Geosystems and Geoenvironment最新文献_第10页

Ozone patterns in Maceió: Insights into seasonal and geographic varibility Maceió中的臭氧模式：对季节和地理变化的洞察

Geosystems and Geoenvironment

Pub Date : 2025-05-01 Epub Date: 2025-03-13 DOI: 10.1016/j.geogeo.2025.100379

Amaury de Souza , Celina M. Takemura , Deniz Özonur , Elias Silva de Medeiros , Ivana Pobocikova , Janice F. Leivas , José Francisco de Oliveira-Júnior , Kelvy Rosalvo Alencar Cardoso , Marcel Carvalho Abreu , Wagner Alessandro Pansera , Jose Roberto Zenteno Jimenez , Sneha Gautam

This study analyzes the Total Ozone Column (TCO) over six cities in Alagoas, Brazil, aiming to evaluate their spatial and temporal homogeneity and identify seasonal and annual patterns from 2008 to 2016. TCO is a key indicator for monitoring the ozone layer and its implications for public health, given ozone's role in filtering ultraviolet radiation. The analysis utilized satellite-derived TCO data, with variance homogeneity assessed using the Bartlett test at a 95% significance level. Descriptive statistical analyses characterized the temporal distribution of TCO values, and probability density functions (PDFs) identified the best-fitting statistical distribution.

The findings indicate significant homogeneity in annual and seasonal TCO concentrations, with an annual mean of 263.24 ± 9.91 DU. A biannual TCO cycle was observed, with peaks in spring and lows in fall, influenced by Earth's orbit and ozone photochemistry. The data were best represented by a normal distribution, reflecting the role of the Brewer-Dobson Circulation in maintaining ozone uniformity and mitigating disruptions from phenomena like the Antarctic Polar Vortex.

These results emphasize the need for continuous monitoring of ozone variability, as fluctuations in TCO can affect ultraviolet radiation levels and, consequently, public health outcomes such as skin cancer and ocular diseases. The study underscores the importance of integrating TCO data into environmental policies and public health strategies, particularly in regions with high solar radiation exposure. The study's limited statistical sensitivity and geographic coverage highlight the necessity of further research on factors influencing ozone distribution and its broader environmental and health implications.

本研究分析了巴西阿拉戈斯州6个城市的总臭氧柱（TCO），旨在评估其时空均匀性，并确定2008 - 2016年的季节和年度模式。考虑到臭氧在过滤紫外线辐射方面的作用，总逸度是监测臭氧层及其对公众健康影响的关键指标。分析使用卫星衍生的TCO数据，方差同质性评估使用Bartlett检验在95%显著性水平。描述性统计分析表征了TCO值的时间分布，概率密度函数（pdf）确定了最适合的统计分布。结果表明，TCO浓度的年际和季节分布具有显著的均匀性，年平均值为263.24±9.91 DU。在地球轨道和臭氧光化学的影响下，观测到一年两次的TCO循环，春季达到峰值，秋季达到低点。正态分布最能代表数据，反映了布鲁尔-多布森环流在维持臭氧均匀性和减轻南极极地涡旋等现象造成的破坏方面的作用。这些结果强调需要持续监测臭氧变异性，因为总逸度的波动会影响紫外线辐射水平，从而影响皮肤癌和眼病等公共健康结果。该研究强调了将TCO数据纳入环境政策和公共卫生战略的重要性，特别是在太阳辐射高的区域。这项研究有限的统计敏感性和地理覆盖范围突出表明，有必要进一步研究影响臭氧分布的因素及其更广泛的环境和健康影响。

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引用次数: 0

Prioritization of the Tassaoute Watershed (Morocco) for soil erosion using analytical hierarchy process (AHP) and geospatial techniques 利用层次分析法（AHP）和地理空间技术确定摩洛哥塔索特流域土壤侵蚀的优先次序

