Precambrian Research最新文献

{"title":"Pre-Mesoproterozoic crustal framework and Mesoproterozoic evolution of the SW Angolan Shield: structural, geochemical, and isotopic insights from the Kunene Complex and surrounding basement","authors":"Enrique Merino-Martínez ,&nbsp;Ezequiel Ferreira ,&nbsp;Pablo Valverde-Vaquero ,&nbsp;José Feliciano Rodrigues ,&nbsp;Javier Escuder-Viruete ,&nbsp;José Luis García-Lobón ,&nbsp;Aratz Beranoaguirre ,&nbsp;María del Carmen Feria ,&nbsp;Carmen Rey-Moral ,&nbsp;Paulo Bravo Silva ,&nbsp;Pablo González-Cuadra ,&nbsp;João Carlos Sousa ,&nbsp;Julián Potti ,&nbsp;Jaime Máximo ,&nbsp;Miguel Gutiérrez-Medina ,&nbsp;Juan Carlos Gumiel ,&nbsp;Gustavo Galán ,&nbsp;Tania Mochales ,&nbsp;José Manuel ,&nbsp;Domingos Cordeiro ,&nbsp;Carmen Galindo","doi":"10.1016/j.precamres.2025.107937","DOIUrl":"10.1016/j.precamres.2025.107937","url":null,"abstract":"<div><div>The southwestern Angolan Shield hosts the Earth’s largest Mesoproterozoic massif-type anorthosite complex (up to 53,500 km²), the Kunene Complex (KC). This complex is the result of a long-lived (∼200 Ma) episodic emplacement of coalescent magmatic pulses. The recent acquisition of multidisciplinary data during the PLANAGEO project has significantly enhanced our understanding of the Precambrian crustal framework from the southwestern Angolan Shield. Combined multi-isotope, structural and geophysical data reveals distinctive crustal zones in the southwestern Angolan Shield that clearly influenced KC’s emplacement within a back-arc setting. The spatio-temporal arrangement of KC pulses suggests westwards magma migration within a complex contractional regime involving large strike-slip systems. A long-lasting and extensive accretionary orogen was responsible for the tectono-thermal activity recorded during most of the Mesoproterozoic. Crustal thinning and partial melting of isotopically heterogeneous lower-crustal sources through mantle upwelling promoted the episodic felsic magmatism contemporaneous with the KC. Crustal contamination processes are evident in gabbro-anorthosites, indicating mantle metasomatism and interaction with wall-rocks and granite melts during ascent, upwelled by lateral-driven forces. Deposition of extensive metasedimentary sequences (&lt;1.26 Ga) covering the KC, along with 1.23–1.07 Ga sublithospheric and mantle-derived magmatism, indicate a shift from a compressional to an extensional regime during late-Mesoproterozoic times. Regional correlations with other Mesoproterozoic units in African and Brazilian counterparts suggest a shared geological evolution, despite potential differences in tectonic setting. These findings supports a refined geological model for the Mesoproterozoic evolution of the southwestern part of the Congo Craton.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107937"},"PeriodicalIF":3.2,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145327169","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":"Deciphering late Neoarchean orogenesis through structural analysis of the Taishan Group, eastern North China Craton","authors":"Xiaodong Li ,&nbsp;Wei Wang ,&nbsp;Zhonghua Tian ,&nbsp;Du Jia ,&nbsp;Fei Wen ,&nbsp;Fulai Liu","doi":"10.1016/j.precamres.2025.107944","DOIUrl":"10.1016/j.precamres.2025.107944","url":null,"abstract":"<div><div>The scientific community is currently engaged in an ongoing debate and controversy regarding the dominant mechanisms of Archean rock deformation, specifically whether it primarily occurred through vertical processes associated with sinking or through horizontal deformation involving subduction. The Western Shandong Province in the North China Craton represents a key area for investigating this question. In this study, we conducted detailed cross-section mapping and micro/mesoscale structural analysis of the Taishan Group within the central part of the Western Shandong Province. The D_A-1 structure exhibited an early foliation (S₁), while the D_A-2 structure showed F₂ folding, parasitic folds, S₂ crenulation cleavage and spaced cleavage. Furthermore, we identified thrust faults within the D_A-2 structure. The D_A-3 structure was defined by a shear zone and subsequent formation of kink bands. By integrating our geochronological data with regional tectonic information, we found that the D_A-1 deformation predated 2550 Ma, the D_A-2 deformation occurred between 2550 Ma and 2525 Ma, while the D_A-3 deformation took place between 2525 Ma and 2501 Ma. Our study demonstrates that the observed deformation phases produced by Archean orogenesis in the Taishan Group exhibit characteristics consistent with those found in modern orogenic belts. Consequently, we can conclude that the observed NNW-SSE linear structures result from horizontal movements produced by the plate tectonic system rather than dome-and-basin deformation in the Western Shandong Province.