Precambrian Research最新文献

{"title":"Petrogenesis and mineralization potential of spinifex komatiitic basalts in the Bradley Peak greenstone terrane, Wyoming Province","authors":"Lisa J. Zieman,&nbsp;M. Christopher Jenkins,&nbsp;Jacob E. Poletti","doi":"10.1016/j.precamres.2025.107929","DOIUrl":"10.1016/j.precamres.2025.107929","url":null,"abstract":"<div><div>Komatiitic volcanic rocks are important hosts of Ni sulfide mineralization and record early Earth evolution; however, those in the well-studied Archean Wyoming Province have received little attention. Here, we elucidate the timing and petrogenesis of the Bradley Peak komatiitic volcanic rocks using field and textural observations, geochronology, and geochemistry. Detrital and igneous zircon U-Pb ages for two samples from previously undated units support published age determinations, placing the eruption age at 2.72 Ga. Stratigraphy of the volcanic flows was mapped and 36 samples including cumulates, greenschists, and spinifex-textured rocks were collected. Whole-rock geochemistry was used to classify the spinifex-textured samples as Al-undepleted komatiitic basalts (11–17 wt% MgO). Platinum-group element concentrations (n = 25) are like those in global Al-undepleted komatiitic basalts, and PGE/Ti ratios do not indicate the volcanic flows likely host sulfide mineralization. Initial ε_Nd values of −0.5 to +4.7 (n = 16), indicate that these lavas were derived from a depleted mantle source and have negligible evolved crust contamination. The primary magma to the komatiitic basalt flows is estimated to have had 19 wt% MgO and be derived from ∼15 to 25 % mantle partial melting at 3–4 GPa. Trace element chemistry and thermodynamic modeling suggest the primary melt assimilated local banded iron formation. Although the Bradley Peak komatiitic basalts do not contain positive evidence of magmatic sulfide deposits, depleted Au in the flows suggests they could be source rocks for nearby orogenic gold deposits.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107929"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159010","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":"Igneous apatite geochemistry indicates early cratonization of continents","authors":"Adrien Vezinet ,&nbsp;Javiera Flores-Rojas ,&nbsp;Alexander V. Sobolev ,&nbsp;Julien Léger ,&nbsp;Aleksandr V. Chugunov ,&nbsp;Valentina G. Batanova ,&nbsp;Marlina A. Elburg ,&nbsp;Axel Hofmann ,&nbsp;Mélanie Balvay ,&nbsp;Nouméa Paradis","doi":"10.1016/j.precamres.2025.107927","DOIUrl":"10.1016/j.precamres.2025.107927","url":null,"abstract":"<div><div>Processes and mechanisms accounting for the stabilization of Archean (4.0–2.5 Ga) continental crust remain a matter of debate. Over the last decades, major efforts have been made to determine the chemical and isotopic composition of rocks belonging to the Tonalite-Trondhjemite-Granodiorite (TTG) suite, i.e. those forming the bulk of Archean continental crust, as well as late-Archean sanukitoids, the typical marker of cratonization. The extensive use of zircon elemental and isotopic signatures has indisputably been an unrivalled source of information; yet it has also biased interpretations through the prism of a single mineral, hence not reflecting the whole geological history of these magmas. To extend our understanding of early continent stabilization, a pivotal aspect of Earth’s evolution, a fresh perspective is necessary. Here, we present in-situ analyses of igneous apatite, Ca₅(PO₄)₃(OH,Cl,F), from Archean granitoids exposed in the eastern Kaapvaal craton for major/trace elements and U–Pb/Sr isotopes. The trace element signatures of these apatite crystals, with a clear enrichment in LREE and an elevated LREE/HREE, resemble that of apatite from sanukitoids and Phanerozoic I-type granites, a signature which can be blurred at the whole-rock scale. We interpret this signature as indicating that the studied granitoids are formed via interaction between (i) a TTG melt, formed via partial melting of a subducting oceanic crust and (ii) a mantle component, causing chemical depletion of the mantle domain involved and thus production of long-lived and stable lithospheric keels pivotal in the long-term preservation of Archean lithosphere at the Earth’s surface. Therefore, the identification of this signature—in igneous apatite from Paleo to Meso-Archean TTGs of the eastern Kaapvaal—indicates an early onset of cratonization in this region.