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Petrology, Age and Geodynamic Implication of the Panafrican Granitoids Associated with the Glito-Kpatala Shear Zone (South-East Togo)
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作者 Gnanwasou Alayi Sarakawa Abalo Malibida Kpanzou +3 位作者 Yao Agbossoumondé Essodina Padaro René-Pierre Menot Mahaman Sani Tairou 《International Journal of Geosciences》 2023年第12期1193-1225,共33页
The granitic plutons associated with the Glito-Kpatala shear zone are composed of biotite and amphibole granodiorites, biotite granites, two-mica granites and aplitic granites, which are very poorly represented. The c... The granitic plutons associated with the Glito-Kpatala shear zone are composed of biotite and amphibole granodiorites, biotite granites, two-mica granites and aplitic granites, which are very poorly represented. The chemical and mineralogical compositions of these facies indicate that they are I type and belong to high-K calc-alkaline series, with a chemical metaluminous character displayed by the granodiorites relative to the biotite and two-mica facies whose chemical compositions vary between metaluminous and peraluminous caracter. The Th/Ta (14.04 - 43.82 ppm, mean = 26.05), Th/U (2.58 to 15.05 ppm, mean = 5.85 ppm), Zr/Hf (25.27 to 37.21, mean = 30.67 ppm) and Rb/Sr (0.16 to 4.32;mean = 1.67 ppm) ratios of these granitoids reveal a strong crustal involvement in their magmatogenesis. Variations in CaO/Na<sub>2</sub>O (0.47 - 1.44 ppm), Rb/Sr (0.14 - 0.27 ppm), Rb/Ba (0.07 - 0.14 ppm) and Sr/Y (38.21 - 174.42 ppm) ratios indicate that biotite and amphibole granodiorites with their excessive Ni (135.37 - 139.51 ppm) and Cr (395.73 - 447.74 ppm) were derived from a mafic to intermediate lower continental crust where garnet and/or amphibole were stable residual assemblage minerals. The moderate Sr/Y ratios (1.81 - 9.47 ppm) and low transition elements Ni (1 - 6.44 ppm) and Cr (7.89 - 13.47 ppm) contents in both the two-mica and biotite granites are consistent with their emplacement at relatively shallow depths in the upper to mean continental crust, at pressures below 10 Kbar. In the two-mica granites, moderate CaO/Na<sub>2</sub>O (0.20 - 0.57 ppm, mean = 0.38 ppm) and Rb/Ba (0.39 - 1.37, mean = 0.84 ppm) ratios and quite varied Rb/Sr (1.53 - 4.23 ppm, mean = 2.85 ppm) ratios indicate a predominant derivation from psammitic and pelitic metasediments rather than metagreywackes. These low ratios (0.25 ≤ CaO/Na<sub>2</sub>O ≤ 0.32, mean = 0.28 ppm;0.31 ≤ Rb/Ba ≤ 0.44, mean = 0.39 ppm;1.11 ≤ Rb/Sr ≤ 1.78, mean = 0.39 ppm) in biotite granites are more consistent with melting from a metagreywacke-derived source. Evidence for the contribution of mantle-derived mafic magma with granitic magma in the plutons studied is materialized by the presence of magmatic enclaves in both granodiorites and two-mica granites, the volcanic arc geochemical signatures displayed by the plutons in geotectonic diagrams and Nb/Ta ratios (14.14 - 34.61 ppm) closer to mantle estimates. Geochemical data and radiometric dating elements suggest that the granitoids studied can be integrated into the pan-African late magmatic episode, which corresponds between 606 and 583 Ma, to the activity of transcurrent ductile strike-slips and to the synchronous emplacement of high K calc-alkaline plutons in a post-collisional context. 展开更多
关键词 pan-african Granitoids Post-Collisional Shear Zone South-East Togo
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Distribution domains of the Pan-African event in East Antarctica and adjacent areas 被引量:3
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作者 REN Liudong ZONG Shi +1 位作者 WANG Yanbin LI Chong 《Advances in Polar Science》 2018年第2期87-107,共21页
