The Columbia supercontinent is considered as the oldest widely-accepted supercontinent on Earth, but its precise paleogeographic reconstruction, particularly the specific locations of peripheral continents (e.g., the Tarim Craton), still remains contentious due to the lack of key geological evidence. Here, we report new whole-rock major- and trace-elemental, Sr-Nd isotopic, and zircon U-Pb-Hf isotopic data of Mesoproterozoic amphibolites newly found in the Central Tianshan (CTS) block along the northern margin of the Tarim Craton. LA-ICP-MS U-Pb dating on magmatic-type zircons yielded weighted mean 207Pb/206Pb ages of ca. 1405–1393 Ma, interpreted as the crystallization ages of parental magma of the amphibolites. The amphibolites are characterized by relatively low contents of SiO2 (46.2–50.5 wt%) and total alkalis, but relatively high contents of MgO (7.0–12.9 wt%), Fe2O3T, and Nb (23.4–42.7 ppm). The rocks show typical ocean island basalt (OIB) signatures, such as enrichments in light rare earth and large ion lithophile elements, without negative Nb, Ta, and Ti anomalies. In addition, they exhibit positive whole-rock εNd(t) values of +1.4 to +5.8 and zircon εHf(t) values of −1.7 to +12.7 (mostly >+2.1), suggesting derivation from an OIB-like, asthenospheric mantle source. Considering the occurrences of ca. 1458–1405 Ma subduction-related granitoids in the region, our new data establish a tectonic transition from oceanic subduction to slab rollback-related intracontinental extension at ca. 1400 Ma along the northern margin of the Tarim Craton. Combined with previous investigations, we suggest that the Tarim Craton (or northern Tarim) was most probably connected to Siberia on the periphery of the Columbia supercontinent, with its northern margin (i.e., the CTS block) facing an oceanic subduction in the Mesoproterozoic.
{"title":"Locating Tarim on the periphery of the Columbia supercontinent: New evidence from Mesoproterozoic amphibolites from the Central Tianshan block","authors":"Jinyu Xi , Xiaoran Zhang , Shuiyue Xue , Guochun Zhao","doi":"10.1016/j.precamres.2025.107967","DOIUrl":"10.1016/j.precamres.2025.107967","url":null,"abstract":"<div><div>The Columbia supercontinent is considered as the oldest widely-accepted supercontinent on Earth, but its precise paleogeographic reconstruction, particularly the specific locations of peripheral continents (e.g., the Tarim Craton), still remains contentious due to the lack of key geological evidence. Here, we report new whole-rock major- and trace-elemental, Sr-Nd isotopic, and zircon U-Pb-Hf isotopic data of Mesoproterozoic amphibolites newly found in the Central Tianshan (CTS) block along the northern margin of the Tarim Craton. LA-ICP-MS U-Pb dating on magmatic-type zircons yielded weighted mean <sup>207</sup>Pb/<sup>206</sup>Pb ages of ca. 1405–1393 Ma, interpreted as the crystallization ages of parental magma of the amphibolites. The amphibolites are characterized by relatively low contents of SiO<sub>2</sub> (46.2–50.5 wt%) and total alkalis, but relatively high contents of MgO (7.0–12.9 wt%), Fe<sub>2</sub>O<sub>3T</sub>, and Nb (23.4–42.7 ppm). The rocks show typical ocean island basalt (OIB) signatures, such as enrichments in light rare earth and large ion lithophile elements, without negative Nb, Ta, and Ti anomalies. In addition, they exhibit positive whole-rock ε<sub>Nd</sub>(t) values of +1.4 to +5.8 and zircon ε<sub>Hf</sub>(t) values of −1.7 to +12.7 (mostly >+2.1), suggesting derivation from an OIB-like, asthenospheric mantle source. Considering the occurrences of ca. 1458–1405 Ma subduction-related granitoids in the region, our new data establish a tectonic transition from oceanic subduction to slab rollback-related intracontinental extension at ca. 1400 Ma along the northern margin of the Tarim Craton. Combined with previous investigations, we suggest that the Tarim Craton (or northern Tarim) was most probably connected to Siberia on the periphery of the Columbia supercontinent, with its northern margin (i.e., the CTS block) facing an oceanic subduction in the Mesoproterozoic.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"432 ","pages":"Article 107967"},"PeriodicalIF":3.2,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145521184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-14DOI: 10.1016/j.precamres.2025.107942
Anna Grabarczyk-Gurba , Ewa Krzemińska , Leonid Shumlyanskyy , Janina Wiszniewska
The Sejny Intrusion, a part of the anorthosite–mangerite–charnockite–granite (AMCG) Mazury Complex in NE Poland, comprises mafic to intermediate rocks, including gabbro, (gabbro)norite, anorthosite, and jotunite dykes. Zircon U–Pb ages of 1513 ± 2 Ma to 1499 ± 3 Ma define its emplacement. The primitive jotunites, with relatively high SiO2 and low Fe-Ti-P contents, display chilled margins, reflecting a composition close to the parental magma. Their REE patterns and isotopic signatures (εNd(t) of −1.6 to −1.8, 87Sr/86Sr(i) of 0.7040−0.7044, and maximum single εHf(t) of 2.3 (mean = −2.5)) are consistent with a lower crustal source. Fractionation of plagioclase and minor Ca-poor pyroxene from jotunitic melts occurred at ca. 35 km depth and is evidenced by orthopyroxene with exsolved plagioclase lamellae, originally forming high-Al orthopyroxene megacrysts (HAOMs; 5.9–6.7 wt% Al2O3), typical of high-pressure