Precambrian Research最新文献

{"title":"Carbonaceous macrofossils from the Ediacaran–Cambrian lower shale member of the Soltanieh formation, Northwestern Iran","authors":"Najmeh Etemad-Saeed ,&nbsp;Shuhai Xiao ,&nbsp;Steve C. Wang ,&nbsp;Kristin D. Bergmann ,&nbsp;Andrew H. Knoll","doi":"10.1016/j.precamres.2025.107722","DOIUrl":"10.1016/j.precamres.2025.107722","url":null,"abstract":"<div><div>The Ediacaran–lower Cambrian Soltanieh Formation exposed in the Soltanieh Mountains of northwestern Iran is a mixed siliciclastic-carbonate succession that hosts skeletal animals, metazoan trace fossils, and macroalgal compressions, in addition to a well-resolved C isotopic record. Here we attempt to clarify the systematic paleontology of carbonaceous compression macrofossils found at the base of the Lower Shale Member of this formation, close to the Ediacaran–Cambrian boundary, and discuss their implications for our understanding of the early evolution of complex multicellular organisms. We identified five distinct morphological groups: (1) small discoidal fossils (chuarids), (2) branching thalli (<em>Eoholynia corumbensis</em>), (3) large discoidal fossils (<em>Doulia rara</em>), (4) simple ribbon-like compressions, and (5) chuarid-like discoidal structures with an attached filament. These fossils display limited diversity but include representatives of the three groups that dominate Ediacaran–Cambrian macrophyte diversity globally. All are present at the stratigraphic level in which Cambrian animals and trace fossils first appear, providing broader biological context for understanding early animal diversification.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"419 ","pages":"Article 107722"},"PeriodicalIF":3.2,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349329","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":"Middle Paleoproterozoic tectonic evolution of the North China Craton: Constraints from the A-type granites in the Wutai area","authors":"Jingyu Wang ,&nbsp;Yujing Wang ,&nbsp;Wei Hong ,&nbsp;Caiyun Lan ,&nbsp;Jingjing Fan ,&nbsp;Xiaoping Long","doi":"10.1016/j.precamres.2025.107711","DOIUrl":"10.1016/j.precamres.2025.107711","url":null,"abstract":"<div><div>The Paleoproterozoic tectonic evolution of the Trans-North China Orogen of the North China Craton (NCC) has long been controversial. One of the key factors is the difference in the understanding of the A-type granites in the middle Paleoproterozoic. In this study, whole-rock geochemistry and Nd isotope, zircon U-Pb and Hf-O isotope, and zircon H₂O content are reported for middle Paleoproterozoic syenogranite, monzogranite, and alkali-feldspar granite in the Wutai area. LA-ICP-MS zircon dating results show that the intrusions have emplacement ages from 2117 to 2133 Ma. The 2.1<!--> <!-->Ga granites in the Wutai area exhibit elevated SiO₂ (72.20–78.01 wt%), K₂O + Na₂O (7.32–8.78 wt%) and Zr + Nb + Y + Ce (&gt; 528 ppm) concentrations, high FeOt/(FeOt + MgO) (0.78–0.89), 10000*Ga/Al (&gt; 3) and K₂O/Na₂O (1.0–1.9) ratios, low TiO₂/MgO ratios (0.4–1.4), and significant depletion of Ba, Sr, Eu, as well as high zirconium saturation temperatures (785–892°C), showing typical characteristics of aluminous A-type granites. The samples display characteristics of relatively enriched zircon Hf isotopes (εHf(t) = −5.6 to + 2.7), whole-rock Nd isotopes (εNd(t) = −2.9 to + 0.3), and old two-stage Hf model ages (2.56–3.05 Ga) similar to those of Neoarchean TTG gneisses in the same area. Furthermore, the oxygen isotope composition of zircon (δ¹⁸O = 4.7 to 7.4 ‰) are lower than those of zircons from the A-type granites derived from <em>meta</em>-sedimentary melts, indicating that the A-type granites are predominantly derived from the partial melts of Archaean TTGs. These granites contain both ilmenite and magnetite, indicating a relatively oxidizing environment. Zircon (log(fO₂) = −14.9 to − 7.8) and biotite (log(fO₂) = −13.5 to − 11) also show high oxygen fugacity. The water content of zircon is 104–842 ppm, with an average of 414 ppm, showing a relatively wet environment. These oxidised and water-rich A-type granites are likely to form in a back-arc extensional setting. Combined with the published NCC data, the Trans-North China Orogen is inferred to be an Andean-type continental arc setting in the middle Paleoproterozoic, suggesting the possibility of continuous subduction in the Paleoproterozoic.