The Pan-African event is widely distributed in East Antarctica (EA) craton, including both the coastal regions and interior of the EA. From aspects of the shear zones, granites, pegmatites, time of high-grade meta... The Pan-African event is widely distributed in East Antarctica (EA) craton, including both the coastal regions and interior of the EA. From aspects of the shear zones, granites, pegmatites, time of high-grade metamorphism and detrital zircon age peaks of the downflowing sediments from the inland, the Pan-African event in the EA and adjacent areas in the Gondwana reconstruction, like SE Africa, southern India and SW Australia, was described in the paper. The water or fluid available along the shear zones was responsible for retrogression of the earlier, e.g., Grenville age, high-grade outcrops to later Pan-African amphibolite to granulite facies metamorphism. In geochemistry, the granites are generally anorogenic, ocassionally with some gabbros or dolerite dykes, showing sign of bimodal feature. Meanwhile, the event has influenced most isotopic systems, including the U-Pb, Sm-Nd, Rb-Sr and Ar-Ar systems, giving Pan-African apparent ages. Spatially, the Pan-African event is demonstrated from possibly local granitic magmatism, to wider medium-high grade metamorphism, and mostly widespread in resetting for some isotope systems, suggesting the prevailing thermal effect of the event. Before Gondwana formation, local depressions in the EA may have been filled with sediments, implying the initial breakup period of the Rodinia. The later Pan-Gondwana counterrotating cogs shaped the interstitial fold belts between the continent blocks and formed a set of shear zones. The mafic underplating in the Gondwana may be responsible for the typical features of the Pan-African event. The event may be an overwhelmingly extensional and transcurrent tectonics in mechanism and is a possible response of the plate movement surrounding the continent swarms in the non-stable interior of the yet consolidated Gondwana. 展开更多
关键词 pan-african event DISTRIBUTION GRANITE METAMORPHISM East Antarctica
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Petrogenesis and geotectonic setting of the Pan-African basement rocks in Bamenda Massif, Obudu Plateau, southeastern Nigeria: Evidence from trace element geochemistry 被引量:1
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作者 UKAEGBU V.U EKWUEME B.N 《Chinese Journal Of Geochemistry》 EI CAS 2006年第2期122-131,共10页
The rocks of the Obudu Plateau range from high-grade metagreywacke-pelite sequence to metaigneous (granitic to tholeiitic) and polymagmatic (calc-alkaline granitic to olivine tholeiitic) igneous rocks. Several co-vari... The rocks of the Obudu Plateau range from high-grade metagreywacke-pelite sequence to metaigneous (granitic to tholeiitic) and polymagmatic (calc-alkaline granitic to olivine tholeiitic) igneous rocks. Several co-variance diagrams and other parameters indicate that the trace elements of rocks in southern Obudu Plateau exhibit systematic variations and suggest highly heterogeneous protoliths. The tectonic setting of the rocks indicates rifting and collisional to non-orogenic emplacements in oceanic to ensialic environments. The calc-alkaline and tholeiitic nature of the magmatism as well as the greywacke-pelite sequence is suggestive of an Andean-type continental environment. 展开更多
关键词 微量元素 岩石成因论 地壳构造 花岗岩 橄榄石
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Rare-earth elements as source indicators of Pan-African granites from Obudu Plateau,Southeastern Nigeria 被引量:1
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作者 Ukaegbu V.U. Beka F.T. 《Chinese Journal Of Geochemistry》 EI CAS 2008年第2期130-134,共5页
