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The Lanthanide Tetrad Effect in Argillic Alteration: An Example from the Jizvan District, Northern Iran 被引量:3
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作者 Ali ABEDINI Mansour REZAEI AZIZI Ali Asghar CALAGARI 《Acta Geologica Sinica(English Edition)》 CAS CSCD 2018年第4期1468-1485,共18页
Intrusion of quartz-monzodioritic igneous bodies of Oligocene age into Eocene lithic crystal tufts and trachy-basalts resulted in the occurrence of a widespread argillic alteration zone in the Jizvan district (northe... Intrusion of quartz-monzodioritic igneous bodies of Oligocene age into Eocene lithic crystal tufts and trachy-basalts resulted in the occurrence of a widespread argillic alteration zone in the Jizvan district (northern Iran). Mineralogically, the argillie alteration zone includes minerals such as kaolinite, quartz, smectite, pyrophyllite, muscovite-illite, alunite, rutile, calcite, feldspar, chlorite, hematite and goethite. Therefore, the non-CHARAC behaviour for trace elements in the argillic samples is reflected in the non-chondritic Y/Ho and Zr/Hf ratios and the irregular REE patterns, which appear related to the tetrad effect phenomenon. The chondrite-normalized REE distribution patterns indicate both concave (W-shaped) and convex (M-shaped) tetrad effects in the argillic samples. Based on the field evidence and the results from geochemical studies, it can be concluded that the samples from the argillic alteration zone having high fourth tetrad effect values (〉0.30) were developed in the fault and breccia zones. The results indicate that factors such as preferential scavenging by Mn-oxides, crystallization of clay minerals, fluid-rock interaction, overprint of hypogene mineral assemblage by supergene ones, and the structural control, have all played an important role in the occurrence of tetrad effects in samples of the argillic zone in the Jizvan district. 展开更多
关键词 REE geochemistry tetrad effect argillic alteration Jizvan Iran
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REE Tetrad Effect as a Powerful Indicator of Formation Conditions of Karst Bauxites: A Case Study of the Shahindezh Deposit, NW Iran 被引量:1
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作者 Ali ABEDINI Mansour REZAEI AZIZI Ali Asghar CALAGARI 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2019年第4期912-927,共16页
Study of the concentration of major,trace,and rare earth elements(REE)in the Shahindezh karst bauxite deposit,northwestern Iran clarifies the relationship of the tetrad effect with geochemical parameters in the bauxit... Study of the concentration of major,trace,and rare earth elements(REE)in the Shahindezh karst bauxite deposit,northwestern Iran clarifies the relationship of the tetrad effect with geochemical parameters in the bauxite ores.The existence of irregular curves in the chondrite-normalized REE patterns as well as non-CHARAC behavior of geochemically isovalent pairs(Y/Ho)are related to the tetrad effect.The meaningful positive correlation between the sizes of the calculated T3 tetrad effect and some geochemical factors such as Y/Ho,ΣREE,La/Y,(La/Yb)N,and(LREE/HREE)N as well as some major oxides-based parameters like Al2O3+LOI/SiO2+Fe2O3,Al2O3/Fe2O3,Al2O3+LOI,IOL,and SiO2+Fe2O3indicate that the studied bauxite horizon was likely deposited by different(acidic and/or alkalic)solutions at different stages.The lower part of the studied horizon with a thickness of^4.7 m displays alkali characteristics whereas the upper parts of the horizon with a thickness of^5.3 m are characterized by more acidic conditions.These results are fully supported by the co-occurrence of convex-concave tetrad effect curves in the chondrite-normalized REE patterns.Therefore,the tetrad effect phenomenon used in this study has proved to be a good and reliable geochemical proxy to assess the conditions of the depositional environment in the Shahindezh bauxite ores. 展开更多
