Pub Date : 2025-12-12DOI: 10.1016/j.precamres.2025.107979
Paula F.T. Alvim, Elton L. Dantas, Reinhardt A. Fuck, Alanielson C.D. Ferreira
The Tectono-Magmatic Lull (TML), or Siderian Quiet Interval, represents a pivotal stage in Earth’s history between 2.36 and 2.23 Ga, marked by a global reduction in tectonic activity, magmatism, and crustal growth. It features a global decline in tectonic activity, magmatism, and crustal formation, creating a major gap in the geotectonic record worldwide. To investigate this interval, detailed field mapping, petrography, U–Pb zircon geochronology, whole-rock geochemistry, and Sm–Nd isotopic analyses were carried out on rocks from the Santa Luzia Sequence in the Lajes Block, Borborema Province (NE Brazil). The sequence, consisting of amphibolites, calc-silicate rocks, and hornblendites, yields U–Pb zircon ages ranging from 2.48 to 2.31 Ga, along with an older amphibolite dated at 3.14 Ga. Whole-rock geochemical patterns exhibit pronounced negative Nb, Ta, and Ti anomalies, indicating oceanic and arc-related affinities. Sm–Nd isotopic data reinforce this framework: juvenile lithotypes show positive εNd(t) values and Nd TDM ages of 2.36–2.12 Ga, whereas a subset of amphibolites preserves significantly older Nd TDM ages (3.97–2.62 Ga), revealing an Archean crustal substrate predating arc assembly. Coeval plutonic rocks document continued crustal reworking and juvenile addition from the Siderian into the Rhyacian. Spatial, geochemical, and isotopic relationships indicate that the calc-silicate rocks formed through metasomatic alteration of mafic precursors. Despite later metasomatic and hydrothermal overprints that produced LREE enrichment and fluid-driven metamorphism, the primary magmatic signatures remain well preserved. Collectively, these results show that subduction-related magmatism persisted locally in Borborema, in contrast with the TML and tectonic shutdown theories.
{"title":"A lost fragment of Siderian oceanic and juvenile arc crust preserved in the Borborema province, northeast Brazil","authors":"Paula F.T. Alvim, Elton L. Dantas, Reinhardt A. Fuck, Alanielson C.D. Ferreira","doi":"10.1016/j.precamres.2025.107979","DOIUrl":"10.1016/j.precamres.2025.107979","url":null,"abstract":"<div><div>The Tectono-Magmatic Lull (TML), or Siderian Quiet Interval, represents a pivotal stage in Earth’s history between 2.36 and 2.23 Ga, marked by a global reduction in tectonic activity, magmatism, and crustal growth. It features a global decline in tectonic activity, magmatism, and crustal formation, creating a major gap in the geotectonic record worldwide. To investigate this interval, detailed field mapping, petrography, U–Pb zircon geochronology, whole-rock geochemistry, and Sm–Nd isotopic analyses were carried out on rocks from the Santa Luzia Sequence in the Lajes Block, Borborema Province (NE Brazil). The sequence, consisting of amphibolites, calc-silicate rocks, and hornblendites, yields U–Pb zircon ages ranging from 2.48 to 2.31 Ga, along with an older amphibolite dated at 3.14 Ga. Whole-rock geochemical patterns exhibit pronounced negative Nb, Ta, and Ti anomalies, indicating oceanic and arc-related affinities. Sm–Nd isotopic data reinforce this framework: juvenile lithotypes show positive εNd<sub>(t)</sub> values and Nd T<sub>DM</sub> ages of 2.36–2.12 Ga, whereas a subset of amphibolites preserves significantly older Nd T<sub>DM</sub> ages (3.97–2.62 Ga), revealing an Archean crustal substrate predating arc assembly. Coeval plutonic rocks document continued crustal reworking and juvenile addition from the Siderian into the Rhyacian. Spatial, geochemical, and isotopic relationships indicate that the calc-silicate rocks formed through metasomatic alteration of mafic precursors. Despite later metasomatic and hydrothermal overprints that produced LREE enrichment and fluid-driven metamorphism, the primary magmatic signatures remain well preserved. Collectively, these results show that subduction-related magmatism persisted locally in Borborema, in contrast with the TML and tectonic shutdown theories.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"433 ","pages":"Article 107979"},"PeriodicalIF":3.2,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749403","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 : 2025-12-09DOI: 10.1016/j.precamres.2025.107990
Jianhui Liu , Wei Jin , Fulai Liu , Zhengjiang Ding , Yuanshuo Li , Weinan Xu