The rare-earth element (REE) concentrations of representative granite samples from the southeast of the Obudu Plateau, Nigeria, were analyzed with an attempt to determine the signatures of their source, evolutionary h... The rare-earth element (REE) concentrations of representative granite samples from the southeast of the Obudu Plateau, Nigeria, were analyzed with an attempt to determine the signatures of their source, evolutionary history and tectonic setting. Results indicated that the granites have high absolute REE concentrations (190×10-6-1191×10-6; av.=549×10-6) with the chondrite-normalized REE patterns characterized by steep negative slopes and prominent to slight or no negative Eu anomalies. All the samples are also characterized by high and variable concentrations of the LREE (151×10-6-1169×10-6; av.= 466×10-6), while the HREE show low abundance (4×10-6-107×10-6; av.=28×10-6). These are consistent with the variable levels of REE fractionation, and differentiation of the granites. This is further supported by the range of REE contents, the chondrite-normalized patterns and the ratios of LaN/YbN (2.30-343.37), CeN/YbN (5.94-716.87), LaN/SmN (3.14-11.68) and TbN/YbN (0.58-1.65). The general parallelism of the REE patterns, suggest that all the granites were comagmatic in origin, while the high Eu/Eu* ratios (0.085-2.807; av.=0.9398) indicate high fO2 at the source. Similarly, irregular variations in LaN/YbN, CeN/YbN and Eu/Eu* ratios and REE abundances among the samples suggest behaviors that are related to mantle and crustal sources. 展开更多
关键词 指示剂 稀土元素 非洲 花岗岩
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Origin and geochemistry of Pan-African granitoid rocks in the Gabal Um Shomer area,Southwestern Sinai,Egypt 被引量:1
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作者 E1-Tokhi M.M. Musallum A. Amin B.M. 《Chinese Journal Of Geochemistry》 EI CAS 2009年第2期125-135,共11页
Geological, petrological and geochemical studies indicated that there are two distinct types of granitoid rocks: older quartz diorites to granodiorite assemblage and younger granitoids, the latter occurring in two pha... Geological, petrological and geochemical studies indicated that there are two distinct types of granitoid rocks: older quartz diorites to granodiorite assemblage and younger granitoids, the latter occurring in two phases. The older granitoids have a meta-aluminous chemistry and a calc-alkaline character, with high MgO, Fe2O3, TiO2, CaO, P2O5, Sr and low SiO2, K2O, and Rb. Their major and trace elements data, together with low 87Sr/ 86Sr ratios (0.7029±0.0008) are indicative of I-type affinities. The second- and third-phase granitoids range from calc-alkaline to alkaline, respectively. The second-phase granitoids have a peraluminous chemistry and high Sr, Ba, CaO, MgO, Al2O3 and Ti2O and low SiO2, K2O, Nb, Y and Rb relative to the third-phase granitoids. The corundum normative nature and field observations suggested that it was formed by partial melting of the lower crust. The third-phase granitoids are alkaline in nature and characterized by higher SiO2, Rb, Y, Nb and lower MgO, Sr and Ba values than the younger granitoids (phase Ⅱ). They are A-type granitoids which were generated from below or within the existing continental crust. 展开更多
关键词 花岗岩类岩石 地球化学 西奈半岛 过铝质花岗岩 起源 西南 埃及 石英闪长岩
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Structural Organization and Tectono-Metamorphic Evolution of the Pan-African Suture Zone: Case of the Kabye and Kpaza Massifs in the Dahomeyide Orogen in Northern Togo (West Africa) 被引量:1
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作者 M. S. Tairou Pascal Affaton 《International Journal of Geosciences》 2013年第1期166-182,共17页