Geosystems and Geoenvironment

Pub Date : 2025-05-01 Epub Date: 2025-04-04 DOI: 10.1016/j.geogeo.2025.100389

Khalid Ziadi , Ahmed Barakat , Abdenbi El Aloui , Mustapha Ouayah , Mustapha Namous

Identifying areas vulnerable to soil erosion is essential for the sustainable management of natural resources and the implementation of effective prevention strategies. This study proposes a robust multi-criteria decision analysis (MCDA)framework integrated with geographic information system (GIS) technology to evaluate susceptibility to water erosion in the upstream watershed of Tassaoute (Central High Atlas, Morocco). Elevation, slope, SPI, TWI, NDVI, LULC, lithology, rainfall, distance from river, and drainage density were the ten factors we employed to establish the soil erosion vulnerability map. Criteria weights were measured using the AHP method based on suggestions from different studies and research that ensured an effective way of soil erosion control. The final susceptibility map, created from GIS data and a classification of natural phenomena, identified five distinct levels: very low, low, moderate, high and very high. It reveals a significant erosion threat, with around 60 % of the study area showing moderate to very high levels of erosion. On the other hand, 40 % of the area studied is considered to be at low risk of erosion. Areas at high risk of erosion are more common on steep slopes, with high rainfall and rocks of the marl and clay formation. The accuracy of the results is assessed using the ROC (receiver operating characteristic) curve. The area under the curve (AUC) is 0.782, equivalent to a prediction accuracy of 78.2 %. In conclusion, this model is proving to be a valuable tool for effectively guiding future planning with regard to sustainable soil and water management, in particular by addressing the problem of soil erosion.

确定易受土壤侵蚀影响的地区对于自然资源的可持续管理和有效预防战略的执行至关重要。本研究提出了一个强大的多标准决策分析（MCDA）框架，结合地理信息系统（GIS）技术来评估Tassaoute上游流域（Central High Atlas，摩洛哥）对水侵蚀的敏感性。利用高程、坡度、SPI、TWI、NDVI、LULC、岩性、降雨量、离河距离和排水密度等10个因子建立土壤侵蚀脆弱性图。根据不同研究的建议，采用层次分析法测算各指标权重，确保土壤侵蚀治理的有效途径。根据地理信息系统数据和自然现象分类绘制的最终敏感性图确定了五个不同的级别：极低、低、中等、高和极高。它揭示了严重的侵蚀威胁，大约60%的研究区域显示出中度到非常严重的侵蚀。另一方面，研究区域的40%被认为处于低侵蚀风险。受侵蚀风险高的地区多在陡峭的山坡上，那里降雨量大，岩石由泥灰岩和粘土组成。使用ROC（受试者工作特征）曲线评估结果的准确性。曲线下面积（AUC）为0.782，预测精度为78.2%。总之，这一模式证明是有效指导关于可持续水土管理的未来规划的宝贵工具，特别是通过解决土壤侵蚀问题。

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引用次数: 0

Source-to-sink history of detrital garnet from coastal dune sands in SW Mexico 墨西哥西南部海岸沙丘砂中石榴石碎屑的源-汇历史

Geosystems and Geoenvironment

Pub Date : 2025-05-01 Epub Date: 2025-03-22 DOI: 10.1016/j.geogeo.2025.100381

Lizeth Carlos Delgado , Juan J. Kasper-Zubillaga , Raymundo G. Martínez-Serrano , Mayumy Amparo Cabrera Ramírez , Elsa Arellano-Torres , José Luis Sánchez Zavala

