Precambrian Research最新文献

{"title":"The significance of Paleoarchean granitoids from the Saglek Block, Labrador, Canada","authors":"Tanmay Keluskar ,&nbsp;Monika A. Kusiak ,&nbsp;Daniel J. Dunkley ,&nbsp;Simon A. Wilde ,&nbsp;Martin J. Whitehouse ,&nbsp;Keewook Yi ,&nbsp;Shinae Lee","doi":"10.1016/j.precamres.2024.107504","DOIUrl":"https://doi.org/10.1016/j.precamres.2024.107504","url":null,"abstract":"<div><p>The Saglek Block in the Nain Province of northeast Canada is part of the North Atlantic Craton. It comprises Archean gneisses that record magmatic and metamorphic ages between <em>ca.</em> 3.9 and 2.5 Ga. In this study, a grey banded gneiss from Maidmonts Island records an age of 3.72 Ga, which is equated with Uivak I gneisses reported from across the Saglek Block, and contains 3.8 Ga xenocrysts. These rocks were deformed and metamorphosed prior to the intrusion of augen gneiss protoliths on both Maidmonts and Mentzel islands that record U-Pb zircon ages of 3.33 Ga. These rocks are composed of ferroan calc-alkaline granite and granodiorite and were likely generated by partial melting of pre-existing quartzo-feldspathic crust, as attested by the presence of <em>ca.</em> 3.8 Ga xenocrysts. Such augen gneiss was previously classified as <em>ca.</em> 3.6 Ga ‘Uivak II gneiss’, a term we argue should now be abandoned. The final magmatic events recorded on Maidmonts and Mentzel islands took place in the Neoproterozoic with the emplacement of granitic stocks at <em>ca.</em> 2.72 Ga, and sills and dykes at <em>ca.</em> 2.57 Ga. This sequence of magmatic events from the Eoarchean to Neoarchean is very similar to that recorded in the Itsaq Gneiss Complex of southwest Greenland, where, based on the Hf signature, it has been suggested that a change in tectonic environment resulted from the initiation of subduction at <em>ca.</em> 3.2 Ga. Although Lu-Hf and Sm-Nd isotopic signatures from the <em>ca.</em> 3.33 Ga gneisses have been interpreted in the literature as due to partial melting of Hadean mafic crust, alternatively, they can be generated by partial melting of Eoarchean continental crust in a continental arc setting. We argue this is more consistent with the non-TTG geochemistry of the augen gneisses.</p></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0301926824002171/pdfft?md5=bd1fa6f94889e2ef81df787b68999743&pid=1-s2.0-S0301926824002171-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141539997","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":"Late Paleoproterozoic tectonothermal events in the North China Craton as revealed by rutile U-Pb dating of the Sushui Complex","authors":"Bowen Si ,&nbsp;Chunrong Diwu ,&nbsp;Tingyi Wang ,&nbsp;Baoping Gan","doi":"10.1016/j.precamres.2024.107495","DOIUrl":"https://doi.org/10.1016/j.precamres.2024.107495","url":null,"abstract":"<div><p>The Sushui Complex is an important component of the Precambrian basement in the southern North China Craton (NCC), and it mainly formed in the time interval from the Neoarchean to Paleoproterozoic. Although it is confirmed that the Paleoproterozoic is a key period for the final amalgamation of the NCC, and the granulite facies metamorphism can be recognized in the Sushui Complex. However, limited studies suggest that the Sushui Complex has undergone Paleoproterozoic metamorphism. Thus, a significant controversy exists regarding whether the Sushui Complex has been involved and reworked by the final assembly of the NCC. Rutile, one of the most important titanium minerals, occurs in a variety of medium- to high-grade metamorphic rocks, which have a lower closure temperature (500–630 °C) than zircon (&gt;850 °C), thus rutile can record a wealth of useful and additional information about subsequent magmatic and metamorphic events, which makes it a complementary mineral to zircon to reveal the complete geologicalal history. In this contribution, we carried out the LA-ICP-MS U-Pb dating on zircon and rutile