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107944"},"PeriodicalIF":3.2,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333343","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":"Aravalli A-type granites (ca. 1.72 Ga), NW India: Petrogenesis, geodynamic evolution, and global implications for late Paleoproterozoic crustal reworking","authors":"Parampreet Kaur ,&nbsp;Armin Zeh ,&nbsp;Naveen Chaudhri ,&nbsp;Prabhakar Dutta ,&nbsp;Axel Gerdes","doi":"10.1016/j.precamres.2025.107936","DOIUrl":"10.1016/j.precamres.2025.107936","url":null,"abstract":"<div><div>The geochemical and isotopic data for ca. 1.72 Ga A-type granites in the central Aravalli orogen, NW India, remain limited, hindering a detailed evaluation of their petrogenesis and tectonic setting. New results of combined zircon U-Pb-Hf isotope analyses and whole-rock geochemical data reveal that the A-type granites are characterised by high liquidus temperatures (≥850 °C), enrichment in rare earth elements and incompatible elements, and oxidised in nature. They were generated through partial melting of a silica-poor dioritic source within a post-collisional extensional setting. This A-type magmatism is synchronous with the emplacement of charnockites and granulite-facies metamorphism in the region. The coeval formation of A-type and charnockite magmas is attributed to partial melting of evolved Neoarchean crust (εHf_t = -12.5 to −5.2 and T_DM2 = 3.02 to 2.68 Ga) at moderate depth (20–25 km), triggered by upwelling of asthenospheric mantle following a slab break-off at ca. 1730 Ma. This process induced lithospheric extension and granulite-facies metamorphism in the lower crust. A global compilation of zircon Hf isotope and whole-rock Nd isotope data for late Paleoproterozoic A-type granites suggests that these rocks primarily formed by large-scale reworking of existing crustal sources, with only limited melt contributions from depleted mantle sources, thereby having a negligible impact on crustal growth over time. On the contrary, the Phanerozoic A-type granites largely represent addition of new crust.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107936"},"PeriodicalIF":3.2,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333344","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":"Unprecedented U–Pb-Th SHRIMP and Lu–Hf isotopic data in zircon from Tandilia basement rocks, Argentina: new insights into Palaeoproterozoic and Neoproterozoic crustal reworking of the Río de la Plata craton","authors":"Melisa Angeletti ,&nbsp;Martim Chichorro ,&nbsp;Antonio Castro ,&nbsp;María Cristina Frisicale ,&nbsp;Rita Solá ,&nbsp;Luis Vicente Dimieri ,&nbsp;Juan Cruz Martínez","doi":"10.1016/j.precamres.2025.107941","DOIUrl":"10.1016/j.precamres.2025.107941","url":null,"abstract":"<div><div>We present new geochronological zircon data from the Siempre Amigos Hill (SAH), a small but representative portion of Tandilia Terrane within the Río de la Plata Craton (RPC). U-Pb-Th SHRIMP data indicate a heterogeneous Palaeoproterozoic (Rhyacian) crust. A garnet-bearing granite (2165 ± 16 Ma) hosts felsic (2108 ± 13.6 Ma) to intermediate gneiss protolith (2104 ± 8 Ma), andesite with a sanukitoid signature (2094 ± 47 Ma) and granulites or charnockites. Additionally, calc-alkaline granitoids (2092 ± 13 Ma) intruded, as a result of differentiation from an igneous mafic sanukitoid source. Localised low-temperature shear zones affected the sequence. Lu-Hf isotopic data for the post-orogenic stage (&lt; 2.1 Ga) complement previous results, showing progressive negative _ƐHf_(t) values. These isotopes suggest post-orogenic transtension. New Neoproterozoic ages (652 ±37 Ma, 618.4 ±11.2 Ma and 686 ±60 Ma) from granites, with low-to-very low zircon Th/U ratios, are presented as evidence of U-Th-Pb systems overprinting by Neoproterozoic (Cryogenian) thermal-hydrothermal events. Those Neoproterozoic ages are, within analytical uncertainty, equivalent to the 656 ± 19 Ma metamorphic age obtained for the Palaeoproterozoic granulite. These new Neoproterozoic ages, suggests a thermal perturbation linked either to the collision of the Nico Pérez Terrane against the passive margin of RPC, or the Neoproterozoic evolution of the Ventania System basement during the Brasiliano/ Pan-African orogeny.