Precambrian Research最新文献

{"title":"Late Neoarchean–Paleoproterozoic granitoid basement serves as an effective helium source rock in cratonic basins","authors":"Wenqi Li ,&nbsp;Huichuan Liu ,&nbsp;Greg Holland ,&nbsp;Zheng Zhou ,&nbsp;Jianfa Chen ,&nbsp;Xiaoping Liu ,&nbsp;Zhiqi Yu ,&nbsp;Jian Li ,&nbsp;Xiaobo Wang","doi":"10.1016/j.precamres.2025.107905","DOIUrl":"10.1016/j.precamres.2025.107905","url":null,"abstract":"<div><div>The growing shortage of helium reserves presents a pressing worldwide concern. However, it remains ambiguous that how, when, and which type of tectonic environment the helium source rocks were formed. Recently, several helium-enriched gas fields have been discovered in the northern Ordos Block and confirmed to be crust-derived. Why late Neoarchean–Paleoproterozoic effective helium source rocks are distributed in the northern Ordos Block are still not clear. Detailed petrological, geochemical, geochronology, Sr-Nd isotopic and in-situ EPMA of U,-Th rich minerals studies were analyzed on the outcrops and drill cores of the basement of the northern Ordos Block to investigate the helium source rocks. The results show that (1) Late Neoarchean–Paleoproterozoic A-type granite and S-type granitoids are effective helium source rock types, and a large amount of U-Th rich accessory minerals (e.g., phosphate minerals, zircon, magnetite et al.) are preserved in alkaline feldspar and quartz. (2) The helium source rocks are classified into distinct temporal intervals: 2.60–2.45 Ga, 2.45–2.30 Ga and 1.95–1.80 Ga, respectively. 2.60–2.45 Ga granitoids exhibit compositional signatures of I-type granites, consistent with magmatic arc tectonic settings linked to subduction zones. 2.45–2.30 Ga granitoids display both A-type and I-type granitic affinities, indicating long live continental magmatic arc environment characteristics.1.95–1.80 Ga granitoids exhibit both A-type and S-type characteristics, suggesting formation in an extensional tectonic regime following continental collision. (3) 2.60–2.45 Ga period is late Archean subduction-accretion and arc magmatism, followed by arc-continent collision; 2.45–2.30 Ga period is a long-time arc-continental accretion process with multiple arc magmatism; 1.95–1.80 Ga period represents continent-continent collision to post-collisional extension setting. Thus, the long-term arc-continental accretion and multistage crustal recycling of terrigenous sediments with high U and Th content, comparable to Phanerozoic subduction-accretionary orogens, explain why effective helium source rocks are enriched in the northern Ordos Block. By the comparison of Khondalite Belts in North China Craton with global Khondalite Belts, global Khondalite belts could be favorable areas for predicting the worldwide distribution of helium source rocks.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107905"},"PeriodicalIF":3.2,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050237","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}

{"title":"Temporal and magmatic evolution of the Neoproterozoic ultramafic and mafic Ougda arc complex and associated granitoids (Western Tuareg Shield, Algeria)","authors":"Chaouki Djallel Eddine Bendimerad ,&nbsp;Abderrahmane Bendaoud ,&nbsp;Julien Berger ,&nbsp;Renaud Caby ,&nbsp;Gaston Godard ,&nbsp;Karel Schulmann","doi":"10.1016/j.precamres.2025.107903","DOIUrl":"10.1016/j.precamres.2025.107903","url":null,"abstract":"<div><div>The Ougda area, located within the Tassendjanet terrane of the Western Tuareg Shield, hosts a large (ultra)mafic complex associated with granitoid intrusions. This magmatic complex represents a Neoproterozoic continental arc, active between 749 ± 2 Ma and 653 ± 4 Ma ago; during this time, various ultramafic and mafic (meta)cumulates (serpentinites, hornblendites, garnet amphibolites, amphibolites and leucogabbros) and non-cumulates (amphibole gabbros, quartz diorites, diorites) were emplaced. The latter exhibit a