Geosystems and Geoenvironment最新文献_第5页

Paleo-weathering and paleoclimate of the Miocene syn-rift sandstones in the Midyan Basin, NW Saudi Arabia: Petrographic and geochemical constrains 沙特阿拉伯西北部米甸盆地中新世同裂谷砂岩的古风化和古气候：岩石学和地球化学约束

Geosystems and Geoenvironment

Pub Date : 2025-08-15 DOI: 10.1016/j.geogeo.2025.100451

Madyan A. Yahya , Hamdalla A. Wanas , Faisal A. Alqahtani , Amara Masrouhi , Murad R. Abdulfarraj

This study aims to investigate the provenance, tectonic setting, paleo-weathering, and paleoclimate of sandstones of the syn-rift Oligocene?-Middle-Miocene Sharik and Nutaysh formations in the Midyan Basin, located in the northwestern portion of Saudi Arabia. This has been achieved by a multidisciplinary approach combining fieldwork, petrographic analysis, and bulk-rock geochemistry (major, trace and rare earth elements) of sandstones of the Sharik and Nutaysh formations. Integrated petrographic and geochemical data indicate that the studied sandstones are predominantly of sublithic and subarkose arenites. These sandstones were mainly derived from felsic plutonic igneous (mainly granite) and volcanic (mainly andesite and rhyolite tuff) rocks, with a lesser contribution from recycled sedimentary (mainly sandstone, mudrock and chert) and metamorphic (mainly gneiss) sources. These source rocks are typical of a craton interior with notable input from transitional continental and quartzose recycled orogenic tectonic provenance. They were belonged to the nearby Neoproterozoic basement rocks located in the northwest of the study area, as indicated by paleocurrent direction. These source rocks were tecttonically linked to an active continental margin to a continental island arc. These tectonic settings were subsequently influenced by rifting, as evidenced by discrimination function diagrams based on the high-and low-silica sandstone samples. In terms of paleoweathering and paleoclimate,the studied sandstones experienced a week to moderate chemical weathering under semi-arid to semi-humid climatic condition (low to moderate rainfall ranges from 250 to 1000 mm per year). With respect to tectono-sedimentary evolution, the alluvial sandstones of the Sharik Formation were deposited during the initial stages of continental extension and gradual subsidence linked to the early syn-rift phase in the Oligocene?-Early Miocene. The deposition of the deep-sea sandstones of the Nutaysh Formation were deposited during a period of accelerated subsidence in the Early-Middle Miocene, corresponding to the rift climax. Findings of the present study is consistent with the Oligo-Miocene broader tectono-sedimentary evolution of the region.

本研究旨在探讨同裂谷渐新统砂岩的物源、构造背景、古风化和古气候特征。中中新世Sharik和Nutaysh组位于沙特阿拉伯西北部的Midyan盆地。这是通过多学科方法结合实地考察、岩石学分析和Sharik和Nutaysh地层砂岩的整体岩石地球化学（主要、痕量和稀土元素）来实现的。综合岩石学和地球化学资料表明，研究的砂岩主要为亚岩屑砂质和亚花岗岩砂质砂质。这些砂岩主要来自长英质深生火成岩（主要是花岗岩）和火山（主要是安山岩和流纹岩凝灰岩），少量来自再循环沉积（主要是砂岩、泥岩和燧石）和变质岩（主要是片麻岩）。这些烃源岩是典型的克拉通内部烃源岩，有明显的过渡性大陆和石英再循环造山带构造物源输入。从古水流方向看，它们属于研究区西北部附近新元古代基底岩。这些烃源岩在构造上与活动大陆边缘和大陆岛弧相连。基于高硅砂岩和低硅砂岩样品的判别函数图表明，这些构造环境随后受到裂谷作用的影响。在古风化和古气候方面，研究的砂岩在半干旱至半湿润气候条件下（年降雨量250 ~ 1000 mm）经历了一周至中度的化学风化。在构造-沉积演化方面，沙里克组的冲积砂岩沉积于渐新世早期同裂谷期的大陆伸展和逐渐沉降的初始阶段。中新世初期。Nutaysh组深海砂岩沉积于中新世早-中加速沉降期，与裂谷高潮期相对应。本研究结果与渐新世-中新世更广泛的构造-沉积演化相一致。

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引用次数: 0

Morphological, mineralogical and geochemical characterization of Ngaoundal soils (Adamawa-Cameroon): Implications for weathering mechanisms and trajectories in tropical zones Ngaoundal土壤（Adamawa-Cameroon）的形态、矿物学和地球化学特征：对热带地区风化机制和轨迹的影响