关键词 Geochemistry REE tetrad effect Karst bauxite Shahindezh Iran
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Theoretical probe into universal tetrad effect for complexation discrepancy between lanthanide elements and organophosphoric extractant diethyl phosphoric acid 被引量:1
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作者 Haifeng Zheng Yanling Li +6 位作者 Xuyi Zhang Jinglu Han Songsong Li Guolong Wu Qingshi Liu Xiaojuan Liu Wuping Liao 《Journal of Rare Earths》 SCIE EI CAS CSCD 2024年第6期1142-1148,I0006,共8页
The deep understanding of 4f-correlated electron motion behavior is experimentally limited due to similar physicochemical properties of rare earth elements(REEs).While the solvent extraction behavior originating from ... The deep understanding of 4f-correlated electron motion behavior is experimentally limited due to similar physicochemical properties of rare earth elements(REEs).While the solvent extraction behavior originating from the continuous occupation of 4f electrons along the lanthanide family provides a particular platform to probe the 4f electrons motion behavior and its correlations to their versatile functions.Herein,the complexation between REEs and the prototypical extractant of diethyl phosphoric acid(DEP)was substantially studied based on quantum mechanical calculation.The results firstly show that the average bond lengths between Ln and six coordinated oxygen atoms are consistent with lanthanide contraction phenomenon,and gadolinium break effect is also obviously observed.Secondly,the"tetrad effect"is figured out based on the subtle discrepancy of 4f electrons occupation,namely La-Nd,Sm-Eu,Gd-Dy and Ho-Lu.Specifically,the main composition is 4f5d6p for La-Nd,while the discrepancy is due to the increasing electrons in the 5d shell,while it is 4f5d for Pm-Eu.For Gd-Dy,their 4f orbitals accept little electrons and the donating electrons flow into 6s5d subshells due to the half-filled stability and the enhancement of shielding effect.The electrons donate into 5d6p subshells due to multiply electrons occupation of 4f orbitals for Ho-Lu.These detailed analyses obviously clarify the"tetrad effect"along the lanthanide family due to the different variation of 4f orbital occupation.It is expected that these microscopic understandings provide important guidance for the separation of REEs and the design of new extractants. 展开更多
关键词 Theoretical calculation Rare earths 4f electron tetrad effect Gadolinium break
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Petrology, REE Geochemistry and Tetrad Effect of Some Muscovite Granites at Wadi El Gemal Area, South Eastern Desert, Egypt 被引量:1
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作者 Ahmed S. Shalan 《Journal of Geoscience and Environment Protection》 2022年第2期75-93,共19页
