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Assessment of groundwater quantity, quality, and associated health risk of the Tano river basin, Ghana
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作者 Adwoba Kua-Manza Edjah Bruce Banoeng-Yakubo +6 位作者 Anthony Ewusi Enoch Sakyi-Yeboah David Saka Clara Turetta Giulio Cozzi David Atta-Peters Larry Pax Chegbeleh 《Acta Geochimica》 EI CAS CSCD 2024年第2期325-353,共29页
In the Tano River Basin,groundwater serves as a crucial resource;however,its quantity and quality with regard to trace elements and microbiological loadings remain poorly understood due to the lack of groundwater logs... In the Tano River Basin,groundwater serves as a crucial resource;however,its quantity and quality with regard to trace elements and microbiological loadings remain poorly understood due to the lack of groundwater logs and limited water research.This study presents a comprehensive analysis of the Tano River Basin,focusing on three key objectives.First,it investigated the aquifer hydraulic parameters and the results showed significant spatial variations in borehole depths,yields,transmissivity,hydraulic conductivity,and specific capacity.Deeper boreholes were concentrated in the northeastern and southeastern zones,while geological formations,particu-larly the Apollonian Formation,exhibit a strong influence on borehole yields.The study identified areas with high transmissivity and hydraulic conductivity in the southern and eastern regions,suggesting good groundwater avail-ability and suitability for sustainable water supply.Sec-ondly,the research investigated the groundwater quality and observed that the majority of borehole samples fall within WHO(Guidelines for Drinking-water Quality,Environmental Health Criteria,Geneva,2011,2017.http://www.who.int)limit.However,some samples have pH levels below the standards,although the groundwater generally qualifies as freshwater.The study further explores hydrochemical facies and health risk assessment,highlighting the dominance of Ca–HCO3 water type.Trace element analysis reveals minimal health risks from most elements,with chromium(Cr)as the primary contributor to chronic health risk.Overall,this study has provided a key insights into the Tano River Basin’s hydrogeology and associated health risks.The outcome of this research has contributed to the broader understanding of hydrogeologi-cal dynamics and the importance of managing groundwater resources sustainably in complex geological environments. 展开更多
关键词 GROUNDWATER Unsupervised machine learning technique HYDROCHEMISTRY Aquifer hydraulic parameter Health risk
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Characteristics of Gold Mineralization at the Baguiomo Gold Panning Site, Koudougou Region, Burkina Faso, West Africa
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作者 Pascal Ouiya Aziz Fayçal Tarnagda Martial Eric Fozing 《Open Journal of Geology》 CAS 2024年第1期1-18,共18页
The Birimian Baguiomo formations are located in the northern part of the Boromo greenstone belt. In this belt, the volcanic rocks (tholeiitic basalt, calcalkaline basalt, andesite) hosting the gold mineralization are ... The Birimian Baguiomo formations are located in the northern part of the Boromo greenstone belt. In this belt, the volcanic rocks (tholeiitic basalt, calcalkaline basalt, andesite) hosting the gold mineralization are located in the Kwademen-Baguiomo shear zone. This mineralization, located only a few kilometers from the Kwademen gold deposit, is uncharacterized and, together with the latter, could constitute a gold potential capable of being economically exploitable. It is in this sense that this work is carried out with a view to characterizing the gold mineralization of the Baguiomo gold panning site. To carry out this work, we have made direct field measurements, combined with microstructures, and combined all this with data from geochemical rock analysis of the basalts that are the main host formations. Geochemical data show that tholeitic basalts formed from a mantle plume that was emplaced in an oceanic plateau context. Calc-alkaline basalts and andesites are comparable to Paleoproterozoic tholeitic basalts (PTH3), which are slightly enriched in light rare earths. Fertility tests show that these basalts concentrate between 3 and 6 ppb of gold at the time of accretion, which is sufficient for remobilization of this primary gold during the Eburnian orogeny to yield a deposit of around 4 - 5 Moz. Gold mineralization is associated with pyrite crystals when the latter are disseminated in the rock mass, whereas it is associated with hematite in quartz veins concordant with S1 shear deformation. It is mainly the pyrite crystals in the pressure shadows that contain the gold grains, whose development would be synchronous with micro-shear zone reactivation during the first phase of D1<sub>B</sub> deformation. The second phase of D2<sub>B</sub> deformation, which is a crenulation or fracture schistosity, does not significantly affect the shear deformation that controls mineralization. 展开更多
关键词 Kwademen-Baguiomo Shear Zone Gold Panning Site Gold Mineralization Eburnian Orogeny