Geosystems and Geoenvironment

Pub Date : 2025-08-08 DOI: 10.1016/j.geogeo.2025.100450

Abdoul Aboubakar , Ilalie Bertille Kentsa Manefouet , Loique Rodolph Mbounou Azefack , Yannick Langollo Tchedele , Dalil Adoulko , Demonstel Yvan Ntomb , Abakar Mahamat , Jacques Wadjou Wassouo , Quentin marc Anaba Fotze

Ngaoundal, located in the Adamaoua region of Cameroon, has a tropical climate and is known for its characteristic soils. The aim of the present study was to evaluate the action of weathering on Ngaoundal's lateritic soils. Morpho-structural, mineralogical and geochemical analyses enabled us to carry out this study. The morphological study carried out on 15 soil samples shows a variation in colour from reddish (2.5YR 5/8) to dark brown (7.5YR 6/8), varying from reddish yellow (7.5YR 6/8), orange brown (10YR 5/6) and yellowish brown (10YR 5/4), and have clayey to sandy-clayey matrices with nodules of the order of millimetres to centimetres. X-ray diffractometry and x-ray fluorescence show the following mineral phases in Ngaoundal's lateritic soils: quartz, goethite, gibbsite, kaolinite, hematite, magnetite, anatase and boehmite. Geochemical analysis of these soils shows high average levels of SiO₂ (36.41 %), Fe₂O₃ (31.48 %) and Al₂O₃ (17.72 %), and low average levels of TiO₂ (1.02 %) and CaO (0.36 %), which characterise characteristic soils rich in ferruginous oxide and alumina oxide. The weathering indices of Ngaoundal soils (sesquioxide ratio) vary between 0.22 and 2.98 with an average of 1.09. This average value qualifies these soils as lateritic soils rich in gibbsite and kaolinite (average CIA = 96.38 %) and resulting from chemical alteration of the hydrolysis type (alloying and monosiallitisation).

Ngaoundal位于喀麦隆的Adamaoua地区，属于热带气候，以其特有的土壤而闻名。本研究的目的是评价风化作用对恩昂达尔红土的影响。形态构造、矿物学和地球化学分析使我们得以开展这项研究。对15个土壤样品进行的形态学研究表明，土壤的颜色从红色（2.5年5/8）到深棕色（7.5年6/8）不等，从红黄色（7.5年6/8）、橙棕色（10年5/6）和黄褐色（10年5/4）不等，具有粘土到砂质粘土基质，具有毫米至厘米级的结节。x射线衍射和x射线荧光显示，在恩翁达尔红土中有以下矿物相：石英、针铁矿、三长石、高岭石、赤铁矿、磁铁矿、锐钛矿和薄铝石。土壤的地球化学分析表明，SiO2（36.41 %）、Fe2O3（31.48 %）和Al2O3（17.72 %）的平均含量较高，TiO2（1.02 %）和CaO（0.36 %）的平均含量较低，具有富含氧化亚铁和氧化氧化铝的特征。Ngaoundal土的风化指数（倍半氧化物比）在0.22 ~ 2.98之间变化，平均为1.09。这个平均值表明这些土壤是红土土，富含三长石和高岭石（平均CIA = 96.38 %），是由水解类型（合金化和单唾液化）的化学变化造成的。

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引用次数: 0

Pore size characterization of Cretaceous ironstone by low-field nuclear magnetic resonance technique 用低场核磁共振技术表征白垩纪铁矿的孔隙大小