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107927"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221693","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":"Identification of survived Archean continental fragments in the Paleoproterozoic Trans-North China Orogen","authors":"Hui C.G. Zhang ,&nbsp;Guochun Zhao ,&nbsp;Wanfeng Zhang ,&nbsp;Guo-Dong Wang ,&nbsp;Chun-Ming Wu","doi":"10.1016/j.precamres.2025.107932","DOIUrl":"10.1016/j.precamres.2025.107932","url":null,"abstract":"<div><div>The late Archean granulite was found as tectonic slices amalgamated with the late Paleoproterozoic metamorphic rocks in the Pingquan area within the Paleoproterozoic Trans-North China Orogen. The late Archean intermediate granulite rocks with distinctive ‘red-eye socket’ texture record anticlockwise <em>P-T</em> paths and were metamorphosed at ∼2.5 Ga, whereas the late Paleoproterozoic mafic granulite and amphibolite with “white-eye socket” texture record clockwise <em>P-T</em> paths and were metamorphosed at 1.86–1.80 Ga. The ⁴⁰Ar/³⁹Ar ages (1.81–1.79 Ga) of hornblende further constrain the synchronous exhumation of these disparate metamorphic units, providing critical constraints on the Paleoproterozoic uplifting and cooling process. The juxtaposition of late Archean continental fragments with Paleoproterozoic subduction-related lithologies within a confined orogenic zone highlights the capacity of orogenic systems to preserve both juvenile accreted terranes and reworked more ancient continental fragments, implying remarkable longevity of continental materials through accretionary cycles. This phenomenon suggests that without detailed metamorphic-petrochronological analyses, amalgamated tectonic slices formed at different ages may remain unresolved, potentially leading to erroneous interpretations.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107932"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221691","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":"Rhyacian magmatism at the southern Bacajá Domain: implications for the crustal evolution of the SE Amazonian Craton and Columbia assembly","authors":"Arthur Santos da Silva Neri ,&nbsp;Roberto Dall’Agnol ,&nbsp;Elton Luiz Dantas ,&nbsp;Gilmara Regina Lima Feio ,&nbsp;José de Arimatéia Costa de Almeida ,&nbsp;Marco Antonio Galarza","doi":"10.1016/j.precamres.2025.107926","DOIUrl":"10.1016/j.precamres.2025.107926","url":null,"abstract":"<div><div>Collisional orogenesis represents one of the most complex geodynamic processes, leading to the formation of diverse granitoids, including charnockites and strongly peraluminous granites. The coexistence of I-A and S-type granites in these settings reflects crustal thickening and the extreme thermal conditions of orogenic belts. However, the nature, timing, and tectonic setting of the Rhyacian magmatism in the SE Amazonian Craton remain poorly understood. This study addresses this gap by integrating geological mapping, petrography, whole-rock geochemistry, U-Pb geochronology, and Nd-Hf isotopic studies conducted in the southern portion of the Bacajá Domain, a Paleoproterozoic collisional orogen in the SE Amazonian Craton. Our results identify previously unrecognized Rhyacian granitic and charnockitic rocks, formerly assigned to the Mesoarchean Cajazeiras Complex: (i) 2.12 Ga high-K calc-alkaline Bandeirante Granite (εHf_(t) = -6.5 to -4.6, εNd_(t) = -3.40); (ii) 2.10 Ga to 2.07 Ga calc-alkaline to high-K calc-alkaline Alto Rio Preto Granite (εHf_(t) = -10.2 to -6.3, εNd_(t) = -8.96 to -2.84); (iii) 2.09 Ga ferroan Maravilha Charnockite (εHf_(t) = -9.2 to -8.2, εNd_(t) = -3.01 to -1.91); (iv) 2.06 Ga magnesian Serra Azul Charnockite (εHf_(t) = -8.8 to -5.8_, εNd_(t) = -6.41 to -4.71); and (v) 2.05 Ga strongly peraluminous