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Geochemistry and multivariate statistical evaluation of major oxides, trace and rare earth elements in coal occurrences and deposits around Kogi east, Northern Anambra Basin, Nigeria 被引量:7
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作者 E.G.Ameh 《International Journal of Coal Science & Technology》 EI 2019年第2期260-273,共14页
The Cretaceous Mamu Formation coal samples located within the Northern Anambra Basin were collected, analysed and interpreted using multivariate statistical approach to determine the major, trace and rare elements ass... The Cretaceous Mamu Formation coal samples located within the Northern Anambra Basin were collected, analysed and interpreted using multivariate statistical approach to determine the major, trace and rare elements association with a view to determine the source of the terrestrial rocks, palaeoweathering/climatic conditions and tectonic setting. The dominant oxides such as SiO2, A12O3, Fe2O3, TiO2 and CaO were identified in the coal to suggest terrigenous origin. The ratio of SiO2/Al2O3 of 4.8 suggests that the coal was formed from low land peat associated with freshwater continental marine or blackish water with low salinity as indicated by Sr/Ba and CaO + MgO/K2O + Na2。ratios. The major oxides also revealed stable condition of deposition, low degree of tectonic setting but constant subsidence in the basin. The condition of deposition was acidic in nature as indicated by TiO2/Zr plot. Based on the abundance of Zr, Zn, Ba, Ni, Co, Sr, V, and Y, moderate salinity, sub-oxic to oxic bottom water condition was prevalent and also indication of marine influence. Based on the ratios of La/Yb;La/Sm and Gd/Yb, LREE has higher enrichment than HREE. Humid climatic conditions were observed at the coal formation stage while weak laterization to kaolinization was also evidence. 展开更多
关键词 Kogi EAST MULTIVARIATE Factor and cluster Varimax Eucledean
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Spatial variation of coda wave attenuation using aftershocks of the Al Hoceima earthquake of 24 February, 2004, Morocco 被引量:1
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作者 Abderrahim Boulanouar Lahcen El Moudnib +4 位作者 Mimoun Harnafi Taj-Eddine Cherkaoui Abdelaali Rahmouni Mohamed Boukalouch Jamal Sebbani 《Natural Science》 2013年第8期72-77,共6页
On 24th February 2004 a significant earthquake (Md = 6.4) occurred in the north of Moroccocausing great damage in the vicinity of Al Hoceima region. This area is characterized by a complex faulting system as a result ... On 24th February 2004 a significant earthquake (Md = 6.4) occurred in the north of Moroccocausing great damage in the vicinity of Al Hoceima region. This area is characterized by a complex faulting system as a result of compressional tectonic forces. Three short period seismic stations are set in this area of interest and recordings from these stations were used in this study. In order to complete our knowledge of attenuation, 60 local earthquakes are recorded a few days after the great earthquake with magnitude Ml 2.6 - 5.0 to estimate seismic attenuation. For this purpose, we applied the single backscattering model of Aki & Chouet 1975 inthe frequency range for 1 to 8 Hz. The study of coda waves was limited to a relatively short lapse time (20 Seconds) in order to sample the earth’s crust only. The values of Qc estimated for all the three stations show a strong frequency dependent relationship of the form Qc = Q0fn, where Q0 is Qc at 1 Hz , and n represents the degree of frequency dependence, and reflects the level of crustal heterogeneities to varying degrees. The average frequency dependent attenuation relationship has been obtained which indicates that the attenuation is high in this region. Finally to conclude our work, the values of Q0 suggest that Al Hoceima area is highly heterogeneous and the n parameter indicates a meaning frequency dependence of Qc. 展开更多
关键词 ATTENUATION CODA Waves Single Backscattering Model AL Hoceima Morocco Seismic EARTHQUAKE
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Zircon SHRIMP U–Pb geochronology,geochemistry,and geological significance of dacite in the Zhesang gold district,southeast Yunnan Province,China 被引量:1
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作者 Bo Wang Jiasheng Wang +3 位作者 Jinlong Li Hao Fu Yuehua Ma Bin Ye 《Acta Geochimica》 EI CAS CSCD 2023年第2期290-308,共19页