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107941"},"PeriodicalIF":3.2,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333340","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":"Metamorphic timescales of Neoproterozoic high-pressure granulites constrained by multi-mineral petrochronology: A case study from the Southern Brasília Orogen (SE Brazil)","authors":"Lorena de Toledo Queiroz ,&nbsp;Brenda Chung Rocha ,&nbsp;Bruno Vieira Ribeiro ,&nbsp;Cauê Rodrigues Cioffi ,&nbsp;Vinícius Tieppo Meira ,&nbsp;Lucas Ramos Tesser ,&nbsp;Armando Lucas Souza de Oliveira ,&nbsp;Gyovana Patrícia Gonçalves Costa ,&nbsp;George Luiz Luvizotto","doi":"10.1016/j.precamres.2025.107943","DOIUrl":"10.1016/j.precamres.2025.107943","url":null,"abstract":"<div><div>Timescales of Neoproterozoic high-pressure granulites from the Carvalhos Klippe (Southern Brasília Orogen) were constrained through multi-mineral petrochronology. The high-grade metamorphism is related to continental collision processes during the assembly of West Gondwana and provides valuable insights on duration and rates of collisional settings in the Neoproterozoic. Most of the investigated samples comprises coarse-grained rutile-kyanite-garnet-orthoclase granulites, reaching peak metamorphic conditions of ∼ 825 °C and 12 kbar, based on phase equilibrium modelling and Zr-in-rutile thermometry. Prograde to a near peak stage (630–620 Ma) was constrained by garnet Lu-Hf and U-Pb ages from high Y-HREE and low Th/U monazite domains. Low Y-HREE, high Th/U and Eu/Eu* monazite domains record the metamorphic peak (615–605 Ma) after substantial garnet growth, presence of melt and plagioclase consumption. The retrograde stage highlighted by high Y-HREE and Th/U and depleted Eu/Eu* monazite domains, reflects garnet dissolution and melt crystallization during the retrograde path (605–600 Ma). Zircon ages have a main cluster between 630 and 605 Ma, most likely related to near-peak cooling. Cooling ages obtained by rutile and apatite U-Pb and biotite Rb-Sr ranging from 570 to 540 Ma suggest slow cooling rates of 2–8 °C/Myr during the retrograde path, contrasting with the modern collisional orogens due to hotter mantle temperatures or low erosion rate and/or heat-producing elements concentration. This study demonstrates that the timescales of high-pressure granulites may provide a robust framework for understanding continental settings throughout the Earth’s history.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107943"},"PeriodicalIF":3.2,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268581","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":"Were there any snow algae on the Cryogenian ‘Snowball Earth’?","authors":"Morten Smelror","doi":"10.1016/j.precamres.2025.107935","DOIUrl":"10.1016/j.precamres.2025.107935","url":null,"abstract":"<div><div>Unicellular algae have unique adaptation capacities for primary production in different extreme environments. In Neoproterozoic times (1000–542 Ma) a group of green algae developed evolutionary production and survival strategies like those of modern snow algae, and during the Cryogenian Sturtian and Marinoan global glaciations these algae inhabited ice covered shelves. To what extent snow algae existed on inland glaciers and snow-covered terrains is discussed. Evidence supporting a ‘Snowball Earth’ with terrestrial biomes and snow algae are morphological resemblances between aplanospores of modern cryophilic microalgae (Chlamydomonadaceae) found in high mountains in central Norway and Meso- and Neoproterozoic clusters of organic-walled microfossils and sphaeromorphic acritarchs. Geochemical biomarkers in Proterozoic rocks also provide possible links to carotenoids found in modern ‘red snow’. The abundant and diverse communities of present-day continental snow algae on glaciers and snow fields around the world may serve as a modern analogue to the Neoproterozoic ‘Snowball Earth’ glacial terrestrial biomes.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107935"},"PeriodicalIF":3.2,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268580","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":"2025-10-08","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":"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":"2025-10-08","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":"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":"2025-10-06","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":"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":"2025-10-03","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}