IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2026-06-15 Epub Date: 2026-02-13 DOI: 10.1016/j.clay.2026.108162

Jiaxing Han , Meng Liu , Tianming Liu , Libing Liao , Ritong Huang , Wenfeng Li , Guocheng Lv

Clay minerals have emerged as promising materials for electrochemical energy technologies, owing to their unique nanostructures, sustainability, and low cost. This review summarizes recent advances in their applications, primarily in electrochemical energy storage (e.g., batteries and supercapacitors), followed by electrocatalysis (e.g., hydrogen/oxygen evolution, and oxygen reduction reaction). The structure-property relationships are highlighted: fibrous chain-layered clays are effective in forming conductive networks and inhibiting agglomeration, while layered clays facilitate rapid ion transport through tunable interlayer spacing. In energy storage, these structural features help address critical challenges such as electrode volume expansion, lithium dendrite growth, and polysulfide shuttling, thereby enhancing device cycling stability, rate capability, etc.; In electrocatalysis, the high surface area, abundant surface functional group, and favorable ion transport pathways of clays contribute to improve active site dispersion, electron transfer efficiency, etc. The roles of various clay mineral structures in these fields are discussed, and perspectives on future performance optimization through tailored structural design are provided.

粘土矿物因其独特的纳米结构、可持续性和低成本而成为电化学能源技术的重要材料。本文综述了近年来其在电化学储能（如电池和超级电容器）和电催化（如氢/氧释放和氧还原反应）方面的应用进展。强调了结构-性能关系：纤维链层状粘土在形成导电网络和抑制团聚方面是有效的，而层状粘土通过可调节的层间距促进离子的快速传输。在储能方面，这些结构特征有助于解决电极体积膨胀、锂枝晶生长和多硫化物穿梭等关键挑战，从而提高器件循环稳定性、速率能力等；在电催化中，粘土的高表面积、丰富的表面官能团和有利的离子传递途径有助于提高活性位点的分散、电子传递效率等。讨论了各种粘土矿物结构在这些领域的作用，并提出了通过定制结构设计来优化未来性能的观点。

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引用次数: 0

Novel use of waste calcined clay brick powder in sustainable ultra-high ductility strain-hardening geopolymer composites: Micro-characteristics and mechanical behavior 废煅烧粘土砖粉在可持续超高延性应变硬化地聚合物复合材料中的新应用：微观特性和力学行为

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2026-06-15 Epub Date: 2026-02-13 DOI: 10.1016/j.clay.2026.108161

Zhiming Ma , Yuanhui Wu , Shifeng Li , Dingyi Yang , Changqing Wang

Strain-hardening geopolymer composites (SHGC) exhibit low-carbon characteristics and excellent mechanical performance, but the conventional precursors used in SHGC preparation are limited in supply and expensive. Using recycled brick powder (RBP) ground from calcined clay brick waste as a green precursor for fabricating ultra-high ductility SHGC promotes the high-value utilization of calcined clay brick waste while decreasing the reliance on conventional mineral precursors such as fly ash (FA) and slag. This investigation systematically studied the microstructural characteristics and mechanical performance of RBP-SHGC. Incorporating RBP as a moderate substitute for FA and slag had negligible influence on the microstructure and geopolymeric products of SHGC, but substituting RBP for high-dosage slag negatively affected the microstructure. The mechanical strength initially rose and then decreased with the increasing substitution ratios of RBP for FA and slag, though RBP-blended SHGC maintained considerable strength even at 100% replacement rates. Substituting RBP for an appropriate proportion of FA and slag improved both the uniaxial tensile strength and strain capacity. The SHGC in which RBP simultaneously replaced 50% of FA and 50% of slag exhibited an ultimate tensile strain comparable to that of the reference SHGC. Raising the alkali-activator modulus and alkali content effectively improved the microstructure and mechanical behavior of RBP-blended SHGC.

应变硬化地聚合物复合材料（SHGC）具有低碳特性和优异的力学性能，但用于制备SHGC的传统前驱体供应有限且价格昂贵。利用从煅烧粘土砖废料中提取的再生砖粉（RBP）作为绿色前驱体制备超高延性SHGC，促进了煅烧粘土砖废料的高价值利用，同时减少了对粉煤灰和矿渣等传统矿物前驱体的依赖。本研究系统地研究了RBP-SHGC的显微组织特征和力学性能。以RBP替代FA和矿渣对SHGC的微观结构和地聚合物产物的影响可以忽略不计，但以RBP替代高用量矿渣对SHGC的微观结构有负面影响。随着RBP对FA和矿渣替代率的增加，机械强度先上升后下降，尽管RBP-混合SHGC在100%替代率下仍保持相当的强度。用RBP代替适当比例的FA和矿渣，提高了单轴抗拉强度和应变能力。RBP同时替代50% FA和50%渣的SHGC的极限拉伸应变与参考SHGC相当。提高碱活化剂模量和碱含量可有效改善rbp -共混SHGC的微观结构和力学性能。