The Late Paleozoic and Mesozoic tectonic framework of the Nanpanjiang Basin has much been disputed.Herein,the middle-acid volcanic rock,dacite,exposed to the Zhesang gold district,southeast Yunnan Province,has been an... The Late Paleozoic and Mesozoic tectonic framework of the Nanpanjiang Basin has much been disputed.Herein,the middle-acid volcanic rock,dacite,exposed to the Zhesang gold district,southeast Yunnan Province,has been analyzed.The results show that the dacite belongs to a calc-alkaline series,SiO_(2)contents range from 62.79 to 76.66 wt%.Zircon SHRIMP U–Pb dating of dacite demonstrates that they were formed in the Early Triassic(247.8±1.7 Ma,MSWD=1.2).All samples exhibit enrichment in LILE(e.g.Rb,K,Th,and U),and depletion in HFSE(e.g.Nb,Ta,and Ti),which has the geochemical affinity of I-type granite.La–La/Sm and La–La/Yb discrimination diagrams show that the partial melting,mainly of the mafic lower crust,of rocks,plays a major role in the formation process.The dacite has low initial ^(87)Sr/^(86)Sr ratios(0.706954 to 0.708589)and negative ε_(Nd)(t)values(-11.77 to-10.88).Zircons in dacite have ε_(Hf)(t)values of-16.2 to-8.3,and the two-stage Hf model ages are 1799–2301 Ma,mostly concentrated between 1800 and 1900 Ma,indicating that the magma source area is the reconstructed ancient lower crust mixed with some mantle materials,and crystal fractionation process underwent in the late stage of magma migration.This study reveals that the arc-volcanic rocks of the Early Triassic in the southern margin of the Nanpanjiang Basin were formed by the subduction of the Late Paleozoic ocean basin within the border region between China and Vietnam. 展开更多
关键词 DACITE Zircon SHRIMP U–Pb geochronology Sr–Nd–Hf isotope GEOCHEMISTRY Arcvolcanic rock Late Paleozoic ocean basin
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From landslide characterization to nature reserve management:The“Scialimata Grande di Torre Alfina”landslide Geosite(Central Apennines,Italy)
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作者 Gianluca TRONTI Francesca VERGARI +4 位作者 Irene Maria BOLLATI Filippo BELISARIO Maurizio DELMONTE Manuela PELFINI Paola FREDI 《Journal of Mountain Science》 SCIE CSCD 2023年第3期585-606,共22页
Italy is characterized by widespread geomorphological instability,among which landslides leave impressive marks on the landscape.Nevertheless,landslide bodies may represent key sites for thematic and educational itine... Italy is characterized by widespread geomorphological instability,among which landslides leave impressive marks on the landscape.Nevertheless,landslide bodies may represent key sites for thematic and educational itineraries,especially in protected areas,where their management becomes an important issue.Our study focuses on the"Monte Rufeno Nature Reserve"(Central Apennines,Italy),where iconic landslides are present.Here,the"Scialimata Grande di Torre Alfina"landslide(SGTA)is listed in the regional Geosite database.This work aims to propose a multiscale procedure for landslide analysis,in terms of both hazard sources but also educational and geoheritage enhancement opportunities in natural reserves.After performing a Landslide Susceptibility conditional Analysis(LSA)for the reserve territory,attention was focused on the SGTA,to define properly its features and morphodynamics.A multi-disciplinary approach was adopted,by applying both remote sensing(UAV structure from motion,Photointerpretation)and field survey(geomorphological and GPS monitoring).From the LSA,based on drainage density,curvature,and slope triggering factors,the road and trail susceptibility maps were derived,as base tools for future risk assessments and trail paths management within the reserve.At the SGTA scale,the monitoring showed a displacement of up to 23 m during the time interval between 2015 and 2018.The landslide dynamics seem to be driven by alternating dry and extremely wet periods;moreover,leaks from the aqueduct in the detachment area and piping effects through clays may have also decreased the substrate cohesion.The SGTA complex influence on the Paglia River valley geometry was also hypothesized,underlining the action of landslide through different spatial scales(on-site and off-site)and on different environment features(sediment connectivity,hydrology).Finally,the SGTA appears highly representative of the geomorphic dynamics within the Nature Reserve(i.e.,scientific value)and it could be classified as an active geosite.Since the site was featured by a tourist trail,adequate management strategies must be adopted,considering the educational value and safety issues. 展开更多
关键词 LANDSLIDES GEOHERITAGE Geosites Nature reserves management UAV structure from motion Landslides conditional analyses
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Comprehensive Review on Air Pollution Control Measures for Non-Attainment Cities of Uttar Pradesh, India
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作者 Khyati Sharma Anchal Garg Varun Joshi 《Journal of Environmental Protection》 CAS 2023年第3期139-162,共24页