crystallization. Plagioclase-rich (anorthositic) and gabbro-noritic mushes were then emplaced within the shallow crust. Evolved jotunites, enriched in Fe-Ti-P and depleted in SiO2, represent residual melts after fractionation of the anorthosite-gabbronorite suite. Anorthosites and gabbros (εNd(t) of −1.4 to −2.0, 87Sr/86Sr(i) of 0.7041−0.7049, mean εHf(t) of −2.2 to −3.6) isotopically overlap with primitive jotunites. Conversely, evolved quartz jotunite (εNd(t) = −2.4, 87Sr/86Sr(i) = 0.7053, mean εHf(t) = −4.1), quartz gabbronorite (εNd(t) = −2.5, 87Sr/86Sr(i) = 0.7043), and quartz norite (εNd(t) = −2.7, 87Sr/86Sr(i) = 0.7072, mean εHf(t) = −5.5 and −7.5) exhibit a gradual decrease in εNd and εHf, and mostly higher 87Sr/86Sr values. This is consistent with zircon O−Hf trends for quartz jotunite and quartz norite (δ18O = 6.8−10.2 ‰, εHf(t) = −0.4 to −10.1), reflecting interaction between a low δ18O, high εHf (∼0) ‘juvenile’ source, and a supracrustal component of high δ18O and low εHf values. The decrease in zircon εHf(t) with decreasing age indicates progressive contamination during ascent. Inherited 1825 ± 4 Ma zircons in one sample corroborate the influence of Paleoproterozoic metasedimentary wall-rock during emplacement. Based on coeval relationship with A-type granitoids, the Sejny Intrusion is interpreted as anorogenic. This magmatism likely resulted from asthenospheric upwelling beneath the Columbia supercontinent, where heat accumulation (thermal blanket effect) induced partial melting of the lower mafic crust.
{"title":"Magma source and tectonic setting of gabbronorite–anorthosite massifs: geochemical and isotopic evidence from the 1.5 Ga Sejny Intrusion (Mazury Complex, NE Poland)","authors":"Anna Grabarczyk-Gurba , Ewa Krzemińska , Leonid Shumlyanskyy , Janina Wiszniewska","doi":"10.1016/j.precamres.2025.107942","DOIUrl":"10.1016/j.precamres.2025.107942","url":null,"abstract":"<div><div>The Sejny Intrusion, a part of the anorthosite–mangerite–charnockite–granite (AMCG) Mazury Complex in NE Poland, comprises mafic to intermediate rocks, including gabbro, (gabbro)norite, anorthosite, and jotunite dykes. Zircon U–Pb ages of 1513 ± 2 Ma to 1499 ± 3 Ma define its emplacement. The primitive jotunites, with relatively high SiO<sub>2</sub> and low Fe-Ti-P contents, display chilled margins, reflecting a composition close to the parental magma. Their REE patterns and isotopic signatures (ε<sub>Nd(t)</sub> of −1.6 to −1.8, <sup>87</sup>Sr/<sup>86</sup>Sr<sub>(i)</sub> of 0.7040−0.7044, and maximum single ε<sub>Hf(t)</sub> of 2.3 (mean = −2.5)) are consistent with a lower crustal source. Fractionation of plagioclase and minor Ca-poor pyroxene from jotunitic melts occurred at ca. 35 km depth and is evidenced by orthopyroxene with exsolved plagioclase lamellae, originally forming high-Al orthopyroxene megacrysts (HAOMs; 5.9–6.7 wt% Al<sub>2</sub>O<sub>3</sub>), typical of high-pressure crystallization. Plagioclase-rich (anorthositic) and gabbro-noritic mushes were then emplaced within the shallow crust. Evolved jotunites, enriched in Fe-Ti-P and depleted in SiO<sub>2</sub>, represent residual melts after fractionation of the anorthosite-gabbronorite suite. Anorthosites and gabbros (ε<sub>Nd(t)</sub> of −1.4 to −2.0, <sup>87</sup>Sr/<sup>86</sup>Sr<sub>(i)</sub> of 0.7041−0.7049, mean ε<sub>Hf(t)</sub> of −2.2 to −3.6) isotopically overlap with primitive jotunites. Conversely, evolved quartz jotunite (ε<sub>Nd(t)</sub> = −2.4, <sup>87</sup>Sr/<sup>86</sup>Sr<sub>(i)</sub> = 0.7053, mean ε<sub>Hf(t)</sub> = −4.1), quartz gabbronorite (ε<sub>Nd(t)</sub> = −2.5, <sup>87</sup>Sr/<sup>86</sup>Sr<sub>(i)</sub> = 0.7043), and quartz norite (ε<sub>Nd(t)</sub> = −2.7, <sup>87</sup>Sr/<sup>86</sup>Sr<sub>(i)</sub> = 0.7072, mean ε<sub>Hf(t)</sub> = −5.5 and −7.5) exhibit a gradual decrease in ε<sub>Nd</sub> and ε<sub>Hf</sub>, and mostly higher <sup>87</sup>Sr/<sup>86</sup>Sr values. This is consistent with zircon O−Hf trends for quartz jotunite and quartz norite (δ<sup>18</sup>O = 6.8−10.2 ‰, ε<sub>Hf(t)</sub> = −0.4 to −10.1), reflecting interaction between a low δ<sup>18</sup>O, high ε<sub>Hf</sub> (∼0) ‘juvenile’ source, and a supracrustal component of high δ<sup>18</sup>O and low ε<sub>Hf</sub> values. The decrease in zircon ε<sub>Hf(t)</sub> with decreasing age indicates progressive contamination during ascent. Inherited 1825 ± 4 Ma zircons in one sample corroborate the influence of Paleoproterozoic metasedimentary wall-rock during emplacement. Based on coeval relationship with A-type granitoids, the Sejny Intrusion is interpreted as anorogenic. This magmatism likely resulted from asthenospheric upwelling beneath the Columbia supercontinent, where heat accumulation (thermal blanket effect) induced partial melting of the lower mafic crust.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"432 ","pages":"Article 107942"},"PeriodicalIF":3.2,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145521186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-14DOI: 10.1016/j.precamres.2025.107968
Cendi D.P. Dana , Steven P. Hollis , Lorenzo Tavazzani , Cyril Chelle-Michou , Stijn Glorie , Yusuke Kuwahara , Kazuhide Mimura , Moei Yano , Junichiro Ohta , David Selby , Yasuhiro Kato , Vanessa Pashley , Megan James , Darryl Podmore