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引用次数: 0

High-efficiency removal of fluoride ions in real fluorine-containing wastewater using red mud-metakaolin based geopolymer microspheres 赤泥-偏高岭土基地聚合物微球高效去除含氟废水中的氟离子

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2026-06-01 Epub Date: 2026-02-05 DOI: 10.1016/j.clay.2026.108145

Yuxiao Jiang , Liu He , Yang Tang , Wenwen Chen , Lin Shao , Xinpeng Wang , Kaituo Wang

To address the problem of fluoride pollution and red mud accumulation, this study prepared red mud-metakaolin geopolymer microspheres (RM-MGMs) using dispersion-suspension-curing method, maximizing the utilizing of 60% red mud. The RM-MGMs prepared by this method exhibit excellent mechanical strength and the fluoride adsorption capacity, while simultaneously overcoming the difficulty in recovering traditional powder materials in actual wastewater treatment. The F⁻ removal performance of <75 μm and 75–150 μm RM-MGMs at the dosage of 1 g/L and the pH of 1 for the simulated fluoride-containing solution indicated that the residual F⁻ concentration met the World Health Organization (WHO) standard (F⁻ concentration < 1.5 mg/L) within 30 min and equilibrium was reached within 90 min. The results showed that RM-MGMs with smaller particle sizes had a faster adsorption rate and less intra-particle diffusion resistance, demonstrating a higher adsorption capacity. The adsorption kinetics and isotherm models of <75 μm and 75–150 μm RM-MGMs for F⁻ conformed to pseudo-second-order kinetic model and Langmuir model, with maximum equilibrium adsorption capacity (Q_max) of 175.15 mg/g and 172.25 mg/g respectively. The actual wastewater (with 190 mg/L F⁻ concentration) treated by RM-MGMs decreased to 9.58 mg/L within 1 min, meeting the national discharge standard (F⁻ concentration < 10 mg/L) and reaching the WHO standard within 45 min. In addition, RM-MGMs with the dosage of 1.50 g demonstrated outstanding dynamic separation performance at 1 mL/min flow rate. The excellent fixation effect of RM-MGMs for F⁻ demonstrates its eco-friendliness, providing a dual treatment scheme for addressing fluoride pollution and utilizing red mud.

为了解决赤泥的氟污染和堆积问题，本研究采用分散-悬浮-固化法制备赤泥-偏高岭土聚合物微球，使赤泥的利用率达到60%。该方法制备的rm - mgm具有优异的机械强度和氟吸附能力，同时克服了传统粉体材料在实际废水处理中难以回收的困难。模拟含氟溶液在添加量为1 g/L、pH = 1的条件下，75 μm和75 ~ 150 μm RM-MGMs对F−的去除性能表明，残留F−浓度在30 min内达到世界卫生组织（WHO）标准（F−浓度为1.5 mg/L），在90 min内达到平衡。结果表明，粒径越小的rm - mgm吸附速率越快，颗粒内扩散阻力越小，具有较高的吸附能力。75 μm和75 ~ 150 μm RM-MGMs对F−的吸附动力学和等温线模型符合拟二级动力学模型和Langmuir模型，最大平衡吸附容量（Qmax）分别为175.15 mg/g和172.25 mg/g。经RM-MGMs处理的实际废水（含氟190 mg/L）在1 min内降至9.58 mg/L，达到国家排放标准（含氟10 mg/L）， 45 min内达到WHO标准。在1 mL/min流速下，1.50 g mg - mms的动态分离效果较好。rm - mgm对F−的良好固定效果证明了其生态友好性，为解决氟污染和利用赤泥提供了双重处理方案。

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引用次数: 0

Mineralogical evolution of glauconite and smectite in a peat bog environment: Results of a one-year natural experiment 泥炭沼泽环境中海绿石和蒙脱石的矿物学演化：一年自然实验的结果