Introduction: The Indian state of Uttar Pradesh (UP) for the past many years has been reported to have many cities with highly polluted air quality. The state has been taking meticulous steps in combating air pollutio... Introduction: The Indian state of Uttar Pradesh (UP) for the past many years has been reported to have many cities with highly polluted air quality. The state has been taking meticulous steps in combating air pollution in the form of action plans, introduced especially in its 17 non-attainment cities (NAC). To assess the progress and development of these action plans in UP, the present study has done an in-depth analysis and review of the state’s action plans and city micro action plans. Materials and Methods: In this research study, the analysis of the latest action plan reports, micro action plan reports as well as the recommendations for combating air pollution-related issues in the 17 NAC of the UP state has been well documented. Uttar Pradesh Pollution Control Board (UPPCB) has prepared these reports to highlight the progress of the plans in response to the growing air pollution in these cities. The information present in the reports has been used to further study sector-specific, category-specific action plans, institutional responsibility, and the present status of the action plans. Results: On average, the highest weightage in action plans was given to sector-specific categories such as Road dust and construction activities (24%). It was also observed that Urban local bodies (~50%) were majorly responsible to implement the action points and 56% of the action points were jointly implemented by multiple agencies. 展开更多
关键词 Air Pollution Air Quality Air Pollution Control Non-Attainment Cities INDIA Uttar Pradesh Particulate Matter
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Lamprophyre Rocks in the Nassara Gold Deposit, Southwest Burkina Faso: Characteristics and Implication for Mining Exploration
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作者 Pascal Ouiya Adama Ouédraogo Yaméogo +1 位作者 Sâga Sawadogo Séta Naba 《Open Journal of Geology》 2023年第12期1291-1311,共21页
The lamprophyres are late dykes that cut the formations hosting the gold mineralization in the Nassara deposit. They are geographically and spatially related to most orogenic gold deposits. It is with the aim of chara... The lamprophyres are late dykes that cut the formations hosting the gold mineralization in the Nassara deposit. They are geographically and spatially related to most orogenic gold deposits. It is with the aim of characterizing them and seeing their implications for exploration that this work is carried out. To achieve our objective, petrographic studies and chemical analyses of minerals (pyroxenes, amphiboles, feldspars, chromite) and geochemical analyses of total rock were carried out. These studies have enabled us to classify the Nassara lamprophyres as calc-alkaline lamprophyres of the spessartite type. The Cr, Co, Ni and Mg enrichment of these rocks would indicate a depleted mantle source, with LILE enrichment by fluids probably related to metasomatic activity. The various diagrams show that they are depleted in HREE and enriched in LREE. The high Nb/Ta ratios in our data indicate metasomatic activity probably linked to amphibole and rutile in the mantle prior to melting. The geodynamic context of spessartite-type lamprophyres indicates a signature linked to late-orogenic to post-collisional subduction. They are late-orogenic to post-collisional lamprophyres enriched in compatible elements (Cr, Ni, Co) and display a negative Ta-Nb-Ti (TNT) anomaly. The frequent association of these lamprophyre dykes with the deposits does not indicate the source of the gold for these deposits, but rather zones of crustal permeability capable of draining hydrothermal fluids at the time of emplacement. Good mapping of lamprophyre dykes, especially in shear zones, could therefore guide prospecting and identify potential zones of hydrothermal fluid circulation. 展开更多
关键词 Nassara Calc-Alkaline Lamprophyre Metasomatic Activity LILE HREE LREE
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Predicting Groundwater Level Using Climate Change Scenarios in the Southern Part of Mali
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作者 Oumou Diancoumba Adama Toure +3 位作者 Souleymane Keita Sériba Konare Zakari Mahamadou Mounir Hamadoun Bokar 《American Journal of Climate Change》 2023年第1期21-38,共18页
Groundwater is mainly demanded in all the activities for the population of the southern part especially in the Koda catchment, the studied area. These resources are affected by various factors especially climate chang... Groundwater is mainly demanded in all the activities for the population of the southern part especially in the Koda catchment, the studied area. These resources are affected by various factors especially climate change. Therefore, knowing the impact of projected climate change on groundwater recharge is an important issue for water resources management, especially for those responsible for the Koda catchment. In this work, the impact of climate change on groundwater resources in the study area in Mali, West Africa is investigated. The Hydrogeological modeling was performed using the Gardenia model, and the monthly precipitation and temperature data were used as the Baseline. These data considered the past 30-year period (1987-2016) and the projections for the next 30 years (2021-2050). Projected precipitation and air temperatures, extracted from the Rossby Centre regional Atmospheric climate model (RCA 4) statistically downscaled from the GCM-IHEC-EC-EARTH and the GCM-MPI-M-MPI-ESM-LR under the Representative Concentration Pathways RCP 4.5 and RCP 8.5 and corrected with the Multiscale Quantile Mapping bias correction method, were used as input data to the gardenia model. Potential evapotranspiration (PET) values