grains that collected from the Sushui Complex. Zircons from two trondhjemitic gneiss samples yield crystallization ages of 2520 and 2509 Ma. Rutile grains from the samples give the metamorphic ages of 1937, 1840, and 1811 Ma, respectively. The mica schist sample records the two populations of rutile U-Pb ages of 1924 and 1832 Ma. Zircon U-Pb dating reveal that the monzogranite sample was emplaced at 2300 Ma, and rutiles in the sample yield variable ages ranging from 2079 to 1715 Ma with a main peak age of 1820 Ma. The rutile U-Pb ages of the Sushui Complex reveal two distinct stages of metamorphism. The period of 1937–1924 Ma corresponds to the timing that is close to the peak metamorphism; whereas the subsequent period of 1840–1811 Ma indicates the cooling age associated with the exhumation of the basement in the Zhongtiao Mountains. Available studies reveal that the Sushui Complex has experienced Paleoproterozoic metamorphism during the final assembly of the NCC. In addition, our study provides an excellent example of how rutile U-Pb dating is a valuable geochronological tool for revealing late tectonothermal events of the Precambrian metamorphic terranes.</p></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141539203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origin of early Neoproterozoic orogenic gold deposits in the Yangtze Craton: Examples from the Banchanghe, Hongwucun, and Sunjiahe gold deposits in the Huangling region, South China","authors":"Jinyu Li ,&nbsp;Shao-Yong Jiang ,&nbsp;Feng Yuan ,&nbsp;Zhou Zhou ,&nbsp;Yin Gong ,&nbsp;Peng Yang ,&nbsp;Huashan Sun ,&nbsp;Meng Xiang ,&nbsp;Zeyu E ,&nbsp;Mingzheng Shen ,&nbsp;Fanyue Song ,&nbsp;Hangde Wu","doi":"10.1016/j.precamres.2024.107503","DOIUrl":"https://doi.org/10.1016/j.precamres.2024.107503","url":null,"abstract":"<div><p>The Huangling region of northwestern Hubei Province, which contains 76 gold deposits with more than 310 gold-quartz veins, is located in the northern part of the Yangtze Craton, South China Block. Despite several geological and geochronological studies conducted on gold deposits in this region, the timing and origin of gold mineralization remain controversial. This study utilizes in situ U–Pb dating of apatite and monazite from representative ores from the Banchanghe, Hongwucun, and Sunjiahe gold deposits to determine the timing of gold mineralization. The results indicate that gold mineralization occurred ca. 830–800 Ma, which is consistent with the period of tectonic transformation in the region. This study proposes that the gold deposits in the Huangling region represent typical orogenic gold deposits. These findings indicate a rare example of a well-preserved early Neoproterozoic orogenic gold system, suggesting the existence of orogenic gold deposits during the growth of the Rodinia supercontinent. This study highlights the significant potential for further exploration in the deep of the Huangling region to uncover additional gold veins. These findings also suggest that the Neoproterozoic orogenic belts of the Yangtze Craton may serve as important targets for gold deposit exploration in the future.</p></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141539244","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":"An arc terrane separated from the Yangtze Craton during Rodinia breakup: Insights from Neoproterozoic sedimentary successions of the Erguna Block, Northeast China","authors":"Ke Wang ,&nbsp;Yilong Li ,&nbsp;Wenjiao Xiao ,&nbsp;Haitian Zhang ,&nbsp;Guoqing Wang ,&nbsp;Jianping Zheng ,&nbsp;Xiujuan Bai ,&nbsp;Guang Yang ,&nbsp;Guohui Zhang ,&nbsp;Fraukje M. Brouwer","doi":"10.1016/j.precamres.2024.107497","DOIUrl":"https://doi.org/10.1016/j.precamres.2024.107497","url":null,"abstract":"<div><p>The Central Asian Orogenic Belt (CAOB) is one of the largest and most complex accretionary systems and is responsible for considerable Phanerozoic juvenile crustal growth. The Erguna Block