Bernardino Granite (εNd_(t) = -6.71). Overlapping ages suggest a prolonged magmatic activity (∼70 Ma). These rocks are mostly calc-alkaline and magnesian but vary to calcic or alkali-calcic and ferroan. Whole-rock geochemistry, zircon U–Pb–Hf, and whole-rock Nd isotopes point to a collisional origin for the magmatic rocks with extensive reworking of Archean sources and limited mantle contribution. We propose a two-stage geodynamic model: (1) collision between the Archean Bacajá basement and pre-collisional island arcs with the Carajás Province (∼2.12–2.10 Ga), leading to significant crustal thickening and the generation of small <em>syn</em>-collisional plutons; (2) the thickened crust becomes unstable, leading to crustal delamination and the generation of late- to post-collisional magmas (2.09–2.05 Ga). Compiled zircon U–Pb–Hf data reveals crustal reworking and juvenile input patterns similar to the Guiana Shield and West African Craton, supporting the hypothesis of their juxtaposition during the Columbia assembly.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107926"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221690","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":"Comment on ’’Revealing the early geological history of the Istanbul Zone (Far-East Avalonia) through zircon U-Pb-Hf isotopic data’’ by Yılmazer et al. (2025), Precambrian research 427, 107855","authors":"Fatih Şen","doi":"10.1016/j.precamres.2025.107939","DOIUrl":"10.1016/j.precamres.2025.107939","url":null,"abstract":"<div><div>Yılmazer et al. (2025) interpret a single detrital zircon U–Pb age of 530 ± 29  Ma from the Kurtköy Formation as evidence for an Upper Cambrian or younger depositional age. However, this interpretation merits re-evaluation in light of the relatively large analytical uncertainty (±5.5 %) and the absence of corroborating biostratigraphic or sedimentological evidence. Stratigraphic relationships and multiple well-defined zircon age populations (582 ± 5 Ma, 554 ± 8 Ma, and 544 ± 10 Ma) strongly support a Late Ediacaran depositional age. Additionally, the purported unconformable contact between the Kurtköy Formation and the underlying Yellice Volcanics is not supported by field observations, which instead suggest a tectonic boundary. Provenance data also indicate derivation from the nearby Yellice Arc rather than distant sources such as the Timanide Belt. An alternative interpretation of the depositional age and provenance of the Kurtköy Formation is proposed here, with broader implications for the tectono-stratigraphic evolution of the İstanbul Zone.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107939"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268089","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":"∼790 Ma OIB type mafic dykes in the North Altyn block, southeastern Tarim: Insights into the reconstruction and geodynamics of Rodinia breakup","authors":"Xijun Zhao ,&nbsp;Jinlong Yao ,&nbsp;Guochun Zhao ,&nbsp;Yigui Han ,&nbsp;Qian Liu ,&nbsp;Donghai Zhang ,&nbsp;Long Chen","doi":"10.1016/j.precamres.2025.107930","DOIUrl":"10.1016/j.precamres.2025.107930","url":null,"abstract":"<div><div>Deciphering the extensive magmatic records of the Rodinia supercontinent preserved within the Tarim Craton provides valuable insights into the geodynamics of supercontinent evolution. Here, we report ∼ 790 Ma OIB-type mafic dykes from the North Altyn Tagh belt in the southeastern margin of the Tarim Craton. Zircon U-Pb dating and geochemical analyses reveal that these dykes are typical continental flood basalts, which display light rare earth elements (LREE) enriched patterns with Eu depletion, along with slight enrichment of Nb and Ta and depletion of Sr. Chemical and thermodynamic modelling suggest that these mafic dykes were originated from a garnet-spinel mantle source modified by subduction-related fluids, with an estimated partial melting degree of ∼ 10 %. This was followed by fractional crystallization of Ol-Cpx-Pl during subsequent magma evolution process. Therefore, the here identified OIB dykes indicate that the Tarim Craton