calc-alkaline affinity. Sr-Nd isotope data reveal a distinct contrast between North and South Ougda ultramafic and mafic units. The North Ougda units have a more juvenile signature (<em>ε_Nd</em> = +6.3 to +9.4, <em>ISr</em> = 0.70248–0.70377) than the South Ougda units (<em>ε_Nd</em> = +5.3 to +6.3, <em>ISr</em> = 0.70267–0.70400). Early arc construction is represented by the emplacement of the South Ougda units into a thinned juvenile crust at shallow crustal levels. In contrast, the younger and more juvenile North Ougda units were emplaced at deeper crustal levels, likely at the base of the arc crust.</div><div>Syn-collisional granitoids, dated at 626 ± 5 Ma and 627 ± 4 Ma, intruded the Tassendjanet terrane and show a hybrid juvenile-crustal signature (<em>ε_Nd</em> = +2.68 to −8.04, <em>ISr</em> = 0.70296–0.70743), interpreted as resulting from the partial melting of juvenile basaltic rocks in the lower crust of the Ougda arc, followed by the crustal contamination of primitive magmas. In addition, aplitic dykes crosscutting these granitoids display geochemical characteristics similar to those of the post-collisional granites that sealed the Panafrican orogeny in the Tuareg Shield. The Ougda continental arc complex is believed to have formed during the closure of an oceanic basin, leading to the amalgamation of West Gondwana and ultimately to the Pan-African orogeny observed across the Neoproterozoic NW African provinces.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107903"},"PeriodicalIF":3.2,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027881","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}

{"title":"Paired metamorphic belts in the Usagaran Orogen of Tanzania: evidence for one-sided oceanic subduction in the Palaeoproterozoic","authors":"V. Schenk ,&nbsp;T. Sarkar ,&nbsp;D. Wiemer","doi":"10.1016/j.precamres.2025.107891","DOIUrl":"10.1016/j.precamres.2025.107891","url":null,"abstract":"<div><div>Paired metamorphic belts (PMB) are the tectono-metamorphic expression of the one-sided subduction of oceanic lithosphere beneath continental margins and island arcs, which represents a key characteristic of terrestrial plate tectonics. PMB that are spatially and timely paired are mainly known from Phanerozoic orogenic belts, although the metamorphic rock record points to a duality of thermal regimes since the Palaeoproterozoic. Here we describe the tectono-metamorphic evolution of the Usagaran Orogen at the SE-margin of the Tanzania Craton, which includes PMB of Palaeoproterozoic age. The orogen’s lithological inventory reflects a Wilson cycle: (1) The passive margin sequence (Konse Group) was deposited during the Lomagundi carbon isotope excursion (2.22–2.06 Ga) and metamorphosed at 2.03 Ga during the Usagaran orogeny. (2) The precursors of most eclogites were ocean-floor basalts, but those of the Ky- and Opx-eclogites of boninite chemistry were related to subduction-initiation. Peak eclogite metamorphism at mantle depths (850–880 °C/18–19 kbar) was followed by transient granulite-facies conditions during exhumation (750–800 °C/6–10 kbar). High-<em>T-P</em> shear zones in Opx-eclogites and felsic mylonites formed at P &lt; 15 &gt; 10 kbar are related to exhumation. (3) High-P amphibolite-facies metamorphism of metasediments enveloping the eclogite belt (770 °C/13.2 kbar at 2.0 Ga) is attributed to an accretionary wedge setting. The concurrent evolutions and the preserved growth zonations in garnet of both units point to a shared short-lived metamorphism. (4) Low-P Grt-Crd-Sil-granulites, which overlie the accretionary wedge metasediments as a nappe, experienced a counter-clockwise <em>P-T</em> path at ca. 2.06 Ga (peak 820 °C/7.2 kbar) in an arc setting that predates the orogeny for 50–60 Myr. We attribute their protomylonitic texture to post-peak NW-thrusting towards the orogenic foreland during collision. Late-stage <em>P-T</em> paths of all units in the nappe stack (isobaric