A morphological and geochemical study of detrital garnet was conducted to assess its utility in understanding sedimentary processes in coastal dune sands caused by in a weathering-limited erosion regime along the southwestern coast of Mexico. Multiple analytical techniques helped to elucidate the garnet's provenance, shape modification and surface alteration during its source-to-sink sedimentary dispersal. A Wavelength Dispersive Spectrometry (WDS) in an Electron Microprobe Analyzer (EMPA) (n = 89) revealed the dominance of almandine as the main mineral type related to the ortho-paragneiss source rocks from the Oaxacan Complex with a lesser contribution from the Xolapa Complex, outcropping in northwestern of the coastal dune sands. Scanning Electron Microscopy (SEM) helped to assess the compactness and convexity of shape descriptors by contouring the outline of detrital garnet (n = 200) and to identify the microtextures of the mineral's surface. A Raman Spectroscopy (n = 17) was employed to determine the presence of hydroxide or oxyhydroxide coatings to quantify the chemical weathering degree caused by steady and shallow burial conditions. Results show that the detrital garnet mainly underwent aeolian abrasion followed by fluvial subaqueous and marine controls. The former was supported by the quantification of moderate to high compactness and convexity values and the SEM observation of aeolian mechanical microtextures like bulbous edges, adhering particles and abrasion fatigue compared to the subaqueous microtextures as large conchoidal fractures (>50 µm). Finally, we found that low to moderate chemical dissolution control modified the detrital garnet's surficial texture, evidenced by chemical microtextures like solution pits, etch pits, etch features, imbricate wedge marks and mound features. Hence, detrital garnet dissolution was dominated by its chemical composition, the nonstoichiometric character of the dissolution rate and its crystallographic forms.

对碎屑石榴石进行了形态和地球化学研究，以评估其在理解墨西哥西南海岸风化有限侵蚀机制引起的海岸沙丘砂沉积过程中的效用。多种分析技术有助于阐明石榴石在源-汇沉积扩散过程中的物源、形态修饰和表面蚀变。电子探针分析仪（EMPA）（n = 89）的波长色散光谱（WDS）分析显示，瓦哈卡杂岩的准副长烃源岩主要矿物类型为almandine，西北方滨海沙丘砂露头的Xolapa杂岩贡献较小。扫描电子显微镜（SEM）通过绘制碎屑石榴石（n = 200）的轮廓，帮助评估形状描述符的密实度和凹凸度，并识别矿物表面的微观纹理。采用拉曼光谱（n = 17）测定氢氧化物或氧化氢氧化物涂层的存在，以量化稳定和浅埋条件引起的化学风化程度。结果表明，碎屑石榴石主要受风蚀作用，其次受河流水下和海洋侵蚀作用。前者得到了中高密实度和凹凸度值的量化，以及与大贝壳状断裂（>50µm）的水下微织构相比，风成力学微织构（如球根边缘、粘着颗粒和磨损疲劳）的SEM观察的支持。结果表明，低至中等化学溶蚀控制改变了碎屑石榴石的表面结构，主要表现为溶液坑、蚀刻坑、蚀刻特征、瓦叠楔形痕迹和丘状特征等化学显微结构。因此，碎屑石榴石的溶解主要由其化学组成、溶解速率的非化学计量特征和晶体形态决定。

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引用次数: 0

The future of recycling for critical metals: The example of EV batteries 关键金属回收的未来：以电动汽车电池为例

Geosystems and Geoenvironment

Pub Date : 2025-05-01 Epub Date: 2025-03-03 DOI: 10.1016/j.geogeo.2025.100376

Yanyan Zhao, Gurpreet Kaur

Across the globe, the uptake of electric vehicles (EVs) has grown rapidly in recent years. With most EVs using lithium-ion batteries, there is a keen focus on the recovery of key battery metals: lithium (Li), nickel (Ni) and cobalt (Co), as well as graphite for the sustainable growth of the electric vehicle industry. This short review briefly introduces EV batteries, discusses EV battery recycling status and market outlook, recent technology advancement, challenges and opportunities and current government initiatives.