Geosystems and Geoenvironment

Pub Date : 2025-08-07 DOI: 10.1016/j.geogeo.2025.100449

A.A. Ige-Adeyeye , O.B. Olatinsu , V.C. Ozebo , L. Esteban

The microstructure of Cretaceous ironstone samples of Yewa within Eastern Dahomey Basin in Southwest Nigeria, has been investigated using low-field nuclear magnetic resonance and conventional porosity measurements. The aim was to evaluate the porosity and pore structure for heat flow consideration in blast furnace or rotary kiln. A total of eighteen iron core samples were analyzed using: X-ray fluorescence (XRF) spectroscopy to determine the percentage composition of iron content; water imbibition porosity (WIP) from dry and saturated sample weights; and low-field nuclear magnetic resonance (NMR) measurements at full water saturation for pore structure and pore size distribution. The average percentage by weight of iron content in the samples is 55 %. Porosity and water content from NMR and WIP shows high degree correlation of 79 % and 97 %, respectively with average porosities from both procedures given as 22.06 pu. and 21.96 pu., respectively. The NMR-T₂ distributions depict multimodal pore system with high degree of connectivity. The transverse relaxation time ranges have been classified into three regions: micropores, 0.3162–0.5012 ms, mesopores, 19.95–84.28 ms and macropores, 199.5–2117 ms, respectively. Using an established average surface relaxivity value (338 µms⁻¹) for haematite, the logarithmic mean of pore radius was estimated from the pore size distributions with values of 0.3098 µm, 33.57 µm and 733.3 µm, for micropores, mesopores and macropores, respectively. The strong pore connectivity demonstrated by the NMR-T₂ distribution, porosity values, and pore geometry all provide strong evidence that the iron ore samples from the study site will maximize heat and gas flow, improve reducibility and increase process efficiency in a rotary kiln or blast furnace. These findings provide valuable insights into the petrophysical characteristics of Yewa iron ores, thereby enhancing our understanding of its potential applications in the mining and ore processing industries.

利用低场核磁共振和常规孔隙度测量技术，研究了尼日利亚西南部东达荷美盆地Yewa白垩纪铁石样品的微观结构。目的是评价高炉和回转窑热流条件下的孔隙率和孔隙结构。共对18个铁芯样品进行了分析：x射线荧光（XRF）光谱法测定铁含量的百分比组成；干样和饱和样的吸水孔隙度（WIP）；低场核磁共振（NMR）全含水饱和度下的孔隙结构和孔径分布。样品中按重量计的平均铁含量百分比为55%。核磁共振和WIP的孔隙度和含水量的相关性分别为79%和97%，两种方法的平均孔隙度为22.06 pu。21.96磅。,分别。核磁共振- t2分布描述了具有高度连通性的多模态孔隙系统。横向弛豫时间范围分为微孔（0.3162 ~ 0.5012 ms）、中孔（19.95 ~ 84.28 ms）和大孔（199.5 ~ 2117 ms）三个区域。利用已建立的赤铁矿平均表面弛豫值（338µms−1），从微孔、中孔和大孔的孔径分布分别为0.3098µm、33.57µm和733.3µm，估算出孔隙半径的对数平均值。核磁共振- t2分布、孔隙度值和孔隙几何形状所显示的强孔隙连通性都有力地证明，研究地点的铁矿石样品将最大化热量和气体流动，改善还原性，提高回转窑或高炉的工艺效率。这些发现为了解叶洼铁矿的岩石物理特征提供了有价值的见解，从而增强了我们对其在采矿和矿石加工行业中的潜在应用的认识。

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引用次数: 0

Identifying seawater intrusion in coastal areas using the transient electromagnetic method at Santolo Beach, Garut, West Java, Indonesia 利用瞬变电磁法在印度尼西亚西爪哇加鲁特的Santolo海滩识别沿海地区的海水入侵

Geosystems and Geoenvironment

Pub Date : 2025-08-05 DOI: 10.1016/j.geogeo.2025.100440

Vitasha Adha Chaerul , I Gede Putu Fadjar Soerya Djaja , Prihandhanu Mukti Pratomo , Supriyadi , Elfitra Desifatma , Anggie Susilawati , Dini Andriani , Harry Mahardika , Eleonora Agustine , Wahyu Srigutomo

Seawater intrusion contaminates freshwater in coastal areas, disrupting the environment and posing health risks due to high chloride content. Monitoring and mapping the seawater-freshwater interface is essential for evaluating and mitigating the environmental damage caused by this phenomenon. A widely used geophysical technique for mapping is the transient electromagnetic (TEM) method, which detects seawater intrusion by leveraging the significant resistivity differences between saline water, freshwater, and other geological layers.

This study utilized 21 TEM sounding points at Santolo Beach, Garut, West Java, Indonesia. The data were processed through an iterative inversion procedure using a smoothness constraint scheme. Interpretation of the transient magnetic field across all sounding points revealed a resistivity structure comprising three main layers: (1) a surface layer with high resistivity (>50 Ωm) extending to a depth of 15 m and thinning as it moves away from the coastline; (2) a middle layer with moderate resistivity (5–50 Ωm), ranging from 15 m to 40 m and thickening inland; and (3) a conductive layer, identified as seawater intrusion, with low resistivity (<5 Ωm), situated >40 m deep and deepening farther from the coastline. Additionally, water quality at several TEM sounding points was assessed using parameters such as total dissolved solids (TDS), electrical conductivity (EC), pH, and water temperature. The findings indicate that surface water in the area, obtained from wells and swamps, meets the required quality standards for potable water.