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"419 ","pages":"Article 107711"},"PeriodicalIF":3.2,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140512","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":"Spatial U-Pb age distribution in botryoidal dolomite in the terminal Ediacaran Dengying Formation, South China: Constraints on “dolomite seas” and formation process","authors":"Entao Liu ,&nbsp;Detian Yan ,&nbsp;Jian-xin Zhao ,&nbsp;Jingbin Wang ,&nbsp;Yuexing Feng ,&nbsp;Lifeng Zhong ,&nbsp;Hua Jiang ,&nbsp;Nengping Shen ,&nbsp;Junming Zhan","doi":"10.1016/j.precamres.2024.107636","DOIUrl":"10.1016/j.precamres.2024.107636","url":null,"abstract":"<div><div>Widespread fibrous dolomite cements in upper Ediacaran Dengying Formation’s botryoidal dolomite were traditionally thought to form through secondary processes, but recent studies indicate they were likely the direct products of unique “dolomite seas” conditions. To elucidate botryoidal dolomite’s formation and the unique “dolomite seas,” it’s vital to date the age variability in its dolomite cements via absolute methods. In this study, we performed the first comprehensive geochronological and geochemical (C-O-Sr-REE) analyses on a representative botryoidal dolomite hand specimen PTHB-1, which is divisible into three distinct components: microbialite matrix, fibrous marine dolomite, and crystalline dolomite. Through <em>in-situ</em> laser-ablation ICP-MS U-Pb analyses of 720 meticulously selected laser spots across the specimen, we obtained a dataset of 14 U-Pb age determinations for the various dolomite cements. Notably, ten laminae of U-enriched fibrous dolomite cements yielded ten high-precision U-Pb ages bracketing a time range between 550.1 ± 8.0 Ma and 542 ± 14 Ma (weighted mean 546.8 ± 3.2 Ma), aligning chronologically with the stratigraphic age interval (551.1–542 Ma). These findings, coupled geochemical signatures and petrographic evidence, suggest that the fibrous dolomite cements were initially direct marine precipitates, challenging previous secondary genetic interpretations. This revelation points to a short-lived “dolomite sea” existed in the terminal Ediacaran Ocean in the upper Yangtze region. Conversely, the later stages of vug-filling crystalline dolomite cements exhibit pronounced positive Eu and Y anomalies along with lower δ¹³C and δ¹⁸O, indicating hydrothermal fluid precipitation. Our results reveal at least three phases of crystalline dolomite cements at ca. 411 ± 17 Ma, 358.7 ± 6.1 Ma, and 257.2 ± 8.4 Ma, respectively, contributing significantly to the modification of reservoir properties. The insights gleaned from this research provide crucial chronological data for comprehending the formation and evolutionary history of botryoidal dolomite reservoirs, with substantial implications for hydrocarbon exploration efforts.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"417 ","pages":"Article 107636"},"PeriodicalIF":3.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137578","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":"Crustal reworking during the transition of tectonic regime in the Paleoproterozoic Era: Constraints from geochemistry, Sm-Nd isotope and U-Pb geochronology of granitic gneisses, Dudhi Granitoid Complex, Mahakoshal belt, Central Indian Tectonic Zone (CITZ), India","authors":"Mahendra Shukla ,&nbsp;Sanjeet K. Verma ,&nbsp;Vivek P. Malviya ,&nbsp;Elson P. Oliveira ,&nbsp;Sumit Mishra ,&nbsp;Ravi K. Umrao ,&nbsp;Satya Prakash ,&nbsp;Erik Emmanuel M. Torres","doi":"10.1016/j.precamres.2024.107660","DOIUrl":"10.1016/j.precamres.2024.107660","url":null,"abstract":"<div><div>The Paleoproterozoic Dudhi Granitoid Complex is composed of numerous granitoid intrusions and