Precambrian Research最新文献

{"title":"Trace elements of pyrite in the Ediacaran Doushantuo Formation reveal ancient methane release events","authors":"Can Chen ,&nbsp;Jiasheng Wang ,&nbsp;Thomas J. Algeo ,&nbsp;Zhou Wang ,&nbsp;Xiaochen Ma ,&nbsp;Qiang Song ,&nbsp;Kunlong Geng","doi":"10.1016/j.precamres.2024.107627","DOIUrl":"10.1016/j.precamres.2024.107627","url":null,"abstract":"<div><div>Multiple records of extremely negative carbon isotopes have been reported from the Ediacaran Doushantuo Formation in South China (ca. 635–551 Ma), implying frequent methane release from seafloor sediments of the Yangtze Sea at that time. The incorporation of Ni and Co from AOM-modified biomass into pyrite has emerged as a novel indicator for ancient methane release events, while the widespread presence of pyrite in sedimentary rocks has the potential to yield a continuous long-term record of submarine methane flux. To better understand the magnitude of ancient methane release events during the Ediacaran, we measured trace-elemental compositions for pyrite and bulk rock in the Qinglinkou section and compared these results with data from the more distal (deeper-water) Wuhe section. Three episodes of methane release were identified, one each in the lower, middle, and upper parts of the Doushantuo Formation. The first two release events were observed at both Qinglinkou and Wuhe and may have been linked to destabilization of gas hydrates due to sea-level falls associated with the Marinoan and Gaskiers glaciations. In contrast, the third release event is present only within the Wuhe section, which implies that methane release may have been associated with either a potential glaciation or increased sulfate transport to offshore areas during an oceanic oxygenation event. The methanic signals revealed by pyrite trace elements are consistent with the extremely low carbon isotopic compositions found locally within the study sections. Thus, our study is significant in demonstrating the utility of pyrite trace elements as proxies for ancient methane release events. Determining the spatial extent of a given methane release event will require analysis of correlative units in multiple globally distributed basins and/or cratons. In addition, our results provide new insights into the regulation of methane releases, ocean-redox variation, atmospheric oxygen levels, and bioevolution during the Ediacaran Period.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"416 ","pages":"Article 107627"},"PeriodicalIF":3.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705702","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":"Multi-mineral geochronology reveals a protracted Mesoproterozoic tectonic and metallogenic link between southeastern Australia and Laurentia","authors":"Sheree Armistead ,&nbsp;Sebastien Meffre ,&nbsp;Ralph Bottrill ,&nbsp;Andrew Cross ,&nbsp;David Huston ,&nbsp;Grace Cumming","doi":"10.1016/j.precamres.2024.107619","DOIUrl":"10.1016/j.precamres.2024.107619","url":null,"abstract":"<div><div>Plate tectonic reconstructions place Laurentia and eastern Australia together during the Mesoproterozoic. Specifically, the Belt-Purcell Basin in the USA and Canada has been linked to the Rocky Cape Group in northwest Tasmania based on detrital zircon studies. The Belt-Purcell Basin is highly endowed in economic deposits of Cu, Pb, Zn, Ag and critical metals such as Co, formed during the Mesoproterozoic. The Rocky Cape Group of northwest Tasmania hosts several sediment-hosted Cu-Pb-Zn ± Co prospects, however they were previously thought to be Devonian in age. New laser ablation inductively-couple plasma mass spectroscopy (LA-ICP-MS) in situ U-Pb monazite, xenotime and apatite data, sensitive high resolution ion microprobe (SHRIMP) in-situ U-Pb monazite data, and LA-ICP-MS galena Pb isotope data were collected from these prospects. By using multiple minerals with different U–Pb closure temperatures, we have unravelled a complex and protracted history of thermal pulses in the Rocky Cape region associated with Cu-Pb-Zn ± Co mineralisation. These data indicate that primary sulphide mineralisation formed at c. 1350 Ma, with several resetting or remobilisation events recorded at c. 1250 Ma, c. 1100 Ma and c. 950 Ma. These ages are contemporaneous with previously published authigenic monazite and metamorphic monazite ages from the Rocky Cape Group. This suggests that mineralisation is broadly <em>syn</em>-sedimentary and related to the development of the basin into which the Rocky Cape Group was deposited. These new ages are similar to those of sediment-hosted ore deposits in the Belt-Purcell Basin in the USA and Canada, further supporting the proposed link between northwest Tasmania and North America during the Mesoproterozoic. The high metal endowment of age-equivalent rocks in the Belt-Purcell Basin, highlight the potential for new discoveries of base and critical metals in southeastern Australia.