The muscovite granites at the study area are being emplaced into biotite granites and ophiolitic mélange settings. They occur in four exposures namely;Umm Seleimat, Sikait, Umm El Kheran and Umm Addebaa exposure.... The muscovite granites at the study area are being emplaced into biotite granites and ophiolitic mélange settings. They occur in four exposures namely;Umm Seleimat, Sikait, Umm El Kheran and Umm Addebaa exposure. The presence of garnet and muscovite flakes may reflect the peraluminous nature of the studied muscovite granites. Petrographically, the studied granites are mostly subsolvus and consist of plagioclase, K-feldspars, quartz, muscovite and biotite. Garnet, zircon, allanite and opaques are accessories. The textural features of these granites are expressed by bent plagioclase lamellae, distorted microcline twinning, deformed mica flakes and development of myrmekite and recrystallization of feldspars into fine-grained aggregates. Umm Seleimat and Sikait exposures are more differentiated due to the presence of high content of K-feldspar and LREEs. The REE budget decreased from Umm Seleimat-Sikait exposures to Umm El Kheran-Umm Addebaa exposures as (514.5 - 495.6) to (195.9 - 197.7), respectively. Umm Seleimat-Sikait exposures have lower HREE/LREE (0.12 - 0.67), relative to Umm El Kheran-Umm Addebaa exposures (0.99 - 2.06). The studied granites revealed that the chondrite normalized REE patterns are the normal M-type of tetrad effect, where TE1,3 tetrad effect is higher than 1 in all samples which implies that there was an interaction between melt and water-haloid-rich fluid when these granites are crystallized from magma. Spectrometric values of Umm Seleimat and Umm Addebaa indicate that U content is more than Th content. Applying the U mobilization equation proved that the studied granites have been originated from a late magmatic phase of magma very rich in radioelements, also the majority of measurements lie above the zero line indicating that the studied granites affected with hydrothermal solutions rich in uranium than thorium which indicates uranium addition. 展开更多
关键词 Wadi El Gemal Umm El Kheran REE Geochemistry tetrad effect EGYPT
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REE Tetrad Effects in Rare-metal Granites 被引量:9
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作者 赵振华 AKIMASA MASUDA M.B.SHABANI 《Chinese Journal Of Geochemistry》 EI CAS 1993年第3期206-219,共14页
Described in this paper are the characteristics of tetrad effects of REE in rare-metal granites.Based on the analytical data and experimental geochemical data available,it is pointed out that the tetrad effects of REE... Described in this paper are the characteristics of tetrad effects of REE in rare-metal granites.Based on the analytical data and experimental geochemical data available,it is pointed out that the tetrad effects of REE in the granites are produced in the metal-fluid system.Intense fractional crystallization of granitic melt(containing REE accessary minerals)and its interaction with volatile-rich(F,Cl)fluid are the major factors leading to the tetrad effects of REE.From this,this paper presents a composite genetic model for high-degree fractional crystallization-volatile-rich fluid metasomatism of rare-metal granites.With the model,quantitative calculations have been made.Meanwhile,it is pointed out that the tetrad effects of REE can be used as an important indicator to distinguish mineralized granites from barren ones. 展开更多
关键词 花岗岩 稀土元素 成因
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Mineralogy,M-type tetrad effect and radioactivity of altered granites at the G.Abu Garadi shear zone,central Eastern Desert,Egypt 被引量:3