IF 5.8 2区地球科学 Q2 CHEMISTRY, PHYSICAL

Applied Clay Science

Pub Date : 2026-06-01 Epub Date: 2026-02-12 DOI: 10.1016/j.clay.2026.108146

Maxim Rudmin , Hongling Bu , Oleg Savichev , Ivan Khitrin , Alexey Ruban

This study examines the crystal-chemical and sorption transformations of glauconite and smectite during prolonged exposure in a peat bog environment, as part of a natural experiment conducted in the oligotrophic zone of the Vasyugan Mire (Western Siberia). The Vasyugan Mire was selected as a natural acidic and organic-rich sedimentary system that promotes ion exchange and low-temperature mineral transformations, representing an analogue of early diagenetic conditions. Samples were incubated in situ at 25, 50, and 75 cm depths for one year. Recovered samples underwent comprehensive physicochemical characterization using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and mass spectrometry (TG-DSC-MS). Glauconite underwent significant structural changes, including: (1) loss of interlayer K⁺, (2) relative depletion of Fe-associated components, and (3) absorption of organic compounds and NH₄⁺ ions. These transformations were more pronounced in the reducing conditions of deeper soil layers. XRD and chemical data show trends that may be consistent with an initial expansion of interlayers and a possible early-stage development of smectite-like features. Smectite maintained a stable crystal structure but exhibited significant ion exchange activity and sorption of inorganic substances (including CO₂, NH₃/NH₄⁺) and low-molecular-weight organic acids within its interlayer region. Its charge balance is modified by the incorporation of ammonium and organic species within the interlayer, which mask deeper structural transformations. The distinct buffering mechanisms arise from fundamental structural differences: glauconite buffers via crystallochemical rearrangement, whereas smectite uses its expandable interlayer and high cation exchange capacity. The results demonstrate that peat bogs play a role as natural geochemical reactors, accelerating the early diagenetic processes of clay mineral transformation. This highlights the potential of glauconite and smectite as effective buffering and sorbent materials in environmentally friendly technologies such as barrier screens and water purification systems.

本研究考察了长时间暴露在泥炭沼泽环境中的海绿石和蒙脱石的晶体化学和吸附转变，作为在瓦苏干沼泽（西伯利亚西部）的贫营养带进行的自然实验的一部分。瓦苏干泥沼是一种促进离子交换和低温矿物转化的天然酸性富有机质沉积体系，具有早期成岩条件的模拟特征。样品在25、50和75 cm深度原位孵育1年。利用x射线衍射（XRD）、扫描电子显微镜（SEM-EDS）、傅里叶变换红外（FTIR）光谱、热重分析、差示扫描量热法和质谱（TG-DSC-MS）对回收的样品进行了全面的物理化学表征。海绿石发生了明显的结构变化，包括：(1)层间K+的损失，(2)铁相关成分的相对耗损，(3)有机化合物和NH4+离子的吸收。这些变化在较深土层的还原性条件下更为明显。XRD和化学数据显示的趋势可能与夹层的初始膨胀和蒙脱石样特征的早期发展相一致。蒙脱石保持了稳定的晶体结构，但在其层间区域表现出显著的离子交换活性和对无机物（包括CO2、NH3/NH4+）和低分子量有机酸的吸附。它的电荷平衡被中间层内的铵和有机物质的掺入所改变，这掩盖了更深层次的结构转变。不同的缓冲机制源于基本的结构差异：海绿石通过晶体化学重排来缓冲，而蒙脱石则利用其可膨胀的中间层和高阳离子交换能力。结果表明，泥炭沼泽具有天然的地球化学反应器作用，加速了粘土矿物的早期成岩转化过程。这突出了海绿石和蒙脱石作为有效缓冲和吸附材料在环境友好型技术中的潜力，如屏障和水净化系统。

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引用次数: 0

From policy to practice: Evaluating gender mainstreaming in Namibia's water sector 从政策到实践：评价纳米比亚水务部门的性别主流化

IF 4.1 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Physics and Chemistry of the Earth