Accurately determining the timing of mineralization is essential for exploring syn-genetic stratiform mineral systems, such as volcanic-hosted massive sulfide (VHMS) deposits. This study integrates multiple geochronological techniques to constrain both the age of syn-genetic mineralization and subsequent overprinting magmatic, metamorphic and deformation events at the King VHMS deposit, Western Australia. The timing of syn-genetic mineralization is collectively constrained by consistent ages from U–Pb zircon geochronology of host felsic volcanic rocks (2725 ± 10 Ma), a Re–Os pyrite isochron (2730 ± 26 Ma), and Pb–Pb galena model ages (ca. 2714–2718 Ma). Pyrrhotite, formed via metamorphic desulfidation of pyrite, records a younger Re–Os age of 2652 ± 32 Ma, overlapping with the timing of prograde metamorphism dated by in situ Lu–Hf garnet analysis at 2680 ± 28 Ma. A Re–Os age from massive sulfide ore (2664 ± 23 Ma), reflecting a mixture of pyrite and pyrrhotite, produces a geologically meaningless average due to metamorphic re-equilibration, highlighting limitations of bulk Re–Os dating in high-grade metamorphosed systems. Quartz monzonite intrusions that crosscut the deposit and are associated with the regional M2 metamorphism yielded weighted mean U–Pb zircon ages of ca. 2676–2665 Ma, and are associated with minor molybdenite mineralization (Re–Os ages ca. 2650–2655 Ma). Collectively, these results confirm that the King Zn deposit represents the first phase of VHMS mineralization during the formation of the Kalgoorlie-Kurnalpi Rift (KKR), and significantly predates other VHMS deposits of the Eastern Goldfields. This study also demonstrates that the Re–Os isotopic signature of syn-genetic pyrite can be retained through amphibolite-facies metamorphism, providing a new opportunity to directly date VHMS deposits affected by high-grade metamorphism in Archean cratons globally. In contrast, Re–Os ages of pyrrhotite record prograde metamorphism, offering a potential tool for constraining metal remobilization events.
{"title":"Resolving the syn-genetic mineralization age of a metamorphosed Archean VHMS deposit using multiple geochronological approaches","authors":"Cendi D.P. Dana , Steven P. Hollis , Lorenzo Tavazzani , Cyril Chelle-Michou , Stijn Glorie , Yusuke Kuwahara , Kazuhide Mimura , Moei Yano , Junichiro Ohta , David Selby , Yasuhiro Kato , Vanessa Pashley , Megan James , Darryl Podmore","doi":"10.1016/j.precamres.2025.107968","DOIUrl":"10.1016/j.precamres.2025.107968","url":null,"abstract":"<div><div>Accurately determining the timing of mineralization is essential for exploring <em>syn</em>-genetic stratiform mineral systems, such as volcanic-hosted massive sulfide (VHMS) deposits. This study integrates multiple geochronological techniques to constrain both the age of <em>syn</em>-genetic mineralization and subsequent overprinting magmatic, metamorphic and deformation events at the King VHMS deposit, Western Australia. The timing of <em>syn</em>-genetic mineralization is collectively constrained by consistent ages from U–Pb zircon geochronology of host felsic volcanic rocks (2725 ± 10 Ma), a Re–Os pyrite isochron (2730 ± 26 Ma), and Pb–Pb galena model ages (ca. 2714–2718 Ma). Pyrrhotite, formed via metamorphic desulfidation of pyrite, records a younger Re–Os age of 2652 ± 32 Ma, overlapping with the timing of prograde metamorphism dated by <em>in situ</em> Lu–Hf garnet analysis at 2680 ± 28 Ma. A Re–Os age from massive sulfide ore (2664 ± 23 Ma), reflecting a mixture of pyrite and pyrrhotite, produces a geologically meaningless average due to metamorphic re-equilibration, highlighting limitations of bulk Re–Os dating in high-grade metamorphosed systems. Quartz monzonite intrusions that crosscut the deposit and are associated with the regional M2 metamorphism yielded weighted mean U–Pb zircon ages of ca. 2676–2665 Ma, and are associated with minor molybdenite mineralization (Re–Os ages ca. 2650–2655 Ma). Collectively, these results confirm that the King Zn deposit represents the first phase of VHMS mineralization during the formation of the Kalgoorlie-Kurnalpi Rift (KKR), and significantly predates other VHMS deposits of the Eastern Goldfields. This study also demonstrates that the Re–Os isotopic signature of <em>syn</em>-genetic pyrite can be retained through amphibolite-facies metamorphism, providing a new opportunity to directly date VHMS deposits affected by high-grade metamorphism in Archean cratons globally. In contrast, Re–Os ages of pyrrhotite record prograde metamorphism, offering a potential tool for constraining metal remobilization events.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"432 ","pages":"Article 107968"},"PeriodicalIF":3.2,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145521185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-14DOI: 10.1016/j.precamres.2025.107963
Sinan Yılmazer , Gültekin Topuz , Marcel Guillong , Aral I. Okay , İnal Demirkaya , Fulya Uzun
{"title":"Reply to Comment on “Revealing the early geological history of the Istanbul Zone (Far-East Avalonia) through zircon U-Pb-Hf isotopic data”","authors":"Sinan Yılmazer , Gültekin Topuz , Marcel Guillong , Aral I. Okay , İnal Demirkaya , Fulya Uzun","doi":"10.1016/j.precamres.2025.107963","DOIUrl":"10.1016/j.precamres.2025.107963","url":null,"abstract":"","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"432 ","pages":"Article 107963"},"PeriodicalIF":3.2,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145521183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-14DOI: 10.1016/j.precamres.2025.107958