In this study, zircon U–Th–Pb dating coupled with zircon morphology and texture observations, and trace element and Hf isotope analyses conducted on ultrahigh-pressure (UHP) eclogites and the host granitic gneiss in the central Dabie UHP belt has identified Neoarchean (ca. 2.5 Ga), Palaeoproterozoic (ca. 1.9 Ga) metamorphic events and Triassic UHP metamorphism at ca. 236 Ma. The Palaeoproterozoic metamorphic zircons from two eclogite samples and one granitic gneiss sample have consistent weighted mean ages of 1871 ± 26, 1890 ± 15, and 1915 ± 41 Ma, respectively. They exhibit low Th/U ratios (mostly < 0.1), depletions in light rare earth elements (LREE) and enrichments in heavy rare earth elements (HREE) characterized by steep chondrite-normalized patterns, and yielded a large range of Ti-in-zircon temperatures varying from 892 ℃ to 642 ℃, indicating their metamorphic recrystallization or growth under wide metamorphic condition. The Palaeoproterozoic metamorphic zircons from the eclogites have mostly uniform Hf compositions and positive εHf(t) values distinctly different from the Palaeoproterozoic metamorphic zircons with variable Hf compositions and negative εHf(t) values from the host granitic gneiss. The Triassic metamorphic zircons from two eclogite samples and one granitic gneiss sample gave weighted-mean ages of 236 ± 2, 236 ± 1 and 234 ± 3 Ma, respectively. They exhibit low Th/U ratios (mostly < 0.1), depletions in LREE and distinctively flat chondrite-normalized HREE patterns, and mostly consistent Hf isotope compositions with extremely low 176Lu/177Hf ratios and negative εHf(t) values, and yielded Ti-in-zircon temperature of ca. 724℃ consistent with Triassic UHP metamorphic temperature, thus, these zircons is interpreted to be formed under Triassic UHP metamorphism. The host granitic gneiss has a minimum estimate of magmatic crystallization age of 2723 Ma. Therefore, it can be concluded that mafic protolith of the eclogite and the host granitic gneiss together experienced Palaeoproterozoic metamorphism at ca. 1.9 Ga and then Triassic UHP metamorphism at ca. 236 Ma. Additionally, it has further been suggested that the Early Precambrian basement exists and was involved in Triassic UHP metamorphism in the central Dabie UHP belt.
{"title":"Identification of eclogites that record Palaeoproterozoic and Triassic metamorphism in the Dabie UHP orogenic belt, eastern-central China","authors":"Jianhui Liu , Wei Jin , Fulai Liu , Zhengjiang Ding , Yuanshuo Li , Weinan Xu","doi":"10.1016/j.precamres.2025.107990","DOIUrl":"10.1016/j.precamres.2025.107990","url":null,"abstract":"<div><div>In this study, zircon U–Th–Pb dating coupled with zircon morphology and texture observations, and trace element and Hf isotope analyses conducted on ultrahigh-pressure (UHP) eclogites and the host granitic gneiss in the central Dabie UHP belt has identified Neoarchean (ca. 2.5 Ga), Palaeoproterozoic (ca. 1.9 Ga) metamorphic events and Triassic UHP metamorphism at ca. 236 Ma. The Palaeoproterozoic metamorphic zircons from two eclogite samples and one granitic gneiss sample have consistent weighted mean ages of 1871 ± 26, 1890 ± 15, and 1915 ± 41 Ma, respectively. They exhibit low Th/U ratios (mostly < 0.1), depletions in light rare earth elements (LREE) and enrichments in heavy rare earth elements (HREE) characterized by steep chondrite-normalized patterns, and yielded a large range of Ti-in-zircon temperatures varying from 892 ℃ to 642 ℃, indicating their metamorphic recrystallization or growth under wide metamorphic condition. The Palaeoproterozoic metamorphic zircons from the eclogites have mostly uniform Hf compositions and positive ε<sub>Hf</sub>(t) values distinctly different from the Palaeoproterozoic metamorphic zircons with variable Hf compositions and negative ε<sub>Hf</sub>(t) values from the host granitic gneiss. The Triassic metamorphic zircons from two eclogite samples and one granitic gneiss sample gave weighted-mean ages of 236 ± 2, 236 ± 1 and 234 ± 3 Ma, respectively. They exhibit low Th/U ratios (mostly < 0.1), depletions in LREE and distinctively flat chondrite-normalized HREE patterns, and mostly consistent Hf isotope compositions with extremely low <sup>176</sup>Lu/<sup>177</sup>Hf ratios and negative ε<sub>Hf</sub>(t) values, and yielded Ti-in-zircon temperature of ca. 724℃ consistent with Triassic UHP metamorphic temperature, thus, these zircons is interpreted to be formed under Triassic UHP metamorphism. The host granitic gneiss has a minimum estimate of magmatic crystallization age of 2723 Ma. Therefore, it can be concluded that mafic protolith of the eclogite and the host granitic gneiss together experienced Palaeoproterozoic metamorphism at ca. 1.9 Ga and then Triassic UHP metamorphism at ca. 236 Ma. Additionally, it has further been suggested that the Early Precambrian basement exists and was involved in Triassic UHP metamorphism in the central Dabie UHP belt.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"433 ","pages":"Article 107990"},"PeriodicalIF":3.2,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749410","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}