gneissic components that is located in the Mahakoshal belt, which is an important supracrustal belt of the Central Indian Tectonic Zone (CITZ) and played a vital role in the crustal accretion of the Columbia supercontinent. Thus, we present new geochemical data, Sm-Nd isotope analyses, and U-Pb geochronology of the granitic gneisses from the Dudhi Granitoid Complex to understand their origin, evolution and tectonic setting. The LA-ICP-MS zircon U-Pb dating yields ages of 1707.9 ± 7.4 Ma, 1724.3 ± 8.6 Ma, 1736.8 ± 9.9 Ma, 1748.3 ± 7.9 Ma, and 1756.3 ± 10 Ma for studied granitic gneisses. These rocks are strongly metaluminous and show enrichment in high field strength elements (HFSE) and depletion in large ion lithophile elements (LILE). The trace element composition allows classifying these rocks as an A₂-type affinity in an extensional environment. They show negative values of ɛNd(t) (−5.7 to −0.4) and old Nd-model ages (T_DM: 2068–2420) support their crustal origin. Geochemical and Nd isotope data indicate that they were derived by partial melting of older granites and granitic gneisses crust i.e., Archean Bundelkhand crust and Paleoproterozoic (&gt;1.9 Ga) juvenile crustal basement of the Mahakoshal basin. Finally, their magmatism during 1.75–1.70 Ga is linked to the transition period of accretion and dispersal of the Columbia supercontinent, which is incorporated into the lithosphere of the CITZ.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"417 ","pages":"Article 107660"},"PeriodicalIF":3.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137427","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":"Depositional age and environment of the Xinyu iron deposit in the Nanhua Basin, South China","authors":"Xiufang Wang ,&nbsp;Hui Ye ,&nbsp;Yuan Gao ,&nbsp;Matthew J. Brzozowski ,&nbsp;Xiang Li ,&nbsp;Ru-Xiong Lei ,&nbsp;Chang-Zhi Wu","doi":"10.1016/j.precamres.2024.107671","DOIUrl":"10.1016/j.precamres.2024.107671","url":null,"abstract":"<div><div>Deposition of Neoproterozoic iron formations (IFs) was typically associated with Cryogenian glaciations and the breakup of the Rodinia supercontinent. Neoproterozoic IFs in South China are distinct, however, as they lack evidence for glacial and volcanic influence. The correlation of these IFs with Neoproterozoic sedimentary successions and their depositional environment remain controversial. Here we present new geochronological and geochemical constraints on the depositional age and environment of the Xinyu IF, one of the largest Neoproterozoic IFs in the Nanhua Basin of South China. The Xinyu IF, intercalated with clastic rocks and not in direct contact with glaciogenic sedimentary rocks, suggests deposition in an open water environment during the Sturtian glacial period. The Xiafang Formation, which hosts the Xinyu IF, overlies the diamictite-bearing Gujia Formation and underlies the gravel-containing and manganese (Mn)-bearing of the Dashajiang Formation. The youngest three zircon grains of the Xiafang Formation give a weighted mean ²⁰⁶Pb/²³⁸U age of 694 ± 17 Ma, representing the maximum depositional age of this formation. The Xiafang Formation is, therefore, likely correlated to the Liangjiehe Member of the Fulu Formation in the western Nanhua Basin, and was likely deposited between 694 ± 17 and 691 ± 12 Ma. Shale-normalized rare earth element (REE) plus Y (REY) patterns of the Xinyu IF samples display light REE depletion (average (LREE/HREE)_SN = 0.37) relative to heavy REE, insignificant Eu anomalies (Eu* = 0.85−1.21), and no Ce anomalies (Ce* = 0.95−1.00). These geochemical characteristics suggest that the Xinyu IF was likely deposited in anoxic seawater in which Fe(II) was likely sourced from low-temperature hydrothermal fluids. Collectively, we suggest that the Xinyu IF is a Cryogenian IF deposited in open water during the Sturtian glaciation.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"417 ","pages":"Article 107671"},"PeriodicalIF":3.