zhang ,&nbsp;Xiaoman Wu ,&nbsp;Jingyu Zhong ,&nbsp;Xiaowei Li","doi":"10.1016/j.chemer.2025.126258","DOIUrl":"10.1016/j.chemer.2025.126258","url":null,"abstract":"<div><div>Fluids play a critical role in the formation of porphyry copper (Cu)‑gold (Au) deposits, although the mechanism of metal transport remains enigmatic. The presence of phengite in the Oubulage porphyry Cu-Au deposit in Inner Mongolia provides a unique opportunity to evaluate this problem. In this study, we present results from texture, elemental and isotopic composition of phengite and calcite in the Oubulage quartz porphyry, with a view to understand the role of fluids in the ore genesis. The quartz phenocrysts from this deposit show shock-induced textures, substantial fragmentation, and deformation lamellae in quartz porphyry. The phenocrysts are frequently intersected by veins which consist of phengite, K-feldspar, rutile, ankerite, apatite, and sulfide. Phengite, with Si contents peaking at 3.40 apfu indicates a maximum pressure of approximately 14.4 Kbar. The quartz porphyry shows vesicular and amygdaloidal structures, with vesicular volumes reaching a maximum of 25 %. The elevated Nb + Ta contents and a Nb/Ta ratio exceeding 17.7 in phengite, suggest the important role of supercritical fluids for the origin of phengite. According to the Zr thermometer for rutile, the temperature of these supercritical fluids is approximately 788.3 °C. In-situ carbon‑oxygen isotopic measurements in calcite associated with the sulfide mineralization (δ¹³C_PDB ranging from −6.54 ‰ to −4.26 ‰ and δ¹⁸O_VSMOW between 8.24 ‰ and 9.13 ‰)， and the strontium isotope measurements in apatite (⁸⁷Sr/⁸⁶Sr = 0.7056–0.7060) associated with sulfide mineralization, suggest a mantle source for the fluids. We propose that the injection of supercritical fluids rich in Si, Ti, Al, K, Fe, C and F into sulfide melt might have caused fluid overpressure in the magma chamber. This resulted in the fracturing of the phenocryst minerals and formation of high-Si phengite, as well as propelling the upward movement of the ore-bearing melt-fluid towards the upper crust. Our findings also have implications for the exploration of porphyry ore deposits.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126258"},"PeriodicalIF":2.6,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithospheric thinning of the North China Craton: Constraints from Mesozoic mafic dikes in the Jiaodong Peninsula","authors":"Hui Chen,&nbsp;Bin Li","doi":"10.1016/j.chemer.2025.126254","DOIUrl":"10.1016/j.chemer.2025.126254","url":null,"abstract":"<div><div>The North China Craton (NCC) has undergone substantial thinning of its Paleozoic lithosphere. The original lithosphere was supplanted by a juvenile one during the Mesozoic era. Nevertheless, ongoing scholarly discourse exists concerning the precise age and mechanism of this lithospheric thinning. In this paper, we examined U-Pb dates on gold-related diabase-porphyry along with whole-rock elemental and Nd-Sr isotopes. Three categories of diabase-porphyry have been identified based on their petrographic features and titanium content. These are the low-Ti diabase-porphyry from Shangzhuang, the medium-Ti lamprophyres from Huangbuling, and the high-Ti diabase-porphyry from Qilishan. Their TiO₂ content are &lt;1.1, 1.1, and &gt;1.1 wt% for the Shangzhuang, Huangbuling, and Qilishan, respectively. The Ti/Y ratio varies among them, with the highest value in the Qilishan diabase-porphyry, a lower value in the Shangzhuang diabase-porphyry (370), and medium values between 270 and 370 in the Huangbuling lamprophyres.</div><div>The geochemical nature of the low-Ti diabase-porphyry, which are LREE-rich and have a higher LILE/HFSE ratio, are evocative of volcanic arcs. The Nd-Sr isotopes of the low-Ti rocks closely resemble those of mafic dikes originating from a fertile mantle lithosphere in the Jiaodong Peninsula. Conversely, the high-Ti diabase-porphyry display OIB-like characteristics, featuring HFSE enrichment with no Nb-Ta depletion. Their Sr-Nd isotope compositions are similar to isotopic signatures from asthenosphere-derived rocks, suggesting that the high-Ti diabase-porphyry may have originated in an asthenospheric mantle. Lastly, the Sr-Nd compositions of the medium-Ti diabase-porphyry fall between