近年来，全球范围内电动汽车（EV）的使用率迅速增长。由于大多数电动汽车使用锂离子电池，因此人们非常关注关键电池金属：锂（Li）、镍（Ni）和钴（Co）以及石墨的回收，以促进电动汽车行业的可持续发展。本短评简要介绍了电动汽车电池，讨论了电动汽车电池回收现状和市场前景、最新技术进展、挑战和机遇以及当前的政府举措。

引用次数: 0

Geohazard impact and gas reservoir pressure dynamics in the Zagros Fold-Thrust Belt: An environmental perspective 扎格罗斯褶皱冲断带地质灾害影响与气藏压力动态：环境视角

Geosystems and Geoenvironment

Pub Date : 2025-05-01 Epub Date: 2025-03-07 DOI: 10.1016/j.geogeo.2025.100362

Mahsa Asghari , Zahra Maleki , Ali Solgi , Mohammad Ali Ganjavian , Pooria Kianoush

The Zagros Fold-Thrust Belt (ZFTB) presents a unique intersection of geohazards and gas reservoir dynamics, shaped by the ongoing tectonic activity resulting from the collision of the Arabian and Eurasian plates. This study aims to assess the risk of earthquake-induced landslides and their impact on gas reservoir pressure dynamics – with a particular focus on the Kabir Kuh gas field – identified as a critical area for monitoring due to its vulnerability to seismic events. A novel hybrid model is introduced that integrates geographic information system (GIS) mapping, decision support system (DSS) modeling, and machine learning algorithms. By analyzing a century's worth of seismic data alongside real-time environmental parameters, the model demonstrates a predictive accuracy of 92% using Random Forest algorithms, significantly outperforming traditional methods. The findings reveal a strong correlation between seismic activity and fluctuations in gas reservoir pressure, with an average pressure change of ±150 psi observed during significant seismic events. A landslide susceptibility map was generated, pinpointing regions that require proactive management strategies, particularly where significant landslide potential threatens gas field stability. Identifying the Seymareh landslide as a monumental geological event underscores the impact of landslide hazards on gas field integrity. This research emphasizes the integration of advanced predictive techniques into seismic risk assessments, providing actionable insights for the sustainable gas reservoir management in seismically active regions. The necessity for continuous monitoring and the implementation of advanced geotechnical measures are highlighted as essential components of effective geohazard management. This study contributes to understanding the interplay between seismic hazards and gas reservoir dynamics, offering a comprehensive framework for future research and practical applications in risk management and environmental sustainability.

扎格罗斯褶皱冲断带（ZFTB）呈现出独特的地质灾害和天然气储层动力学的交叉点，由阿拉伯板块和欧亚板块碰撞引起的持续构造活动形成。这项研究的目的是评估地震诱发滑坡的风险及其对气藏压力动态的影响——特别关注Kabir Kuh气田——由于容易受到地震事件的影响，该气田被确定为一个需要监测的关键区域。提出了一种融合地理信息系统（GIS）制图、决策支持系统（DSS）建模和机器学习算法的新型混合模型。通过分析一个世纪以来的地震数据和实时环境参数，该模型使用随机森林算法的预测精度达到92%，显著优于传统方法。研究结果表明，地震活动与气藏压力波动之间存在很强的相关性，在重大地震事件期间观察到的平均压力变化为±150 psi。生成了滑坡易感性图，确定了需要采取主动管理策略的区域，特别是那些严重滑坡潜在威胁气田稳定的区域。将Seymareh滑坡确定为重大地质事件，凸显了滑坡灾害对气田完整性的影响。本研究强调将先进的预测技术整合到地震风险评估中，为地震活跃地区的可持续气藏管理提供可操作的见解。持续监测和实施先进岩土技术措施的必要性被强调为有效的地质灾害管理的重要组成部分。这项研究有助于理解地震灾害与气藏动态之间的相互作用，为未来的研究和风险管理和环境可持续性的实际应用提供了一个全面的框架。

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引用次数: 0

Geospatial assessment of soil erosion in the Basantar and Devak watersheds of the NW Himalaya: A study utilizing USLE and RUSLE models 西北喜马拉雅Basantar和Devak流域土壤侵蚀的地理空间评价：基于USLE和RUSLE模型的研究

Geosystems and Geoenvironment

Pub Date : 2025-05-01 Epub Date: 2025-01-29 DOI: 10.1016/j.geogeo.2025.100355

Ajay Kumar Taloor , Varun Khajuria , Gurnam Parsad , Shikha Bandral , Sugandha Mahajan , Sachchidanand Singh , Meenakshi Sharma , Girish Ch Kothyari