C.R. Calver , G.V. Cumming , G.P. Halverson , J.L. Crowley , N.J. Roberts , M. Schmitz
Ediacaran glacial deposits are widespread, but their distribution in space and time is still poorly understood, hindering global correlation and a better understanding of their association with environmental and biological change. Of these deposits, the Gaskiers Formation and nearby Trinity Diamictite in eastern Newfoundland are the best constrained radiometrically at ca. 579––581 Ma, although recent evidence suggests glaciation initiated several million years earlier. Here we report two new U-Pb (zircon) CA-ID-TIMS dates on rhyodacite units immediately below, and within the Croles Hill Diamictite in northwest Tasmania previously interpreted as glacial in origin: 579.20 ± 0.09 Ma and 578.86 ± 0.23 Ma respectively. These ages make the Croles Hill Diamictite slightly younger than the Gaskiers Formation (>579.88 ± 0.44 Ma) but permit correlation with the Trinity Diamictite. Deposition of all three diamictites took place in a narrow (<2.7 m.y.) temporal window. Features consistent with a glacial origin for the Croles Hill Diamictite include rare, laminated mudstones with dropstones, a single, consistent stratigraphic position within the Togari Group, and compositional diversity of clasts.
{"title":"High-resolution U-Pb dating of the Croles Hill Diamictite, Tasmania: Near-synchroneity of widely separated mid-Ediacaran glacial deposits","authors":"C.R. Calver , G.V. Cumming , G.P. Halverson , J.L. Crowley , N.J. Roberts , M. Schmitz","doi":"10.1016/j.precamres.2025.107958","DOIUrl":"10.1016/j.precamres.2025.107958","url":null,"abstract":"<div><div>Ediacaran glacial deposits are widespread, but their distribution in space and time is still poorly understood, hindering global correlation and a better understanding of their association with environmental and biological change. Of these deposits, the Gaskiers Formation and nearby Trinity Diamictite in eastern Newfoundland are the best constrained radiometrically at ca. 579––581 Ma, although recent evidence suggests glaciation initiated several million years earlier. Here we report two new U-Pb (zircon) CA-ID-TIMS dates on rhyodacite units immediately below, and within the Croles Hill Diamictite in northwest Tasmania previously interpreted as glacial in origin: 579.20 ± 0.09 Ma and 578.86 ± 0.23 Ma respectively. These ages make the Croles Hill Diamictite slightly younger than the Gaskiers Formation (>579.88 ± 0.44 Ma) but permit correlation with the Trinity Diamictite. Deposition of all three diamictites took place in a narrow (<2.7 m.y.) temporal window. Features consistent with a glacial origin for the Croles Hill Diamictite include rare, laminated mudstones with dropstones, a single, consistent stratigraphic position within the Togari Group, and compositional diversity of clasts.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"432 ","pages":"Article 107958"},"PeriodicalIF":3.2,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145521187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-10DOI: 10.1016/j.precamres.2025.107965
Sutthida Noptalung, Ioan V. Sanislav, Helen A. Cocker, Avish Kumar
The Mount Isa Inlier, located along the eastern margin of the North Australia Craton (NAC) preserves a long history of intrusive activity linked to the assembly of the Nuna supercontinent. The intrusive rocks in the Inlier formed during six igneous events between ca. 1880 and 1490 Ma. Intrusive rocks in the south-western part of the Inlier (Dajarra region) were previously assigned ages of ca. 1680–1650 Ma without direct U-Pb geochronological constraints. New U-Pb zircon ages from granitic rocks in the Dajarra region reveal intrusive events at ca. 1860 Ma, ca. 1820–1780 Ma, ca. 1710–1690 Ma, and ca. 1670–1650 Ma corresponding to the Kalkadoon, Argylla, Wonga-Burstall and Sybella Igneous Events, respectively. These results indicate that these granites are much older than previously thought and have important implications for intrusive relationships and stratigraphic correlations. Zircon Hf isotopic compositions show negative ɛHf(t) values (+0.0 to −5.5) at ca. 1860 Ma, mixed values (−5.3 to + 8.4) at ca. 1820–1780 Ma, and unradiogenic signatures at ca. 1710–1690 Ma (−8.1 to −0.1) and ca. 1650 Ma (−5.1 to −4.3). These isotopic data indicate that the magmas were generated predominantly by internal reworking of older crust with limited juvenile input. The magmatic belts corresponding to the Kalkadoon and Argylla Igneous Events can be correlated with coeval igneous events in the NAC and the South Australia Craton (SAC) and may have formed in response to a northerly dipping subduction system located along the southern margin of the NAC. The Wonga-Burstall and the Sybella Igneous Events may have formed in response to a westward dipping subduction system developed along the eastern margin of the NAC during the final stages of Nuna assembly. The new geochronological and isotopic data presented here fill in an important gap in the magmatic history of the Mount Isa Inlier and contributes towards a more comprehensive understanding of tectonic activity along the eastern margin of the NAC and the final assembly of the Nuna supercontinent.