The overall paleogeographic configuration of the Rodinia supercontinent has been well defined, but the paleo-position of some East Asian microcontinents remains ambiguous, such as the Central Qilian Block (CQB), hindering robust Rodinia reconstruction. The South Qilian Belt separates the CQB from the Quanji Block, and preserves abundant Neoproterozoic rocks, providing a critical window for elucidating the Neoproterozoic tectonic evolution of the CQB and its paleo-position in Rodinia. Herein, this study focuses on the Neoproterozoic metasedimentary rocks in the South Qilian Belt and conducts integrated field geology, petrography, whole-rock geochemistry, and zircon U–Pb–Hf isotopes and trace element analyses. Our new data reveal that the Neoproterozoic metasedimentary rocks were likely deposited in a back-arc basin during 820–713 Ma. Provenance analysis indicates dominant derivation from the Neoproterozoic continental arc unit in the CQB and the Paleoproterozoic basement rocks in the Quanji Block. Synthesis of these results with existing data supports a model wherein protracted Neoproterozoic oceanic subduction coupled with associated back-arc extension probably drove the detachment of the CQB from the Quanji Block at the periphery of Rodinia. Based on compiled detrital zircon U–Pb–Hf isotopes and geological records from major Rodinia blocks, we propose that the unified Qilian-Quanji-Qaidam Block (QQB) was situated between Tarim and South China. The composite Tarim-QQB-South China probably occupied the northern periphery of the Rodinia supercontinent, adjacent to North India-East Antarctica. Our study links the subduction zone along the northern margin of the CQB to the circum-Rodinia subduction-accretion system, highlighting the crucial role of plate-boundary processes in facilitating lithospheric extension and thereby contributing to the breakup of Rodinia.
{"title":"Tectonic evolution of the Central Qilian Block and its reconstruction within Rodinia: insights from Neoproterozoic metasedimentary rocks in the South Qilian Belt, NW China","authors":"Yu Qin , Yunpeng Dong , Qiao Feng , Xiaoli Zhang , Qi Wang","doi":"10.1016/j.precamres.2025.107991","DOIUrl":"10.1016/j.precamres.2025.107991","url":null,"abstract":"<div><div>The overall paleogeographic configuration of the Rodinia supercontinent has been well defined, but the paleo-position of some East Asian microcontinents remains ambiguous, such as the Central Qilian Block (CQB), hindering robust Rodinia reconstruction. The South Qilian Belt separates the CQB from the Quanji Block, and preserves abundant Neoproterozoic rocks, providing a critical window for elucidating the Neoproterozoic tectonic evolution of the CQB and its paleo-position in Rodinia. Herein, this study focuses on the Neoproterozoic metasedimentary rocks in the South Qilian Belt and conducts integrated field geology, petrography, whole-rock geochemistry, and zircon U–Pb–Hf isotopes and trace element analyses. Our new data reveal that the Neoproterozoic metasedimentary rocks were likely deposited in a back-arc basin during 820–713 Ma. Provenance analysis indicates dominant derivation from the Neoproterozoic continental arc unit in the CQB and the Paleoproterozoic basement rocks in the Quanji Block. Synthesis of these results with existing data supports a model wherein protracted Neoproterozoic oceanic subduction coupled with associated back-arc extension probably drove the detachment of the CQB from the Quanji Block at the periphery of Rodinia. Based on compiled detrital zircon U–Pb–Hf isotopes and geological records from major Rodinia blocks, we propose that the unified Qilian-Quanji-Qaidam Block (QQB) was situated between Tarim and South China. The composite Tarim-QQB-South China probably occupied the northern periphery of the Rodinia supercontinent, adjacent to North India-East Antarctica. Our study links the subduction zone along the northern margin of the CQB to the circum-Rodinia subduction-accretion system, highlighting the crucial role of plate-boundary processes in facilitating lithospheric extension and thereby contributing to the breakup of Rodinia.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"433 ","pages":"Article 107991"},"PeriodicalIF":3.2,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749411","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 : 2025-12-06DOI: 10.1016/j.precamres.2025.107982
Xing Wei , Shuang-ying Li , Zhen-sheng Li , Dong-Dong Yang , Song Wang , Wei Xie , Bo Hu , Min Li , Cheng Cheng