those of the low and high titanium diabase-porphyry, and they show weak enrichments in LILE/HFSE and LREE. This implies that a mixed melt of lithosphere and asthenosphere may have generated the medium-Ti lamprophyres. Zircon U-Pb isotopes suggests that the medium-Ti lamprophyres record weak lithospheric thinning in response to the sinking and/or rollback of the subducting oceanic slab at 155 Ma. The coexistence of high-Ti and low-Ti diabase-porphyry signifies a rapid shift in the magma sources from those derived from the lithosphere to those derived from the asthenosphere. This suggests lithospheric detachment (at 75–85 km depth) just before 127 Ma beneath the Jiaodong Peninsula.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126254"},"PeriodicalIF":2.6,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The carbonate and zeolite alterations in bitumen-containing volcanic rocks of the Minusa Basin, eastern Siberia","authors":"Alexey Ruban,&nbsp;Anastasiya Nikolaeva,&nbsp;Diana Molukpaeva,&nbsp;Evan Dasi,&nbsp;Marina Shaminova,&nbsp;Maxim Rudmin","doi":"10.1016/j.chemer.2025.126257","DOIUrl":"10.1016/j.chemer.2025.126257","url":null,"abstract":"<div><div>Intense alterations in the form of secondary carbonates, zeolites, and phyllosilicates characterize the volcanic rocks widespread in the Minusa Basin. A common feature of the studied Early Devonian sheet-like and Triassic dyke volcanics is the amygdules of solid bitumen, indicating a potential water-volcanic rocks-hydrocarbons interaction. This paper presents new data on petrography, mineralogy, and stable isotope geochemistry of carbonates and zeolites in Devonian and Triassic basaltic rocks of the Minusa Basin. Calcite and analcime are the main secondary minerals filling pores and fractures in the studied volcanic rocks. These rocks include basalts, trachybasalts, and trachyandesibasalts of the Early Devonian Byskar series, as well as altered olivine basalts of the Triassic Kopievo complex. Calcite was found in all studied samples, whereas analcime was identified only in altered olivine basalts. The carbon isotopic composition of calcite in the Devonian volcanic rocks indicates that the main carbon source was seawater, which could infiltrate into the basaltic bodies through numerous fractures after flooding the region. Atmospheric water and hydrothermal influence were present, as indicated by differences in the carbon isotopic composition of calcite from different locations. In Triassic altered olivine basalts, calcite is represented by two types differing in textural features, isotopic composition, and manganese content. Very low δ¹⁸O values indicate that calcite formation in Triassic volcanic rocks occurred through precipitation from high-temperature solutions. It is assumed that these solutions were of mixed origin and consisted of both meteoric waters from the surrounding rocks and deep hydrothermal fluids, the generation of which may have occurred due to the magma cooling. Analcime fills numerous primary pores, and its formation appears to result from the interaction between volcanic material and Na-enriched water. Secondary minerals in both Early Devonian and Triassic volcanics were formed in two stages. Filling of primary pores with calcite and analcime occurred during the early postmagmatic stage. In contrast, calcite veins formed later under the conditions of marine (Devonian rocks) or meteoric (Triassic rocks) water dominance, which was controlled by the fracture development.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126257"},"PeriodicalIF":2.6,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-lived mantle plume for the emplacement of Paleoproterozoic Dharwar-Bastar Large Igneous Province: Geochemical and SrNd isotope constraints from mafic rocks of Dharwar craton, India","authors":"V. Parashuramulu,&nbsp;Tavheed Khan,&nbsp;Aurovinda Panda,&nbsp;D. Srinivasa Sarma","doi":"10.1016/j.chemer.2025.126256","DOIUrl":"10.1016/j.chemer.2025.126256","url":null,"abstract":"<div><div>A Paleoproterozoic large igneous province (LIP) has been identified between ∼1.89–1.85 Ga with evidence of precise U-Pb/Pb-Pb baddeleyite geochronology and spread over Dharwar, Bastar and Yilgarn cratons. Here, we present whole rock geochemistry and Sr, Nd isotopic results for the first time