The Kabye and Kpaza Massifs correspond to two main granulitic suites in the suture zone of the Pan-African Dahomeyide orogenic belt, in northern Togo. The Kabye Massif is composed of an important west verging nappe pi... The Kabye and Kpaza Massifs correspond to two main granulitic suites in the suture zone of the Pan-African Dahomeyide orogenic belt, in northern Togo. The Kabye Massif is composed of an important west verging nappe pile subdivided into two petrographic units. The nappes in its western petrographic unit are made up of leucocratic garnetbearing granulites defined as the “Lassa-Soumdina Granulites” (GLS). The eastern petrographic unit consists of mela-nocratic granulites, with metagabbroic structures, called the “Ketao-Sirka Granulites” (GKS). These two petrographic units are separated by the Panalo Mylonitic Zone (ZMP). This major west verging zone includes a syn-Dn + 2 dextral shear contact. The Kpaza Massif comprises nappes of melanocratic granulites (GKM), comparable to the GKS of the Kabye Massif. All these granulitic nappes include boudins of pyroxenites or meta-anorthosites, and ultramafic rocks represented by serpentinites, talcschists, actinolite- and chlorite-schists which generally mark thrust soles. The GLS nappes are thrust over the Kara-Niamtougou orthogneissic unit (UKN) which is considered as the easternmost structural unit of the Dahomeyide external zone. On the other hand, the GKS nappes underlie those of the Binah meta-volcano sedimentary Complex (CB) which belongs to the Dahomeyide internal zone. As regards the Kpaza Massif, it occurs as a geologic window tectonically enclosed in the Mono Complex nappes (CM) corresponding to the southern part of the CB. The organization of the Kabye and Kpaza Massifs, as west verging nappe piles, and their relationships with the surrounding structural units express the tangential and folding tectonics that structured the Pan-African belt in northern Togo. The microstructures and mineral parageneses of the granulites and associated rocks in these two massifs indicate a polyphase tectono-metamorphic evolution: a syn-Dn granulitization (collision phase);a syn-Dn + 1 amphibolitization (obduction or tangential phase);and a syn- to post-Dn + 2 greenschist facies retrogressive metamorphism (post-nappe folding phase). 展开更多
关键词 TOGO pan-african Dahomeyide SUTURE Zone Microstructures Tectono-Metamorphic Evolution
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Rare-earth and trace element imprints on the origin and tectonic setting of gabbro-diorite complex in the Pan-African belt of Southeast Obudu Plateau,Nigeria 被引量:1
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作者 Ukaegbu V.U. Beka F.T. 《Chinese Journal Of Geochemistry》 EI CAS 2009年第3期239-247,共9页
A gabbro-diorite plutonic complex from the Southeast Obudu Plateau, representing limited volumes of magma, was studied for its trace and rare-earth element characteristics, in an attempt to document its genetic and ge... A gabbro-diorite plutonic complex from the Southeast Obudu Plateau, representing limited volumes of magma, was studied for its trace and rare-earth element characteristics, in an attempt to document its genetic and geodynamic history. Geochemical studies indicate that the gabbro samples are characterized by variable concentrations and low averages of such index elements as Cr (40×10-6–200×10-6; av. 80×10-6), Ni (40×10-6–170×10-6; 53.33×10-6) and Zr (110×10-6–240×10-6; 116.67×10-6); variable and high averages of Rb (3×10-6–270×10-6; 80.67×10-6), Sr (181×10-6–1610×10-6; 628.17×10-6) and U (0.14×10-6–3.46×10-6; 1.51×10-6), and fairly uniform Co (34×10-6–49×10-6; 36.33×10-6) and Sc (23×10-6–39×10-6; 34.5×10-6), while the diorite samples exhibit higher trace element compositions. The range of REE