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作者 El Nahas H.A. El Feky M.G. Mira H. 《Chinese Journal Of Geochemistry》 EI CAS 2011年第2期153-164,共12页
The G. Abu Garadi area is covered mainly by metasediments, alkali feldspar granites and stream sediments. The alkali feldspar granite is traversed by a major strike-slip fault trending in an N-S direction as well as t... The G. Abu Garadi area is covered mainly by metasediments, alkali feldspar granites and stream sediments. The alkali feldspar granite is traversed by a major strike-slip fault trending in an N-S direction as well as two subordinate sets of faults trending NW to WNW for the first one and NE for the second one. These faults represent the shear zones affected by magmatic (syngenetic) as well as hydrothermal (epigenetic) activities causing alteration of the granitic rocks. The most common alteration features are albitization, greisenization and koalinitization. The mass balance calculations of the studied altered samples show enrichments in Zr, Y, Ni, U, Th and Ga and depletions in Zn, Sr, Nb, Ba, Pb, Cu and V. Only the greisenized samples exhibit a significant enrichment in Nb, ∑REE budget and pronounced lanthanide tetrad effect (M-type), especially TE1,4, while weakly expressed tetrad effects are for the other albitized and koalinitized samples. Mineralogically, the common accessory minerals in the altered samples include samarskite-(Y), betafite, uranothorite, zircon, fluorite and cassiterite. The greisenized granites contain high eU and eTh than the other altered types, where they are characterized by an assemblage of the radioactive minerals; samarskite-(Y), betafite, uranothorite in addition to zircon. The inter-element relationships between U and Th and also their ratios illustrate that the radioelement distribution in these granites is mainly governed by magmatic processes, in addition to post-magmatic ones. The distribution of chemical elements and the fractionation of some isovalents within the shear zone are largely controlled by the newly formed mineral phases. With respect to uranium mobilization, uranium migrated from the host alkali feldspar granites of G. Abu Garadi, while the shear zones acted as traps for the migrated uranium. Moreover, U migrated in the shear zone during greisenization and albitization, and migrated out during koalinitization. 展开更多
关键词 M 类型四个效果 改变的花岗石 G。Abu Garadi 砍地区 中央东方沙漠 埃及
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The Hizeh-Jan Kaolin Deposit of NW Iran:the Tetrad Effect in REE Distribution Patterns 被引量:1
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作者 ABEDINI Ali REZAEI AZIZI Mansour 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2019年第1期74-87,共14页
The Hizeh-Jan kaolin deposit(northwest of Varzeghan, East-Azarbaidjan Province, NW Iran) is a product of the alteration of Eocene andesitic rocks. Based on mineralogical examinations, kaolinite, quartz, smectite, pyro... The Hizeh-Jan kaolin deposit(northwest of Varzeghan, East-Azarbaidjan Province, NW Iran) is a product of the alteration of Eocene andesitic rocks. Based on mineralogical examinations, kaolinite, quartz, smectite, pyrophyllite, muscovite-illite, alunite, calcite, diaspore, goethite and hematite are the most abundant mineral phases in this deposit. The geochemical indicators, such as Y/Ho and Zr/Hf, indicate the non-CHARAC(non-Charge-radius control) behavior of these pairs, which are likely to be due to the occurrence