on precisely dated two disparate mafic dyke/sill swarms (∼1.89 Ga and ∼1.86 Ga) from the Dharwar craton to identify their mantle source signatures and emplacement mechanism. The majority of the samples from both swarms indicate basaltic composition and sub-alkaline tholeiitic nature. The ∼1.89 Ga and ∼1.86 Ga dykes exhibit enriched LREE and flat HREE patterns. Both swarms show LILE enrichment and negative Nb, Ta, and Ti anomalies, indicating that crustal components were involved in the generation of these dykes. Based on the batch melting model, the ∼1.89 Ga and ∼1.86 Ga swarms show varying degrees of partial melting (5–15% and 5–10%, respectively) and are emplaced from a shallower spinel lherzolitic source. The ∼1.89 Ga swarm is characterized by sub-chondritic Nd isotopic nature (_ƐNd_{(1.89 Ga)}=−8.9 to −3.1), while ∼1.86 Ga swarm decipher sub-chondritic to slight super chondritic Nd isotopic signatures (_ƐNd_{(1.86 Ga)}=−5.8 to +2.2). The correlation of Nd isotopic data with coeval mafic dykes from the Bastar and Yilgarn cratons indicates that the Dharwar and Bastar dykes originated from the partial melting of enriched subcontinental lithospheric mantle (SCLM), while Yilgarn dykes from the depleted SCLM during their emplacement at ∼1.89 Ga. Based on precise ages, dyke geometry, geochemical and Sr, Nd isotopic results of ∼1.89 to ∼1.85 Ga mafic events, the Indian dykes (Dharwar and Bastar cratons) and Western Australian dykes (Yilgarn craton) display different geochemical and isotopic characteristics, suggesting that these mafic events were emplaced in two separate pulses from a common plume source.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126256"},"PeriodicalIF":2.6,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coprecipitation of Ce with lead phosphates","authors":"Kacper Staszel ,&nbsp;Julia Sordyl ,&nbsp;Bartosz Puzio ,&nbsp;Maciej Manecki","doi":"10.1016/j.chemer.2025.126252","DOIUrl":"10.1016/j.chemer.2025.126252","url":null,"abstract":"<div><div>Current development of sustainable technologies creates a demand for new sources of Rare Earth Elements (REE). Recent studies suggest that coprecipitation in the form of Pb-phosphates is one of the most effective methods in REE removal from aqueous solutions. This work focuses on the experimental study of the mechanisms of Ce coprecipitation with Pb phosphates, in particular with lead apatite - pyromorphite (Pb₅(PO₄)₃Cl). Coprecipitation experiments were conducted at ambient conditions, at pH range 1–11, by mixing solutions containing high concentrations of Pb and Ce (∼66,700 ppm and ∼ 7600 ppm, respectively) with solutions containing stoichiometric concentrations of PO₄ and Cl. As a result of coprecipitation with Pb phosphates, the Ce concentration decreased significantly to &lt;2 ppm. The main product of the coprecipitation was Ce-doped pyromorphite (Pym<img>Ce). Removal of Ce was most effective under alkaline conditions, while performance was slightly worse under acidic conditions, due in part to the slightly higher solubility of the precipitate. This was compared with a series of control experiments in the absence of either Pb, Cl, or Ce. Precipitation in the absence of Pb resulted in the formation of fibrous rhabdophane-Ce. In the absence of Cl, various phases were formed depending on pH conditions, such as ‘phosphoschultenite’ (PbHPO₄), Pb-hopeite (PbPb₂(PO₄)₂·<em>n</em>H₂O), mixed Pb and Ce hydrous phosphates, and hydroxylpyromorphite (Pb₅(PO₄)₃OH). In the absence of Ce, pure microcrystalline pyromorphite precipitated. Coprecipitation of Ce with Pb phosphates in the presence of Cl is advantageous due to the recovery of almost all Ce from solution in the form of a micro-crystalline Pym-Ce that is a very stable, insoluble phase easily separated from suspension. The precipitation of Pym-Ce is homogenous over a wide range of pH, assuring consistency in the obtained phases regardless of starting conditions. Achieved high Ce removal levels may be crucial for the progress of the REE extraction industry, in terms of this method being applicable to other REE for their recovery from solutions, including apatite leachates.