Pub Date : 2026-06-01 Epub Date: 2026-01-14 DOI: 10.1016/j.pce.2026.104287

Rennie Munyayi , Benjamin Mapani , Rosemary Shikangalah

The Southern African Development Community (SADC) Member States adopted regional gender instruments that set targets for gender equality and were subsequently domesticated through national policies, including Namibia's National Gender Policy (2010–2020). This study examines the extent to which the Department of Water Affairs (within the Ministry of Agriculture, Water and Land Reform at the time of study) has translated formal gender equality commitments into substantive gender mainstreaming practices beyond policy rhetoric. Using a mixed-methods design, we combined document review with an online survey adapted from the International Labour Organisation gender audit framework. Forty-nine staff members responded (32 % response rate). Results indicate persistent institutional constraints: 87.8 % of respondents reported no formal training on gender equality in policy or programming, while confidence to perform core gender mainstreaming functions remained very low (2–5 %), alongside high non-response across proficiency items. Institutional support mechanisms were weak, with 89.8 % reporting no periodic support from gender focal points. At sector level, Namibia's AMCOW WASSMO Indicator 6.6 score declined from 44 % (2019) to 33 % (2024), suggesting that earlier policy-alignment gains were not sustained. Document review further identified no explicit budget allocations for gender mainstreaming within reviewed annual budgets (2018–2022), indicating limited fiscal institutionalisation. Interpreted through Gender and Development and institutional theory, the findings point to structural decoupling, weak incentives, and limited systematic embedding of gender requirements in planning, budgeting, monitoring, and programme design. We recommend establishing a dedicated gender mainstreaming unit, instituting gender responsive budgeting with tracked allocations, and strengthening applied capacity through mandatory training linked to performance and reporting. Further research should examine accountability architectures that can accelerate measurable gender outcomes across the SADC water sector.

南部非洲发展共同体（SADC）成员国通过了区域性别文书，设定了性别平等的目标，并随后通过国家政策加以规范，包括纳米比亚的《国家性别政策（2010-2020年）》。本研究考察了水利部（在研究时隶属于农业、水和土地改革部）在多大程度上将正式的性别平等承诺转化为超越政策修辞的实质性性别主流化实践。我们采用混合方法设计，将文件审查与改编自国际劳工组织性别审计框架的在线调查相结合。49名工作人员回应（32%的回复率）。结果表明持续的制度限制：87.8%的受访者报告在政策或规划方面没有接受过关于性别平等的正式培训，而执行核心性别主流化职能的信心仍然很低（2 - 5%），同时在熟练程度项目上高度无反应。机构支持机制薄弱，89.8%的人报告没有从性别问题协调中心获得定期支持。在部门层面，纳米比亚的AMCOW WASSMO指标6.6分从44%（2019年）降至33%（2024年），表明早先的政策协调成果没有持续。文件审查进一步发现，在审查的年度预算（2018-2022年）中，没有明确的性别主流化预算拨款，表明财政制度化程度有限。通过对性别与发展和制度理论的解释，研究结果指出了结构性脱钩、激励不力以及在规划、预算、监测和方案设计中系统地纳入性别要求的限制。我们建议设立一个专门的性别平等主流化部门，建立性别平等敏感的预算编制，跟踪拨款情况，并通过与绩效和报告相关的强制性培训加强应用能力。进一步的研究应该审查能够加速整个南部非洲发展共同体水部门可衡量的性别成果的问责制架构。

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引用次数: 0

Spatial distribution and ecological risk evaluation of microplastics in surface water, sediment, and Oreochromis niloticus from the Eravur sector, Batticaloa Lagoon, Sri Lanka 斯里兰卡Batticaloa泻湖Eravur区地表水、沉积物和尼罗褐藻中微塑料的空间分布和生态风险评价

IF 4.1 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Physics and Chemistry of the Earth

Pub Date : 2026-06-01 Epub Date: 2026-01-17 DOI: 10.1016/j.pce.2025.104260

A.S. Samrooth Jahan , J.M. Harris , M.H. Haroon , Sabiqah Tuan Anuar , Jose Hernandez Santos , Chingakham Chinglenthoiba

Batticaloa Lagoon is a major and prominent coastal ecosystem in Sri Lanka. However, increasing anthropogenic activities around the Eravur sector have raised the plastic accumulation thus lead to concern of microplastic contamination and ecological risk. Therefore, this study intends to examine the abundance, spatial distribution and compositional characterization of microplastics in three separate aquatic environmental components such as surface water, sediment, and Oreochromis niloticus at the Eravur lagoon. Total microplastic abundance in surface water and sediment was 512.25, 412.33 ± 19.90 items L⁻¹ and ±29.26 items Kg⁻¹dry weight respectively with significantly higher concentrations at those sites located at lagoon shore (267.6 ± 15.4 items L⁻¹; 329.9 ± 22.3 items Kg-1) than lagoon sample sites (ANOVA, p < 0.001). Sediments had a greater proportion of microplastics (∼55 %) than surface waters, made of fragments and films, mostly white and transparent particles, and the smaller size fractions occupy the largest contributions to total counts (<1-2 mm-1-2mm: 30–34 %) in sediments; While in surface waters (2–4 mm: 41 %). Microplastics were found in 26 of 30 individuals of the O. niloticus (232 particles; 7.73 ± 6.8 ind⁻¹), dominated by filaments (∼69 %), mostly <1 mm (∼62 %), and ingestion was positively correlated with fish weight and length (r = 0.799 and r = 0.793, respectively; p < 0.001). FTIR confirms seven major polymer types where PET was most abundant in sediment (26 %), PS in surface water (30 %) and PE and PP in fish samples (25 % each). The evidence of active microplastic transfer shows significant impacts on lagoon ecology.