海水入侵污染了沿海地区的淡水，破坏了环境，并因氯化物含量高而构成健康风险。监测和绘制海水-淡水界面图对于评价和减轻这一现象造成的环境损害至关重要。一种广泛使用的地球物理测绘技术是瞬变电磁（TEM）方法，该方法利用咸水、淡水和其他地质层之间显著的电阻率差异来探测海水入侵。本研究利用了印度尼西亚西爪哇加鲁特的Santolo海滩的21个透射电镜测深点。采用平滑约束方案对数据进行迭代反演处理。对所有测深点瞬变磁场的解释揭示了一个由三层组成的电阻率结构：(1)高电阻率表面层（>50 Ωm）延伸至15米深，并随着它远离海岸线而变薄；(2)电阻率中等的中间层（5 ~ 50 Ωm），在15 ~ 40 m之间，向内陆加厚；(3)导电层为海水侵入层，电阻率低（<5 Ωm），深度为>； 40m，离海岸线越远越深。此外，利用总溶解固体（TDS）、电导率（EC）、pH值和水温等参数，对几个TEM测深点的水质进行了评估。调查结果表明，该地区从水井和沼泽中获得的地表水符合饮用水的质量标准。

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引用次数: 0

Urbanization induced heat wave risk assessment of Khulna City, Bangladesh: A 30-years analysis of land surface temperature, climate trends and forecasting 孟加拉国库尔纳市城市化引发的热浪风险评估：地表温度、气候趋势和预测的30年分析

Geosystems and Geoenvironment

Pub Date : 2025-08-05 DOI: 10.1016/j.geogeo.2025.100448

Nusrat Jahan Suborna , Raian Islam Evan , Mostafa Jaman Rabby , Maksudur Rahman , Arabe Khan , Md Mahmudul Hasan Rakib , Rahat Khan , Irteja Hasan , Dhiman Kumer Roy

This study examines how urbanization has influenced heatwave risk in Khulna, Bangladesh, from 1993 to 2023 by analyzing changes in land surface temperature (LST) and land use land cover (LULC) using satellite imagery and statistical methods. Over the 30‐year period, mean LST rose by 7 °C, with 23.7 % of Khulna now classified as an excessive heat zone. The Mann–Kendall (MK) test and Sen’s slope (SS) estimator confirm a significant warming trend, particularly during the warmest months. Pearson correlation (PC) analysis indicates a negative relationship between temperature and humidity, exacerbating heatwave severity. LULC results reveal that urbanized areas have expanded approximately threefold while vegetation cover has decreased by nearly 50 %. Using a seasonal-trend decomposition based on LOESS with an auto regressive integrated moving average (STL‐ARIMA) model, the study forecasts 29 additional heatwave days exceeding 36 °C over the next five years. This projection suggests a likely intensification of the urban heat island (UHI) effect driven by rapid urban growth and diminished natural spaces, heightening heat‐related hazards. The findings support the need for sustainable urban development strategies in Khulna, such as increasing green cover and improving water management to inform policy interventions aimed at mitigating rising heat risks in the city’s expanding urban environment.

本研究利用卫星图像和统计方法分析了1993年至2023年孟加拉国库尔纳的地表温度（LST）和土地利用土地覆盖（LULC）的变化，探讨了城市化如何影响热浪风险。在30年期间，平均地表温度上升了7°C，库尔纳的23.7% %现在被列为过热区。Mann-Kendall （MK）检验和Sen’s slope （SS）估计证实了显著的变暖趋势，特别是在最温暖的月份。Pearson相关（PC）分析表明，温度和湿度呈负相关，加剧了热浪的严重程度。LULC结果显示，城市化面积扩大了约三倍，而植被覆盖却减少了近50% %。利用基于黄土的季节趋势分解和自回归综合移动平均（STL‐ARIMA）模型，该研究预测了未来五年超过36°C的额外29个热浪天。这一预测表明，在城市快速增长和自然空间减少的驱动下，城市热岛效应可能会加剧，从而加剧与热有关的危害。研究结果支持了库尔纳需要制定可持续城市发展战略，例如增加绿化覆盖和改善水资源管理，以便为旨在减轻城市不断扩大的城市环境中不断上升的高温风险的政策干预提供信息。