cooling at 20 km depth) are interrelated. Other Palaeoproterozoic PMB in orogens around the Congo Craton and in the Yangtze Craton, in addition to subduction-related eclogites in the Trans-North China Orogen, indicate that subduction of oceanic lithosphere and its partial exhumation after slab breakoff at mantle depths were already viable tectonic processes. Pre-Neoproterozoic eclogites representing exhumed oceanic crust are dominantly known from a short time interval (2.1–1.8 Ga), during which warm (12–14 °C/km) and cold (&lt;11 °C/km) subduction zones existed, which both show the tectono-metamorphic characteristics akin to modern asymmetric one-sided oceanic subduction.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"429 ","pages":"Article 107891"},"PeriodicalIF":3.2,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020962","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}

{"title":"Late Mesoproterozoic mafic magmatism in the southwestern Yangtze Block and its implications for reconstructing the Rodinia supercontinent","authors":"Dongxue Li ,&nbsp;Mingguo Zhai ,&nbsp;Lu Xiang ,&nbsp;Hailong He ,&nbsp;Junping Liu ,&nbsp;Hanlin Chen","doi":"10.1016/j.precamres.2025.107904","DOIUrl":"10.1016/j.precamres.2025.107904","url":null,"abstract":"<div><div>Late Mesoproterozoic igneous rocks are traditionally considered a key hallmark of the Grenvillian Orogeny and have been widely utilized in reconstructing the Rodinia supercontinent. Despite increasing attention to Late Mesoproterozoic magmatism in the southwestern Yangtze Block, the tectonic evolution of this region during that time still remains unresolved, leading to ongoing debate regarding the role of the Yangtze Block in Rodinia assembly. Here, we report two suites of ca. 1085 Ma mafic rocks from the Dongchuan area in the SW Yangtze Block to investigate their petrogenesis and assess their implications for reconstructing the Yangtze Block in the Rodinia supercontinent. The studied mafic rocks are characterized by high TiO₂ content (1.49–4.49 wt%) and low Mg^# values (22–56), exhibiting slight enrichment in light rare earth elements, with (La/Yb)_N ratios ranging from 1.65 to 5.24, and displaying trace element patterns analogous to E-MORB, without significant Nb-Ta or Zr-Hf anomalies. Their zircon ε_Hf<em>(t)</em> and whole-rock ε_Nd<em>(t)</em> values range from 1.9 to 9.4 and 0.7 to 4.9, respectively, indicating that their primary magmas were derived from the partial melting of a depleted mantle source. In contrast, their zircon δ¹⁸O values vary from 5.50 ± 0.29 ‰ to 6.78 ± 0.39 ‰, likely reflecting the involvement of subducted oceanic mafic crust in the magma source. Moreover, their geochemical characteristics, such as high Zr/Y ratios and elevated Ti concentrations, are consistent with formation in an intra-continental rifting environment. Integrated with the presence of other 1.2–1.0 Ga intraplate magmatism in the SW Yangtze Block, we propose that the block most possibly remained an independent landmass during 1.2–1.1 Ga and began drifting toward Rodinia between 1.1 and 1.0 Ga, ultimately positioning itself on the periphery rather than at the core of the supercontinent.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"429 ","pages":"Article 107904"},"PeriodicalIF":3.2,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020961","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}