Soil erosion poses a substantial threat to environmental and human sustainability, intensified by anthropogenic interference, climate fluctuations, and socio-economic modifications. This study presents a meticulous and systematic analysis of soil erosion within the Basantar and Devak watersheds of the north-western Himalaya, employing geospatial technologies integrated with the USLE (Universal Soil Loss Equation) and RUSLE (Revised Universal Soil Loss Equation) modeling techniques. To derive the USLE and RUSLE based soil loss, various equation-based parameters such as rainfall (R), length slope factor (LS), cover management (C), conservation practice factor (P), and slope erodibility factor (K) were derived to assess the spatial soil loss in the study area. Based on both model outputs spatial maps have been derived in the Geographic Information System (GIS) platform to determine the soil loss in the study area. The results have been classified into five categories: very high, high, medium, low, and very low areas of soil erosion. Further, the analytical approach also involved the derivation of various satellite data-based soil indices to juxtapose remotely sensed soil loss results, enabling a more detailed understanding of soil loss dynamics in the watersheds. The comprehensive analysis demonstrated the practicality of the employed models in formulating geospatial soil erosion databases, aiding future research, planning, conservation strategies, and climate impact assessment, therefore, laying a foundation for informed environmental decision-making and sustainable land-use practices. The multifaceted exploration of soil erosion in the Basantar and Devak watersheds through intricate modeling and geospatial technologies accentuates the study's significance in advancing soil conservation research, and the potential applications of these models in varied environmental contexts.

土壤侵蚀对环境和人类的可持续性构成重大威胁，人为干扰、气候波动和社会经济变化加剧了这一威胁。本研究采用地理空间技术，结合USLE（通用土壤流失方程）和RUSLE（修订通用土壤流失方程）建模技术，对喜马拉雅西北部Basantar和Devak流域的土壤侵蚀进行了细致而系统的分析。为了得到基于USLE和RUSLE的土壤流失量，推导了基于降雨(R)、长度坡度因子（LS）、覆盖管理(C)、保护实践因子(P)和坡度可蚀性因子(K)等方程参数，对研究区空间土壤流失量进行了评价。基于这两种模型的输出，在地理信息系统（GIS）平台上导出了空间图，以确定研究区域的土壤流失量。结果被划分为5类：非常高、高、中、低和非常低的土壤侵蚀区。此外，该分析方法还包括推导各种基于卫星数据的土壤指数，以并列显示遥感土壤流失结果，从而更详细地了解流域土壤流失动态。综合分析表明，所采用的模型在建立地理空间土壤侵蚀数据库方面具有实用性，有助于未来的研究、规划、保护策略和气候影响评估，从而为明智的环境决策和可持续的土地利用实践奠定基础。通过复杂的建模和地理空间技术，对Basantar和Devak流域的土壤侵蚀进行了多方面的探索，强调了该研究在推进土壤保持研究中的重要性，以及这些模型在不同环境背景下的潜在应用。

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引用次数: 0

Mapping of hematite ore deposits using multi-sensor data in the Sekota District, Northern Ethiopia 在埃塞俄比亚北部Sekota地区使用多传感器数据绘制赤铁矿矿床图

Geosystems and Geoenvironment

Pub Date : 2025-05-01 Epub Date: 2025-03-27 DOI: 10.1016/j.geogeo.2025.100385

Jerbaw Tiruneh Abejehu , Binyam Tesfaw Hailu , Worash Getaneh , Karuturi Venkata Suryabhagavan