{"title":"Zircon U-Pb ages and Lu-Hf isotopic systematics in granites from Mt Isa Inlier − evidence of prolonged reworking of an active continental margin during the final assembly of the Nuna (Columbia) supercontinent","authors":"Sutthida Noptalung, Ioan V. Sanislav, Helen A. Cocker, Avish Kumar","doi":"10.1016/j.precamres.2025.107965","DOIUrl":"10.1016/j.precamres.2025.107965","url":null,"abstract":"<div><div>The Mount Isa Inlier, located along the eastern margin of the North Australia Craton (NAC) preserves a long history of intrusive activity linked to the assembly of the Nuna supercontinent. The intrusive rocks in the Inlier formed during six igneous events between ca. 1880 and 1490 Ma. Intrusive rocks in the south-western part of the Inlier (Dajarra region) were previously assigned ages of ca. 1680–1650 Ma without direct U-Pb geochronological constraints. New U-Pb zircon ages from granitic rocks in the Dajarra region reveal intrusive events at ca. 1860 Ma, ca. 1820–1780 Ma, ca. 1710–1690 Ma, and ca. 1670–1650 Ma corresponding to the Kalkadoon, Argylla, Wonga-Burstall and Sybella Igneous Events, respectively. These results indicate that these granites are much older than previously thought and have important implications for intrusive relationships and stratigraphic correlations. Zircon Hf isotopic compositions show negative ɛHf<sub>(t)</sub> values (+0.0 to −5.5) at ca. 1860 Ma, mixed values (−5.3 to + 8.4) at ca. 1820–1780 Ma, and unradiogenic signatures at ca. 1710–1690 Ma (−8.1 to −0.1) and ca. 1650 Ma (−5.1 to −4.3). These isotopic data indicate that the magmas were generated predominantly by internal reworking of older crust with limited juvenile input. The magmatic belts corresponding to the Kalkadoon and Argylla Igneous Events can be correlated with coeval igneous events in the NAC and the South Australia Craton (SAC) and may have formed in response to a northerly dipping subduction system located along the southern margin of the NAC. The Wonga-Burstall and the Sybella Igneous Events may have formed in response to a westward dipping subduction system developed along the eastern margin of the NAC during the final stages of Nuna assembly. The new geochronological and isotopic data presented here fill in an important gap in the magmatic history of the Mount Isa Inlier and contributes towards a more comprehensive understanding of tectonic activity along the eastern margin of the NAC and the final assembly of the Nuna supercontinent.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"432 ","pages":"Article 107965"},"PeriodicalIF":3.2,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145479141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-08DOI: 10.1016/j.precamres.2025.107964
Yang Dai , Li-Xing Li , Yong-Mei Zhang
Archean Nb-Ta-bearing granitic rocks linked with crustal growth events are widely developed within cratons worldwide. However, in the North China Craton where crustal growth is extensive, economic Nb-Ta-bearing granitic rocks are scarce. We identified previously unrecognized Nb-Ta-bearing granites in the Qidashan banded iron formation-hosted iron deposit in the Anshan–Benxi area of northern North China Craton. These granites provide a rare example to investigate the rare metal mineralization process within this craton. The U-Pb geochronology conducted on columbite group minerals (CGMs) and cassiterite from the Nb-Ta-bearing granites yielded weighted mean 207Pb/206Pb ages of 2527 ± 6 Ma and 2535 ± 5 Ma, respectively, which are indistinguishable from each other within analytical uncertainties. The results indicate a late Neoarchean emplacement age for the Qidashan Nb-Ta-bearing granites. The Qidashan Nb-Ta-bearing granites are characterized by high contents of SiO2, Al2O3, Na2O, K2O and Nb-Ta (average on 190.9 ppm), but low contents of CaO, TFe2O3, MgO, and total rare earth elements (ΣREE). Additionaly, these granites are enriched in large-ion lithophile elements (LILEs, e.g., Rb, Th, U), are depleted in high-field-strength elements (HFSEs, e.g., Nb, P, Ti), has a low LREE/HREE ratio, exhibits an obvious negative Eu anomaly, and shows a distinct tetrad effect of REE. These geochemical characteristics indicate that the key factors controlling the formation of Nb-Ta-bearing granites and the subsequent enrichment and mineralization of Nb-Ta rare metals include extensive fractional crystallization of the granitic magma coupled with melt-fluid interactions. The εNd(t) values of the Qidashan Nb-Ta-bearing granites range from −8.1 to −12.6, with two-stage model ages (TDM2) of 3.56–3.96 Ga, indicating their formation by recycling of mature, old continental crust, similar to the genesis of the 2.50 Ga Qidashan K-rich granites. During the late Neoarchean, the North China Craton entered an extensional tectonic regime, where intense tectono-thermal events triggered extensive granitic magmatism, generating voluminous crust-derived granites. The occurrence of the Archean Qidashan Nb-Ta-bearing granites demonstrates that late Neoarchean tectonic-magmatic activities in the North China Craton possess potential for rare metal Nb-Ta mineralization, offering new insights into the metallogenic prospectivity of Precambrian terranes in this region.