contents and distinctive chondrite-normalized patterns indicate moderate fractionation with slight positive Eu anomaly in the diorites to very low fractionation with flat patterns and slight positive Eu anomaly in the gabbros. However, the general element systematics of the samples, especially LILE (Ba, Rb, Sr, Cs and Pb), HFSE (Zr, Th, U, Hf, Mo, W, Nb and Sn), relatively immobile elements (Zr, Ni, Cr) and REE, suggests a differentiation model, involving fractional crystallization of olivine and clinopyroxene from a partial melt generated beneath an island arc complex. A possible model for the complex is therefore an island arc setting, the development of which was dominated by calc-alkaline magmatism across the Obudu Plateau. 展开更多
关键词 构造环境 微量元素 尼日利亚 辉长岩 闪长岩 起源 高原 痕迹
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Geochemistry and Geochronology of Peraluminous High-K Granitic Leucosomes of YaoundéSeries (Cameroon): Evidence for a Unique Pan-African Magmatism and Melting Event in North Equatorial Fold Belt 被引量:4
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作者 Ngnotue Timoleon Ganno Sylvestre +3 位作者 Nzenti Jean Paul Schulz Bernhard Tchaptchet Tchato Depesquidoux I Suh Cheo Emmanuel 《International Journal of Geosciences》 2012年第3期525-548,共24页
Geochemical and geochronological studies have been carry out on the leucosomes of Yaoundé series with the aims to identify the magma sources and to indicate their production periods and emplacement within the for... Geochemical and geochronological studies have been carry out on the leucosomes of Yaoundé series with the aims to identify the magma sources and to indicate their production periods and emplacement within the formations of the Pan-African North-Equatorial Fold Belt (PANEFB) in Cameroon. The Yaoundé series belongs to the Southern domain of the PANEFB and it is composed of migmatites in which two types of granitic leucosomes (in situ leucosomes and injected leucosomes) have been distinguished. These rocks display characteristic of calc-alkaline (in situ leucosomes) and high-K calc-alkaline to shoshonitic series (injected leucosomes). All the rocks are peraluminous with in situ leucosomes conform to S-type and injected leucosomes conform to I- and S-type granitoids. Major and trace elements composition reveal that in situ leucosomes derived from the partial melting of the host metapelite whereas injected leucosomes derived from the melting of metagreywacke. These sources are similar to those of granitoids from central and northern domains of the PANEFB. Th-U-Pb dating by electron microprobe (EMP) and LA-ICP-MS U-Pb dating on zircon have been used to constraints the melting event and emplacement of leucosomes in Yaoundé series. Th-U-Pb monazite dating, undertaken in two samples of leucosomes, gives two groups of monazite ages. The older group gives an age of 658 Ma whereas the age of younger group is 592 Ma. U-Pb dating of zircons from the leucosomes reveals a Pan-African age ranging from 626 to 654 Ma whereas zircons from metapelitic host rock reveal the overprinting of an early Pan-African event 911 - 1127 Ma on Palaeoproterozoic (2127 Ma) inheritance. These data clearly indicate that the host rocks of leucosomes of Yaoundé series have been firstly metamorphosed during Tonien-Stenien period (911 - 1127 Ma) and reveal the existence of extended unique melting event (592 and 658 Ma) in the Yaoundé series which is contemporaneous with the magmatism responsible for the emplacement of granitoids in the other domains of the PANEFB. 展开更多
关键词 pan-african North-Equatorial Fold Belt Yaoundé Series EMP Monazite DATING LA-ICP-MS U-Pb DATING Leucosomes PERALUMINOUS MELTING Event MAGMATISM