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137597","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":"Paleoproterozoic deep carbon cycle recorded in carbonatites","authors":"Dongyang Liu ,&nbsp;Cheng Xu ,&nbsp;Marco Brenna ,&nbsp;Xijun Liu ,&nbsp;Qiuli Li ,&nbsp;Chunwan Wei","doi":"10.1016/j.precamres.2024.107669","DOIUrl":"10.1016/j.precamres.2024.107669","url":null,"abstract":"<div><div>The deep carbon cycle regulates mantle-derived magma and atmospheric CO₂ on geological timescales. However, the timing of initial carbon subduction into the mantle remains debated. Here, we compare the geochemical characteristics and origin of Paleoproterozoic Zhuozi and Fengzhen carbonatite-syenite complexes within the Trans-North China Orogen. The Zhuozi syenitic zircons have an older age than the Fengzhen samples (1941 vs 1810 Ma) and show unusually high δ¹⁸O (11.8 to 13.8 ‰) compared to most Paleoproterozoic igneous zircons. Their associated carbonatites have sediment-like δ¹³C (−1.8 to −1.0 ‰) and δ¹⁸O (10.7 to 18.0 ‰). Both rock types at Zhuozi have high εNd_t (−1.4 to 2.8) and εHf_t (−2.0 to 5.0) values inconsistent with wall rock contamination, in contrast with the Fengzhen complex that has lower Nd-Hf isotopes. However, in-situ Pb isotopes of feldspars in Zhuozi syenites show more radiogenic compositions than the Fengzhen samples (²⁰⁷Pb/²⁰⁴Pb = 15.21–15.38 vs 14.84–14.95, ²⁰⁸Pb/²⁰⁴Pb = 35.06–35.56 vs 34.20–34.49). The Zhuozi and Fengzhen complexes may be products of Columbian supercontinent assembly. The differences of isotopic characteristics indicate that they originated from melting of depleted mantle wedge with sediment-derived fluid metasomatism and melting of deeply subducted sediment-bearing slab, respectively. This provides direct petrological and geochemical evidence for the onset of the Earth’s deep carbon cycle before 1.9 Ga, offering new insights into the carbonatite sources and the early history of the global carbon cycle.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"417 ","pages":"Article 107669"},"PeriodicalIF":3.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137498","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":"Orogenic unroofing of the Taltson and Thelon orogens depicted through detrital zircon geochronology of the Sosan Group, Great Slave Lake Supergroup (Northwest Territories, Canada)","authors":"Jade Lockie ,&nbsp;Alessandro Ielpi ,&nbsp;Rebecca Canam ,&nbsp;Morgann G. Perrot ,&nbsp;Joshua H.F.L. Davies ,&nbsp;Luke Ootes","doi":"10.1016/j.precamres.2025.107706","DOIUrl":"10.1016/j.precamres.2025.107706","url":null,"abstract":"<div><div>The investigation of sedimentary successions broadly contemporaneous with supercontinent amalgamation is critical to understand sediment dispersal in response to collisional tectonics. The Paleoproterozoic Great Slave Supergroup of the East Arm basin is one of three sedimentary successions located along the margins of the Archean Slave craton. U-Pb detrital zircon geochronology with chemical-abrasion laser-ablation inductively-coupled plasma mass spectrometry is employed here to investigate the onset of sedimentation, provenance, and regional correlations of the Sosan Group (the Great Slave Supergroup’s basal succession). Although a detrital age signature of the Slave craton is found in the &lt; 1.97–1.95 Ga Hornby Channel Formation (lowermost Sosan Group) – the dominant component through the strata has a distinct ∼ 2.0–1.97 Ga detrital age population, suggesting that the Sosan Group sediments were derived from the collapsing Thelon-Taltson orogenic topography. Data presented herein support novel correlations in the region, specifically between the East Arm basin and the nearby Kilohigok basin, Coronation margin and Hottah terrane. By these means, this study highlights the importance of stratigraphically complete geochronological analyses to propose regional correlations.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"419 ","pages":"Article 107706"},"PeriodicalIF":3.