{"title":"Archean Nb-Ta-bearing granites recognized in the Anshan–Benxi area, North China Craton: Petrogenesis and rare metal potential","authors":"Yang Dai , Li-Xing Li , Yong-Mei Zhang","doi":"10.1016/j.precamres.2025.107964","DOIUrl":"10.1016/j.precamres.2025.107964","url":null,"abstract":"<div><div>Archean Nb-Ta-bearing granitic rocks linked with crustal growth events are widely developed within cratons worldwide. However, in the North China Craton where crustal growth is extensive, economic Nb-Ta-bearing granitic rocks are scarce. We identified previously unrecognized Nb-Ta-bearing granites in the Qidashan banded iron formation-hosted iron deposit in the Anshan–Benxi area of northern North China Craton. These granites provide a rare example to investigate the rare metal mineralization process within this craton. The U-Pb geochronology conducted on columbite group minerals (CGMs) and cassiterite from the Nb-Ta-bearing granites yielded weighted mean <sup>207</sup>Pb/<sup>206</sup>Pb ages of 2527 ± 6 Ma and 2535 ± 5 Ma, respectively, which are indistinguishable from each other within analytical uncertainties. The results indicate a late Neoarchean emplacement age for the Qidashan Nb-Ta-bearing granites. The Qidashan Nb-Ta-bearing granites are characterized by high contents of SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, Na<sub>2</sub>O, K<sub>2</sub>O and Nb-Ta (average on 190.9 ppm), but low contents of CaO, TFe<sub>2</sub>O<sub>3</sub>, MgO, and total rare earth elements (ΣREE). Additionaly, these granites are enriched in large-ion lithophile elements (LILEs, e.g., Rb, Th, U), are depleted in high-field-strength elements (HFSEs, e.g., Nb, P, Ti), has a low LREE/HREE ratio, exhibits an obvious negative Eu anomaly, and shows a distinct tetrad effect of REE. These geochemical characteristics indicate that the key factors controlling the formation of Nb-Ta-bearing granites and the subsequent enrichment and mineralization of Nb-Ta rare metals include extensive fractional crystallization of the granitic magma coupled with melt-fluid interactions. The <em>ε</em><sub>Nd</sub>(<em>t</em>) values of the Qidashan Nb-Ta-bearing granites range from −8.1 to −12.6, with two-stage model ages (<em>T</em><sub>DM2</sub>) of 3.56–3.96 Ga, indicating their formation by recycling of mature, old continental crust, similar to the genesis of the 2.50 Ga Qidashan K-rich granites. During the late Neoarchean, the North China Craton entered an extensional tectonic regime, where intense tectono-thermal events triggered extensive granitic magmatism, generating voluminous crust-derived granites. The occurrence of the Archean Qidashan Nb-Ta-bearing granites demonstrates that late Neoarchean tectonic-magmatic activities in the North China Craton possess potential for rare metal Nb-Ta mineralization, offering new insights into the metallogenic prospectivity of Precambrian terranes in this region.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107964"},"PeriodicalIF":3.2,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-04DOI: 10.1016/j.precamres.2025.107962
El Hassane Beraaouz, Jamal El Kabouri
The Ediacaran–Cambrian transition represents a pivotal interval in Earth’s history, marked by the emergence of tubular organisms during the Late Ediacaran and the subsequent appearance of modern animal phyla in the early Cambrian. However, such tubular organisms have never been described from the Neoproterozoic cover of the West African Craton, leaving a gap in our understanding of their exact paleogeographic distribution during this critical evolutionary period.
In this study, we describe the first occurrence of tubular fossils from the Late Ediacaran Lower unit of the Tabia Member (Taroudant Group) of the Anti-Atlas (Morocco), including Conotubus and cf. Wutubus, as well as associated oldest trace fossils (e.g., Helminthoidichnites and Gordia) and microbial structures (Ivesheadiomorphs) from shallow marine tidal flat and peritidal environments. Conotubus consists of fully pyritized, annulated tubular fossils with distinct apex–aperture differentiation. cf. Wutubus is characterized by annulated impressions with similar apex–aperture features. Notably, cf. Wutubus from the Anti-Atlas preserves a discoidal holdfast, supporting the interpretation of this taxon as a sessile organism.
The integration of these new data within both regional and global frameworks provides new insights into the Ediacaran–Cambrian boundary in the Anti-Atlas, expands the known paleogeographic distribution of Wutubus to the northern margin of Gondwana, and raises important questions regarding the biostratigraphic distribution of ichnotaxa such as Monomorphichnus and Treptichnus bifurcus.