rifted from Rodinia at around ∼ 790 Ma. This, together with review of overall Neoproterozoic magmatic records across the Tarim Craton, along with detrital zircon ages and Hf isotopic data, demonstrates that the craton preserves complete record of the transition from Rodinia convergence to rifting. Moreover, the Tarim Craton, Central Altyn, Qilian-Qaidam-East Kunlun, Yangtze and Cathaysia blocks were located along the periphery of Rodinia and all recorded the super-mantle plume that broke the Rodinia supercontinent at 850–740 Ma. The plume activity partially overlapped with circum-Rodinia subduction. Overall, the contribution of subduction fluid to Rodinia OIB type plume magmatism and the spatial–temporal correlation of super mantle plume and circum-Rodinia subduction suggest that the Rodinia breakup mantle plume was likely induced by circum-Rodinia subduction. These findings therefore argue for the “top-down” model for supercontinent breakup dynamics, emphasizing the critical role of subduction-induced mantle plume that broke up the Rodinia supercontinent. This study demonstrates that subduction drives supercontinent fragmentation, clarifying how subduction zones and mantle plumes interact within Earth’s supercontinent cycles.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107930"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268087","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 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":"2025-11-01","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":"Authigenic titanite constraints on fast Mesoproterozoic basin formation in hot Antarctic crust","authors":"Naomi Tucker ,&nbsp;Samantha March ,&nbsp;Martin Hand ,&nbsp;Mitchell Bockmann ,&nbsp;Patrick Kolesik","doi":"10.1016/j.precamres.2025.107928","DOIUrl":"10.1016/j.precamres.2025.107928","url":null,"abstract":"<div><div>Geochronological data from detrital zircon, two generations of titanite, and authigenic sericite in glacial erratics transported to the Bunger Hills provide new insights into a deep subglacial basin in East Antarctica. Basin formation occurred during the late Mesoproterozoic, with diagenesis coinciding with granulite facies metamorphism in the underlying basement rocks. In line with previous studies, we interpret this basin to have formed as a rift sequence, but we extend this model by proposing that rifting was directly associated with Mesoproterozoic orogenesis, and that upper crustal extension was coupled with mid–lower-crustal ductile flow. The basin detritus was primarily sourced from a felsic magmatic-rich carapace emplaced at ca. 1180–1160 Ma. The authigenic mineralogy of the erratics, supported by chlorite thermometry and authigenic titanite geochronology, suggests that within the ensuing ca. 50–70 million years, the detritus was buried deeply and subjected to low-grade metamorphism (∼300 °C). Sericite ages complement the zircon and titanite dataset and reveal that the basin was largely unaffected by Cambrian tectonism, meaning that it was situated in thermomechanically stable crust and geographically distant to the major Gondwanan Indo–Australo–Antarctic suture. This study demonstrates the utility of coupled authigenic and detrital mineral geochronology in constraining sedimentary basin formation ages, and linking deep-crustal and near-surface processes.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107928"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159005","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":"Integrated geophysical and emplacement modelling of the Märjamaa and Kloostri rapakivi granitoids, Estonia: Insights into intrusion geometry and tectonic controls","authors":"Juan David Solano-Acosta ,&nbsp;Alvar Soesoo ,&nbsp;Rutt Hints","doi":"10.1016/j.precamres.2025.107938","DOIUrl":"10.1016/j.precamres.2025.107938","url":null,"abstract":"<div><div>The <span><math><mrow><mo>∼</mo><mn>1</mn><mo>.