Batticaloa泻湖是斯里兰卡重要的沿海生态系统。然而，在Eravur地区，越来越多的人为活动增加了塑料的积累，从而引起了对微塑料污染和生态风险的关注。因此，本研究旨在研究Eravur泻湖地表水、沉积物和尼罗河Oreochromis niloticus三种不同的水环境组分中微塑料的丰度、空间分布和组成特征。地表水和沉积物中总微塑料丰度分别为512.25、412.33±19.90项L−1和±29.26项Kg−1干重，其中泻湖岸边的微塑料丰度（267.6±15.4项L−1；329.9±22.3项Kg-1）显著高于泻湖样地（方差分析，p < 0.001）。沉积物中微塑料的比例（~ 55%）高于地表水，它们由碎片和薄膜组成，主要是白色和透明的颗粒，较小的颗粒占沉积物总数的最大贡献（<1-2 mm-1-2mm: 30 - 34%）；而在地表水（2-4毫米：41%）。30条O. niloticus中有26条（232粒；7.73±6.8 ind - 1）中发现了微塑料，以细丝为主（~ 69%），大部分为1 mm(~ 62%)，摄取量与鱼的体重和长度呈正相关（r = 0.799和r = 0.793; p < 0.001）。FTIR确认了7种主要的聚合物类型，其中PET在沉积物中含量最多（26%），PS在地表水中含量最多（30%），PE和PP在鱼类样本中含量最多（各占25%）。活性微塑料转移的证据显示对泻湖生态有显著影响。

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引用次数: 0

Ridge subduction and island arc evolution in the Duobaoshan region during early Paleozoic: Insights from crustal thickness and lava geochemistry 多宝山地区早古生代脊俯冲和岛弧演化：来自地壳厚度和熔岩地球化学的启示

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2026-06-01 Epub Date: 2026-01-07 DOI: 10.1016/j.gr.2025.12.007

Tianjiao Sang , Fuping Pei , Bingqian Ding , Kai Song , Pengyi Li , Guanwen Yu

The Duobaoshan island arc contains early Paleozoic association of adakitic high-Mg andesite, Nb-enriched basalt, and porphyry Cu deposits, concurrently indicating the ridge subduction in the eastern Xing’an Massif. This study further understands the unique island arc setting through the mantle metasomatism, oxygen fugacity and crustal thickness based on the zircon U–Pb geochronologic and Hf isotopic data from the early Paleozoic igneous and sedimentary rocks, as well as the whole–rock geochemical and Sr–Nd–Hf isotopic data from the igneous rocks in the Duobaoshan region, Xing’an Massif. The early Paleozoic igneous rocks are typical arc–type with low (La/Yb)_N ratios (3.37–6.60), exhibiting highly depleted zircon Hf (ε_Hf(t) = +12.44∼+16.50) and whole–rock Sr–Nd–Hf isotopic data ((⁸⁷Sr/⁸⁶Sr)_i = 0.7036–0.7048; ε_Nd(t) = +4.76∼+8.17; ε_Hf(t) = +12.44∼+16.50), which were derived from the depleted mantle metasomatized mainly by slab fluid accompanied with the altered oceanic crust melt and pelagic sediment melt, and reflected the maturing process of the island arc. In addition, the Early Ordovician igneous rocks indicated the increase of mantle temperature and oxygen fugacity (ΔFMQ > 2) leading to the solubility of metallogenetic elements, and the thickening crust was also conducive to the mineralization. Then we further revealed the existence of a Precambrian basement of the Xing’an Massif based on the sedimentary rocks, the geochronology of which revealed the youngest ages of 504–478 Ma, yielding the age peaks at 771 Ma, ∼860 Ma, ∼950 Ma, and ∼1800 Ma ∼2500 Ma. In the meanwhile, the Hf isotopic data of 600–478 Ma detrital zircons show depleted to more enriched ε_Hf(t) values (–10.22 to +12.70) and a proximal depositional traits, indicating that majority of the Neoproterozoic and early Paleozoic detrital zircons migrated from the Duobaoshan region, Xing’an Massif.