{"title":"U–Pb zircon geochronology and geochemistry of Um Genud layered mafic intrusion in the northern tip of the Arabian-nubian shield: implications for the genesis of the plutonic crust of neoproterozoic immature intra-oceanic arc","authors":"Tarek H. Abu El-Kheir ,&nbsp;Keda Cai ,&nbsp;Ayman E. Maurice ,&nbsp;Kai Wang ,&nbsp;Hairuo Wang ,&nbsp;Maher Dawoud","doi":"10.1016/j.precamres.2025.107915","DOIUrl":"10.1016/j.precamres.2025.107915","url":null,"abstract":"<div><div>The Um Genud Neoproterozoic layered mafic intrusion, located in the South Eastern Desert of Egypt, represents the northwestern tip of the juvenile crust of the Arabian-Nubian Shield (ANS). This intrusion is composed of olivine gabbro, gabbro, noritic-gabbro and hornblende gabbro. Zircon U–Pb data constrain the emplacement age of the intrusion to 718 Ma, coinciding with the island arc stages of the ANS. The trace element patterns of pyroxenes, amphiboles, whole-rock samples and calculated melts in equilibrium with clinopyroxene and amphibole show marked Nb-Ta and Zr-Hf troughs and prominent peak of Pb. These features, along with the trace element abundances and ratios in zircon, suggest that the parental magma was generated in an intra-oceanic island arc setting from a depleted mantle source metasomatized by subducted slab-derived aqueous fluids. Textural features, mineral compositions of olivine, pyroxene and plagioclase, whole-rock geochemical characteristics, the calculated ƒO₂ values (FMQ + 1 – FMQ + 1.6), and the estimated water content (5.9 – 9.1 wt%) of melt indicate that the Um Genud gabbroic rocks represent cumulates differentiated from oxidized hydrous low-K tholeiitic magma, essentially by fractional crystallization. The estimated pressure of crystallization (∼3 to ∼ 3.5 kbar; ∼10 km depth), the low-K tholeiitic nature of parental magma and the relative abundance of the exposed gabbroic and granitic arc rocks in the study area are consistent with intrusion emplacement within the lower crust of an immature oceanic arc. This implies that even arcs with thin crust can develop considerable plutonic layers and contribute to continental crust growth through vertical accretion.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"429 ","pages":"Article 107915"},"PeriodicalIF":3.2,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997686","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}

{"title":"Kilometer-scale hook-shaped Type2/Type3 folds due to refolding and transpressional strike-slip reversal in the Egyptian Nubian Shield, east African orogenic belt","authors":"Mohamed A. Abd El‑Wahed ,&nbsp;Ahmed M. Eldosouky ,&nbsp;Osama M.K. Kassem ,&nbsp;Ahmed Abdelhady Abo-Rayan ,&nbsp;Mohamed Attia","doi":"10.1016/j.precamres.2025.107912","DOIUrl":"10.1016/j.precamres.2025.107912","url":null,"abstract":"<div><div>This study combines remote sensing, aeromagnetic data, and field investigations to provide the initial identification of hook-shaped Type 2/Type 3 folds within the Egyptian Nubian Shield. The Western Allaqi shear belt (WASB) exhibits remarkable refolded structures that are distinctly observable from space. This belt primarily comprises ophiolite slices, metavolcanics, and volcanoclastic metasediments, which have been intruded by syn- (729–635 Ma) and post-tectonic granites (610–543 Ma). The WASB region experienced significant compression during the N-S shortening (830–720 Ma), leading to the formation of east–west oriented folds and foliation and N-dipping thrust imbrications. The interference patterns of the folds predominantly display Type 2 and Type 3 refolds characterized by wavelengths on the order of kilometers. The geological observation reveals a complex history of deformation, with refolded folds linked to dextral shear zones, ductile and brittle fabrics, and opposing movement directions. The fold interference structures were formed through the reactivation of NW-trending sinistral strike-slip shear zones, combined with shear-related folding of the initial F₁ folds, and NE-SE compression (625–565 Ma). The subsequent development of NW-trending Haseierbah folds (F₂) was accompanied by a shift in stress orientation from NE-SW to E-W (620–580), resulting in a reversal of shear sense and the reactivation of NW-trending shear zones into dextral strike-slip shear zones, which in turn formed the N-trending El-Quleib fold (F₃) and the NE-trending Haimur and Shilman folds (F₄). This reversal in shear sense contributes to the formation of Type 2 and Type 3 fold interference patterns and the distinctive hook-shaped fold structures observed within the WASB. This study provides a detailed description of refolding and transpressional strike-slip reversal in the WASB, highlighting the innovative tectonic evolution and urging a reassessment of the entire Allaqi-Heinai suture and the major shear zones in the Egyptian Nubian Shield.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"429 ","pages":"Article 107912"},"PeriodicalIF":3.2,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005224","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}