of the tetrad effect phenomenon in this deposit. Simultaneous concave and convex shapes in the chondrite-normalized REE distribution patterns are a remarkable feature of the kaolin samples. Bivariate diagrams of the size of the third tetrad effect(T_3) versus geochemical parameters such as Y/Ho, Nb/Ta and Zr/Hf ratios display two distinct populations for the kaolin samples. The first population is characterized by high T_3 values(>0.13), which are near or on the fault zone. The second population is characterized by low T_3 values(<0.13), and are farther from the fault zone. The obtained results from the geochemical data have furnished compelling evidence that fluidrock interaction, overprint of hypogene processes by supergene ones, and structural control, are key controlling factors for the occurrence of tetrad effects in REE distribution patterns in the Hizeh-Jan kaolin deposit. 展开更多
关键词 REE distribution tetrad effect Kaolin Hizeh-Jan NW Iran
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A peculiar composite M-and W-type REE tetrad effect:Evidence from the Shuiquangou alkaline syenite complex,Hebei Province,China 被引量:23
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作者 ZHAO ZhenHua BAO ZhiWei QIAO YuLou 《Chinese Science Bulletin》 SCIE EI CAS 2010年第24期2684-2696,共13页
A new type of REE tetrad effect,a composite M-and W-type,was recognized in the K-feldsparthized and silicificated Shuiquangou alkaline syenites,Dongping,Hebei Province.Different analytical methods such as ICP-MS and i... A new type of REE tetrad effect,a composite M-and W-type,was recognized in the K-feldsparthized and silicificated Shuiquangou alkaline syenites,Dongping,Hebei Province.Different analytical methods such as ICP-MS and isotopic dilution thermal ion mass spectrometer were exploited to verify the REE concentrations of the samples in three laboratories in China,France and Korea.The results are reliable and consistent within errors.In situ quantitative analysis of REE concentrations of individual zircons and apatites extracted from the very same sample has shown that fractional crystallization of magma and the superimposed hydrothermal alteration might have taken place in at least two-stage hydrothermal activities to generate the composite M-and W-type REE tetrad effect.The coexisting melt and aqueous phases,the superimposed alteration by volatile(Cl,CO2) -and Si,K, Al-enriched high temperature hydrothermal fluids might be the important facts for this new MW-type of REE tetrad effect.In addition,the peculiar MW-type tetrad effect might be an indicator for Au mineralization of reworked plutons. 展开更多
关键词 四重效应 碱性正长岩 水泉沟 河北省 稀土 W型 复合 中国
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Petrology, geochemistry, radioactivity, and M–W type rare earth element tetrads of El Sela altered granites, south eastern desert,Egypt 被引量:1
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作者 A.M.El Mezayen M.A.Heikal +3 位作者 M.G.El-Feky H.A.Shahin I.K.Abu Zeid S.R.Lasheen 《Acta Geochimica》 EI CAS CSCD 2019年第1期95-119,共25页