多宝山岛弧发育早古生代艾达质高镁安山岩、富铌玄武岩和斑岩型铜矿组合，同时显示了兴安地块东部的脊状俯冲。本研究基于兴安地块多宝山地区早古生代火成岩和沉积岩的锆石U-Pb年代学和Hf同位素数据，以及火成岩的全岩地球化学和Sr-Nd-Hf同位素数据，通过地幔交代作用、氧逸度和地壳厚度进一步了解独特的岛弧背景。早古生代火成岩为典型的弧型，低（La/Yb）N比值（3.37 ~ 6.60），锆石Hf高度贫化（εHf(t) = +12.44 ~ +16.50），全岩Sr-Nd-Hf同位素数据(（87Sr/86Sr） = 0.7036 ~ 0.7043；εNd (t) = + 5.71∼+ 8.17;εHf(t) = +12.44 ~ +16.50)，主要来源于以板块流体为主的衰竭地幔交代作用，并伴有蚀变的洋壳熔体和上层沉积物熔体，反映了岛弧的成熟过程。此外，早奥陶世火成岩表明地幔温度和氧逸度升高（ΔFMQ > 2），导致成矿元素溶解度增大，地壳增厚也有利于成矿作用。根据沉积岩进一步揭示了兴安地块前寒武纪基底的存在，其最年轻年龄为504 ~ 478 Ma，年龄峰值为771 Ma、864 Ma、942 Ma、~ 1800 Ma和~ 2500 Ma。同时，600 ~ 478 Ma碎屑锆石Hf同位素数据显示εHf(t)值（-10.22 ~ +12.70）为贫至富，具有近端沉积特征，表明新元古代和早古生代碎屑锆石主要来自兴安地块多宝山地区。

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引用次数: 0

Sedimentary dynamics and sources at the “Tsunami conglomerate locality” (Fig Tree Group, 3.28–3.23 Ga, Barberton Greenstone Belt, South Africa) “海啸砾岩地区”的沉积动力学及物源（南非Barberton绿岩带3.28-3.23 Ga Fig Tree Group）

IF 3.2 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Precambrian Research

Pub Date : 2026-06-01 Epub Date: 2026-02-21 DOI: 10.1016/j.precamres.2026.108060

Quentin Aquila , Marion Garçon , Nicolas Olivier , Christophe Thomazo , Johanna Marin-Carbonne

To illustrate the peculiarity of early Earth sedimentary dynamics and terrigenous pathways to the first oceans, a detailed sedimentological, petrographical, and geochemical study was conducted on a 40 m succession of the 3.28–3.23 Ga Mapepe Formation in the Barberton greenstone belt (South Africa). The “Tsunami conglomerate locality” includes terrigenous sediments (sandstones, conglomerates) and chemical sediments consisting of banded ferruginous chert (BFC) and banded iron formation (BIF). These deposits reflect a deep-water hemipelagic depositional system dominated by chemical sedimentation, punctuated by discrete terrigenous lobes and slope aprons. The 4.5-m-thick chert-plate conglomerate, known as the “Tsunami conglomerate”, represents high-density flow deposits, indicating gravity-driven instabilities near an abyssal plain. Although it lacks petrographically identifiable terrigenous material, these gravity-reworked BFC deposits exhibit a trace element signature indicating 10 % terrigenous inputs. Trace element signatures of terrigenous rocks indicate a source of 70 ± 10 % (ultra)mafic (75 % basalt, 25 % komatiite) and 30 ± 10 % felsic volcanic material, likely from erosion of the (ultra)mafic Onverwacht Group and related felsic volcanic deposits. These findings fill a gap in sample representativeness at the base of the Mapepe Formation in the Lower Manzimnyama Jaspillite Syncline and challenge previous interpretations of a gradual provenance shift from felsic to mafic sources. Instead, they suggest a predominantly mafic–ultramafic source for most of the Mapepe Formation, except for the lowermost Loenen Member, which consists almost entirely of felsic volcaniclastic material. Finally, most BFC, BIF, and terrigenous-rich units at the studied locality display highly variable Ce anomalies, suggesting that these rocks experienced syn- or post-depositional oxygenated conditions. In-situ analyses indicate that positive Ce anomalies are generally associated with goethite-rich cements, whereas negative anomalies are linked to sericite-(+/- rutile)-rich cements. The preferential distribution of Ce anomalies in secondary minerals demonstrates that these redox features were likely not acquired during sediment deposition, but rather during post-depositional history.