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引用次数: 0

Geochemical and mineralogical constraints on lithium mineralization in rare-metal pegmatites of the Amareshwar region, Eastern Dharwar Craton, India 印度东Dharwar克拉通Amareshwar地区稀有金属伟晶岩中锂矿化的地球化学和矿物学约束

Geosystems and Geoenvironment

Pub Date : 2025-07-25 DOI: 10.1016/j.geogeo.2025.100439

C.S. Sindhuja , M. Satyanarayanan , Srijita Banerjee , Soumi Chatterjee

Around 50 percent of global lithium resources are hosted in the rare-metal pegmatites. The present study deals with whole-rock geochemistry as well as zinnwaldite mineral chemistry of rare-metal pegmatites from Amareshwar, Gurugunta schist belt, Eastern Dharwar Craton to understand the source of lithium bearing ore fluids in these pegmatites and to evaluate their mineralization potential. Detailed petrography and mineral chemistry of Amareshwar pegmatites indicate that lithium is hosted in both spodumene and zinnwaldite. The zinnwaldite mineral chemistry elucidates the incorporation of lithium in mica crystal lattice along the vector Al₂(R²⁺)_–3. The whole rock geochemical signatures suggest that these pegmatites are alkaline to calc-alkaline in nature, peraluminous and emplaced in S-type and syn-collisional tectonic setting. The chondrite normalized REE patterns are characterized by prominent negative Eu anomalies coupled with significant LREE enrichment and HREE depletion indicating fractional crystallization with plagioclase separation. Elevated concentrations of Li (Avg. = 1355 ppm), Cs (Avg. = 246 ppm), Ta (Avg. = 124 ppm), Sr (Avg. = 105 ppm) and Rb (Avg. = 2234 ppm) coupled with their geochemical characteristics classify them as LCT type of rare-metal pegmatites. The relationship between La/Ta versus Mg/Li and Zr/Hf versus Nb/Ta attest that the studied samples are lithium mineralized pegmatites of magmatic-hydrothermal origin. Extremely low ratios of Mg/Li (0.004), K/Rb (0.004), K/Cs (0.05), K/Ba (0.07), Al/Ga (0.23) fingerprint that these pegmatites have evolved from highly fractionated, fertile parental granitic magma having promising economic potential.

全球约50%的锂资源蕴藏在稀有金属伟晶岩中。本文对东Dharwar克拉通Amareshwar、Gurugunta片岩带稀有金属伟晶岩进行了全岩地球化学和锌walite矿物化学研究，以了解这些伟晶岩中含锂矿流体的来源，并评价其成矿潜力。阿玛列什瓦尔伟晶岩的详细岩石学和矿物化学特征表明，锂在锂辉石和锌walite中均有赋存。锌walite矿物化学解释了锂沿矢量Al2(R2+) -3在云母晶格中的掺入。整体岩石地球化学特征表明，这些伟晶岩为碱性至钙碱性，过铝质，位置于s型和同碰撞构造环境。球粒陨石归一化稀土模式的特征是显著的负Eu异常，伴随着明显的LREE富集和HREE亏缺，表明斜长石分离的分馏结晶。Li （Avg = 1355 ppm）、Cs （Avg = 246 ppm）、Ta （Avg = 124 ppm）、Sr （Avg = 105 ppm）和Rb （Avg = 2234 ppm）含量的升高，结合其地球化学特征，将其归类为LCT型稀土晶岩。La/Ta与Mg/Li、Zr/Hf与Nb/Ta的关系表明，研究样品为岩浆热液型锂矿化晶岩。极低的Mg/Li（0.004）、K/Rb（0.004）、K/Cs（0.05）、K/Ba（0.07）、Al/Ga（0.23）指纹图谱表明，这些辉晶岩是由高分馏、肥沃的母花岗质岩浆演化而来，具有广阔的经济潜力。

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引用次数: 0

A lacustrine record of rainfall-induced variations in the pedogenic and weathering processes during the Late Holocene 在晚全新世期间降雨引起的成土和风化过程变化的湖相记录

Geosystems and Geoenvironment

Pub Date : 2025-07-25 DOI: 10.1016/j.geogeo.2025.100441

Adichinalniravel S. Yamuna , Anish K. Warrier , Bharti Sharma , Kizhur Sandeep , Mamilla Venkateshwarlu , Powravi Sai , George S. Joju , Geetha H. Aravind , Abdul K. Rafaz , Kakunja V. Reshma , Rajveer Sharma