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126252"},"PeriodicalIF":2.6,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence of a Cenomanian carbonatite emplacement linked with the Marion mantle plume and breakup of India–Madagascar: Constraints from 40Ar-39Ar geochronology and geochemistry of carbonatite xenolith within the Ambadungar–Saidivasan carbonatite breccia, Western India","authors":"Rajesh K. Srivastava ,&nbsp;Fei Wang ,&nbsp;Amiya K. Samal ,&nbsp;Wenbei Shi ,&nbsp;Bijay K. Das","doi":"10.1016/j.chemer.2025.126250","DOIUrl":"10.1016/j.chemer.2025.126250","url":null,"abstract":"<div><div>A carbonatite xenolith from a carbonatite breccia exposure within the Ambadungar-Saidivasan alkaline carbonatite complex in western India has been examined for its emplacement age, mineral chemistry, and whole-rock geochemistry. Although this complex is generally linked with magmatic activities of the Réunion plume, which produced the ca. 66.0–65.5 Ma Deccan large igneous province, the studied xenolith yields phlogopite ⁴⁰Ar/³⁹Ar weighted plateau age of 97.0 ± 2.2 Ma. This age predates the arrival of the Réunion plume and likely reflects the crystallization and emplacement age of the xenolith. The timing coincides with the main India-Madagascar breakup, driven by the Marion hotspot, which occurred between 92 and 88 Ma. However, evidence suggests that the Marion hotspot was active along the rifted eastern margin of Madagascar as early as 120 Ma, continuing until the breakup at ca. 88 Ma. Several magmatic events with ages ranging from 93 Ma to 86 Ma from both the Indian and Madagascar plates highlight a connection to the Marion plume. The new ⁴⁰Ar/³⁹Ar date for the carbonatite xenolith, previously unreported from this region, along with its geochemical characteristics, suggests an association with early magmatic activity of the Marion plume, likely predating the rift and breakup phases. In addition to the older age, the carbonatite xenolith is distinguished from the other associated carbonatites by its higher Rb content (20 ppm) and a spoon-shaped HREE. These findings, along with existing geochronological and geophysical evidence, support the presence of the Marion hotspot beneath the western margin of the Indian Shield and the eastern margin of the Madagascar plate, driving widespread magmatism beginning as early as 120 Ma or potentially earlier.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126250"},"PeriodicalIF":2.6,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The magmatic to post-magmatic evolution of the Nooitgedacht Carbonatite Complex, South Africa","authors":"Mohsin Raza ,&nbsp;R. Johannes Giebel ,&nbsp;Sebastian Staude ,&nbsp;Aratz Beranoaguirre ,&nbsp;Jochen Kolb ,&nbsp;Gregor Markl ,&nbsp;Benjamin F. Walter","doi":"10.1016/j.chemer.2025.126249","DOIUrl":"10.1016/j.chemer.2025.126249","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Carbonatites are unusual, mantle-derived igneous rocks characterized by distinctive mineralogical and geochemical fingerprints that may decipher complex processes during their multi-stage evolution. A systematic petrographic, whole rock geochemistry, apatite and pyrochlore mineral chemistry, U-Pb geochronology, and C-O stable isotope study was performed on the carbonatites of the Nooitgedacht Carbonatite Complex in the Republic of South Africa in order to understand their genesis and evolution including the significant differences in the nature of their HFSE-REE endowment. Early carbonatite intrusion is reflected by a plug-like calcite carbonatite. A second stage carbonatite intrusion formed a ring-shaped, quartz-Fe-dolomite-calcite carbonatite comprising apatite and monazite. The third stage of carbonatite intrusion formed dolomite carbonatite dikes. The calcite carbonatite exhibits a well-developed magmatic stage characterized by the presence of oscillatory zoned, F-rich pyrochlore, pill-shaped apatite, magnetite and forsterite, while the hydrothermal stage is indicated by the presence of quartz, baryte, massive apatite, bastnäsite, and monazite. Although the second carbonatite generation is very similar to the first generation in terms of mineralogy, the hydrothermal overprint in particular is much more pronounced in the later. The third carbonatite generation, however, differs significantly from its two predecessors mineralogically and does not show any hydrothermal overprint. Whole rock ΣREE concentrations in early stage carbonatite