{"title":"Origin of the Brunovistulian microcontinent: Geochemical and Sr–Nd–Pb–Hf isotope evidence","authors":"Simona Krmíčková ,&nbsp;Lukáš Krmíček ,&nbsp;Martin J. Timmerman ,&nbsp;Jiří Sláma ,&nbsp;Jitka Míková","doi":"10.1016/j.precamres.2025.107902","DOIUrl":"10.1016/j.precamres.2025.107902","url":null,"abstract":"<div><div>The Brunovistulian microcontinent (BVM) represents the largest (up to 30 000 km²) geological unit of Proterozoic provenance in the eastern part of the Variscan collision zone in Central Europe. We present whole-rock, mineral and Sr–Nd–Pb–Hf isotope compositions of representative samples from exposures and deep boreholes (up to 3 km in depth) situated in the Czech part of the BVM. The oldest rocks are ∼ 740 Ma Tonian basic metavolcanic rocks and associated felsic dykes and metatuffs of the Metavolcanic Zone. Geochemical and isotope characteristics of these felsic rocks confirm that their parent melts were derived from the upper mantle, similar to their metabasite hosts. The Tonian (Pan-African) age of the Metavolcanic Zone and its MORB-like geochemical and isotope signature (⁸⁷Sr/⁸⁶Sr = 0.7027; ɛNd = +5.6; ɛHf = +10) reflect the main phase of rifting during breakup of Rodinia and subsequent formation of volcanic island arcs. Granitoids forming the two principal domains of the BVM, the Slavkov Domain situated to the NE, and the Thaya domain situated to the SW, both intruded during the dominant magmatic activity at ∼ 600 Ma. The Sr–Nd–Pb–Hf isotope compositions of granitoids of the Slavkov Domain are typical of relatively primitive volcanic arc magmas. Thus, the Slavkov Domain may represent an eroded relic of a juvenile Neoproterozoic volcanic arc that developed above a subduction zone, very probably at an active Gondwanan margin of the Tornquist Ocean. Possibility of slab breakoff during arc formation cannot be ruled out. In contrast, the Thaya Domain originated by melting of Proterozoic mature continental crust above the same subducting slab at the Gondwanan margin. During subduction, significantly older remnants of an island arc (∼655 Ma Metadiorite Zone) and MORB-like volcanic rocks (∼740 Ma Metavolcanic Zone) were accreted to the continental margin, leading to the assemblage of the Brunovistulian microcontinent. Based on the depleted mantle Nd model ages, the lithosphere of the BVM has retained an isotope signature similar to Avalonia.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"428 ","pages":"Article 107902"},"PeriodicalIF":3.2,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894503","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}

{"title":"Petrogenesis of the Wuhe complex, southeastern margin of the North China Craton: implications for the Meso-Neoarchean crustal growth and evolution","authors":"Hai-Yan Su ,&nbsp;Yang Yang ,&nbsp;Yi-Can Liu ,&nbsp;Chris Yakymchuk","doi":"10.1016/j.precamres.2025.107901","DOIUrl":"10.1016/j.precamres.2025.107901","url":null,"abstract":"<div><div>Archean granitoids and mafic igneous rocks are crucial records of the generation and differentiation of Archean continental crust. New U–Pb zircon geochronological data from granitoids, sanukitoids and mafic igneous rocks from the Wuhe complex, southeastern margin of the North China Craton (NCC) constrain the processes of early crustal growth and evolution in the Meso-Neoarchean period. Magmatic zircons