In recent decades, extreme weather events have become more frequent across the globe. It necessitates a deeper understanding of the underlying driving mechanisms. This study reconstructs the paleoclimatic variability of southern India, particularly the coastal Karnataka, over the past two millennia using a multiproxy approach (geochronology, environmental magnetism, sedimentology, inorganic geochemical analysis, Fourier Transform Infrared Spectroscopy, Diffuse Reflectance Spectroscopy, and loss-on-ignition). The study was conducted on a 1.54-m-long lacustrine sediment core covering the past 1566 years, from 2005 to 439 cal yr BP. Four distinct climatic phases were delineated, reflecting successive stages of the Indian Summer Monsoon (ISM) strengthening in the Late Holocene. Phase 1, which spans from 2000 to 1550 cal yr BP, experienced moderately low rainfall and weak pedogenesis. In Phase 2 (1550–1230 cal yr BP), the monsoon strengthened, leading to strong precipitation, intense weathering and pedogenesis, and high lake levels. Phases 3 (1230–570 cal yr BP) and 4 (570–439 cal yr BP) experienced stronger monsoons and a burst of rainfall that strengthened catchment streams, elevated lake levels, and increased productivity and sedimentation rate. A comparative study with regional records suggests a similar trend in broad climate variability, revealing a global teleconnection. The climatic evolution of coastal Karnataka aligns with the shifts in the Intertropical Convergence Zone (ITCZ), El Niño Southern Oscillation (ENSO), and Total Solar Irradiance (TSI). Additionally, the signatures of global factors like ITCZ, ENSO, and TSI have been overprinted by the signatures of regional factors such as sea surface temperature (SST), especially during periods of active Indian Ocean Dipole (IOD).

近几十年来，极端天气事件在全球范围内变得越来越频繁。这需要对潜在的驱动机制有更深的理解。本研究利用多代理方法（地质年代学、环境磁学、沉积学、无机地球化学分析、傅里叶变换红外光谱、漫反射光谱和着火损失）重建了印度南部，特别是卡纳塔克邦沿海地区过去两千年的古气候变化。该研究是在一个1.54米长的湖泊沉积物岩心上进行的，覆盖了过去1566年，从2005年到439 calyr BP。描述了四个不同的气候阶段，反映了晚全新世印度夏季风（ISM）增强的连续阶段。第1阶段为2000 ~ 1550 calyr BP，降水偏少，成土作用弱。第2阶段（1550-1230 calyr BP），季风增强，降水强，风化作用强，成土作用强，湖泊水位高。第3阶段（1230-570 cal yr BP）和第4阶段（570-439 cal yr BP）经历了更强的季风和降雨，这些降雨加强了流域溪流，提高了湖泊水位，增加了生产力和沉积速率。一项与区域记录的比较研究表明，广泛的气候变率也有类似的趋势，揭示了全球遥相关。沿海卡纳塔克邦的气候演变与热带辐合带（ITCZ）、厄尔尼诺Niño南方涛动（ENSO）和太阳总辐照度（TSI）的变化一致。此外，ITCZ、ENSO和TSI等全球因子的特征已经被海温（SST）等区域因子的特征叠加，特别是在印度洋偶极子（IOD）活跃期间。

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引用次数: 0

Assessment of the potential for using PET waste as geomaterials in soil micro-reinforcement PET废弃物作为土壤微加固材料的潜力评价

Geosystems and Geoenvironment

Pub Date : 2025-07-21 DOI: 10.1016/j.geogeo.2025.100438

Carlos J.P. Graça , Luís M. Ferreira-Gomes , Luis Andrade Pais , Antonio Albuquerque , Maria Vitoria Morais , André Studart , Leonardo Marchiori

The use of synthetic fibers to enhance soil properties is a growing area of research. This study investigates the incorporation of granulated polyethylene terephthalate (PET) waste – derived from crushed plastic soda bottles – into dune sand at 3 % and 5 % ratios to develop a novel composite material and promote PET fiber reuse as a sustainable solution. By valorizing PET waste, this approach reduces plastic pollution and mitigates the demand for natural resource extraction. Physical and mechanical characterization tests, including specific gravity, particle size distribution, normal proctor compaction, direct shear (DS), consolidated isotropic drained (CID) triaxial, and oedometric tests, were conducted on the dune sand, soil-PET mixtures, and pure PET residue. Results demonstrate that the addition of PET significantly influences the friction angle of the composite material, as evidenced by DS and triaxial CID tests. Specifically, the soil-PET mixtures exhibited enhanced shear strength compared to pure sand, while introducing 5 % of PET, the internal friction angle increased up to 12 % and 22 %, according to DS and CID triaxial tests, respectively, maintaining cohesionless behavior. These improvements are attributed to the reinforcing effect and interlocking behavior of PET particles within the sand matrix. The results indicate that PET addition enhances the shear strength and stability of sandy soils, supporting its use in earthworks. This study highlights the dual environmental and mechanical advantage of PET micro-reinforcement, providing a feasible route for plastic waste reuse in geotechnical engineering.