range between 380 and 2200 ppm, the quartz-Fe-dolomite-calcite carbonatite shows a higher ΣREE concentrations between 3010 and 5900 ppm, while the third stage dolomite carbonatite has ΣREE concentrations between 574 and 2239 ppm. This trend follows a positive correlation with the degree of alteration, as REE mineralization occurs mainly in the hydrothermal post-magmatic stage. Pyrochlore observed in early calcite carbonatite shows oscillatory zoning overgrowing U-Ta rich resorbed cores (entrained from associated syenite). Pyrochlores observed in quartz-Fe-dolomite-calcite carbonatites exhibit relicts of fluorcalciopyrochlore (magmatic stage) overgrown by hydroxycalciopyrochlore (hydrothermal stage: characterized by patchy zonation) and hydropyrochlore (supergene stage: mainly characterized by narrow rims around the pyrochlore grains). Textural and compositional variations in apatite further allow tracking the evolution of Nooitgedacht carbonatites. Pill and ovoidal shaped apatites from calcite carbonatite and quartz-Fe-dolomite-calcite carbonatite, respectively, with marginal higher Si and less F concentrations shows a magmatic origin, while irregular apatite masses from calcite carbonatite and quartz-Fe-dolomite-calcite carbonatite (with higher Sr and F concentrations) suggest a hydrothermal origin. However, the dolomite carbonatite (third intrusion stage) lack both, apatite and pyrochlore. The in-situ","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126249"},"PeriodicalIF":2.6,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Formation and age of granites and molybdenum in Shuangyangshu, NE China: Insights from UPb and ReOs geochronology geochemistry, and Hf isotopes","authors":"Yufan Shi ,&nbsp;Bile Li ,&nbsp;YaMing Sun ,&nbsp;Zhihua Li ,&nbsp;YuTai Liu","doi":"10.1016/j.chemer.2025.126251","DOIUrl":"10.1016/j.chemer.2025.126251","url":null,"abstract":"<div><div>Recent research indicates that the magmatic–metallogenic events in Northeast China were mainly influenced by the tectonic regimes of the Paleo–Asian Ocean and the Paleo–Pacific Ocean. Nonetheless, significant challenges remain in comprehending the petrogenesis and source regions of the mineralizing magmas for metallogenic event. This study examines the geological chronology and geochemical data of ore–bearing granites and molybdenite from the Shuangyangshu molybdenum deposit in central Jilin. The objective is to ascertain their petrogenetic and metallogenic ages, petrogenesis, magmatic activity, and their implications for the geodynamic evolution of central Jilin. LA–ICP–MS zircon U<img>Pb dating reveals that the Shuangyangshu K–feldspar granite has an age of 179 Ma, and the monzogranite has an age of 178 Ma, indicating that they are synchronous phase change granites. Re<img>Os isotopic analysis of molybdenite indicates a metallogenic age of 176.3 Ma for the Shuangyangshu molybdenum deposit, which is closely associated with K–feldspar granite diagenesis. The Re content ranges from 9.4 to 17.8 μg/g, suggesting that the metallogenic source is predominantly crustal with a minor mantle–derived component. Petrological geochemical data classify the Shuangyangshu granites as high–potassium calc–alkaline series highly fractionated I–type granites. The εHf (t) values are positive, ranging from 7.1 to 9.1 and 6.2 to 8.9, respectively. The two–stage model ages (tDM2) range from 477 to 560 Ma and 558 to 697 Ma, indicating that the granite source is the partial melting of the Neoproterozoic high–potassium basaltic crust caused by the underplating of mantle–derived magma. Subsequently, the magma experienced extensive crystallization of plagioclase, K–feldspar, titanium–bearing minerals, monazite, apatite and allanite. Tectonic discrimination diagrams based on trace elements and their characteristic ratios suggest that Shuangyangshu granites formed during the subduction of the Paleo–Pacific Ocean. This implies that the Paleo–Pacific Ocean had already subducted in the early Jurassic, leading to the formation of numerous endogenic metal deposits. The subduction of the ancient Pacific Ocean plate led to regional compression, which was conducive to the accumulation of a large amount of magma in the deep, and finally formed a large molybdenum deposit.