is a Precambrian microcontinent located in the eastern part of the CAOB. Controversy has long surrounded the origin and tectonic affinity of the Erguna Block, limiting reconstruction of its position in the supercontinent Rodinia. This study presents a systematic study of the petrology, whole-rock geochemistry and zircon U-Pb-Hf isotopes of metasedimentary rocks from the Ergunahe Formation, the Jiageda Formation and the Xinghuadukou Group, which are the oldest units in the Erguna Block. The samples from the Ergunahe Formation comprise phyllite and schist with detrital zircon ages of 2476–743 Ma, maximum protoliths depositional ages of 817–743 Ma and peaks at 763 Ma, 896 Ma and 1162 Ma, εHf_(t) values of −15.54 to +11.66 and T_DM2 model ages of 3464–978 Ma. The Jiageda Formation samples include metasandstone, metapelite and schist with detrital zircon ages of 2976–766 Ma, maximum protoliths depositional ages of 837–766 Ma and peaks at 776 Ma, 843 Ma, 918 Ma and 984 Ma, εHf_(t) values of −9.46 to +14.68 and T_DM2 model ages of 3207–866 Ma. From the Xinghuadukou Group, schists are studied with detrital zircon ages of 2908–785 Ma, maximum protoliths depositional ages of 839–785 Ma and peaks at 837 Ma and 907 Ma, εHf_(t) values of −14.35 to +12.68 and T_DM2 model ages of 3949–926 Ma. The protoliths of the metasedimentary rocks from the three groups have similar depositional age spans and source rocks. They are mainly siltstones and greywackes and represent a sedimentary sequence in a continental arc-related basin. The source rocks for the protoliths were mainly arc magmatic rocks in the Erguna Block, which were formed in a continental arc as oceanic lithosphere subducted during the assembly and break-up of the Rodinia supercontinent. Combined with existing data, the age spectrum and multidimensional scaling (MDS) analysis of detrital zircon indicate the Erguna Block originated from a continental arc at the margin of the Yangtze Craton. Long-term subduction at <em>ca.</em> 963–737 Ma accompanied by back-arc extension during <em>ca.</em> 904–737 Ma led to rifting of the Erguna Block off the Yangtze Craton. Neoproterozoic sedimentary rock assemblages from the Erguna Block were deposited in a large-scale long-term trench-arc-basin system that formed in front of the Yangtze Craton, along the northwest margin of Rodinia.</p></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141539204","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 ‘New evidence for the Baltican cratonic affinity and Tonian to Ediacaran tectonic evolution of West Avalonia in the Avalon Peninsula, Newfoundland, Canada’","authors":"Ed Landing,&nbsp;Gerd Geyer","doi":"10.1016/j.precamres.2024.107489","DOIUrl":"https://doi.org/10.1016/j.precamres.2024.107489","url":null,"abstract":"","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141539993","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 comment on: Carbonaceous matter in ∼3.5 Ga black bedded barite from the Dresser Formation (Pilbara Craton, Western Australia) – Insights into organic cycling on the juvenile earth","authors":"L. Weimann ,&nbsp;M. Reinhardt ,&nbsp;J.-P. Duda ,&nbsp;H. Mißbach-Karmrodt ,&nbsp;H. Drake ,&nbsp;J. Schönig ,&nbsp;J. Holburg ,&nbsp;L.B. Andreas ,&nbsp;J. Reitner ,&nbsp;M.J. Whitehouse ,&nbsp;V. Thiel","doi":"10.1016/j.precamres.2024.107494","DOIUrl":"https://doi.org/10.1016/j.precamres.2024.107494","url":null,"abstract":"","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141484376","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 Rocha et al. (2024): “The passive margin of the southern São Francisco paleocontinent, metamorphic record and implications for the assembly of West Gondwana: Evidence from the Lima Duarte Nappe, Ribeira Orogen (SE Brazil)”, Precambrian Research 404, 107338","authors":"Rudolph A.J. Trouw,&nbsp;André