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143096739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neoarchean orogenic belt evolution in the northeast North China Craton: Implications for the reconstruction of early Earth’s microplates","authors":"Guozheng Sun ,&nbsp;Shuwen Liu ,&nbsp;Sanzhong Li ,&nbsp;Timothy M. Kusky ,&nbsp;Fangyang Hu ,&nbsp;Han Bao ,&nbsp;Lei Gao ,&nbsp;Yalu Hu ,&nbsp;Shengyao Yu ,&nbsp;Liming Dai ,&nbsp;Lintao Wang ,&nbsp;Xi Wang","doi":"10.1016/j.precamres.2024.107659","DOIUrl":"10.1016/j.precamres.2024.107659","url":null,"abstract":"<div><div>Identification and detailed studies of ancient orogens are one of the most important scientific problems for understanding the formation and evolution of early continental crust. However, it is tough to identify the original architecture of ancient orogenic belts due to the strong disturbances of late tectonothermal events, which makes it hard to reconstruct the formation mechanism and evolution process of early microplates. Here we used the spatial–temporal evolution of Neoarchean tectono-magmatism to trace orogenic processes of the Neoarchean continental crust of the North China Craton. Regional investigations in lithological assemblages, structural geology, chronology, geochemistry, and isotopic characteristics suggest that the Archean crystalline basement of the Eastern Liaoning Range in the northeastern North China Craton may be divided into three tectonic zones, each with its independent tectono-thermal evolution. We suggest therefore that these are independent terranes, namely microplates. Anshan-Benxi microplate in the southwest is a ∼ 3.8 to ∼ 2.9 Ga ancient continental nucleus with abundant Neoarchean (2.54–2.49 Ga) crust-derived K₂O-rich granitoids. Waitoushan-Weiziyu-Jiubing microplate in the center is mainly composed of ∼ 2.7 Ga tonalite-trondhjemite-granodiorite suite and 2.6–2.5 Ga diversified granitoids with some remnants of ancient oceanic lithosphere. Liaobei microplate in the northeast contains mainly late Neoarchean (2.57–2.52 Ga) magmatic rocks with minor Mesoarchean (∼3.1 Ga) crustal materials. We summarize the formation mechanism, essential features, and identification marks of the Archean orogenic belt, and conclude that the Eastern Liaoning Range experienced the following four stages of Neoarchean geodynamic evolution. (1) In the early Neoarchean (2.71–2.68 Ga), intra-oceanic subduction generated the ∼ 2.7 Ga island arc belt (proto-Waitoushan-Weiziyu-Jiubing microplate); (2) The 2.60–2.56 Ga warm subduction of oceanic slabs reformed proto-Liaobei microplate, and re-deformed the residual ∼ 2.7 Ga island arc belt; (3) During 2.56–2.54 Ga, the Waitoushan-Weiziyu-Jiubing microplate and Liaobei microplate were amalgamated by an ‘arc-arc’ collision; (4) At the end of Archean (2.54–2.50 Ga), the Waitoushan-Weiziyu-Jiubing microplate + Liaobei microplate and proto-Anshan-Benxi microplate were finally aggregated through the ‘arc-proto-continental’ collision, forming a unified crystalline basement of the Eastern Liaoning Range. Our work suggests that the short-term, small-scale subduction-collision orogenic cycles within pristine plate tectonic regimes played a crucial role in the Neoarchean crustal growth and evolution of the North China Craton.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"417 ","pages":"Article 107659"},"PeriodicalIF":3.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137579","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":"Low-pressure ∼3.53 Ga trondhjemite in the Eastern Hebei: Implications on the continental nucleus formation of the North China Craton","authors":"Chen Zhao ,&nbsp;Jin Liu ,&nbsp;Hongxiang Zhang ,&nbsp;Chao Zhang ,&nbsp;Jingsheng Chen ,&nbsp;Dandan Cui ,&nbsp;Jirui Zhang","doi":"10.1016/j.precamres.2024.107668","DOIUrl":"10.1016/j.precamres.2024.107668","url":null,"abstract":"<div><div>Continental nuclei provide essential genetic insights into the formation and evolution of the continental crust during the early Archean. This study reported the discovery of a ∼3.53 Ga trondhjemite from the newly identified Eoarchean–Paleoarchean Labashan Complex, located within the Eastern Hebei continental nucleus of the North China Craton (NCC). This