from two granitoid gneisses yield weighted mean ²⁰⁷Pb/²⁰⁶Pb ages of 2986 ± 24 Ma and 2935 ± 11 Ma, followed by metamorphism at ca. 2.5 Ga and ca. 1.85 Ga. Sanukitoid gneisses have protolith crystallization ages of 2739 ± 5 Ma with zircon overgrowth rims at 2501 ± 22 Ma. Amphibolite yields a weighted mean ²⁰⁷Pb/²⁰⁶Pb age of 2500 ± 39 Ma, with metamorphism at 1846 ± 17 Ma. The granitoid gneisses show that they are characterized by steep rare earth element (REE) patterns, obviously negative Nb, Ta, Ti anomalies and positive Eu anomalies, high Sr/Y and (La/Yb)_N ratios, and positive ε_Hf(t) (+5.4 to +7.5) values. Their chemical compositions are similar to those of the TTG-like melts derived from juvenile mafic crust in the deep crust, implying a crustal growth event at ca. 3.0 Ga. The sanukitoid gneisses exhibit high MgO, Cr and Ni concentrations but relatively low (La/Yb)_N values, positive ε_Hf(t) values (+0.6 to +3.0). They were most likely originated from partial melting of mantle peridotite, which was significantly metasomatized by slab-derived granitoid melts, i.e. they plot on an evolution line. The amphibolites display the depleted mantle-derived geochemistry with positive ε_Hf(t) (+1.2 to +3.2) values. Geochemical and zircon Hf isotopic compositions suggest that amphibolite was derived from partial melting of a depleted mantle with minor crustal contamination. Based on comparison of the spatial–temporal distribution and geochemical features of 3.0–2.9, ∼2.7 Ga and ∼2.5 Ga granitoids and amphibolites in the NCC, we propose that the Meso-Neoarchean crustal evolution of the Wuhe complex is similar to the whole NCC, which recorded significant crustal growth and reworking events at 3.0–2.9, 2.7 Ga and 2.5 Ga.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"428 ","pages":"Article 107901"},"PeriodicalIF":3.2,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894502","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}

{"title":"Linking borate remobilization and mineralization to ∼1.85 Ga post-tectonic granitic magmatism in the northern North China Craton: Constraints from in-situ monazite, baddeleyite U-Pb and molybdenite Re-Os ages","authors":"Li-Xing Li ,&nbsp;Jian-Wei Zi ,&nbsp;Yu Liu ,&nbsp;Hou-Min Li ,&nbsp;Yi Wang","doi":"10.1016/j.precamres.2025.107890","DOIUrl":"10.1016/j.precamres.2025.107890","url":null,"abstract":"<div><div>Precambrian borate deposits are generally considered to have formed by multiple stages of metamorphic-hydrothermal events subsequent to boron-rich evaporite deposition, but determining the ages of hydrothermal overprinting and remobilization has proven to be challenging. The lack of robust geochronology data has hindered understanding of the geological controls on this type of mineralization. The Houxianyu boron deposit and Wengquangou boron-iron deposit, hosted in 2.05–1.93 Ga metamorphosed evaporites in northern North China Craton, represent the largest occurrences of Precambrian borate deposits. Monazite, molybdenite, baddeleyite and apatite are intergrown with borate minerals of szaibelyite and ludwigite, and thus can be dated to constrain the timing of boron-iron mineralization. <em>In situ</em> U-Pb and Re-Os geochronology yielded consistent Paleoproterozoic ages of 1854 ± 11 Ma (U-Pb monazite age), 1815 ± 4 Ma (U-Pb baddeleyite age) and 1825 ± 22 Ma (Re-Os molybdenite age) related to borate mineralization. These ages constrain the timing of boron and boron-iron mineralization to 1.86–1.81 Ga, which is younger than the ∼1.90 Ga regional metamorphism but contemporaneous with the ∼1.85 Ga post-tectonic granitic magmatism. This interpretation is further supported by field relationships which show that hydrothermal quartz-tourmalinite veins cross-cut the schistosity of the leptynites, and by the granitoid-affiliated accessory mineral assemblage (molybdenite, monazite and uraninite). Additionally, chondrite-normalized rare earth element (REE) patterns of apatite