estimated from Blaney Criddle method and groundwater levels measured in three piezometers were used to calibrate the Gardenia model. The outputs display the reduction of groundwater level in the three piezometers in the Koda catchment for all the two Regional Climate Models (RCMs) during the periods of rainy season from July to October. From the results of GCM IHEC-EC-EARTH, the projected decline in GWL reaches 1.09 m for the RCP 4.5 and it up to 1.26 m for the RCP 8.5 in the study area while the GCM MPI-M-MPI-ESM-LR presentes the decline in groundwater level (GWL) during winter season from about 0.62 m for the RCP 4.5 up to 1.93 m for the RCP 8:5. Both RCMs project a reduction trend of groundwater recharge over time. It is noticeable that this decline is greater in RCP8.5 for all the three piezometers. The results also show that the average groundwater recharge (90 mm) in the future (2021-2050) is lower (180 mm) than that of the current drought (1987-2016), which could lead to severe drought events. The projected impacts of climate change would have a significant impact on groundwater in the period of 2029-2039;this situation could have a negative impact the socioeconomic activities especially on agriculture, which depends on water resources. The results will help also to take some adaptation measures to climate change, the famers could have a possibility to know the period of groundwater recharge where they have more water infiltration therefore, where to seek crops that need less or more water. The study area presents numerous potential of groundwater, the results could be a tool for groundwater management and to determine the favorable sites to implant new boreholes. 展开更多
关键词 Climate Change RCM-GCMs GROUNDWATER Projection MALI
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节理网络有限元在倾倒斜坡稳定分析中的应用 被引量:13
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作者 宋彦辉 黄民奇 孙苗 《岩土力学》 EI CAS CSCD 北大核心 2011年第4期1205-1210,共6页
节理网络有限元是指具有节理网络模拟功能的有限元,它不但能将野外节理统计特征直接输入到模型中,同时允许节理按一定的破坏准则产生屈服,从而较好地模拟边坡的实际结构及破坏特征。论述了倾倒变形边坡的分析方法及存在的问题,介绍了节... 节理网络有限元是指具有节理网络模拟功能的有限元,它不但能将野外节理统计特征直接输入到模型中,同时允许节理按一定的破坏准则产生屈服,从而较好地模拟边坡的实际结构及破坏特征。论述了倾倒变形边坡的分析方法及存在的问题,介绍了节理网络有限元的功能及参数输入,说明了其在倾倒变形边坡应用中的优势,并以黄河上游茨哈峡电站Ⅰ号倾倒体为例,计算了该倾倒边坡的稳定性及破坏趋势,结果表明,节理网络有限元是倾倒变形边坡稳定分析的一种有效、可靠的方法。 展开更多
关键词 节理网络 有限元 倾倒 斜坡 稳定分析
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预条件最小二乘逆时偏移方法 被引量:13
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作者 李闯 黄建平 +2 位作者 李振春 王蓉蓉 李庆洋 《石油地球物理勘探》 EI CSCD 北大核心 2016年第3期513-520,416,共8页
针对最小二乘逆时偏移方法收敛速度较慢,并且对深部及盐下构造照明补偿不足的问题,结合Hessian算子的近似及一种快速高通滤波方法对梯度进行预处理,发展了一种预条件最小二乘逆时偏移算法。在实现算法的基础上对SEG/EAGE二维盐丘模型进... 针对最小二乘逆时偏移方法收敛速度较慢,并且对深部及盐下构造照明补偿不足的问题,结合Hessian算子的近似及一种快速高通滤波方法对梯度进行预处理,发展了一种预条件最小二乘逆时偏移算法。在实现算法的基础上对SEG/EAGE二维盐丘模型进行了成像测试。计算结果表明:预条件最小二乘逆时偏移方法能够加快收敛速度,提高深部及盐下构造成像的分辨率和保幅性,对不规则的地震数据,该方法具有更好的适应性。 展开更多
关键词 最小二乘偏移 预条件算子 HESSIAN矩阵 计算效率 保幅偏移
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基于Kelvin黏声介质的最小二乘品质因子线性反演 被引量:3
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作者 杨宇 黄建平 +2 位作者 李振春 田坤 李庆洋 《石油物探》 EI CSCD 北大核心 2015年第6期705-715,共11页
品质因子Q值是描述介质黏性大小最重要的物理量,准确获取地下介质Q值分布,是黏性介质叠前属性反演、地震波正演模拟及黏性介质偏移成像的基础。为此,基于迭代反演思想,将地下介质的黏滞性引入最小二乘框架中,对品质因子Q值进行线性反演... 品质因子Q值是描述介质黏性大小最重要的物理量,准确获取地下介质Q值分布,是黏性介质叠前属性反演、地震波正演模拟及黏性介质偏移成像的基础。为此,基于迭代反演思想,将地下介质的黏滞性引入最小二乘框架中,对品质因子Q值进行线性反演,形成了一种基于多次迭代策略的Q值反演方法;通过简单Q模型、二维盐丘Q模型试算,验证了方法的正确性及适应性。研究结果表明,利用最小二乘迭代反演方法不仅可以得到地下Q值扰动界面,而且可以得到Q绝对值分布。 展开更多
关键词 黏声介质 品质因子 最小二乘迭代 线性反演 Q值扰动界面
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Jurassic Intra-plate Basaltic Magmatism in Southeast China:Evidence from Geological and Geochemical Characteristics of the Chebu Gabbroite in Southern Jiangxi Province 被引量:11
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作者 XIE Guiqing MAO Jingwen +4 位作者 HU Ruizhong LI Ruiling JIANG Guohao CAO Jinjian ZHAO Junhong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2005年第5期662-672,共11页
Geochemical and isotopic investigations have been carded out on the Chebu gabbroite in southern Jiangxi Province, southeast China and these results are compared with gabbro bodies along the coast of Fujian Province in... Geochemical and isotopic investigations have been carded out on the Chebu gabbroite in southern Jiangxi Province, southeast China and these results are compared with gabbro bodies along the coast of Fujian Province in order to understand their magma sources and tectonic implications. The Chebu intrusion formed at the beginning of the Middle Jurassic (172~4.3 Ma). These rocks are Ti-rich and Al-poor in major elements, characterized by strong enrichment in large-ion lithophile elements (LILE) and moderate enrichment in high field strength elements (HFSE) and light rare-earth elements CLREE), without pronounced Nb or Ta anomalies. Age-correlated Sr-Nd isotope ratios show moderately high ranges of (^87Sr/^86Sr)i from 0.7065 to 0.7086 and 0.5124 to 0.5125 of (^143Nd/^144Nd)i. The geochemical characteristics of the Chebu gabbroite suggest that it is notably different from island-arc basalt and similar to intra-plate basaltic rocks. By combining interpretations of its geological and geochemical characteristics and the regional geological development history, the Chebu gabbroitic intrusion is thought to be the product of asthenosphere upwelling and rapid lithosphere extension during a transition of tectonic systems in southeast China. The tectonic environment and source characteristics of the intrusion are different from Cretaceous gabbro bodies along the coast of Fujian Province, The former formed in a tectonic environment of rapid intra-plate lithospheric extension and the source characteristics were of a weakly enriched primitive mantle, whereas the latter originated mainly in a volcanic-magmatic arc extensional tectonic environment and the nature of the source was an enriched mantle with more subduct subducted components. 展开更多