Neoproterozoic magmatic and sedimentary records in Yangtze Block are widely used to investigate the assembly and breakup processes of the supercontinent Rodinia. However, the tectonic setting of the Yangtze Block and its paleoposition within Rodinia still remain highly controversial. To address these issues, we conducted an integrated provenance study—combining field observations, whole-rock geochemistry, heavy mineral analysis, and detrital zircon U–Pb–Hf isotopes—on the well-preserved Cryogenian to Ediacaran sedimentary sequence in the Zhangbaling uplift along the northern margin of the lower Yangtze Block. Results indicate that the Zhougang and Sujiawan formations as Cryogenian units (ca. 700–635 Ma) and the Beijiangjun and Doushantuo formations as Ediacaran units (ca. 600–565 Ma). The Cryogenian deposits were derived from the underlying late Tonian volcanics and were deposited in a back-arc setting. Conversely, the Ediacaran sediments were formed in a cratonic rift setting, with the interior of the lower Yangtze Block as the primary source and the early Ediacaran arc as the secondary one. Notably, the trace element characteristics of the Neoproterozoic detrital zircons reveal two stages of arc-related magmatism along the northern margin of the lower Yangtze Block, with peak ages around 827–820 Ma and 781–757 Ma. This evidence, combined with the comparison with the northwestern Yangtze, indicates three evolutionary stages: two-stage island arcs during the Tonian, a residual back-arc basin during the Cryogenian, and a passive continental margin during the Ediacaran. The Neoproterozoic tectonics and evolutionary processes of the northern Yangtze Block suggest its peripheral position within Rodinia and offer new constraints for Neoproterozoic supercontinental reconstructions.
{"title":"Neoproterozoic three-stage evolution in the northern margin of the lower Yangtze Block: Evidence from low-grade metamorphic sedimentary sequence in the Zhangbaling uplift","authors":"Xing Wei , Shuang-ying Li , Zhen-sheng Li , Dong-Dong Yang , Song Wang , Wei Xie , Bo Hu , Min Li , Cheng Cheng","doi":"10.1016/j.precamres.2025.107982","DOIUrl":"10.1016/j.precamres.2025.107982","url":null,"abstract":"<div><div>Neoproterozoic magmatic and sedimentary records in Yangtze Block are widely used to investigate the assembly and breakup processes of the supercontinent Rodinia. However, the tectonic setting of the Yangtze Block and its paleoposition within Rodinia still remain highly controversial. To address these issues, we conducted an integrated provenance study—combining field observations, whole-rock geochemistry, heavy mineral analysis, and detrital zircon U–Pb–Hf isotopes—on the well-preserved Cryogenian to Ediacaran sedimentary sequence in the Zhangbaling uplift along the northern margin of the lower Yangtze Block. Results indicate that the Zhougang and Sujiawan formations as Cryogenian units (ca. 700–635 Ma) and the Beijiangjun and Doushantuo formations as Ediacaran units (ca. 600–565 Ma). The Cryogenian deposits were derived from the underlying late Tonian volcanics and were deposited in a back-arc setting. Conversely, the Ediacaran sediments were formed in a cratonic rift setting, with the interior of the lower Yangtze Block as the primary source and the early Ediacaran arc as the secondary one. Notably, the trace element characteristics of the Neoproterozoic detrital zircons reveal two stages of arc-related magmatism along the northern margin of the lower Yangtze Block, with peak ages around 827–820 Ma and 781–757 Ma. This evidence, combined with the comparison with the northwestern Yangtze, indicates three evolutionary stages: two-stage island arcs during the Tonian, a residual back-arc basin during the Cryogenian, and a passive continental margin during the Ediacaran. The Neoproterozoic tectonics and evolutionary processes of the northern Yangtze Block suggest its peripheral position within Rodinia and offer new constraints for Neoproterozoic supercontinental reconstructions.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"433 ","pages":"Article 107982"},"PeriodicalIF":3.2,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694795","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 : 2025-12-06DOI: 10.1016/j.precamres.2025.107989
Yuan Xia , Yajun Xu , Peter A. Cawood , Jiahui Zhang , Jie Zhang
Whole rock geochemistry, detrital zircon U-Pb geochronology, and Lu-Hf isotopic data from late Neoproterozoic strata within the Nanhua Basin, South China, provide crucial insights into the amalgamation history of the Yangtze and Cathaysia blocks. Strata from the central part of the basin (Xinyu and Ji’an regions) overlie the western margin of the Cathaysia Block and consist of, from bottom to top, the Shenshan, Kuli, Shangshi, Xiafang, Bali, and Laohutang formations. Detrital zircon age spectra of the samples from the Shenshan Formation to the Xiafang Formation show a unimodal distribution around 770–700 Ma. In contrast, samples from the overlying Xiafang and Bali formations are dominated by zircons with ages in the range 1100–900 Ma, along with some aged 2600–2400 Ma, 1950–1750 Ma, 1500–1300 Ma, and ca. 688 Ma. Based on the ages of the youngest detrital zircons and regional