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"415 ","pages":"Article 107619"},"PeriodicalIF":3.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704964","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":"Layered intrusions in the Precambrian: Observations and perspectives","authors":"William D. Smith ,&nbsp;M. Christopher Jenkins ,&nbsp;Claudia T. Augustin ,&nbsp;Ville J. Virtanen ,&nbsp;Zoja Vukmanovic ,&nbsp;Brian O’Driscoll","doi":"10.1016/j.precamres.2024.107615","DOIUrl":"10.1016/j.precamres.2024.107615","url":null,"abstract":"<div><div>Layered intrusions are plutonic bodies of cumulates that form by the crystallization of mantle-derived melts. These intrusions are characterized by igneous layering distinguishable by shifts in mineralogy, texture, or composition. Layered intrusions have been fundamental to our understanding of igneous petrology; however, it is their status as important repositories of critical metals – such as platinum-group elements, chromium, and vanadium – that has predominantly driven associated research in recent decades. Many layered intrusions were emplaced during the Precambrian, predominantly at the margins of ancient cratons during intervals of supercontinent accretion and destruction. It appears that large, layered intrusions require rigid crust to ensure their preservation, and their geometry and layering is primarily controlled by the nature of melt emplacement.</div><div>Layered intrusions are best investigated by integrating observations from various length-scales. At the macroscale, intrusion geometries can be discerned, and their presence understood in the context of the regional geology. At the mesoscale, the layering of an intrusion may be characterized, intrusion-host rock contact relationships studied, and the nature of stratiform mineral occurrences described. At the microscale, the mineralogy and texture of cumulate rocks and any mineralization are elucidated, particularly when novel microtextural and mineral chemical datasets are integrated. For example, here we demonstrate how mesoscale observations and microscale datasets can be combined to understand the petrogenesis of the perplexing <em>snowball oiks</em> outcrop located in the Upper Banded Series of the Stillwater Complex. Our data suggest that the orthopyroxene oikocrysts did not form in their present location, but rather formed in a dynamic magma chamber where crystals were transported either by convective currents or within crystal-rich slurries.</div><div>Critical metals may be transported to the level of a nascent intrusion as dissolved components in the melt. Alternatively, ore minerals are entrained from elsewhere in a plumbing system, potentially facilitated by volatile-rich phases. There are many ore-forming processes propounded by researchers to occur at the level of emplacement; however, each must address the arrival of the ore mineral, its concentration of metals, and its accumulation into orebodies. In this contribution, several of these processes are described as well as our perspectives on the future of layered intrusion research.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"415 ","pages":"Article 107615"},"PeriodicalIF":3.2,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662505","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":"Two phases of late Paleoproterozoic metamorphism in the western margin of the North China Craton: Records from pelitic gneisses in the Bayanwulashan complex of the eastern Alxa Block","authors":"Feng Zhou,&nbsp;Longlong Gou,&nbsp;Yunpeng Dong,&nbsp;Chengli Zhang,&nbsp;Xiaoping Long,&nbsp;Zhibo Tian,&nbsp;Yeting Ma,&nbsp;Xuefeng Liu","doi":"10.1016/j.precamres.2024.107614","DOIUrl":"10.1016/j.precamres.2024.107614","url":null,"abstract":"<div><div>The recognition and characterization of polymetamorphism are critical for understanding the tectonic evolution and geodynamic processes of metamorphic basement rocks and orogenic belts. In this study, pelitic gneisses, leucosomes, and felsic gneisses from the Bayanwulashan complex in the eastern Alxa Block, North China Craton (NCC), were investigated on the basis of petrography, mineral chemistry, phase equilibrium modelling, geothermometry, and laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) zircon U–Pb analysis. Detailed petrographic observations of the crn-bearing grt–sil–bt–pl gneiss sample