关键词 gabbroite geochemical characteristics geodynamics setting JURASSIC Jiangxi southeast China
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On the Kinematic Characteristics and Dynamic Process of Boundary faults of the Nansha Ultra-crust Layer-Block 被引量:10
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作者 LIU Hailing SUN Yan +4 位作者 GUO Lingzhi SHU Liangshu YANG Shukang ZHOU Di ZHANG Yixiang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1999年第4期452-463,共12页
Abstract The Nansha ultra-crust layer-block is confined by ultra-crustal boundary faults of distinctive features, bordering the Kangtai-Shuangzi-Xiongnan extensional faulted zone on the north, the Baxian-Baram-Yoca-Cu... Abstract The Nansha ultra-crust layer-block is confined by ultra-crustal boundary faults of distinctive features, bordering the Kangtai-Shuangzi-Xiongnan extensional faulted zone on the north, the Baxian-Baram-Yoca-Cuyo nappe faulted zone on the south, the Wan'an-Natuna strike-slip tensional faulted zone on the west and the Mondoro-Panay strike-slip compressive faulted zone on the east. These faults take the top of the Nansha asthenosphere as their common detachmental surface. The Cenozoic dynamic process of the ultra-crust layer-block can be divided into four stages: K2-E21, during which the northern boundary faults extended, this ultra-crust layer-block was separated from the South China-Indosinian continental margin, the Palaeo-South China Sea subducted southwards and the Sibu accretion wedge was formed; E22-E31, during which the Southwest sub-sea basin extended and orogeny was active due to the collision of the Sibu accretion wedge; E32-N11, during which the central sub-sea basin extended, the Miri accretion wedge was formed and “A-type” subduction of the southern margin of the north Balawan occurred; N12-the present, during which large-scale thrusting and napping of the boundary faults in the south and mountain-building have taken place and the South China Sea stopped its extension. 展开更多
关键词 Nansha ultra-crust layer-block boundary fault layer slip glide dip slip strike slip fault system dynamic process
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Hydrothermal Dolomite in the Upper Sinian (Upper Proterozoic) Dengying Formation, East Sichuan Basin, China 被引量:12
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作者 LIU Shugen HUANG Wenming +5 位作者 JANSA Luba F. WANG Guozhi SONG Guangyong ZHANG Changjun SUN Wei MA Wenxin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第5期1466-1487,共22页
Hydrothermal Dolomite (HTD) is present in the Upper Sinian (Upper Proterozoic) Dengying Formation, east Sichuan Basin, China. The strata are comprised by primary dolomite. The HTD has various textures, including z... Hydrothermal Dolomite (HTD) is present in the Upper Sinian (Upper Proterozoic) Dengying Formation, east Sichuan Basin, China. The strata are comprised by primary dolomite. The HTD has various textures, including zebra dolomite, subhorizontal sheet-like cavities filled by saddle dolomite and breccias cemented by saddle dolomites as well occur as a fill of veins and fractures. Also co-occur MVT type lead-zinc ores in the study area. The δ13C and δ18O isotopes of HTD in the Upper Sinian Dengying Formation are lighter than those of the host rocks, while STSr/86Sr is higher. The apparent difference in carbon, oxygen and strontium isotopes, especially the large difference in S7Sr/S6Sr isotopes ratio indicate crystallization from hot basinal and/or hydrothermal fluids. Saddle dolomite was precipitated at temperatures of 270-320℃. The diagenetic parasequences of mineral assemblage deposited in the Dengying Formation are: (1) dolomite host rock →sphalerite-galena-barite-fluorite; (2) dolomite host rock →saddle dolomite →quartz; (3) dolomite host rock →saddle dolomite→bitumen; (4) dolomite host rock →saddle dolomite →barite. The mean chemical composition of the host dolomite matrix and HTD didn't change much during hydrothermal process. The fluids forming the HTDs in the Dengying Formation were mixtures of freshwater from the unconformity at the top of Sinian, fluids from diagenetic compaction and hydrocarbon generation & expulsion from the Lower Cambrian Niutitang Formation mudstones or the Doushantuo Formation silty mudstones, and hydrothermal fluids from the basement. The hydrocarbon reservoirs associated with the HTD were mostly controlled by the basement faults