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U-Th-Pb monazite and Sm-Nd dating of high-grade rocks from the Grove Mountains, East Antarctica: further evidence for a Pan-African-aged monometamorphic terrane 被引量:1
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作者 LIU Xiaochun LING Xiaoxiao JAHN Bor-ming 《Advances in Polar Science》 2018年第2期108-117,共10页
The Grove Mountains, 400 km south of the Chinese Antarctic Zhongshan Station, are an inland continuation of the Pan-African-aged (i.e., Late Neoproterozoic/Cambrian) Prydz Belt, East Antarctica. In this paper we car... The Grove Mountains, 400 km south of the Chinese Antarctic Zhongshan Station, are an inland continuation of the Pan-African-aged (i.e., Late Neoproterozoic/Cambrian) Prydz Belt, East Antarctica. In this paper we carried out a combined U-Th-Pb monazite and Sm-Nd mineral-whole-rock dating on para- and orthogneisses from bedrock in the Grove Mountains. U-Th-Pb monazite dating of a cordierite-bearing pelitic paragneiss yields ages of 523 ? 4 Ma for the cores and 508 ? 6 Ma for the rims. Sm-Nd mineral-whole-rock isotopic analyses yield isochron ages of 536 ? 3 Ma for a coarse-grained felsic orthogneiss and 507 ? 30 Ma for a fine-grained quartzofeldspathic paragneiss. Combined with previously published age data in the Grove Mountains and adjacent areas, the older age of ~530 Ma is interpreted as the time of regional medium- to low-pressure granulite-facies metamorphism, and the younger age of ~510 Ma as the cooling age of the granulite terrane. The absence of evidence for a Grenville-aged (i.e., Late Mesoproterozoic/Early Neoproterozoic) metamorphic event indicates that the Grove Mountains have experienced only a single metamorphic cycle, i.e., Pan-African-aged, which distinguishes them from other polymetamorphic terranes in the Prydz Belt. This will provide important constraints on the controversial nature of the Prydz Belt. 展开更多
关键词 U-Th-Pb monazite dating Sm-Nd mineral-whole-rock dating pan-african-aged Grove Mountains East Antarctica
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刚果盆地西南缘Inkisi组碎屑锆石U-Pb年代学:对地层时代及物源的约束
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作者 靳立杰 张洪瑞 +6 位作者 罗迪柯 贾鹏飞 高继雷 李春稼 王子圣 刘伟 周永刚 《地质与勘探》 CAS CSCD 北大核心 2024年第3期515-529,共15页
Inkisi组是泛非运动之后刚果盆地最早的沉积地层之一。确定Inkisi组地层时代、物源及恢复构造演化过程,对研究刚果盆地的演化具有重要地质意义。本文通过对Inkisi组碎屑锆石进行U-Pb年代学研究,深入探讨了其形成时代,对泛非运动进行了约... Inkisi组是泛非运动之后刚果盆地最早的沉积地层之一。确定Inkisi组地层时代、物源及恢复构造演化过程,对研究刚果盆地的演化具有重要地质意义。本文通过对Inkisi组碎屑锆石进行U-Pb年代学研究,深入探讨了其形成时代,对泛非运动进行了约束,并进一步探讨了其物源。研究发现,Inkisi组下段与上段碎屑锆石最小年龄分别为526±6 Ma和534±14 Ma,最年轻的4颗锆石的加权平均年龄为532±9.4 Ma,由此限定了Inkisi组的最大沉积时代。因此将其时代划归早寒武世,并将其从新元古界Xisto-Gresoso群解体。另外,Inkisi组岩石并未发生变质变形,也说明其形成于泛非运动之后。碎屑锆石年龄谱结果显示,Inkisi组碎屑锆石的年龄变化范围较广,整体呈现五个年龄峰值:>2800 Ma、2800~2400 Ma、2100~1750 Ma、1500~900 Ma、850~500 Ma。通过将年龄峰值及周围地质体进行对比,认为西刚果造山带、卡赛克拉通、安哥拉克拉通是其主要的物源,卢弗里安构造带等是其次要物源。 展开更多
关键词 Inkisi组 碎屑锆石年代学 地层时代 物源 泛非运动 刚果盆地
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Geochemistry and mineral chemistry of Pan-African amphibolites of South Sinai,Egypt
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作者 Mohamed El-Tokhi Bahaa Eldin Amin +1 位作者 Sulaiman Alabeed Abdulla Musallam 《Chinese Journal Of Geochemistry》 EI CAS 2010年第3期246-254,共9页
In the Wadi Feiran area, amphibolites occur as inclusions, bands, linear bodies of variable thickness and irregular lenses in para-geneisses. Chemical evidence indicates that these amphibolites display an igneous orig... In the Wadi Feiran area, amphibolites occur as inclusions, bands, linear bodies of variable thickness and irregular lenses in para-geneisses. Chemical evidence indicates that these amphibolites display an igneous origin and were derived from magma essentially of tholelitic rather than alkaline composition; transitional in character between continental and island-arc. The chemistry of amphiboles, related to pressure and temperature conditions of metamorphism, showed that they were formed under low pressure and high temperature conditions. 展开更多