Ribeiro","doi":"10.1016/j.precamres.2024.107458","DOIUrl":"https://doi.org/10.1016/j.precamres.2024.107458","url":null,"abstract":"","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141540000","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":"The 2.03–2.02 Ga arc–back-arc mafic magmatism from the Zhongxiang Complex, northern Yangtze Block: Implications for Columbia supercontinent assembly","authors":"Hao Liu ,&nbsp;Qi Deng ,&nbsp;Jian Wang ,&nbsp;Zhengjiang Wang ,&nbsp;Xiaozhuang Cui ,&nbsp;Guoqing Xiong ,&nbsp;Kuobu Ning ,&nbsp;Guangming Ren","doi":"10.1016/j.precamres.2024.107485","DOIUrl":"https://doi.org/10.1016/j.precamres.2024.107485","url":null,"abstract":"<div><p>To better understand Paleoproterozoic tectonic processes in the Yangtze Block during the assembly of the Columbia supercontinent, an integrated geochronological and geochemical study of amphibolite facies mafic rocks exposed in the Zhongxiang Complex in the northern Yangtze Block is presented. Based on trace element and rare earth element (REE) characteristics, these mafic rocks can be divided into two coeval groups. The MORB-like mafic rocks show flat REE patterns and are enriched in large-ion lithophile elements (e.g. Rb, Ba, K, Sr). Their zircon ɛ_Hf(<em>t</em>) values range from + 3.43 to + 4.90. The other mafic rocks are arc-like and have elevated REE contents and display relatively light REE enriched patterns, as well as depletion in high field strength elements (e.g. Nb, Ta, Ti). The zircon ɛ_Hf(<em>t</em>) values of the latter group range from + 0.17 to + 2.68. Zircon U-Pb dating yielded a weighted mean ²⁰⁷Pb/²⁰⁶Pb age of 2029 ± 15 Ma for the MORB-like mafic rocks, and 2023 ± 14 Ma for the arc-like mafic rocks, respectively. The elemental and isotopic characteristics indicate that the MORB-like mafic rocks may be derived from a depleted asthenospheric mantle source, whereas its counterpart with arc-like signatures originated from a lithospheric mantle source. The low (La/Yb)_CN (1.10–2.84) and Sm/Yb (0.99–1.29) ratios indicate that the mafic rocks are formed by partial melting of spinel lherzolite mantle. Combined with other geological observations, these mafic rocks are inferred to constitute part of a mid-Paleoproterozoic continental arc–back-arc basin system. The 2.03–2.02 Ga mafic rocks from the northern Yangtze Block indicate that the continental margin experienced subduction in response to assembly of the Columbia supercontinent.</p></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141484375","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":"The deformed alkaline Balda granite (Northern Cameroon): A witness of back-arc basin in the northern part of Central African Orogenic Belt","authors":"Aboubakar Bello ,&nbsp;Daouda Dawaï ,&nbsp;Paul Yves Jean Antonio ,&nbsp;Oscar Laurent ,&nbsp;Carmen Irene Martinez Dopico ,&nbsp;Rigobert Tchameni ,&nbsp;Olivier Vanderhaeghe","doi":"10.1016/j.precamres.2024.107490","DOIUrl":"https://doi.org/10.1016/j.precamres.2024.107490","url":null,"abstract":"<div><p>Located on the border between the NW Cameroon and Mayo-Kebbi domains in northern Cameroon, the Balda pluton is a deformed alkaline granite. Due to its unique location and geological features, it holds crucial information for understanding the evolution of the Central African Orogenic Belt (CAOB), which remains poorly understood. This multidisciplinary study combines field data, microscopic observations, Anisotropy of Magnetic Susceptibility (AMS), and U-Pb zircon dating to constrain the geodynamic evolution of the CAOB.