and fractures and karsting processes at the unconformity separating Sinian and Cambrian strata. The hydrocarbon storage spaces of HTD included dissolved cavities and intercrystalline pores. Dissolution cavities are extensive at the top of Dengying Formation, up to about 46m below the unconformity between Sinian and Cambrian and were generated mainly during karstification. Hydrothermal alteration enhanced the reservoir property of the Dengying Formation dolomites with 3%-5% increase in porosity. No agreement has been reached why zebra dolomite occurs only in the Upper Sinian strata, which would indicate that HTD mineralization occurred during two different periods, each of them related to major extensional tectonic event. The early one related to the Xingkai taphrogenesis (Z2-C1) and the later one to the Emei taphrogenesis (D2-T2). But, all the data from saddle dolomite suggest that the predominant crystallization occurred during the latter event. 展开更多
关键词 Hydrothermal dolomite (HTD) Upper Sinian Series Dengying Formation Sichuan basin
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Comparing the Upper Triassic Deep-sea Flysch of the Shannan Terrane with the Coeval Shallow Shelf Sediments of the Tethys Himalaya,Southern Tibet 被引量:2
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作者 LI Xianghui Frank MATTERN 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2021年第2期348-354,共7页
The provenance and paleogeography of the Upper Triassic deep-sea flysch Langjiexue Group(LG)of the Shannan Terrane in the northeastern Himalaya orogen,south of Yarlung Zangbo,have been disputed in recent years since i... The provenance and paleogeography of the Upper Triassic deep-sea flysch Langjiexue Group(LG)of the Shannan Terrane in the northeastern Himalaya orogen,south of Yarlung Zangbo,have been disputed in recent years since its affinity to the Tethys Himalaya was suspected during the early 2000 s.Based on the earlier discoveries of the Upper Permian–Triassic basalts and mafic dykes from the LG and of coeval detrital zircons from the Qulonggongba Formation(QF)in shallow shelf sediments of the Tethys Himalaya,the previous viewpoints on the basin and tectonics of the LG have been recently rejected.We compared the two units of the Upper Triassic,and our results reveal a number of differences,discrepancies,and inconsistencies in the debate,raising crucial questions on the postulation and provenance model of the remote Gondwanide Orogen for the LG.It is suggested that more observations and evidence are needed to further improve the paleogeographic understanding and relationship of the two units. 展开更多
关键词 SEDIMENTOLOGY PALEOGEOGRAPHY FLYSCH shelf sediment Late Triassic Shannan Terrane TETHYS Tibet
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Cretaceous Oceanic Red Beds:Distribution,Lithostratigraphy and Paleoenvironments 被引量:4
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作者 CHEN Xi WANG Chengshan +4 位作者 HU Xiumian HUANG Yongjian WANG Pingkang Luba JANSA ZENG Xuan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2007年第6期1070-1086,共17页
Cretaceous oceanic red beds (CORBs) represented by red shales and marls, were deposited during the Cretaceous and early Paleocene, predominantly in the Tethyan realm, in lower slope and abyssal basin environments. D... Cretaceous oceanic red beds (CORBs) represented by red shales and marls, were deposited during the Cretaceous and early Paleocene, predominantly in the Tethyan realm, in lower slope and abyssal basin environments. Detailed studies of CORBs are rare; therefore, we compiled CORBs data from deep sea ocean drilling cores and outcrops of Cretaceous rocks subaerially exposed in southern Europe, northwestern Germany, Asia and New Zealand. In the Tethyan realm, CORBs mainly consist of reddish or pink shales, limestones and marlstones. By contrast, marlstones and chalks are rare in deep-ocean drilling cores. Upper Cretaceous marine sediments in cores from the Atlantic Ocean are predominantly various shades of brown, reddish brown, yellowish brown and pale brown in color. A few red, pink, yellow and orange Cretaceous sediments are also present. The commonest age of CORBs is early Campanian to Maastrichtian, with the onset mostly of oxic deposition often after Oceanic Anoxic Events (OAEs), during the early Aptian, late Albian-early Turonian and Campanian. This suggests an indicated and previously not recognized relationship between OAEs, black shales deposition and CORBs. CORBs even though globally distributed, are most common in the North Atlantic and Tethyan realms, in low to mid latitudes of the northern hemisphere; in the South Atlantic and Indian Ocean in the mid to high latitudes of the southern hemisphere; and are less frequent in the central Pacific Ocean. Their widespread occurrence during the late Cretaceous might have been the result of establishing a connection for deep oceanic current circulation between the Pacific and the evolving connection between South and North Atlantic and changes in oceanic basins ventilation. 展开更多
关键词 CRETACEOUS pelagic Red Beds PALEOENVIRONMENT PALEOGEOGRAPHY