ALS2270 and crn-bearing sil–grt–bt–pl gneiss sample ALS2274 (pelitic gneisses) revealed two distinct phases of metamorphism. The first-phase metamorphism (M1) can be subdivided into four stages (M1-1–M1-4); the second-phase metamorphism (M2) is marked by the growth of andalusite and non-directional micro-grained biotite (Bt-3) around staurolite, corundum, and sillimanite, as well as within fractures of garnet. Phase equilibrium modelling yielded <em>P–T</em> conditions of 740–830 °C/9.4–10.8 kbar, 730–860 °C/5.9–9.8 kbar, and 660–725 °C/5.3–7.8 kbar for the M1-2, M1-3 and M1-4 of the sample ALS2270, respectively. Similar metamorphic <em>P–T</em> conditions were also obtained for the sample ALS2274. Combing the temperatures by Ti–biotite thermometry for Bt-3 with the pressure range of the andalusite-bearing phase fields in the <em>P–T</em> pseudosection, metamorphic conditions of 492–556 °C/0–4.3 kbar, and 503–557 °C/0–4.3 kbar were obtained for the M2 of sample ALS2270 and sample ALS2274. As a whole, the M1 is characterized by high-pressure granulite-facies metamorphism with a clockwise <em>P–T</em> path involving near isothermal decompression followed by decompressional cooling, whereas the M2 is marked by low-pressure metamorphism with a high geothermal gradient. LA–ICP–MS zircon U–Pb dating of the pelitic gneisses, leucosomes, and felsic gneisses yielded two age groups: ca. 1.98–1.81 Ga and ca. 1.77–1.75 Ga, corresponding to the timing of two separate phases of metamorphism. The M1 is considered as a product of collisional orogeny involving crust thickening and subsequent exhumation, whereas the M2 is likely caused by rift-related activity along the northern margin of the NCC.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"415 ","pages":"Article 107614"},"PeriodicalIF":3.2,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662553","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":"Neoproterozoic basin evolution of the northern Tarim craton from back-arc rift to passive continental margin: Implications for the opening of the South Tianshan Ocean","authors":"Shuoqin Hou ,&nbsp;Di Li ,&nbsp;Dengfa He ,&nbsp;Kaibo Shi ,&nbsp;Yifan Li ,&nbsp;Dan Fan ,&nbsp;Jiajun Chen","doi":"10.1016/j.precamres.2024.107618","DOIUrl":"10.1016/j.precamres.2024.107618","url":null,"abstract":"<div><div>The Neoproterozoic strata in the northern Tarim craton holds valuable tectono-sedimentary insights regarding the opening time and mechanisms of the South Tianshan Ocean, as well as the tectonic reconstruction of the Tarim craton during the breakup of Rodinia. However, debates remain around the Cryogenian–Ediacaran proto-basin type and evolution, as well as the lack of regional geological correlation at a basin scale. In this study, we employed seismic, drilling and outcrop data to conduct a combined tectono-stratigraphic and sedimentary filling analysis of the Cryogenian–Ediacaran strata in the northern Tarim craton, aiming to decipher the Neoproterozoic basin evolution. Our findings show that the deposition of the Cryogenian strata was controlled by normal faults, representing a rift basin receiving sedimentary materials from both the northern Tarim craton and the Central Tianshan block. In contrast, the Ediacaran developed as a depression basin featured by a wedge-shaped deposition with frequent sea-level fluctuations and simple detrital input from the northern Tarim craton, indicative of a passive margin basin. Such a Neoproterozoic basin evolution of the northern Tarim craton, from the Cryogenian rift to the Ediacaran passive margin, likely resulted from a back-arc extension due to the separation of the Central Tianshan arc from the Tarim craton. These results provide new constraints on the initial opening time of the South Tianshan Ocean at ca. 633 Ma and reveal the Neoproterozoic tectonic affinity of the Central Tianshan block and the northern Tarim craton. Our work also implies that the Tarim craton was located on the periphery of Rodinia, and the South Tianshan Ocean may not be a primary ocean basin of the Paleo-Asian Ocean.