The southern part of the Eastern Desert of Egypt—about 30 km southwest of Abu-Ramad city—is mainly covered by ophiolitic rocks(Sul Hamed), island arc assemblage, younger granites(muscovite granites of Qash Amer and ... The southern part of the Eastern Desert of Egypt—about 30 km southwest of Abu-Ramad city—is mainly covered by ophiolitic rocks(Sul Hamed), island arc assemblage, younger granites(muscovite granites of Qash Amer and two mica granites of El Sela), and various acidic and basic dikes. Field, petrological, and geochemical studies indicate that the El Sela shear zone has been subject to hydrothermal and supergene alteration such as kaolinization, albitization, sericitization, and hematitization. It is invaded by quartz ENE–WSW veins associated with hydrothermal alteration accompanied by radioactive mineralization. The investigated younger granitic rocks had very low contents of compatible elements, such as Cr, Ni,and Co; and high contents of incompatible elements, such as Zr, and large ion lithophiles, such as Sr, especially in the El Sela shear zone. Major oxide and trace element analyses revealed calc-alkaline affinity and peraluminous character.These highly differentiated granitic rocks' lower Zr/Hf and higher Y/Ho than the normal ratio are consistent with hydrothermal alteration. Most samples had rare earth element(REE)-patterns with an M-type tetrad effect in the first and fourth segments and a W-type tetrad in the third segment. The average ∑REE in the studied granites was lower than the world granite average; the ratio of light to heavy REEs greater. The main radioactive, uranium-bearing, and uraniferous Fe and Mn minerals are uranothorite,autunite, uranophane and autunite as compounds, kasolite,columbite, xenotime, uranophane-bearing zircon and jarosite, silver-bearing pyrite, hematite, and autunite-bearing pyrolusite. 展开更多
关键词 GEOCHEMISTRY REE-tetrad effect Radioactive minerals Radiometric measurements Qash Amer EL Sela
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双歧杆菌四联活菌片联合奥美拉唑治疗幽门螺杆菌阳性消化性溃疡的临床疗效观察
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作者 张毛 牛思 邵阿康 《四川生理科学杂志》 2025年第10期2243-2245,2249,共4页
目的:探讨不同药物方案治疗幽门螺杆菌阳性消化性溃疡的临床疗效。方法:选取我院收治的幽门螺杆菌阳性消化性溃疡患者90例,选取时间为2023年1月至2023年7月,根据信封法分为试验组和参照组,参照组采用奥美拉唑治疗,试验组在此基础上采用... 目的:探讨不同药物方案治疗幽门螺杆菌阳性消化性溃疡的临床疗效。方法:选取我院收治的幽门螺杆菌阳性消化性溃疡患者90例,选取时间为2023年1月至2023年7月,根据信封法分为试验组和参照组,参照组采用奥美拉唑治疗,试验组在此基础上采用双歧杆菌四联活菌片联合治疗,比较两组患者临床疗效,观察两组患者Hp清除率、Hp清除时间和溃疡愈合时间,并比较两组患者治疗前后胃肠激素和炎性因子水平,观察两组患者不良反应发生情况。结果:试验组治疗总有效率(95.56%)高于参照组(80.00%)(χ^(2)=6.535,P=0.011)。与参照组(77.78%)比较,试验组患者Hp清除率(93.33%)高于参照组,Hp清除时间和溃疡愈合时间更短(P<0.05)。治疗后试验组患者MTL和GAS水平更低,CGRP水平更高(P<0.05)。治疗后试验组患者TNF-α、IL-6和CRP水平更低(P<0.05)。两组不良反应发生率(13.33%vs 11.11%)无明显差异(χ^(2)=0.104,P=0.747)。结论:奥美拉唑基础上采用双歧杆菌四联活菌片联合治疗幽门螺杆菌阳性消化性溃疡的临床疗效显著,可提高Hp清除率,改善胃肠功能,减轻炎症反应,安全性高。 展开更多
关键词 双歧杆菌四联活菌片 奥美拉唑 幽门螺杆菌阳性消化性溃疡 临床疗效
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双歧杆菌四联活菌片结合间歇蓝光照射治疗新生儿病理性黄疸效果及安全性
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作者 王新棉 郭全岭 《黑龙江医药科学》 2025年第5期126-129,共4页
目的:探讨双歧杆菌四联活菌片结合间歇蓝光照射治疗新生儿病理性黄疸效果及安全性。方法:选取2021年1月至2023年10月在南阳南石医院儿科收治的新生儿病理性黄疸患儿98例,按随机法分为对照组(n=49)和观察组(n=49),对照组予以间歇蓝光照射... 目的:探讨双歧杆菌四联活菌片结合间歇蓝光照射治疗新生儿病理性黄疸效果及安全性。方法:选取2021年1月至2023年10月在南阳南石医院儿科收治的新生儿病理性黄疸患儿98例,按随机法分为对照组(n=49)和观察组(n=49),对照组予以间歇蓝光照射(照射12 h,停12 h, 5次1个疗程,连续治疗7 d),观察组予以双歧杆菌四联活菌片(0.5 g/次,2次/d,连续治疗7 d)结合间歇蓝光照射,统计两组临床疗效、血清胆红素、免疫功能指标、不良反应。结果:观察组总有效率95.92%、CD4^(+)、CD4^(+)/CD8^(+)高于对照组(P<0.05),血清总胆红素(total bilirubin, TBiL)、直接胆红素(direct bilirubin, DBil)、间接胆红素(indirect bilirubin, IBil)水平均低于对照组(P<0.05),黄疸消退时间、住院时间均短于对照组(P<0.05),两组不良反应比较差异不显著(P>0.05)。结论:双歧杆菌四联活菌片结合间歇蓝光照射能有效降低血清胆红素水平,改善免疫功能,缩短黄疸消退时间和住院时间,且安全性良好。 展开更多
关键词 新生儿病理性黄疸 双歧杆菌四联活菌片 蓝光照射 临床效果
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高度演化的黄山A型花岗岩:对扬子克拉通东南部中生代岩石圈减薄的约束? 被引量:71
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作者 薛怀民 汪应庚 +3 位作者 马芳 汪诚 王德恩 左延龙 《地质学报》 EI CAS CSCD 北大核心 2009年第2期247-259,共13页