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Biochemical Changes Associated with Long Term Exposure to Pesticide among Farmers in the Gaza Strip 被引量:8
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作者 Yasser El- Nahhal 《Occupational Diseases and Environmental Medicine》 2016年第3期72-82,共11页
The study characterized the biochemical changes associated with long term exposure to pesticides. Practical parameters of pesticides were collected using 500 questionnaires. Farmers having 10 years working period were... The study characterized the biochemical changes associated with long term exposure to pesticides. Practical parameters of pesticides were collected using 500 questionnaires. Farmers having 10 years working period were invited to a private clinic for blood sampling and enzyme analysis. All participants were male farmers of different age groups, and education levels. Occupational parameters indicated that majority of farmers used manual methods for pesticide works. About 130 pesticides are currently used in Gaza. Toxicological symptoms indicated that dizziness, headache, and nausea were dominant among farmers, whereas vomiting abdominal colic and tearing were less dominant. Acetyl Cholinesterase (ACHE) cumulatively inhibited among farmers after work whereas Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST) and Alkaline Phosphatase (ALP) activities were above range after long term exposure. It can be concluded that long term exposure to pesticides may damage liver and kidney cells resulting in hepatic-toxicity and/or nephrotoxicity. 展开更多
关键词 Long Term Exposure Toxicology of Pesticides ALT AST ALP ACHE Activities
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Diagenetic and Depositional Impacts on the Reservoir Quality of the Upper Jurassic Arab Formation in the Balal Oilfield, Offshore Iran 被引量:2
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作者 Sfidari EBRAHIM Amini ABDOLHOSSIEN +2 位作者 Kadkhodaie ALI Sayedali MOHSEN Zamanzadeh SEYED MOHAMMAD 《Acta Geologica Sinica(English Edition)》 CAS CSCD 2018年第4期1523-1543,共21页
The Kimmeridgian-Tithonian aged Arab Formation, as the main reservoir of the Jurassic succession in the Balal oilfield, located in the offshore region of the Iranian sector of the Persian Gulf, is investigated in this... The Kimmeridgian-Tithonian aged Arab Formation, as the main reservoir of the Jurassic succession in the Balal oilfield, located in the offshore region of the Iranian sector of the Persian Gulf, is investigated in this study. The formation is composed of dolomites and limestones with anhydrite interbeds. Based on detailed petrographic studies, six microfacies are recognized, which are classified in four sub-environments including supratidal, intertidal, lagoonal and the high energy shoal of a homoclinal carbonate ramp. The main diagenetic features of the studied succession include dolomitization, anhydritization, cementation, micritization, fracturing and compaction. Based on stable isotope data, dolomitization of the upper Arab carbonates is related to sabkha settings (i.e. evaporative type). In terms of sequence stratigraphy, three shallowing-upward sequences are recognized, based on core and wireline log data from four wells of the studied field. Considering depositional and diagenetic effects on the reservoir quality, the studied facies are classified into eight reservoir rock types (RRT) with distinct reservoir qualities. Dolomitization has played a major role in reservoir quality enhancement, whereas anhydritization, carbonate cementation, and compaction have damaged the pore throat network. Distribution of the recognized RRTs in time and space are discussed within the context of a sequence stratigraphic framework. 展开更多
关键词 reservoir quality Arab Formation Balal oilfield offshore Iran Persian Gulf
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Sintering behaviour of feldspar and influence of electric charge effects 被引量:1
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作者 W.Gallala M.E.Gaied 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2011年第2期132-137,共6页
The characterization of feldspar for electric porcelain and the behaviour of these materials after heating at 1230°C were studied. X-ray diffraction (XRD) and scanning electronic microscopy (SEM) were used to... The characterization of feldspar for electric porcelain and the behaviour of these materials after heating at 1230°C were studied. X-ray diffraction (XRD) and scanning electronic microscopy (SEM) were used to identify the present phases and the densification level. Feldspar sand was treated by flotation. The floated feldspar is constituted by microcline, quartz, and minor amounts of albite. The micro-structure of sintered feldspar at 1230°C is essentially vitreous with open microporosities. The dielectrical properties of composites were characterized by using the induced courant method (ICM), which indicates that the charge trapping capacity depends on the mineralogical and chemical composition of feldspar. 展开更多
关键词 potash ore treatment FELDSPAR SINTERING MICROSTRUCTURE dielectric properties
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