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"415 ","pages":"Article 107618"},"PeriodicalIF":3.2,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662552","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":"Decoding Calymmian juvenile mafic magmatism in the Ribeira Belt, Brazil: Evidence for a long-lived arc system along the margin of Columbia","authors":"Frederico M. Faleiros ,&nbsp;Bruno V. Ribeiro ,&nbsp;Anny J. Forero-Ortega ,&nbsp;Ginaldo A.C. Campanha ,&nbsp;Peter A. Cawood","doi":"10.1016/j.precamres.2024.107588","DOIUrl":"10.1016/j.precamres.2024.107588","url":null,"abstract":"<div><div>The combined São Francisco-Congo Craton, now preserved in South America and Africa, existed from 2050 Ma to 130 Ma, is an important Archean-Paleoproterozoic block for reconstructions of the Proterozoic supercontinents Columbia (Nuna) and Rodinia. Both counterparts contain Calymmian-Stenian rock assemblages along their western margins and as inliers in Neoproterozoic-Cambrian marginal belts. New U–Pb–Hf–Nd isotopic and geochemical data of Calymmian metamafic rocks from the southern Ribeira Belt (Brazil) are integrated with data from the Brasília, Dom Feliciano and Kaoko Belts (Brazil, Uruguay and Namibia) and Angola Shield (Angola and Namibia) to unravel the Mesoproterozoic evolution of the cratonic block. Metamafic rocks from South America present variable geochemical and Hf–Nd isotopic signatures, suggesting contrasting tectonic settings. Rocks with crystallization ages of 1570–1540 Ma and 1500–1450 Ma show signatures of juvenile magmas derived from supra-subduction zone metasomatized mantle sources. Rocks formed at 1310–1280 Ma are dominated by signatures of intracontinental mafic magmatism. The Angola Shield presents voluminous granitoid rocks with crustal and juvenile signatures emplaced within 1530–1360 Ma, recently inferred as related with a convergent margin setting. There are also records of regional high-grade metamorphism and deformation involving a prograde stage at 1530–1510 Ma, peak conditions of 950–1000 °C and 9–10 kbar at ca. 1490 Ma, and a late stage at ca. 1450 Ma, suggesting a protracted orogenic metamorphic event. In a regional context, the available data supports a long-lived convergent margin setting along the present-day western margin of the São Francisco-Congo Craton. In a global perspective, this belt requires an extensive and long-lived (120–210 million years) Calymmian-Stenian ocean subducting beneath an active margin comprising stages of oceanic island arc–back-arc environments between 1570–1450 Ma that evolved to a continental arc on the margin of Columbia between 1450 and 1360 Ma. Regional metamorphism and deformation at 1340–1320 Ma support the existence of a collisional event related with ocean closure, while metamafic rocks of 1310–1280 Ma record lithospheric extension in a continental rifting setting.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107588"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552494","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":"Corrigendum to “A chemical weathering and paleoclimatic reconstruction of the early Cambrian environment of the Wyoming Craton from the Wind River Canyon, WY paleosol on the Great Unconformity” [Precambr. Res. 409 (2024) 107447]","authors":"Zhihong Huang ,&nbsp;Stephen C. Peters ,&nbsp;Frank J. Pazzaglia ,&nbsp;Madison Hernandez","doi":"10.1016/j.precamres.2024.107583","DOIUrl":"10.1016/j.precamres.2024.107583","url":null,"abstract":"","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107583"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663594","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 ultrahigh-temperature metamorphism and anatexis of the pelitic granulites in the Kongling terrane, South China","authors":"Shaoji Yang ,&nbsp;Yanru Song ,&nbsp;Haijin Xu ,&nbsp;Qingsen Han ,&nbsp;Songbai Peng","doi":"10.1016/j.precamres.2024.107591","DOIUrl":"10.1016/j.precamres.2024.107591","url":null,"abstract":"<div><div>Crustal anatexis and ultrahigh-temperature (UHT) metamorphism provide crucial insights into metamorphic evolution and tectonic process at the convergent plate margins. Pelitic granulites in the Kongling terrane record both Paleoproterozoic UHT metamorphism and anatexis, providing an ideal window to reveal the model of plate tectonic during early earth. The pelitic granulites from the Kongling terrane are mostly composed of the coarse-grained unfoliated granulite and the fine-grained foliated or migmatized granulite. The unfoliated granulite preserves a peak granulite-facies metamorphic mineral assemblage of coarse-grained garnet + sillimanite + plagioclase + K-feldspar + biotite + quartz + rutile. The foliated granulite, displaying banded structure of melanosome and leucosome, is composed of fine-grained garnet + biotite + plagioclase + quartz + rutile/ilmenite + felsic melt. The coarse-grained garnets have core-mantle-rim structures. The clean cores are rich in grossular contents and contain oriented needle-like rutile exsolution. Ti-in-garnet thermometer on the garnet cores reveals temperatures ranging from 837 to 1030 °C with a mean ± 1σ uncertainty of 943 ± 12 °C, which are consistent with ternary feldspar temperature (940 °C), suggesting a UHT granulite-facies metamorphism. The garnet ‘dirty’ mantles and rims are almandine-pyrope solutions with inclusions of felsic melt, biotite and ilmenite. Zircon grains have two groups: most of them are anatectic grains, and few of them exhibit granulite-facies core with anatectic rim. The granulite-facies zircons yield ∼2.05 Ga ²⁰⁷Pb/²⁰⁶Pb ages for peak UHT metamorphism, and the anatectic zircons give ∼2.0 Ga ²⁰⁷Pb/²⁰⁶Pb ages for anatexis. Ti-in-zircon thermometer on the anatectic zircons yields temperatures ranging from 595 to 828 °C (692 ± 4 °C), which are consistent with temperatures of the low-temperature perthite grains (670–740 °C, 705 ± 7 °C) but are lower than Ti-in-garnet temperatures of the peritectic garnets (820–916 °C, 855 ± 4 °C), suggesting a process from anatexis to melt crystallization. These results suggest that the pelitic granulites underwent crustal UHT metamorphism and subsequent anatexis during Paleoproterozoic. Together with the contemporaneous low-temperature and high-pressure metapelites from the Shuiyuesi mélange belt in the Kongling terrane, our study suggests the presence of a paired metamorphic belt at a convergent plate margin during the Paleoproterozoic orogeny.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107591"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552493","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":"Mesoproterozoic (∼1.4 Ga) magmatism in northern Alxa, China: Implications for tectonic affinity of microcontinents in the southern Central Asian Orogenic Belt","authors":"Xing-Jun Shi ,&nbsp;Tao Wang ,&nbsp;Heng Zhang ,&nbsp;Chen-Guang Zhang ,&nbsp;Jin-Li Pang ,&nbsp;Lei Zhang ,&nbsp;Jian-Jun Zhang","doi":"10.1016/j.precamres.2024.107611","DOIUrl":"10.1016/j.precamres.2024.107611","url":null,"abstract":"<div><div>The origin and paleogeographic reconstruction of Precambrian microcontinents in the Central Asian Orogenic Belt (CAOB) are crucial for understanding continental crustal evolution, mechanisms of accretionary orogeny, and assemblage and breakup of the supercontinent during the Earth’s early history. The existence and basement nature of the South Gobi microcontinent within the central segment of the southern CAOB remain controversial. This study represents the first work to unveil the presence of Mesoproterozoic (∼1.4 Ga) intrusive rocks in the Zhusileng-Hangwula tectonic zone that is the central segment of the southern CAOB, and is distributed along the border areas between China and Mongolia. It offers pivotal evidence for the existence of the South Gobi microcontinent.</div><div>Three alkali feldspar granite<del>s</del> samples collected from the Zhusileng-Hangwula tectonic zone yielded crystallization ages ranging from 1371 ± 17 Ma to 1420 ± 29 Ma, while detrital zircons from a two-mica quartz schist xenolith yielded similar ²⁰⁶Pb/²³⁸U ages clustered around ∼1.4 Ga. The ∼1.4 Ga zircons display depleted Hf isotopic signatures (εHf(t) = 3.2–6.0) and relatively young two-stage Hf model ages (1.9–1.7 Ga), suggesting rapid reworking of juvenile mantle-derived materials. These findings indicate that the Zhusileng-Hangwula tectonic zone constitutes a microcontinental fragment with Mesoproterozoic basement, rather than a Paleozoic accretionary complex as previously postulated. Combining the contemporaneous magmatism data from the microcontinents in the southern CAOB, the 1.48–1.32 Ga arc-related magmatism exhibits a coherent trend of geochemical evolution, potentially indicating a geodynamic transition from a convergent to an extensional environment. Moreover, the temporal, tectonic evolution, and petrological similarities imply a tectonic affinity between these microcontinents and Fennoscandia, and they may have originated from an accretionary belt along the edge of Nuna during the Mesoproterozoic.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107611"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573170","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":"Reply to the comments on “Late Archean sedimentary basins in the northeastern Superior Province, Canada: Plume-generated crustal tears or syn-convergent accretionary belts?” of Svojtka et al. (2024)","authors":"Jiří Žák ,&nbsp;Martin Svojtka ,&nbsp;Václav Kachlík ,&nbsp;Lukáš Ackerman ,&nbsp;Filip Tomek ,&nbsp;František Vacek ,&nbsp;Jiří Sláma","doi":"10.1016/j.precamres.2024.107613","DOIUrl":"10.1016/j.precamres.2024.107613","url":null,"abstract":"","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"414 ","pages":"Article 107613"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663528","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}