</p><p>The Balda pluton is a NNE-SSW elongated pluton consists mainly of aegirine-riebeckite granite and leucogranite. It displays diverse magnetic susceptibility values (Km) spanning from 0.19 x 10^-3 to 21.98 x 10^-3. Notably, 93 % of the Km values exceed 5 × 10^-4SI, indicating a prevalence of mixed paramagnetic and ferromagnetic mineralogy (such as magnetite-rich). This observation is supported by microscopic examinations and K-T curves. An analysis of AMS unveils high P% values (2.8 to 58.7 %, with a mean of 15 %) and prevalent oblate magnetic fabrics (68 %). The magnetic foliation generally aligns with the field foliation and has steep dips ranging from NNE to NE or from SSW to SW and magnetic lineations exhibit shallow plunges (&lt;35°) from SSW to SW. Microscopic analysis reveals high-temperature, solid-state deformation microstructures, indicating post-emplacement deformation processes and the presence of kinematic markers consistent with sinistral shear. Zircon grain analysis reveals two distinct types: “bright” and “dark.” These types differ in both their appearance under cathodoluminescence and their chemical composition. Bright zircons yield a U-Pb age of 732.7 ± 7.5 Ma, interpreted as the pluton emplacement age. Dark zircons are younger (ca. 680 Ma), suggesting a later tectono-metamorphic or alteration event.</p><p>The integration of these results in a larger geodynamic context suggests that the Balda pluton formed within a <em>syn</em>-orogenic extensional back-arc basin. This emplacement was followed by significant post-emplacement deformation characterized by sinistral simple shear-dominated transpression likely related to the continental collision (ca. 680 Ma) of the NW Cameroon and Mayo-Kébbi domains.</p></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141484374","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":"Episodic hydrothermal supply and microbial anaerobic Fe(II) oxidation in early Archean ocean: Insights from precursor mineral compositions of the 3.46 Ga Marble Bar Chert, Pilbara Craton, Western Australia","authors":"Si Sun ,&nbsp;Yiliang Li","doi":"10.1016/j.precamres.2024.107484","DOIUrl":"https://doi.org/10.1016/j.precamres.2024.107484","url":null,"abstract":"<div><p>The 3.46 Ga Marble Bar Chert (MBC) from the Pilbara Craton in Western Australia is known as the oldest chert on Earth. The origin of its Fe minerals was investigated to decipher the geochemistry and redox conditions of the early Archean ocean, as well as to explore the possible microbial contribution to the earliest sedimentary processes on Earth. However, the composition of the precursor minerals in the MBC remains poorly understood, giving rise to controversies on its genesis. Here we performed high-resolution petrographic, laser Raman, Mössbauer, X-ray diffraction, and Mn K-edge X-ray absorption near edge structure spectroscopic studies on two typical types of finely laminated MBC, grey-black chert and red chert. The grey-black chert contains considerable amounts of siderite, carbonaceous materials, and minor phyllosilicates and hematite. By contrast, the red chert contains high hematite and silicates, minor siderite and rare carbonaceous materials. Microcrystals in the cores of chert polyhedral are among the earliest mineral phases without signs of alterations, recrystallisation, erosion or replacement histories. Ferrihydrite, greenalite, siderite, and green rust are possible precursors of Fe-bearing minerals in the MBC. Their respective proportion in each lamina was regulated by pH, Fe(II)-oxidation rate, DIC, and Fe(II) content in the seawater. Approximately half Fe in the MBC primary minerals existed as Fe(III), indicating the existence of indigenous Fe(II)-oxidation in the Paleoarchean seawater. The element Mn in the MBC is primarily Mn(II) coordinated with O, suggesting a reduced depositional environment and hence implying the involvement of anaerobic microbial Fe(II)-oxidation in the formation of the MBC. Collectively, the grey-black laminae with abundant carbonaceous materials reflect limited Fe(II)-oxidation and increased dissolved inorganic carbon content likely due to enhanced hydrothermal CO₂ supply, while the red laminae with considerable hematite represent substantial Fe(III)-supply due to rapid indigenous anaerobic Fe(II)-oxidation.</p></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141484373","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}