Iron plays a vital role in fueling the economic development and technological advancement of a country. Despite Ethiopia, being endowed with a large amount of iron ore resources in different parts of the country, prospective zones are not delineated properly. Therefore, this study aims to identify the iron ore prospective zones in the Sekota district of Ethiopia utilizing ASTER and Sentinel−2A satellite data for further onsite exploration and testing. In addition, powder diffraction analysis (XRD) was conducted to determine the dominant mineralogical phases. The image processing techniques such as ASTER band 2/band 1 (ASB2/B1) and Sentinel−2A band 4/band 2 (S2B4/B2) band ratios, principal component analysis (PCA), and subpixel level mapping technique, mixture-tuned matched filtering (MTMF) were used to map the distribution of hematite. ASB2/B1 and S2B4/B2 band ratios mapped hematite iron ore covering an area of 102.50 and 97. 68 km². The selected PC4 of ASTER delineated hematite mineralized zones covering 133.40 km² and Sentinel 2 PC3 of 110.70 km² area. A very high spectral feature fit was found between the extracted hematite endmember and USGS resampled hematite spectra. The spectral fit of the endmember was 0.74 for ASTER and 0.86 for Sentinel−2. Hematite anomaly zones were identified with MTMF using these endmembers in different parts of the study area. Powder X-ray diffraction analysis (XRD) revealed high hematite phases ranging from 36.8%−85.5% of Fe₂O₃. A strong positive correlation was found between S2B4/B2 and S2B4/B2 (r = 0.83), ASB2/B1 and ASTER PC4 (r = 0.94). Moderate correlations for ASB2/B2, S2B4/B2 (r = 0.44), PCA (r = 0.44), ASTER and Sentinel−2 MTMF (r = 0.36). Results of both datasets show comparable areal coverage and overlay with three of the existing known iron occurrence polygons. Thus, it is evident that techniques employed are effective in narrowing hematite anomalies zones for further onsite gological exploration.

铁在推动一个国家的经济发展和技术进步方面发挥着至关重要的作用。尽管埃塞俄比亚各地蕴藏着大量铁矿石资源，但远景区的划分却不尽合理。因此，本研究旨在利用 ASTER 和 Sentinel-2A 卫星数据确定埃塞俄比亚 Sekota 地区的铁矿远景区，以便进一步进行现场勘探和测试。此外，还进行了粉末衍射分析（XRD），以确定主要矿物相。利用 ASTER 波段 2/波段 1（ASB2/B1）和 Sentinel-2A 波段 4/波段 2（S2B4/B2）波段比、主成分分析（PCA）和亚像素级绘图技术、混合调谐匹配滤波（MTMF）等图像处理技术绘制赤铁矿分布图。ASB2/B1 和 S2B4/B2 波段比绘制的赤铁矿面积分别为 102.50 平方公里和 97.68 平方公里。68 平方公里。所选的 ASTER PC4 划定的赤铁矿化区面积为 133.40 平方公里，哨兵 2 PC3 划定的赤铁矿化区面积为 110.70 平方公里。提取的赤铁矿内含物与 USGS 重新采样的赤铁矿光谱之间具有很高的光谱特征拟合度。ASTER 和 Sentinel-2 分别为 0.74 和 0.86。在研究区域的不同地方，利用这些内含物通过 MTMF 确定了赤铁矿异常区。粉末 X 射线衍射分析（XRD）显示，赤铁矿相占 Fe2O3 的 36.8%-85.5%。发现 S2B4/B2 和 S2B4/B2 （r = 0.83）、ASB2/B1 和 ASTER PC4 （r = 0.94）之间存在很强的正相关性。ASB2/B2、S2B4/B2（r = 0.44）、PCA（r = 0.44）、ASTER 和 Sentinel-2 MTMF（r = 0.36）之间的相关性中等。这两个数据集的结果显示出相似的区域覆盖率，并与现有的三个已知铁矿分布多边形重叠。由此可见，所采用的技术能有效缩小赤铁矿异常区，以便进一步进行现场地质勘探。

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引用次数: 0

Introduction: Special Issue on critical metals for clean energy transition 引言：清洁能源转型的关键金属特刊