黄山花岗岩以高硅(SiO2>75%)、低钙(CaO=0.51%~0.86%)、贫镁、相对富碱和高FeO*/MgO比值(8.28~87.20)为特征。微量元素地球化学性质上表现为强烈亏损Ba、Sr、Eu(δEu=0.01~0.13),富集Rb、Th和U,高场强元素Zr、Nb、Y和Ga的含量也... 黄山花岗岩以高硅(SiO2>75%)、低钙(CaO=0.51%~0.86%)、贫镁、相对富碱和高FeO*/MgO比值(8.28~87.20)为特征。微量元素地球化学性质上表现为强烈亏损Ba、Sr、Eu(δEu=0.01~0.13),富集Rb、Th和U,高场强元素Zr、Nb、Y和Ga的含量也较高。主量和微量元素均表现为A-型花岗岩的特征。该花岗岩最奇妙的特征是稀土元素分馏模式表现出罕见的"四素组效应"(tetrad effect),一些微量元素的行为也表现出不受离子电荷和半径的控制(non-CHARAC行为),如异常低的K/Rb和Zr/Hf比值以及醒目的高K/Ba比值,该特征仅见于与热液发生过强烈相互作用的高度演化的岩浆中。与钙碱性的太平岩体相比,高度演化的具A-型花岗岩特征的黄山岩体具有相对较低的87Sr/86Sr初时值(0.707,而太平岩体为0.710)和较高的εNd(t)值(-4.45~-4.87,而太平岩体为-6.21~-6.40),二阶段模式年龄(TDM-2)为1.24~1.33Ga,明显年轻于扬子克拉通内不同时期花岗岩所普遍显示的约2.1Ga的模式年龄值,也小于太平岩体的模式年龄(1.44~1.45Ga),指示黄山岩体的母岩浆中包含有较多新加入的软流圈地幔物质。我们认为,由钙碱性的太平岩体转变为碱性的黄山岩体所指示的是扬子克拉通东南部中生代岩石圈的减薄事件。 展开更多
关键词 四素组效应 A型花岗岩 地球化学 岩石圈减薄 黄山 中生代
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湘西沃溪金锑钨矿床中白钨矿的稀土元素地球化学 被引量:51
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作者 彭建堂 胡瑞忠 +2 位作者 赵军红 符亚洲 袁顺达 《地球化学》 CAS CSCD 北大核心 2005年第2期115-122,共8页
对湘西沃溪金锑钨矿床进行了研究,结果表明,该矿床中白钨矿的稀土元素(REE)含量相对较高,为40.5~123.6μg/g;且有明显的空间变化趋势,随矿区标高的增加而减少,这可能与流体运移过程中流体的REE浓度不断降低有关。不同产状的白钨矿均以... 对湘西沃溪金锑钨矿床进行了研究,结果表明,该矿床中白钨矿的稀土元素(REE)含量相对较高,为40.5~123.6μg/g;且有明显的空间变化趋势,随矿区标高的增加而减少,这可能与流体运移过程中流体的REE浓度不断降低有关。不同产状的白钨矿均以轻稀土元素(LREE)亏损、中稀土元素(MREE)和重稀土元素(HREE)富集为特征;白钨矿样品的REE分布模式均存在着明显的M型四分组效应,暗示白钨矿的形成与流体作用或水/岩反应有关。进一步的研究表明,在沃溪白钨矿的沉淀过程中,成矿流体中的REE发生了明显分异,白钨矿对HREE,特别是MREE,具有明显的优先选择性;REE这种分配行为主要是受晶体化学因素的控制,与白钨矿晶体中Ca位置的大小密切相关,而与成矿流体中REE相对浓度、REE络合物的稳定性关系不大。 展开更多
关键词 白钨矿 稀土元素 四分组效应 沃溪金锑钨矿床 湖南省
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诸广-下庄铀矿集区成矿过程中水-岩作用的地质地球化学特征 被引量:30
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作者 张展适 华仁民 +5 位作者 邓平 朱捌 吴烈勤 张彦春 谭正中 尹征平 《地球化学》 CAS CSCD 北大核心 2005年第5期483-494,共12页
诸广-下庄铀矿集区是我国最大的花岗岩型铀成矿区,本文从岩石蚀变、不同介质中稀土元素的四分组效应、方解石中碳、氧和锶同位素组成等方面系统讨论了诸广-下庄铀矿集区内与铀成矿有关的各种水-岩相互作用的地质地球化学特征,得到以下... 诸广-下庄铀矿集区是我国最大的花岗岩型铀成矿区,本文从岩石蚀变、不同介质中稀土元素的四分组效应、方解石中碳、氧和锶同位素组成等方面系统讨论了诸广-下庄铀矿集区内与铀成矿有关的各种水-岩相互作用的地质地球化学特征,得到以下主要认识:(1)铀矿田范围内成矿的花岗岩大多发生了强烈的蚀变,是水-岩作用的直接表现,晶质铀矿表面发生的溶蚀作用是铀活化的直接证据,裂变径迹特征揭示面型分布的绿泥石化是花岗岩中以类质同像形式存在的铀从花岗岩中活化出来的主要反映;(2)与铀成矿有关的花岗岩具有M型四分组效应,而沥青铀矿、黄铁矿、方解石、绿泥石和伊利石等矿石矿物和脉石矿物则具有W型或W-M混合型四分组效应,这种共轭存在的M型和W型四分组效应表明了流体-花岗岩作用是本区铀成矿作用的关键,沥青铀矿主要是从流体中沉淀成矿的;(3)矿田范围内方解石的δ13C、87Sr/86Sr及δ18O组成特征,及87Sr/86Sr与δ18O之间明显的负相关关系,揭示出本区铀成矿过程中的碳、水和铀来源不同———碳是幔源,铀是壳源,流体中的水至少有一部分是大气降水。 展开更多
关键词 水-岩作用 四分组效应 同位素 花岗岩 方解石 电气石 沥青铀矿 诸广-下庄铀矿集区
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贵东花岗杂岩体的稀土元素特征及与铀成矿关系 被引量:29
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作者 张展适 华仁民 +2 位作者 刘晓东 邓平 吴烈勤 《中国稀土学报》 CAS CSCD 北大核心 2005年第6期749-756,共8页
贵东花岗杂岩体是一个由鲁溪岩体、下庄岩体、帽峰岩体、笋洞岩体、隘子岩体和司前岩体等组成的印支—燕山期复式花岗岩体,不同的岩体不仅在主要元素含量、铝过饱和指数等方面存在差异,而且在一系列稀土元素特征方面,如稀土总量、δEu... 贵东花岗杂岩体是一个由鲁溪岩体、下庄岩体、帽峰岩体、笋洞岩体、隘子岩体和司前岩体等组成的印支—燕山期复式花岗岩体,不同的岩体不仅在主要元素含量、铝过饱和指数等方面存在差异,而且在一系列稀土元素特征方面,如稀土总量、δEu值以及LREE/HREE、(La/Yb)N、(La/Sm)N、(Gd/Yb)N比值等,也存在很大的不同。铀矿体常常赋存在强过铝质、并且后期发生了强烈的流体-岩石相互作用的花岗岩体中,这些岩体典型的稀土元素特征是稀土总量、δEu、LREE/HREE、(La/Yb)N、(La/Sm)N、(Gd/Yb)N比值等均较低,并具有M型四分组效应。 展开更多
关键词 贵东花岗杂岩体 流体-岩石相互作用 四分组效应 铀成矿 帽峰岩体 稀土
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滇西含绿柱石伟晶岩锆石U-Pb年代学及其地质意义 被引量:14
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作者 李再会 唐发伟 +3 位作者 林仕良 丛峰 谢韬 邹光富 《吉林大学学报(地球科学版)》 EI CAS CSCD 北大核心 2014年第2期554-565,共12页
对腾冲—梁河地区含绿柱石伟晶岩进行了锆石LA-ICP-MS U-Pb定年和地球化学分析。结果表明:含绿柱石伟晶岩的形成时代为(48.1±0.8)Ma(MSWD=4.0),锆石形态特征和微量元素特征显示,伟晶岩锆石受到热液的改造。含绿柱石伟晶岩与55... 对腾冲—梁河地区含绿柱石伟晶岩进行了锆石LA-ICP-MS U-Pb定年和地球化学分析。结果表明:含绿柱石伟晶岩的形成时代为(48.1±0.8)Ma(MSWD=4.0),锆石形态特征和微量元素特征显示,伟晶岩锆石受到热液的改造。含绿柱石伟晶岩与55-52 Ma的白云母花岗岩在主量元素、微量元素及稀土元素方面表现出极其相似的特征,为钙碱性系列,过铝质花岗岩,表现出强烈的Eu亏损,δEu为0.074-0.083,相对富集HREE,(La/Yb)N=1.61-1.92,总体表现出典型的"M"型稀土元素四分组效应。含绿柱石伟晶岩是白云母花岗岩浆高度演化的结果,伟晶岩结晶温度为581℃,代表了印度—欧亚板块碰撞导致地壳加厚的构造背景。 展开更多