stratigraphic correlations with the well-established glacial and interglacial strata in the Jinping-Congjiang region, the maximum depositional ages of the units are 717 Ma for the Shenshan Formation, 717–690 Ma for the Kuli to Shangshi formations, between 690 Ma and 635 Ma for the Xiafang Formation, between 635 Ma and 550 Ma for the Bali Formation, and post-550 Ma for the Laohutang Formation. U-Pb ages, Lu-Hf isotopic compositions, and whole-rock geochemistry data indicate that detrital zircons with ages from 770 Ma to 700 Ma were sourced from the coeval arc-related magmatic rocks along the northern margin of the Yangtze Block. The transport of sediments across the Yangtze and Cathaysia blocks suggests that the Nanhua Basin is a late Tonian to Cryogenian intracontinental basin, and the amalgamation of the Yangtze and Cathaysia blocks occurred before the late Tonian. Older zircons aged 1100–900 Ma, 1500–1300 Ma, 1950–1750 Ma, and 2600–2400 Ma came from the Gondwana continent. Synchronous sediment input into the Nanhua Basin from both the northern margin of the Yangtze Block volcanic arc and Gondwana sources during the late Tonian to Cryogenian, suggesting a back-arc tectonic setting developed along the northern margin of East Gondwana. Integration with previous geochronological data, the two episodic propagation processes of Gondwana-derived sediments toward the northeast of the Nanhua Basin in the late Cryogenian and Cambrian are likely related to pulses of crustal thickening and topographic uplift during the assembly of Gondwana.
{"title":"Late Neoproterozoic development of the Nanhua Basin and implications for assembly of the South China Block","authors":"Yuan Xia , Yajun Xu , Peter A. Cawood , Jiahui Zhang , Jie Zhang","doi":"10.1016/j.precamres.2025.107989","DOIUrl":"10.1016/j.precamres.2025.107989","url":null,"abstract":"<div><div>Whole rock geochemistry, detrital zircon U-Pb geochronology, and Lu-Hf isotopic data from late Neoproterozoic strata within the Nanhua Basin, South China, provide crucial insights into the amalgamation history of the Yangtze and Cathaysia blocks. Strata from the central part of the basin (Xinyu and Ji’an regions) overlie the western margin of the Cathaysia Block and consist of, from bottom to top, the Shenshan, Kuli, Shangshi, Xiafang, Bali, and Laohutang formations. Detrital zircon age spectra of the samples from the Shenshan Formation to the Xiafang Formation show a unimodal distribution around 770–700 Ma. In contrast, samples from the overlying Xiafang and Bali formations are dominated by zircons with ages in the range 1100–900 Ma, along with some aged 2600–2400 Ma, 1950–1750 Ma, 1500–1300 Ma, and ca. 688 Ma. Based on the ages of the youngest detrital zircons and regional stratigraphic correlations with the well-established glacial and interglacial strata in the Jinping-Congjiang region, the maximum depositional ages of the units are 717 Ma for the Shenshan Formation, 717–690 Ma for the Kuli to Shangshi formations, between 690 Ma and 635 Ma for the Xiafang Formation, between 635 Ma and 550 Ma for the Bali Formation, and post-550 Ma for the Laohutang Formation. U-Pb ages, Lu-Hf isotopic compositions, and whole-rock geochemistry data indicate that detrital zircons with ages from 770 Ma to 700 Ma were sourced from the coeval arc-related magmatic rocks along the northern margin of the Yangtze Block. The transport of sediments across the Yangtze and Cathaysia blocks suggests that the Nanhua Basin is a late Tonian to Cryogenian intracontinental basin, and the amalgamation of the Yangtze and Cathaysia blocks occurred before the late Tonian. Older zircons aged 1100–900 Ma, 1500–1300 Ma, 1950–1750 Ma, and 2600–2400 Ma came from the Gondwana continent. Synchronous sediment input into the Nanhua Basin from both the northern margin of the Yangtze Block volcanic arc and Gondwana sources during the late Tonian to Cryogenian, suggesting a back-arc tectonic setting developed along the northern margin of East Gondwana. Integration with previous geochronological data, the two episodic propagation processes of Gondwana-derived sediments toward the northeast of the Nanhua Basin in the late Cryogenian and Cambrian are likely related to pulses of crustal thickening and topographic uplift during the assembly of Gondwana.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"433 ","pages":"Article 107989"},"PeriodicalIF":3.2,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694796","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 : 2025-12-05DOI: 10.1016/j.precamres.2025.107980
J.W.D. Strong , A.R. Cruden , P.A. Cawood , X. Wang , P. Hollings , D. Li , K. Ross , A.J.M. Lalonde , J. Marsh , J.M. Simmons