study conducted comprehensive analyses, including zircon geochronology, zircon Hf isotopes, and whole-rock geochemistry, on this ancient rock. Zircon U-Pb dating revealed a crystallization age of 3533 ± 27 Ma. The trondhjemite displays characteristics typical of low-pressure types, such as low Sr/Y (7.5–12.8), (La/Yb)_N (9.2–19.2), and (Gd/Yb)_N (1.1–2.0) ratios, along with slight negative Eu anomalies (0.54–0.86). Most zircons exhibit unradiogenic Hf isotopes, with negative ε_Hf(<em>_t</em>₎ values as low as −7.0 and T_DM² ages ranging from 4501 to 3606 Ma. These results suggest that the parental magma of the ∼3.53 Ga trondhjemite likely originated from the partial melting of Hadean to early Eoarchean hydrated mafic protocrust, and formed at shallow depths with a residue enriched in amphibole and plagioclase. Our findings, alongside previous research, indicate that the NCC possesses a Hadean crustal evolutionary history, positioning it as one of Earth’s oldest fragments. We propose that the formation of the NCC’s continental nuclei, including the Eastern Hebei region, involved multiple stages of crustal reworking and recycling, with minor contributions from juvenile mantle-derived materials before the early Neoarchean. The most plausible mechanism for this evolution is the activity of mantle plumes beneath a stagnant lid.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"417 ","pages":"Article 107668"},"PeriodicalIF":3.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137580","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":"Isotopic constraints on the architecture and early (ca. 2.4–2.3 Ga) Paleoproterozoic evolution of the northwestern Rae craton, Canada","authors":"R.G. Berman,&nbsp;W.J. Davis,&nbsp;M. Sanborn-Barrie","doi":"10.1016/j.precamres.2024.107617","DOIUrl":"10.1016/j.precamres.2024.107617","url":null,"abstract":"<div><div>Queen Maud block (QMb) is re-defined as an area of dominantly Mesoarchean crust forming the northwestern part of the Rae craton. Four U-Pb zircon age determinations (ca. 3.3–2.97 Ga) extend QMb ∼40 km farther west than previously known to a major tectonic boundary marked by a &gt;450 km-long belt of ca. 1.9 Ga peraluminous leucogranite in the Thelon tectonic zone. Crust older than 3.3 Ga is indicated by inherited zircon up to 3.95 Ga in one sample. The absence within QMb of 2.6 Ga plutonic rocks, a dominant component of the central Rae craton, suggests distinct Neoarchean tectonic histories and separation of these crustal blocks prior to accretion of ca. 2.56–2.51 Ga Boothia terrane, stitching by ca. 2.5 Ga Queen Maud granitoids and a shared post-2.5 Ga history.</div><div>Tonalite dated at 2.41 Ga in QMb and monzogranite dated at 2.34 Ga in the adjacent Thelon tectonic zone have geochemical characteristics of convergent plate margin magmatism (arc ± slab-failure). Similarity in the Nd isotopic compositions of 2.34 Ga Thelon monzogranite and ca. 2.3 Ga plutonic rocks in Buffalo Head terrane, as well as 2.07 Ga and 2.0 Ga plutonic rocks in both regions point to a similar Neoarchean basement component. This basement terrane is proposed to have collided with the Rae at ca. 2.41 Ga and driven ca. 2.4–2.3 Ga tectonometamorphism during the Arrowsmith Orogeny.</div><div>The western Rae represented a convergent margin at 2.41–2.3 Ga and potentially 2.6–2.5 Ga, the latter broadly synchronous with the MacQuoid orogeny on the southeastern Rae margin. Throughout this time period, the central Rae craton was in an upper-plate position. Sustained mantle downwelling driving plate convergence towards the central Rae craton, as previously recognized at 2.0–1.9 Ga, was maintained from the Neoarchean through multiple Paleoproterozic orogenies (Arrowsmith, Taltson-Thelon and Hudsonian), establishing the Rae craton as the nucleus of proto-Laurentia within the Nuna supercontinent.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"417 ","pages":"Article 107617"},"PeriodicalIF":3.2,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137503","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}