利用合成纤维增强土壤特性是一个日益发展的研究领域。本研究研究了将颗粒状聚对苯二甲酸乙二醇酯（PET）废料（来自破碎的塑料汽水瓶）以3%和5%的比例掺入沙丘沙中，以开发一种新型复合材料，并促进PET纤维的再利用，作为一种可持续的解决方案。通过使PET废物增值，这种方法减少了塑料污染，减轻了对自然资源开采的需求。对沙丘砂、土壤-PET混合物和纯PET残渣进行了物理力学表征试验，包括比重、粒径分布、正常普罗克特压实、直剪（DS）、固结各向同性排水（CID）三轴和径测试验。结果表明，PET的加入对复合材料的摩擦角有明显的影响，这是DS和三轴CID试验的结果。具体来说，与纯砂相比，土-PET混合物的抗剪强度得到了提高，根据DS和CID三轴试验，当引入5%的PET时，内摩擦角分别增加了12%和22%，保持了无粘结性。这些改进是由于PET颗粒在砂基体中的增强作用和联锁行为。结果表明，PET的加入提高了砂土的抗剪强度和稳定性，支持其在土方工程中的应用。本研究突出了PET微增强材料的环境和力学双重优势，为塑料废弃物在岩土工程中的再利用提供了一条可行的途径。

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引用次数: 0

Hydrostratigraphic characterization using geoelectrostratigraphic information and hydraulic flow unit analysis for high-resolution aquifer mapping in heterogeneous systems 利用地电地层信息和水力流动单元分析进行非均质系统高分辨率含水层制图的水文地层表征

Geosystems and Geoenvironment

Pub Date : 2025-07-16 DOI: 10.1016/j.geogeo.2025.100434

Ndifreke I. Udosen , Kufre R. Ekanem , Nyakno J. George

Accurate characterization of aquifers requires comprehensive understanding of groundwater hydraulic properties. Traditional aquifer assessment techniques are usually insufficient in characterizing hydrostratigraphic variability, leading to inaccurate prediction of aquifer flow dynamics. To address these limitations, this work integrated geoelectrical stratigraphy with hydraulic flow unit, flow zone indicator, and stratigraphic modified Lorenz plot strategies, the goal being to enhance the resolution of aquifer characterization along river channels and tributaries in Akwa Ibom State, Southern Nigeria. Unlike conventional approaches, the stratigraphic modified Lorenz plot (SMLP) provided a more precise strategy for quantifying permeability distribution within the heterogeneous aquifer system, enabling enhanced prediction of aquifer performance. Furthermore, SMLP delineated flow efficiency across the distinct hydrostratigraphic units. Results indicated the presence of four hydraulic flow units, with individual units exhibiting distinctive transmissivity properties. Computed inclination angles of the four flow units were 34°, 29°, 49°, and 33°, respectively, and these indicated the extent of hydraulic efficiency. Hydraulic flow units 1, 3, and 4 had higher transmissivity and were key conduits for groundwater flow. Hydraulic flow unit 2, on the other hand, had reduced transmissivity, indicating restricted fluid migration. The techniques employed in this study enhanced subsurface characterization and generated high-resolution and cost-effective strategies for delineating high-yield aquifer zones within river channels and tributaries with better accuracy than with use of traditional hydrogeological models. These findings are important for optimizing groundwater resource management in the study area and analogous hydrogeological settings worldwide.