{"title":"First evidence of tubular fossils from the Anti-Atlas: Insights into the paleogeography of Late Ediacaran tubular fossils and the Ediacaran–Cambrian boundary in the Anti-Atlas","authors":"El Hassane Beraaouz, Jamal El Kabouri","doi":"10.1016/j.precamres.2025.107962","DOIUrl":"10.1016/j.precamres.2025.107962","url":null,"abstract":"<div><div>The Ediacaran–Cambrian transition represents a pivotal interval in Earth’s history, marked by the emergence of tubular organisms during the Late Ediacaran and the subsequent appearance of modern animal phyla in the early Cambrian. However, such tubular organisms have never been described from the Neoproterozoic cover of the West African Craton, leaving a gap in our understanding of their exact paleogeographic distribution during this critical evolutionary period.</div><div>In this study, we describe the first occurrence of tubular fossils from the Late Ediacaran Lower unit of the Tabia Member (Taroudant Group) of the Anti-Atlas (Morocco), including <em>Conotubus</em> and cf. <em>Wutubus</em>, as well as associated oldest trace fossils (e.g., <em>Helminthoidichnites</em> and <em>Gordia</em>) and microbial structures (<em>Ivesheadiomorphs</em>) from shallow marine tidal flat and peritidal environments. <em>Conotubus</em> consists of fully pyritized, annulated tubular fossils with distinct apex–aperture differentiation. cf. <em>Wutubus</em> is characterized by annulated impressions with similar apex–aperture features. Notably, cf. <em>Wutubus</em> from the Anti-Atlas preserves a discoidal holdfast, supporting the interpretation of this taxon as a sessile organism.</div><div>The integration of these new data within both regional and global frameworks provides new insights into the Ediacaran–Cambrian boundary in the Anti-Atlas, expands the known paleogeographic distribution of <em>Wutubus</em> to the northern margin of Gondwana, and raises important questions regarding the biostratigraphic distribution of ichnotaxa such as <em>Monomorphichnus and Treptichnus bifurcus</em>.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107962"},"PeriodicalIF":3.2,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145467529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-10-31DOI: 10.1016/j.precamres.2025.107959
Jianlong Wang , Chonghui Yang , Pinghua Liu , Derek A. Wyman , Junpeng Wang , Wen Zhang , Wanpeng Zhou , Kang Jiang , Lilin Du
Neoarchean tonalite-trondhjemite-granodiorite (TTG) gneisses are extensively distributed in the central North China Craton (NCC), recording the early history of continental crust. This study presents six tonalitic gneiss from the Zanhuang Complex, which yield crystallization ages of 2.72–2.69 Ga and metamorphism ages of ∼ 2.5 Ga. Two dioritic gneiss gave crystallization ages of 2.72 Ga and 2.69 Ga. One high-Mg dioritic gneiss, with a xenocryst crystallization age of 2.71 Ga, yields an emplacement age of 2.55 Ga. Therefore, the early Neoarchean magmatism is constrained to 2.72–2.69 Ga, underwent metamorphism at ∼ 2.5 Ga, and was locally intruded by high-Mg diorites derived from a metasomatized mantle at 2.55 Ga. Moreover, the εHf(t) values (3.91–7.96) and TDMC(Hf) model ages (2.66–2.93 Ga) of the TTGs indicating a juvenile crustal origin formed from the late Mesoarchean to early Neoarchean.
All banding-free TTG gneisses exhibit relatively homogeneous tonalitic compositions. They have high SiO2 (66.37–68.13 wt%), Na2O (3.85–4.44 wt%), MgO (1.93–2.09 wt%), Cr (25–33 ppm), Ni (21–26 ppm), and Mg# values (45–51), low total ferromagnesian elements (6.59–7.28 wt%), Al2O3 (14.67–15.17 wt%), K2O/Na2O (0.27–0.46), and Sr/Y (29–41). These suggest that they are generated from partial melting of low-K basalt under low-preasure (amphibolite-facies) conditions. Banded TTG gneiss exhibit variable compositions that consistent with tonalite or trondhjemite. They are considered to have resulted from the anatexis and mineral segregation of tonalite in the late Neoarchean.
Through a comprehensive analysis of ∼ 2.7 Ga magmatism in the central NCC, we infer that there may be an magmatic belt through Hengshan, Wutai, Fuping, Zanhuang, Zuoquan, Huixian, Lushan, and Zhongtiao area from north to south. This belt is dominated by TTGs, with minor K-rich granites and mafic rocks. Their Hf-Nd data reveal a pronounced crustal growth and remelting event at ∼ 2.7 Ga. These TTGs exhibit significant geochemical heterogeneity, with some units preserving diagnostic subduction-related signatures including high-pressure and mantle metasomatism imprints. We infer that the magmatic belt formed in a subduction-related setting.