关键词 含绿柱石伟晶岩 地球化学 锆石U-Pb年代 稀土四分组效应 滇西
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湖南骑田岭花岗岩与锡成矿的关系 被引量:44
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作者 汪雄武 王晓地 +1 位作者 刘家齐 常海亮 《地质科技情报》 CAS CSCD 北大核心 2004年第2期1-12,共12页
骑田岭花岗岩是燕山早期深源浅成的高钾钙碱性复式花岗岩岩体。最晚的细粒花岗岩 Rb-Sr等时线年龄为 ( 15 1± 5 )Ma,低温蚀变和矿化的时代约为 13 6Ma。锡矿化分布于外接触带矽卡岩和岩体内部隐爆角砾岩充填的断裂中 ,细粒花岗岩... 骑田岭花岗岩是燕山早期深源浅成的高钾钙碱性复式花岗岩岩体。最晚的细粒花岗岩 Rb-Sr等时线年龄为 ( 15 1± 5 )Ma,低温蚀变和矿化的时代约为 13 6Ma。锡矿化分布于外接触带矽卡岩和岩体内部隐爆角砾岩充填的断裂中 ,细粒花岗岩岩浆作用与蚀变和矿化作用在空间上紧密伴生 ,成因上密切相关。骑田岭花岗岩具有花岗岩岩浆作用与矿化作用密切相关的直接证据——岩浆 -热液过渡阶段典型的地质地球化学特征 :1结构构造变化大 ,出现许多不平衡的结构构造 ,如斑状结构、蠕虫结构、连续不等粒结构、文象结构、花斑结构、细晶结构、环带结构、伟晶岩壳和晶洞构造 ;2石英中含有熔体包裹体和熔体—流体包裹体 ,并与 CO2 流体包裹体和高盐度流体包裹体共存 ;3蚀变广泛 ,特别是存在高温自交代蚀变钠长石化和条纹长石的微斜长石化。这种高温蚀变的花岗岩具有四重效应 ,表现出惰性元素的活动性 ,w( K) /w ( Rb)、w ( Sr) /w( Eu)、w( Y) /w( Ho)和 w( Zr) /w( Hf)等值大大偏离球粒陨石中的值。这些特征反映了富挥发分的晚期花岗岩岩浆由于高位减压“过冷”及淬火从而导致挥发分出溶、顶盖沿构造薄弱带隐爆垮塌以及出溶流体与正在结晶的花岗岩间的流—岩相互作用。岩体冷却及其高热产率驱动长期的热液循环 ,形成广泛的? 展开更多
关键词 骑田岭 细粒花岗岩 锡矿化 流体包裹体 流体出溶 REE四重效应 流-岩相互作用
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大兴安岭中段晚三叠世四分组效应花岗岩的厘定及其地质意义 被引量:18
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作者 李世超 李永飞 +1 位作者 王兴安 朱凯 《岩石学报》 SCIE EI CAS CSCD 北大核心 2016年第9期2793-2806,共14页
布敦化岩体位于中亚造山带东段大兴安岭地区的科尔沁右翼中旗,该岩体由中细粒二云母花岗岩和斑状中细粒白云母花岗岩组成。LA-MC-ICP-MS锆石U-Pb同位素年龄测试显示布敦化岩体形成于晚三叠世早期。地球化学分析表明,该岩体为弱过铝质-... 布敦化岩体位于中亚造山带东段大兴安岭地区的科尔沁右翼中旗,该岩体由中细粒二云母花岗岩和斑状中细粒白云母花岗岩组成。LA-MC-ICP-MS锆石U-Pb同位素年龄测试显示布敦化岩体形成于晚三叠世早期。地球化学分析表明,该岩体为弱过铝质-过铝质、高钾钙碱性系列,主量元素表现出高硅(73.73%-78.33%)、富碱(Na2O+K2O=7.07%-9.06%)、低钙(Ca O=0.01%-0.87%)、贫镁(Mg O=0.12%-0.52%)的特征;稀土元素具有明显的Eu负异常和M型四分组效应配分型式。岩石学和地球化学特征显示布敦化岩体为高分异I型花岗岩。Lu-Hf同位素研究显示其εHf(t)值为7.0-12.4,二阶段Hf模式年龄(tDM2)为812-473Ma。结合邻区晚三叠世地质资料可知,布敦化岩体是在古亚洲洋闭合造山后伸展的构造背景下产生的,是晚元古代-早古生代地壳物质熔融的产物。布敦化地区的四分组效应花岗岩的稀土元素总量高、岩浆侵位后经历了强烈的分异演化,暗示布敦化地区可能具有较好的稀有金属矿的找矿前景。 展开更多
关键词 布敦化 四分组效应 稀有金属矿 晚三叠世 大兴安岭
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贵州水银洞金矿构造蚀变体稀土元素地球化学特征 被引量:13
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作者 杨成富 刘建中 +4 位作者 陈睿 王泽鹏 闫宝文 夏勇 莫荣思 《矿物岩石地球化学通报》 CAS CSCD 北大核心 2012年第4期404-413,共10页
水银洞金矿构造蚀变体(SBT)为产出于茅口租(P2m)和龙潭组(P3l)之间不整合面上的一套强硅化灰岩、灰岩角砾岩、硅化粘土岩组合。采用ICP-MS测定钻孔岩芯中构造蚀变体样品稀土元素组成,对比研究SBT围岩、区域岩浆岩及现代海底热水系统流... 水银洞金矿构造蚀变体(SBT)为产出于茅口租(P2m)和龙潭组(P3l)之间不整合面上的一套强硅化灰岩、灰岩角砾岩、硅化粘土岩组合。采用ICP-MS测定钻孔岩芯中构造蚀变体样品稀土元素组成,对比研究SBT围岩、区域岩浆岩及现代海底热水系统流体稀土元素组成。结果显示,SBT的轻重稀土分馏明显[LREE/HREE=4.92~17.51,(La/Yb)N=5.94~38.37],曲线右倾型;轻稀土分异明显,曲线右倾程度大;重稀土分异不明显,曲线平坦;负Eu(0.61~0.94)、Ce(0.52~1.07)异常明显;SBT及围岩均具有明显W型稀土元素四分组效应,而不同于区域岩浆岩和现代海底热水系统流体,表明热液流体来源以壳源为主。 展开更多
关键词 构造蚀变体 稀土元素 四分组效应 水银洞金矿
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藏南隆子地区恰嘎流纹质次火山岩稀土元素类似四分组效应 被引量:15
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作者 胡古月 曾令森 +1 位作者 高利娥 谢克家 《地质通报》 CAS CSCD 北大核心 2011年第1期82-94,共13页
恰嘎次火山岩侵位于特提斯喜马拉雅沉积岩系的东南部,雅拉香波片麻岩穹隆与藏南拆离系之间的地区。通过镜下鉴定和对岩石的主量元素、微量元素组成的测试和分析,确定为流纹质次火山岩。该岩体以富SiO2、Al2O3、K2O、Na2O,贫MgO、CaO、T... 恰嘎次火山岩侵位于特提斯喜马拉雅沉积岩系的东南部,雅拉香波片麻岩穹隆与藏南拆离系之间的地区。通过镜下鉴定和对岩石的主量元素、微量元素组成的测试和分析,确定为流纹质次火山岩。该岩体以富SiO2、Al2O3、K2O、Na2O,贫MgO、CaO、TFeO为特征,里特曼指数σ介于1.07-2.37之间,指示其属于钙碱性系列岩石。微量元素的测试结果表明,稀土元素总量较低,其配分图上产生类似于四分组的"膝折"效应;富集LILE、亏损HFSE,K/Rb和Rb/Cs比值低于一般酸性岩浆侵入岩体,Y/Ho、Nb/Ta和Zr/Hf的比值均偏离球粒陨石值。结合前人对稀土元素四分组效应的研究,认为富挥发分的流体作用于高度演化的酸性过铝质岩浆后,其稀土元素配分模式也能形成类似四分组的"膝折"配分模式,元素Gd显示正异常。 展开更多
关键词 特提斯喜马拉雅 “四分组”效应 熔体/流体作用 稀土元素 Gd正异常
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