准确表征含水层需要对地下水水力特性有全面的了解。传统的含水层评价技术在表征水文地层变异性方面往往存在不足，导致含水层流动动态预测不准确。为了解决这些限制，本研究将地电地层学与水力流动单元、流动带指示器和地层修正洛伦兹图策略结合起来，目的是提高尼日利亚南部阿夸伊博姆州沿河道和支流的含水层表征的分辨率。与传统方法不同，地层修正洛伦兹图（SMLP）提供了一种更精确的策略来量化非均质含水层系统内的渗透率分布，从而增强了对含水层性能的预测。此外，SMLP还描绘了不同水文地层单元的流动效率。结果表明存在四个水力流动单元，每个单元表现出不同的透射率特性。四个流动单元的计算倾角分别为34°、29°、49°和33°，这表明了水力效率的程度。水力流单元1、3、4具有较高的透水性，是地下水渗流的关键通道。另一方面，水力流量单元2的透过率降低，表明流体运移受到限制。本研究中采用的技术增强了地下特征，并产生了高分辨率和成本效益的策略，用于描绘河道和支流内的高含水含水层，其准确性优于使用传统水文地质模型。这些发现对于优化研究区和世界范围内类似水文地质环境的地下水资源管理具有重要意义。

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引用次数: 0

Spatial distribution and source apportionment of potentially toxic elements in residential soil from Nsuta, a typical manganese mine community in Tarkwa, Southwestern Ghana 加纳西南部塔克瓦典型锰矿社区Nsuta居住土壤中潜在有毒元素的空间分布及来源解析

Geosystems and Geoenvironment

Pub Date : 2025-07-16 DOI: 10.1016/j.geogeo.2025.100435

Eric Gyimah , Samuel Kwamena , Shadrack Fosu , Emmanuel Daanoba Sunkari , David Edem Dinku , Yao Yevenyo Ziggah

The environmental quality of residential areas of urban communities has been threatened by rapid industrial growth, substantial technological innovation, and urban expansion. The present study provides chemometric receptor model-based source apportionment, the ecotoxicological status, and the spatial distribution of arsenic, cadmium, lead, mercury, manganese and iron in residential soils in a mining community in Tarkwa. The distributions of the heavy metals showed a widespread pattern, while the eastern fringe of the study area was identified as a hotspot for mercury contamination. Agreement among the cluster analysis (CA), principal component analysis (PCA), and positive matrix factorization (PMF) along with the correlation matrix (CM) reasonably identified the sources of arsenic, manganese, and iron contamination of residential soils of the Nsuta community to be governed by geogenic influences such as the weathering and hydromorphic dispersion from the metavolcanic rocks. Noteworthily, atmospheric deposition is considered a prioritized source for mercury contamination, with a PMF contribution of 78.50%. Vehicular emission as well as other anthropogenic activities contribute to lead (48.00%) and cadmium (66.20%) contamination of the residential soil within the study area. Ecotoxicological assessment reveals a combined toxic risk index (TRI) of 29.80, with mercury contributing to about 97.50% of the total risk. Moreover, the modified hazard quotient (mHQ_i) for the single metals also indicated that mercury (Hg) has the highest ecological toxicity level with a mHQ_i value of 7.00. The present study provides baseline data that could be valuable for proper environmental management and policy-making to reduce the myriad influx of heavy metal contamination in the study area. To provide a thorough understanding of metal pollution in the Nsuta community, future research on metal speciation, bioavailability, bioaccumulation, potential modes of action in soils, and the implications for human health is also necessary.

城市社区居住区的环境质量受到快速工业增长、大量技术创新和城市扩张的威胁。本研究基于化学计量受体模型进行了塔尔克瓦矿区居住土壤中砷、镉、铅、汞、锰和铁的源解析、生态毒理学状况和空间分布。重金属分布呈广泛分布，研究区东部边缘为汞污染热点地区。聚类分析（CA）、主成分分析（PCA）和正矩阵分解（PMF）与相关矩阵（CM）的一致，合理地确定了Nsuta群落居住土壤中砷、锰和铁的污染来源受变质火山岩风化和水形态分散等地质因素的影响。值得注意的是，大气沉积被认为是汞污染的优先来源，PMF贡献了78.50%。车辆排放和其他人为活动对研究区内居住土壤的铅（48.00%）和镉（66.20%）污染有贡献。生态毒理学评估显示，综合毒性风险指数（TRI）为29.80，汞约占总风险的97.50%。此外，单一金属的修正危害商（mHQi）也表明汞（Hg）具有最高的生态毒性水平，其mHQi值为7.00。本研究提供的基线数据可能对适当的环境管理和决策有价值，以减少研究地区大量重金属污染的流入。为了全面了解Nsuta群落的金属污染，还需要进一步研究金属在土壤中的形态、生物利用度、生物积累、潜在的作用方式以及对人类健康的影响。

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引用次数: 0