{"title":"Intensive ∼ 2.7 Ga magmatism in the Zanhuang Complex, central North China Craton","authors":"Jianlong Wang , Chonghui Yang , Pinghua Liu , Derek A. Wyman , Junpeng Wang , Wen Zhang , Wanpeng Zhou , Kang Jiang , Lilin Du","doi":"10.1016/j.precamres.2025.107959","DOIUrl":"10.1016/j.precamres.2025.107959","url":null,"abstract":"<div><div>Neoarchean tonalite-trondhjemite-granodiorite (TTG) gneisses are extensively distributed in the central North China Craton (NCC), recording the early history of continental crust. This study presents six tonalitic gneiss from the Zanhuang Complex, which yield crystallization ages of 2.72–2.69 Ga and metamorphism ages of ∼ 2.5 Ga. Two dioritic gneiss gave crystallization ages of 2.72 Ga and 2.69 Ga. One high-Mg dioritic gneiss, with a xenocryst crystallization age of 2.71 Ga, yields an emplacement age of 2.55 Ga. Therefore, the early Neoarchean magmatism is constrained to 2.72–2.69 Ga, underwent metamorphism at ∼ 2.5 Ga, and was locally intruded by high-Mg diorites derived<!--> <!-->from a metasomatized mantle at 2.55 Ga. Moreover, the ε<sub>Hf</sub>(t) values (3.91–7.96) and <em>T</em><sub>DM</sub><sup>C</sup>(Hf) model ages (2.66–2.93 Ga) of the TTGs indicating<!--> <!-->a juvenile crustal origin formed from the late Mesoarchean to early Neoarchean.</div><div>All banding-free TTG gneisses exhibit relatively homogeneous tonalitic compositions. They have high SiO<sub>2</sub> (66.37–68.13 wt%), Na<sub>2</sub>O (3.85–4.44 wt%), MgO (1.93–2.09 wt%), Cr (25–33 ppm), Ni (21–26 ppm), and Mg<sup>#</sup> values (45–51), low total ferromagnesian elements (6.59–7.28 wt%), Al<sub>2</sub>O<sub>3</sub> (14.67–15.17 wt%), K<sub>2</sub>O/Na<sub>2</sub>O (0.27–0.46), and Sr/Y (29–41). These suggest that they are generated from partial melting of low-K basalt under low-preasure (amphibolite-facies) conditions. Banded TTG gneiss exhibit variable compositions that consistent with tonalite or trondhjemite. They are considered to have resulted from the anatexis and mineral segregation of tonalite in the late Neoarchean.</div><div>Through a comprehensive analysis of ∼ 2.7 Ga magmatism in the central NCC, we infer that there may be an magmatic belt through<!--> <!-->Hengshan, Wutai, Fuping, Zanhuang, Zuoquan, Huixian, Lushan, and Zhongtiao area from north to south. This belt is dominated by TTGs, with minor K-rich granites and mafic rocks. Their Hf-Nd data reveal a pronounced crustal growth and remelting event at ∼ 2.7 Ga. These TTGs exhibit significant geochemical heterogeneity, with some units preserving diagnostic subduction-related signatures including high-pressure and mantle metasomatism imprints. We infer that the magmatic belt formed in a subduction-related setting.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107959"},"PeriodicalIF":3.2,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145419275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-10-31DOI: 10.1016/j.precamres.2025.107956
Vasiliy Sukhorukov, Olga Turkina
The first data on P–T metamorphic conditions, coupled with U–Pb monazite and zircon ages, were obtained for Neoarchean aluminous gneisses in the central part of the Irkut terrane (the Sharyzhalgay uplift of the Siberian craton). Based on petrological observations, conventional geothermobarometry and thermodynamic modelling, the peak P-T conditions of metamorphism were found to be 760–780 °C and 6–6.8 kbar. This was followed by a ’clockwise’ retrograde P-T path involving episodes of near-isothermal decompression and subsequent cooling, which is typical of collisional settings. Coupled U-Pb dating of zircon and monazite indicates that the metamorphism occurred approximately 2.55 billion years ago. Combining these new data with the Neoarchean age of the granitoids suggests a collisional event occurred in the eastern part of the Sharyzhalgay uplift around 2.55 Ga. The P-T parameters and P-T paths of Neoarchean metamorphism are similar to those of Paleoproterozoic collision-related metamorphism in the Irkut terrane. This implies that the tectonic settings were similar during these two periods.
{"title":"Age and metamorphic P–T evolution of Pelitic Granulites from the Irkut Terrane, Siberian Craton: implications for neoarchean collisional orogenesis","authors":"Vasiliy Sukhorukov, Olga Turkina","doi":"10.1016/j.precamres.2025.107956","DOIUrl":"10.1016/j.precamres.2025.107956","url":null,"abstract":"<div><div>The first data on P–T metamorphic conditions, coupled with U–Pb monazite and zircon ages, were obtained for Neoarchean aluminous gneisses in the central part of the Irkut terrane (the Sharyzhalgay uplift of the Siberian craton). Based on petrological observations, conventional geothermobarometry and thermodynamic modelling, the peak P-T conditions of metamorphism were found to be 760–780 °C and 6–6.8 kbar. This was followed by a ’clockwise’ retrograde P-T path involving episodes of near-isothermal decompression and subsequent cooling, which is typical of collisional settings. Coupled U-Pb dating of zircon and monazite indicates that the metamorphism occurred approximately 2.55 billion years ago. Combining these new data with the Neoarchean age of the granitoids suggests a collisional event occurred in the eastern part of the Sharyzhalgay uplift around 2.55 Ga. The P-T parameters and P-T paths of Neoarchean metamorphism are similar to those of Paleoproterozoic collision-related metamorphism in the Irkut terrane. This implies that the tectonic settings were similar during these two periods.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107956"},"PeriodicalIF":3.2,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145419353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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