Analysis of U-Pb/Lu-Hf isotopes in zircon populations from plutonic orthogneisses and metasedimentary rocks are used to constrain the Paleoarchean to Neoarchean tectonic processes that led to Neoarchean cratonization of the western Superior Province. Plutonic orthogneisses from the North Caribou and western Wabigoon terranes assimilated varying degrees of Paleoarchean to Mesoarchean protoliths in the form of xenocrystic zircon, which indicate that the dominantly juvenile Neoarchean western Wabigoon and juvenile Mesoarchean to Neoarchean North Caribou terranes formed in association with an older Paleoarchean to Mesoarchean crustal basement. In addition, metasedimentary rocks from the North Caribou, English River, Winnipeg River, Wabigoon and Quetico terranes have detrital zircon age spectra and Hf(t) isotope compositions indicating ubiquitous availability of similar sedimentary sources across the western Superior Province during the Neoarchean. Collectively, the xenocrystic and detrital zircon evidence from the western Superior Province supports autochthonous growth of all terranes while the Neoarchean pre/syn-tectonic basins accepted detritus from widely available Mesoarchean to Neoarchean sources.
{"title":"Autochthonous crustal growth and sedimentation in the Superior Province recorded by xenocrystic and detrital zircon","authors":"J.W.D. Strong , A.R. Cruden , P.A. Cawood , X. Wang , P. Hollings , D. Li , K. Ross , A.J.M. Lalonde , J. Marsh , J.M. Simmons","doi":"10.1016/j.precamres.2025.107980","DOIUrl":"10.1016/j.precamres.2025.107980","url":null,"abstract":"<div><div>Analysis of U-Pb/Lu-Hf isotopes in zircon populations from plutonic orthogneisses and metasedimentary rocks are used to constrain the Paleoarchean to Neoarchean tectonic processes that led to Neoarchean cratonization of the western Superior Province. Plutonic orthogneisses from the North Caribou and western Wabigoon terranes assimilated varying degrees of Paleoarchean to Mesoarchean protoliths in the form of xenocrystic zircon, which indicate that the dominantly juvenile Neoarchean western Wabigoon and juvenile Mesoarchean to Neoarchean North Caribou terranes formed in association with an older Paleoarchean to Mesoarchean crustal basement. In addition, metasedimentary rocks from the North Caribou, English River, Winnipeg River, Wabigoon and Quetico terranes have detrital zircon age spectra and Hf(t) isotope compositions indicating ubiquitous availability of similar sedimentary sources across the western Superior Province during the Neoarchean. Collectively, the xenocrystic and detrital zircon evidence from the western Superior Province supports autochthonous growth of all terranes while the Neoarchean pre/<em>syn</em>-tectonic basins accepted detritus from widely available Mesoarchean to Neoarchean sources.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"433 ","pages":"Article 107980"},"PeriodicalIF":3.2,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694344","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 : 2025-11-26DOI: 10.1016/j.precamres.2025.107977
Christian C.B. Rocha , Rafael G. Motta , Nitzschia R.R. Domingos , Frederico C.J. Vilalva , Rogério Cavalcante , Dinarte Lucas
The Acari Batholith is a syntectonic Ediacaran (∼575 Ma) intrusion emplaced in the Seridó Belt, northeastern Brazil, during the Brasiliano Orogeny, a major tectonic event associated with the assembly of West Gondwana. It represents the largest granitic body within the belt. While the exposed geology of the Acari Batholith is well characterized, its subsurface geometry remains poorly constrained. To address this, we performed 2.5D forward gravity modelling to investigate its architecture and integrated the results with existing AMS, thermobarometric, borehole, and regional data. The modelling results represent one plausible subsurface configuration that is consistent with the gravity data and available geological constraints. They reveal an eastward-shifted feeder zone with two NE-SW aligned roots. The model suggests a predominantly shallow body, with a low-angle floor. A thin mica schist layer overlies the northern root and separates the Acari Batholith from the Acauã Stock, a satellite body that belongs to the same magmatic system. Thermobarometric estimates based on the normative quartz–orthoclase–albite geobarometer yield crystallization pressures of 2.6–3.5 kbar, consistent with the HT/LP metamorphism in the Seridó Belt. Synchronicity between magma emplacement and Brasiliano deformation is inferred from the alignment of internal magmatic fabrics with regional structures, while a mylonitic zone along its western margin developed after solidification. Cordierite + sillimanite assemblages in adjacent mica schist further attest to high temperatures near the roots. Combined with regional data, these results support the interpretation that the Acari Batholith represents a magmatic expression of the migmatitic dome system formed during Brasiliano transpression.