Geosystems and Geoenvironment

Pub Date : 2025-05-01 Epub Date: 2025-03-24 DOI: 10.1016/j.geogeo.2025.100382

Jie Zhou , David I. Groves

引用次数: 0

Exploration of iron ore deposits in parts of Kogi State, northcentral Nigeria: Analyses from airborne magnetic and ASTER datasets 尼日利亚中北部科吉州部分地区铁矿床勘探：航空磁和ASTER数据集分析

Geosystems and Geoenvironment

Pub Date : 2025-05-01 Epub Date: 2025-02-09 DOI: 10.1016/j.geogeo.2025.100359

Ayokunle Adewale Akinlalu

Kogi State is known for its iron ore deposits, and Kakanda township is one of those places that possess iron ore deposits. However, little information about the extent and locations of possible iron ore mineralized zones is available due to limited research in that area. Hence, this study utilized aeromagnetic and Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) datasets for the delineation of ironstone and banded iron deposits comprising magnetite and hematite in Kakanda and its environs in Kogi State, northcentral Nigeria. Enhancement techniques such as residual magnetic amplitude and analytic signal amplitude carried out on the aeromagnetic data revealed the concentration of iron ore deposits, especially in the southern, eastern and western parts of the study area. This finding is consistent with signatures derived from other data enhancement techniques involving the total horizontal derivative, tilt derivative and 3D Euler deconvolution techniques, which are principally used to map structures guiding mineralization in the study area. Furthermore, analyses of the ASTER dataset using true and false color composites and combinations of band ratios indicate the occurrence of iron oxide and clay alterations related to iron ore mineralization in the study area. The signatures related to iron ore mineralization in the aeromagnetic data and ASTER dataset are consistent with each other. The overlap of these signatures was used to produce the iron ore prospectivity map of the study area. The study showed that areas of delineated lineament coincide with areas of iron ore mineralization. In the same vein, areas of dense lineaments coincide with areas of iron ore mineralization, especially in the southern and eastern parts of the study area. Therefore, the mineralization in the study area is structurally controlled. The iron ore prospectivity map produced will serve as reference for mineral explorationists in the area to engage in targeted exploration, rather than random exploration and exploitation especially in developing countries which impacts the environment negatively. Hence, further exploration activities involving electrical resistivity and gravity surveys and geochemical studies should focus on areas where there is an evident overlap of lineament and signatures reflecting iron ore mineralization in the study area.

科吉州以其铁矿而闻名，卡坎达镇是拥有铁矿的地方之一。但是，由于在这方面的研究有限，关于可能的铁矿化带的范围和位置的资料很少。因此，本研究利用航空磁和先进的星载热发射反射辐射计（ASTER）数据集来圈定尼日利亚中北部科吉州Kakanda及其周边地区的铁矿和带状铁矿床，包括磁铁矿和赤铁矿。对航磁资料进行残磁幅值、分析信号幅值等增强技术，揭示了研究区南部、东部和西部的铁矿密集度。这一发现与其他数据增强技术（包括总水平导数、倾斜导数和三维欧拉反褶积技术）所获得的特征一致，这些技术主要用于绘制研究区引导成矿的构造。此外，利用真假色组合和带比组合对ASTER数据集进行分析，表明研究区存在与铁矿成矿有关的氧化铁和粘土蚀变。航磁资料与ASTER资料中铁矿成矿相关特征基本一致。利用这些特征的重叠绘制了研究区铁矿远景图。研究表明，圈定的界线区与铁矿成矿区重合。在同一矿脉中，密集的矿化区与铁矿成矿区重合，特别是在研究区南部和东部。因此，研究区成矿受构造控制。制作的铁矿石远景图将作为该地区矿产勘探人员进行有针对性的勘探的参考，而不是在发展中国家进行对环境有负面影响的随意勘探和开采。因此，包括电阻率和重力测量以及地球化学研究在内的进一步勘探活动应集中在研究区内具有明显重叠的地貌和反映铁矿成矿作用的特征的地区。

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引用次数: 0

Petrogenesis and tectonic setting of Neoarchean K-rich granitoids in the Zhulagou area: Implications for the crustal maturation of Yinshan Block, western North China Craton 朱拉沟地区新太古代富钾花岗岩成因及构造背景：华北克拉通西部阴山地块地壳成熟的指示意义