intergrown with ludwigite from borate ores show enrichment of LREEs relative to HREEs and strong negative Eu anomalies. These chemical features are similar to those of apatite from ∼1.85 Ga granites but distinct from those of apatite in metamorphosed rocks. Therefore, we propose that 1.86–1.81 Ga borate mineralization resulted from hydrothermal remobilization associated with the ∼1.85 Ga granitic magmatism. Our results negate the previously proposed genetic link between borate mineralization and ∼1.90 Ga regional metamorphism. These results, combined with previously published data, allow us to establish a hydrothermal B-Fe-U-Nb-Ta-Co-Ni metallogenic belt in relation to the ∼1.85 Ga post-tectonic granitic magmatism in northern North China Craton, potentially valuable for future exploration efforts.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"428 ","pages":"Article 107890"},"PeriodicalIF":3.2,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144866912","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}

{"title":"Subduction-induced crustal growth in the Neoproterozoic continental magmatic arc: Evidence from arc-type high-Mg# diorites and adakitic granitoids in the western Yangtze Block, South China","authors":"Rui-Yang Liu ,&nbsp;Shao-cong Lai ,&nbsp;Yu Zhu ,&nbsp;Ren-Zhi Zhu ,&nbsp;Min Liu ,&nbsp;Jiang-Feng Qin ,&nbsp;Fang-yi Zhang ,&nbsp;Hang Yang","doi":"10.1016/j.precamres.2025.107892","DOIUrl":"10.1016/j.precamres.2025.107892","url":null,"abstract":"<div><div>The coexistence of normal arc-type mafic-intermediate rocks and adakitic granodiorites can provide significant insights into the subduction-induced crustal growth. In this study, we present the comprehensive study of petrology, mineralogy, zircon U-Pb geochronology, bulk rock major and trace elements, Sr-Nd isotopes, zircon Lu-Hf isotopes, and electron microprobe (plagioclase, amphibole, biotite, and clinopyroxene) for the newly identified Neoproterozoic high-Mg^# diorites (HMA) and adakitic granodiorites from the Kangding area along the western margin of the Yangtze Block (South China), to explore the subduction-induced crustal growth in the Neoproterozoic continental arc magma. The results show that the high-Mg^# diorites formed at 792.9 Ma, and have much andesines, labradorites, high magnesium biotites and iron hornblendes, and are characterized by variably high MgO (3.62 ∼ 5.82 wt%) contents and Mg^# (58.36 ∼ 60.49) values, showing the positive bulk rock ε_Nd(t) (+0.84 ∼ +2.19) and zircon εHf(t) (+4.18 ∼ +9.44) values. The adakitic granodiorites formed at 793.5 Ma, and have much mineral of quartz, plagioclase, biotite as well as minor pyroxene and iron calcium magnesium amphibole. They contain high Sr (463.14 ∼ 494.44 ppm) and Y (10.41 ∼ 13.81 ppm) contents as well as Sr/Y (35.69 ∼ 47.49) ratios, indicating the adakitic dffinity. Theses adakitic granodiorites display positive ε_Nd(t) (+1.52 ∼ +1.83) and zircon ε_Hf(t) (+3.45 ∼ +7.14) values. Both types of rocks are enriched in LREEs (Light rare earth elements) and LILEs (Large ion lithophile elements) and depleted in Nb, Ta and Ti. We suggest that these high-Mg^# diorites were derived from the partial melting of metasomatized mantle source enriched by subduction-related fluids, and the adakitic granodiorites were formed by partial melting of thickened juvenile mafic lower crust, which can reveal the subduction-induced crustal growth.</div><div>Combined with 860 ∼780 Ma mafic-intermediate-felsic rocks and 800 ∼750 Ma adakitic granitoids, we support that the Neoproterozoicc crustal growth were induced by metasomatized mantle-derived magmas. The subduction-induced crustal growth is vital for moulding the geochemical characteristics of arc magmatic rock types.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"428 ","pages":"Article 107892"},"PeriodicalIF":3.2,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841253","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}