为了阐明早期地球沉积动力学的独特性和通往第一大洋的陆源通道，对南非巴伯顿绿岩带3.28-3.23 Ga Mapepe组40 m序列进行了详细的沉积学、岩石学和地球化学研究。“海啸砾岩区”包括陆源沉积物（砂岩、砾岩）和由带状含铁燧石（BFC）和带状铁地层（BIF）组成的化学沉积物。这些沉积反映了以化学沉积为主的深水半深海沉积体系，间或有陆源裂片和坡缘。4.5米厚的燧石板块砾岩，被称为“海啸砾岩”，代表高密度的流动沉积物，表明深海平原附近重力驱动的不稳定。虽然缺乏岩石学上可识别的陆源物质，但这些经过重力改造的BFC矿床显示出微量元素特征，表明10%的陆源输入。陆源岩石的微量元素特征表明，其来源为70±10%（超）基性（75%玄武岩，25%科马铁矿）和30±10%的长英质火山物质，可能来自（超）基性Onverwacht群和相关的长英质火山矿床的侵蚀。这些发现填补了下Manzimnyama碧石岩向斜Mapepe组底部样品代表性的空白，并挑战了以前关于物源逐渐从长英质向基性转变的解释。相反，他们认为，除了最底部的洛南段（Loenen Member）几乎完全由长英质火山碎屑物质组成外，大部分马佩组（Mapepe Formation）的主要来源是镁质-超镁质。最后，研究区域的大部分BFC、BIF和陆源富单元显示出高度变化的Ce异常，表明这些岩石经历了同沉积或沉积后的氧合条件。原位分析表明，正Ce异常通常与富含针铁矿的胶结物有关，而负Ce异常与富含绢云母（+/-金红石）的胶结物有关。次生矿物中Ce异常的优先分布表明，这些氧化还原特征可能不是在沉积过程中形成的，而是在沉积后形成的。

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引用次数: 0

3D magnetotelluric and multigeophysical constraints on the tectonic evolution of the Ribeira Orogen (Southeastern Brazil) 巴西东南部Ribeira造山带构造演化的三维大地电磁和多地球物理约束

IF 3.2 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Precambrian Research

Pub Date : 2026-06-01 Epub Date: 2026-02-24 DOI: 10.1016/j.precamres.2026.108047

Adevilson Oliveira Alves , Antonio Lopes Padilha , Sergio Luiz Fontes , Nina Silva Rocha , Artur Santos Benevides , Andrea Cristina Lima dos Santos Matos , Carlos Alberto Moreno Chaves , Maxwell Azuka Meju , Emanuele Francesco La Terra

The Ribeira Orogen in southeastern Brazil preserves the Neoproterozoic–Cambrian processes involved in the final assembly of West Gondwana. To investigate its largely uncharacterized deep lithospheric structure, this study integrates long-period magnetotelluric (MT) data with seismic tomography and geothermal heat-flow information. The MT dataset includes 61 stations along five NW–SE profiles spaced 15–25 km apart, with periods from 10 to 10,000 s. A 3D MT inversion produced a detailed resistivity model examined jointly with the complementary geophysical datasets. The results reveal three high-resistivity lithospheric blocks, bounded by major conductive zones, interpreted as fragments of Rodinia reassembled during the Brasiliano Orogeny. The western block represents the eastward extension of the São Francisco paleocontinent beneath the Ribeira Orogen. The central block, underlying the Paraíba do Sul Domain, corresponds to a preserved microcontinent (Paraíba do Sul–Embu), characterized by high P-wave velocities and low surface heat flow. The eastern block, beneath the Cabo Frio Terrane, is interpreted as a fragment of the Angola–Congo paleocontinent that remained attached to South America after the opening of the South Atlantic. Two main conductive anomalies correspond to distinct tectonic episodes. The older, beneath the Occidental Terrane, records eastward subduction of the São Francisco lithosphere during the Cryogenian–Ediacaran. The younger, located at the boundary with the Cabo Frio Terrane, is associated with Tonian–Cryogenian intra-oceanic magmatic arcs later accreted to the orogen during Cambrian collision. These findings provide robust geophysical evidence that southeastern Brazil evolved through subduction-related accretionary processes, rather than intracontinental deformation.