Geosystems and Geoenvironment

Pub Date : 2025-05-01 Epub Date: 2025-03-30 DOI: 10.1016/j.geogeo.2025.100384

Xiao Wang , Jin Liu , Hai Zhou , Xiaoguang Liu , Chenying Yu , Shuhui Zhang , Jian Zhang

K-rich granitoids are considered as an indicator of the maturation of the continental crust, particularly in correlation to the significant crustal evolution during the Neoarchean Eon. The Yinshan Block, a typical Neoarchean microcontinental block of the western North China Craton (NCC), preserves several typical K-rich granites (monzogranitic gneisses). However, their petrogenesis and tectonic background of these remain unclear, hindering our understanding of the late Neoarchean crustal evolution of the NCC. This study presents new geochronological, geochemical, and Sr-Nd-Pb-Hf isotopic data on the K-rich granites exposed in the Zhulagou area, a key exposure of the Yinshan Block. Zircon U–Pb dating results suggest that the K-rich granites were emplaced at 2.52–2.50 Ga. The K-rich granites exhibit high SiO₂ (68.70–74.10 wt. %) and K₂O (3.40–7.79 wt. %) and lower MgO (0.24–1.04 wt. %) content. They also have high Sr/Y and (La/Yb)_N ratios, as well as low Y and Yb contents. Furthermore, they display variable ε_Hf(t) (–1.1 to +2.5) and ε_Nd(t) (–6.05 to +1.64) values, with relatively low Pb isotopes (²⁰⁶Pb/²⁰⁴Pb_(t) = (13.910485–15.241164), ²⁰⁷Pb/²⁰⁴Pb_(t) = (14.806723–15.259938), and ²⁰⁸Pb/²⁰⁴Pb_(t) = (33.758621–35.592727)), indicating that their parental magmas may have originated from the partial melting of a thickened lower crust with heterogeneous sources. Combined with previous data, we suggest that a pulse or stage of mantle plume may have been operating under the Yinshan Block during late Neoarchean period. The pre-existing thickened (mafic) lower crust was partially melted to generate these K-rich granites at 2.52–2.50 Ga, resulting in a mature and stable continental crust.

富钾花岗岩类被认为是大陆地壳成熟的标志，特别是与新太古代的地壳演化有关。阴山地块是华北克拉通西部一个典型的新太古代微大陆地块，保留了几种典型的富钾花岗岩（二花岗质片麻岩）。然而，它们的岩石成因和构造背景尚不清楚，这阻碍了我们对华北盆地新太古代晚期地壳演化的认识。本文对银山地块关键出露点珠拉沟地区富钾花岗岩进行了年代学、地球化学和Sr-Nd-Pb-Hf同位素研究。锆石U-Pb定年结果表明，富钾花岗岩的侵位时间为2.52 ~ 2.50 Ga。富钾花岗岩SiO2 （68.70 ~ 74.10 wt. %）、K2O （3.40 ~ 7.79 wt. %）含量高，MgO （0.24 ~ 1.04 wt. %）含量低。Sr/Y和（La/Yb）N比值较高，Y和Yb含量较低。此外，它们的εHf(t)（-1.1 ~ +2.5）和εNd(t)（-6.05 ~ +1.64）值变化较大，Pb同位素相对较低(206Pb/204Pb(t) = (13.910485 ~ 15.241164), 207Pb/204Pb(t) = (14.806723 ~ 15.259938), 208Pb/204Pb(t) =(33.758621 ~ 35.592727))，表明它们的母岩浆可能来源于非均质源加厚下地壳的部分熔融。结合前人资料，我们认为在新太古代晚期，阴山地块下可能存在一个地幔柱脉冲或阶段。在2.52 ~ 2.50 Ga，原有的增厚（基性）下地壳部分熔融生成富钾花岗岩，形成成熟稳定的大陆地壳。

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