{"title":"Constraining crustal-level granite emplacement through thermobarometry and gravity modelling: Insights from the Ediacaran Acari Batholith, Borborema Province, NE Brazil","authors":"Christian C.B. Rocha , Rafael G. Motta , Nitzschia R.R. Domingos , Frederico C.J. Vilalva , Rogério Cavalcante , Dinarte Lucas","doi":"10.1016/j.precamres.2025.107977","DOIUrl":"10.1016/j.precamres.2025.107977","url":null,"abstract":"<div><div>The Acari Batholith is a syntectonic Ediacaran (∼575 Ma) intrusion emplaced in the Seridó Belt, northeastern Brazil, during the Brasiliano Orogeny, a major tectonic event associated with the assembly of West Gondwana. It represents the largest granitic body within the belt. While the exposed geology of the Acari Batholith is well characterized, its subsurface geometry remains poorly constrained. To address this, we performed 2.5D forward gravity modelling to investigate its architecture and integrated the results with existing AMS, thermobarometric, borehole, and regional data. The modelling results represent one plausible subsurface configuration that is consistent with the gravity data and available geological constraints. They reveal an eastward-shifted feeder zone with two NE-SW aligned roots. The model suggests a predominantly shallow body, with a low-angle floor. A thin mica schist layer overlies the northern root and separates the Acari Batholith from the Acauã Stock, a satellite body that belongs to the same magmatic system. Thermobarometric estimates based on the normative quartz–orthoclase–albite geobarometer yield crystallization pressures of 2.6–3.5 kbar, consistent with the HT/LP metamorphism in the Seridó Belt. Synchronicity between magma emplacement and Brasiliano deformation is inferred from the alignment of internal magmatic fabrics with regional structures, while a mylonitic zone along its western margin developed after solidification. Cordierite + sillimanite assemblages in adjacent mica schist further attest to high temperatures near the roots. Combined with regional data, these results support the interpretation that the Acari Batholith represents a magmatic expression of the migmatitic dome system formed during Brasiliano transpression.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"432 ","pages":"Article 107977"},"PeriodicalIF":3.2,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145618078","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 : 2025-11-22DOI: 10.1016/j.precamres.2025.107966
Thierry Bineli Betsi , Eric Joseph Njee , Louise Marie Ngo Bidjeck Bondje , Eugene Pascal Binam Mandeng , Kirsten Drüppel , Aratz Beranoaguirre , Hubert Mvondo , Tebogo Kelepile , Elisabeth Eiche , Jochen Kolb , Charles Nkoumbou
The Ngoutchoumi Granite Complex in the Cameroonian Northern Domain (ND) of the Neoproterozoic Central African Orogenic Belt has long been known to host tungsten mineral occurrences. Here, we show that this granite complex also contains a suite of rare metals (Ta, Nb, Zr, Li, Y + REE) and F-bearing minerals, which have not been previously reported. The key genetic aspects pertaining to the genesis of this mineralised system are unconstrained. In this study, that couples in-situ LA-ICP-MS zircon and columbite U-Pb and mica 40Ar-39Ar geochronology with bulk-rock and mineral geochemistry and Raman spectroscopy, the rare metal minerals and their host granite are characterized. The granite is peraluminous and rich in REE (100–445 ppm), with strong LREE enrichment ((La/Yb)N = 2.38–41.4) and typically displays a pronounced negative Eu anomaly (Eu/Eu* = 0.06–0.10). Rare metal minerals, including ferrocolumbite, Nb-rich rutile, zircon and various REE minerals are intimately associated with fluorite. Zircon and ferrocolumbite from the rare metal-rich granite yield Pan-African ages of 639 ± 11 Ma and 640.2 ± 12.7 Ma, respectively, indicating part of the rare metal minerals is orthomagmatic. Textural and mineral chemistry features indicate that the primary orthomagmatic rare metal minerals were overprinted, thus leading to at least three episodes of rare metal mineralisation. On the other hand, biotite and muscovite from granite crosscutting the rare metal granite yield Ar-Ar plateau ages of 549.02 ± 0.85 and 552.17 ± 0.22 Ma, respectively, which, when combined with our ferrocolumbite age, as well as previously reported rare metal-related ages within the ND, bracket the age of rare metal mineralisation events within the ND, between ca.640–580 Ma. Our findings, therefore, extend both the spatial and temporal fingerprints of the ND rare metal mineralisation beyond those previously reported and have significant implications for the exploration of rare metals in Pan-African terranes. The episodes of formation of rare metals at Ngoutchoumi span from the orthomagmatic stage to the hydrothermal stage, and this genetic model sheds new light on the genesis of rare metal granite-type deposits, where debates have revolved around metasomatic vs. magmatic rare metal enrichment processes.