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126251"},"PeriodicalIF":2.6,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrology of Cenomanian basalts on the Brazilian equatorial margin: Implications for the tectonomagmatic evolution of the drift phase","authors":"Antomat Avelino de Macêdo Filho ,&nbsp;Alisson Lopes Oliveira ,&nbsp;Marthe Klöcking ,&nbsp;Valdecir de Assis Janasi ,&nbsp;Carlos José Archanjo ,&nbsp;Lucas Martins Lino","doi":"10.1016/j.chemer.2025.126248","DOIUrl":"10.1016/j.chemer.2025.126248","url":null,"abstract":"<div><div>Olivine basalts from the Serra do Cuó magmatism in the onshore Potiguar basin exhibit SiO₂ = 46–53 wt%, MgO = 9–12 wt%, and total alkalis = 3.5–6 wt%, combined to elevated concentrations of large ion lithophile elements (Rb, Ba, Th, U, K), positive anomalies of Nb and Ta, and fractionated heavy rare earth elements. These lavas constitute a single volcanic event with evidence of fractional crystallization primarily involving olivine and pyroxene. Whole rock ⁴⁰Ar/³⁹Ar geochronology provided a minimum crystallization age of 99 ± 1 Ma, which is chronologically compatible with other Albian/Cenomanian igneous activity in NE Brazil. Clinopyroxene geothermobarometry indicates a range of crystallization depths from 23 km to 6 km, supporting crystal growth in a magma plumbing system before the emplacement. Radiogenic isotopes reveal enriched mantle-type source, akin to Paleogene/Neogene alkali basalts elsewhere in NE Brazil. Rare earth element inverse modeling hints that Serra do Cuó melts originated at a mantle potential temperature of 1350 °C, approximately 60 km depth. The long-lived alkali basaltic volcanism across the NE Brazil likely resulted from decompression melting of the mantle due to a combination of geodynamic factors, including episodes of hotspot influence and changes in South America's drift pattern.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126248"},"PeriodicalIF":2.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Collisional orogeny processes in the Qinling Orogenic Belt during the Late Permian to Early Triassic: Evidence from detrital zircon geochronology in the south of North China","authors":"Wentao Yang,&nbsp;Qiang Fu,&nbsp;Jinkun Zhu","doi":"10.1016/j.chemer.2025.126247","DOIUrl":"10.1016/j.chemer.2025.126247","url":null,"abstract":"<div><div>The Qinling Orogenic Belt serves as a critical geological record documenting the closure of the eastern Paleo-Tethys Ocean during the Late Paleozoic to Early Mesozoic. This study investigates sandstone petrology and detrital zircon geochronology from Late Permian to Early Triassic strata in the south of North China Basin to conduct a provenance analysis. Petrographic data showed that all sample fall into a recycled orogenic provenance. Two detrital zircon samples from the Late Permian Shiqianfeng Formation exhibit two prominent age groups of Late Paleozoic-Early Mesozoic and Paleoarchean-Paleoproterozoic. Additionally, the sample from the upper part of the strata reveals secondary age groups of Early Paleozoic and Meso-Neoproterozoic. Detrital zircon samples from the Liujiagou and Heshanggou formations exhibit a similar age spectrum, encompassing the Late Paleozoic-Ealy Mesozoic, Early Paleozoic, Meso-Neoproterozoic, and Paleoarchean-Paleoproterozoic age groups. Combined detrital zircon ages with the paleogeography and paleocurrent data, we suggest that these sediments predominantly originated from the Southern North China Block and the North Qinling Belt. The uplift of the Qinling Orogenic Belt resulted from the initial collision between the North and South China blocks. Notably, the contributions from the North Qinling Belt increased progressively in younger strata, indicating a continuous enhancement in the uplift process. Further investigations into detrital zircon age data from time-equivalent strata distributed along south of the North China reveal a progressive westward propagation of uplift over time. Thus, our findings suggest that the uplifting pattern of the Qinling Orogenic Belt is consistent with the oblique collision model between the North and South China blocks.</div></div>","PeriodicalId":55973,"journal":{"name":"Chemie Der Erde-Geochemistry","volume":"85 1","pages":"Article 126247"},"PeriodicalIF":2.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}