</mo><mn>62</mn></mrow></math></span> Ga buried Märjamaa and Kloostri rapakivi granitoids in western Estonia consist of three magmatic phases. This study utilizes processed Bouguer gravity and magnetic anomaly data to model the internal architecture and emplacement geometry of the granitic bodies, testing how inherited crustal structures influenced these processes within the context of the Mesoproterozoic Anorthosite–Mangerite–Charnockite–Granite (AMCG) magmatism in Fennoscandia. Potential-field data were processed through spectral separation and derivative filters (TDR, TDX, AS), complemented by lineament extraction and density mapping. A cross-gradient joint inversion using the SimPEG Python module, conducted down to 10 km, delineates three-dimensional density and susceptibility contrasts. Potential lineaments align with Riedel shear patterns along the NW-trending, dextral-oblique Åland–Paldiski–Pskov Deformation Zone (PPDZ), indicating transtensional pull-apart reactivation that focused magma ascent and suggesting that 1.6–1.4 Ga AMCG rapakivi granites and coeval basins formed through reactivation of Svecofennian fabrics. Phase I rooted deeply, formed as a steep-sided tabular granodiorite body that evolved into a piston–cauldron structure through roof collapse and block assimilation, producing positive magnetic and Bouguer anomalies. Phase II intruded as a surrounding granite ring during continued subsidence, associated with negative gravity anomalies. Phase III represents a late-stage trachytic Kloostri leucogranite emplaced by asymmetric subsidence, characterized by positive magnetic and negative Bouguer signatures. The phases were placed during the final stages of the first Fennoscandian rapakivi AMCG event (i.e. Wiborg suite), driven by asthenospheric upwelling and mafic underplating from superswell activity, within Nuna’s breakup configuration. Overall, the results support a crustal structure-controlled emplacement in which shear-zone reactivation affect the geometry of the Fennoscandian rapakivi intrusions.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107938"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268088","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":"Neoarchean subduction unveiled: Discovery of 2.5 Ga Super-Wet magmas in the Zanhuang Complex, Trans-North China Orogen","authors":"Wen Zhang ,&nbsp;Lilin Du ,&nbsp;Pinghua Liu ,&nbsp;Chonghui Yang ,&nbsp;Wanpeng Zhou ,&nbsp;Jianlong Wang ,&nbsp;Qianyu Li ,&nbsp;Guochun Zhao","doi":"10.1016/j.precamres.2025.107931","DOIUrl":"10.1016/j.precamres.2025.107931","url":null,"abstract":"<div><div>Neoarchean lithologies of the North China Craton (NCC) provide essential insights into early continental evolution. This study investigates newly identified dioritic gneisses from the Zanhuang Complex in the central Trans-North China Orogen (TNCO) using zircon U-Pb geochronology, whole-rock geochemistry, and Nd-Hf-O isotopes. The rock types include Luzhuang tholeiitic gabbro-dioritic (2493 ± 6 Ma) and quartz dioritic (2498 ± 7 Ma) gneisses, Longmen tholeiitic garnet-bearing dioritic (2493 ± 6 Ma) and quartz dioritic (2498 ± 8 Ma) gneisses, and Shicao calc-alkaline dioritic gneisses, which are intruded by 2500 ± 18 Ma garnet-bearing anatectic granite vein. Geochemical analysis reveals relatively low MgO concentrations and Mg# values, indicating partial melting of mafic rocks. The dioritic gneisses show positive whole-rock ε_Nd(t) values (+1.9 to + 4.9) and zircon ε_Hf(t) values (+2.0 to + 10.0), suggesting a mantle-derived origin. Oxygen isotope analysis indicates zircon δ¹⁸O values ranging from 5.9 to 7.7 ‰ (average 7.0 ‰), which are higher than typical mantle zircons, indicating a metasomatized mantle source. Hygrometric calculations show 6.2–6.8 wt% H₂O in Luzhuang dioritic gneisses and 12.4–14.5 wt% H₂O in Longmen garnet-bearing varieties. The exceptionally high water content in Longmen dioritic gneisses (super-wet magmas) further supports the hypothesis of a subduction-related metasomatic process in the mantle source. These findings provide definitive evidence for Neoarchean subduction processes.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107931"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221692","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}