{"title":"Petrochronology and genesis of granite-hosted rare metal (Ta, Nb, Li, Y + REE, Zr)-F-bearing mineral occurrences in the Cameroon Northern Domain of the Central African Orogenic Belt","authors":"Thierry Bineli Betsi , Eric Joseph Njee , Louise Marie Ngo Bidjeck Bondje , Eugene Pascal Binam Mandeng , Kirsten Drüppel , Aratz Beranoaguirre , Hubert Mvondo , Tebogo Kelepile , Elisabeth Eiche , Jochen Kolb , Charles Nkoumbou","doi":"10.1016/j.precamres.2025.107966","DOIUrl":"10.1016/j.precamres.2025.107966","url":null,"abstract":"<div><div>The Ngoutchoumi Granite Complex in the Cameroonian Northern Domain (ND) of the Neoproterozoic Central African Orogenic Belt has long been known to host tungsten mineral occurrences. Here, we show that this granite complex also contains a suite of rare metals (Ta, Nb, Zr, Li, Y + REE) and F-bearing minerals, which have not been previously reported. The key genetic aspects pertaining to the genesis of this mineralised system are unconstrained. In this study, that couples <em>in-situ</em> LA-ICP-MS zircon and columbite U-Pb and mica<!--> <sup>40</sup>Ar-<sup>39</sup>Ar geochronology with bulk-rock and mineral geochemistry and Raman spectroscopy, the rare metal minerals and their host granite are characterized. The granite is peraluminous and rich in REE (100–445 ppm), with strong LREE enrichment ((La/Yb)<sub>N<!--> </sub>= 2.38–41.4) and typically displays a pronounced negative Eu anomaly (Eu/Eu* = 0.06–0.10). Rare metal minerals, including ferrocolumbite, Nb-rich rutile, zircon and various REE minerals are intimately associated with fluorite. Zircon and ferrocolumbite from the rare metal-rich granite yield Pan-African ages of 639 ± 11 Ma and 640.2 ± 12.7 Ma, respectively, indicating part of the rare metal minerals is orthomagmatic. Textural and mineral chemistry features indicate that the primary orthomagmatic rare metal minerals were overprinted, thus leading to at least three episodes of rare metal mineralisation. On the other hand, biotite and muscovite from granite crosscutting the rare metal granite yield Ar-Ar plateau ages of 549.02 ± 0.85 and 552.17 ± 0.22 Ma, respectively, which, when combined with our ferrocolumbite age, as well as previously reported rare metal-related ages within the ND, bracket the age of rare metal mineralisation events within the ND, between ca.640–580 Ma. Our findings, therefore, extend both the spatial and temporal fingerprints of the ND rare metal mineralisation beyond those previously reported and have significant implications for the exploration of rare metals in Pan-African terranes. The episodes of formation of rare metals at Ngoutchoumi span from the orthomagmatic stage to the hydrothermal stage, and this genetic model sheds new light on the genesis of rare metal granite-type deposits, where debates have revolved around metasomatic vs. magmatic rare metal enrichment processes.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"432 ","pages":"Article 107966"},"PeriodicalIF":3.2,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145579883","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 : 2025-11-20DOI: 10.1016/j.precamres.2025.107976
D. McIlroy, D. Pérez-Pinedo, S. Rosse-Guillevic, H. Muirhead-Hunt, R.S. Taylor, S.C. Dufour
{"title":"Corrigendum to “Growth and disparity of form in the Ediacaran genus Charnia, with description of Charnia brasieri sp. nov. from the Ediacaran of Avalonia”. [Precambrian Res. (2025) 107947]","authors":"D. McIlroy, D. Pérez-Pinedo, S. Rosse-Guillevic, H. Muirhead-Hunt, R.S. Taylor, S.C. Dufour","doi":"10.1016/j.precamres.2025.107976","DOIUrl":"10.1016/j.precamres.2025.107976","url":null,"abstract":"","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"432 ","pages":"Article 107976"},"PeriodicalIF":3.2,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736754","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}
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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号