巴西东南部的里贝拉造山带保存了西冈瓦纳最终组合的新元古代-寒武纪过程。为了研究其深层岩石圈结构，本研究将长周期大地电磁（MT）数据与地震层析成像和地热热流信息相结合。MT数据集包括沿5条NW-SE剖面的61个站点，间隔15-25公里，周期从10到10,000 s。三维MT反演得到了详细的电阻率模型，并与互补的地球物理数据集进行了联合检验。结果显示，以主要导电带为界的三个高电阻率岩石圈块体被解释为在巴西利亚造山运动期间重新组合的Rodinia碎片。西部地块代表了里贝拉造山带下奥弗朗西斯科古大陆的向东延伸。位于Paraíba do Sul域中的中央地块对应于一个保存完好的微大陆（Paraíba do Sul - embu），其特征是高纵波速度和低表面热流。位于弗里奥角岩层下方的东部板块被解释为安哥拉-刚果古大陆的一块碎片，在南大西洋打开后，它仍然与南美洲相连。两个主要的导电异常对应不同的构造期次。较古老的，在西方地体之下，记录了在低温-埃迪卡拉纪期间，旧金山岩石圈向东俯冲。较年轻的位于卡波弗里奥地体的边界，与后来寒武纪碰撞期间增生到造山带的托尼-低温期洋内岩浆弧有关。这些发现提供了强有力的地球物理证据，表明巴西东南部是通过俯冲相关的增生过程而不是大陆内变形演化而来的。

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引用次数: 0

Paleoenvironmental and tectonic evolution of the Salt Range Formation (Salt Range, Western Himalayas, Pakistan): Inference from geochemical characteristics 巴基斯坦西喜马拉雅盐岭古环境与构造演化：地球化学特征的推断

IF 2 4区地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY

Solid Earth Sciences

Pub Date : 2026-06-01 Epub Date: 2026-02-12 DOI: 10.1016/j.sesci.2026.100291

Waseem Khan , Wang Licheng , Salman Ahmed Khattak , Malik Muhammad Saud Sajid Khan , Junaid Ur Rehman

The Salt Range Formation (SRF) of the western Himalaya in Pakistan provides key information about the late Neoproterozoic (terminal Ediacaran) period, offering clues for understanding the paleoclimate, origin, and tectonic evolution of the northwestern Indian margin, that has not been thoroughly studied. This study integrates field observations and geochemical analyses from six representative stratigraphic sections across the Salt Range, Pakistan. The sandstones of the SRF are compositionally immature, indicated by their SiO₂ and Al₂O₃ contents, ranging from 44.36 to 61.35 wt.% (average 53.75 wt.%) and 11.7–19.42 wt.% (average 14.46 wt.%), respectively. The Cr/Th ratios (range 3.09–25.52; average 7.02) suggests that the provenance is dominantly influenced by felsic to intermediate continental rocks, with a minor mafic component and limited sedimentary recycling. Weathering indices, including PIA (46.13–98.14 average 78.73) and CIA (45.61–75.89, average 60.24), indicate moderate chemical weathering under semiarid climatic conditions, consistent with evaporite deposition in arid to semiarid environments. The provenance data suggest that the source terrains were relatively proximal, indicating sedimentation in an active tectonic setting. Tectonic reconstructions point to deposition along an evolving active continental margin, which progressively transitioned toward continental collision. This finding sharply contrasts with the traditionally held view of a terminal-Ediacaran passive margin along the northwestern margin of the Indian Plate. Collectively, these finding provide significant new constraints on sediment dispersal, paleoclimate evolution, and tectonic reorganization in northern Gondwana during this pivotal interval in Earth's history.

巴基斯坦西喜马拉雅盐岭组（SRF）提供了新元古代晚期（末埃迪卡拉纪）的重要信息，为了解印度西北部边缘的古气候、起源和构造演化提供了线索，而这些研究尚未深入。本研究综合了来自巴基斯坦盐岭六个代表性地层剖面的实地观测和地球化学分析。砂岩的SiO2和Al2O3含量分别为44.36 ~ 61.35 wt.%（平均53.75 wt.%）和11.7 ~ 19.42 wt.%（平均14.46 wt.%），属于未成熟砂岩。Cr/Th比值（范围3.09 ~ 25.52，平均7.02）表明物源主要受长英质至中陆相岩石的影响，基性成分较少，沉积再循环作用有限。PIA（46.13 ~ 98.14，平均78.73）和CIA（45.61 ~ 75.89，平均60.24）显示半干旱气候条件下的中度化学风化，与干旱~半干旱环境下的蒸发岩沉积相一致。物源资料表明物源地形相对近端，表明其沉积处于活动构造环境。构造重建表明，沉积沿着一个演化的活动大陆边缘，逐渐过渡到大陆碰撞。这一发现与传统上认为沿印度板块西北缘存在埃迪卡拉纪末被动边缘的观点形成鲜明对比。总的来说，这些发现为冈瓦纳北部在地球历史上这一关键时期的沉积物扩散、古气候演化和构造重组提供了重要的新限制。

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