关键词 地球化学特征 西奈半岛 矿物 埃及 碱性岩浆 温度条件 高温条件 夹杂物
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Magnetic Characterization of Amphibolites from the Fomopéa Pluton(West Cameroon):Their Implication in the Pan-African Deformation of the Central African Fold Belt
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作者 NJANKO Théophile FOZING Eric Martial +2 位作者 KWéKAM Maurice YAKEU SANDJO Angéline Flore NJONFANG Emmanuel 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2012年第1期73-84,共12页
The Fomopea granitic pluton is emplaced in gnessic and amphibolitic basement. These gneissic and amphibolitic basement rocks are represented in the pluton's body as sub-rounded, elongated or stretched xenoliths. Amph... The Fomopea granitic pluton is emplaced in gnessic and amphibolitic basement. These gneissic and amphibolitic basement rocks are represented in the pluton's body as sub-rounded, elongated or stretched xenoliths. Amphibolitic xenoliths display testimonies of two main tectonic events namely: (i) El flattening deformation event characterized by a NW-SE to E-W foliation with a best pole at 246/57 and a mineral stretched lineation with a best line at 293/47; and (ii) E2 compressive event typified by (1) N-S to NNE-SSW steeply dipping foliation; (2) S-type flexion-fold indicating a sinistral shear movement. These amphibolite rocks indicate a magnetic susceptibility magnitude (Km) range from 418 ~SI to 90092 IISI for 87% of the stations showing a ferromagnetic behavior. K-T curves reveal the presence of Ti-poor magnetite as susceptibility mineral carrier. Magnetic foliation and lineation suggest that the N-S strike direction observed in the Bamendou amphibolite is, as pointed out elsewhere in the Central African Fold Belt, of paramount importance in the tectonic evaluation of the Fomopea area, since it has most likely acted as major deformation phase in the second tectonic event in the belt. 展开更多
关键词 AMPHIBOLITE anisotropy of magnetic susceptibility (AMS) pan-african fold belt Cameroon
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Petrography and Mineralogy of the Quartz and Quartz-Feldspar Sulphide Veins in the Pan-African Syenitic Massif of Guider (North Cameroon)
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作者 Marguerite Boyabe Daouda Dawai +1 位作者 Rigobert Tchameni Periclex Martial Fosso Tchunte 《Open Journal of Geology》 2020年第3期235-259,共25页
In the syenitic pluton of Guider (593 ± 4 Ma) in the North-West Cameroon domain of Central African Fold Belt, mineralized N-S to NE-SW vertical or sub-vertical quartz and quartz feldspar veins has been recently i... In the syenitic pluton of Guider (593 ± 4 Ma) in the North-West Cameroon domain of Central African Fold Belt, mineralized N-S to NE-SW vertical or sub-vertical quartz and quartz feldspar veins has been recently identified. In this contribution, we present petrography and mineralogy of these veins, in order to constrain their genesis and emplacement mechanisms based on detailed field work, petrographic studies and chemical characterization of minerals by using an electron probe microanalyser (EPMA). Field observations and vein microstructures show that the emplacement of the veins has been controlled by the dextral N-S trending strike-slip shear zones related to the regional D2 deformation phase. The results of mineralogical analysis reveal the co-presence of silicates and metallic minerals that include magnetite, ilmenite, pyrite, bismuthite, galena (very rare) and sulphide complexes (BiPbS, BiAgPbS, FeBiPbCuS, BiFe(TeS), FeBiPbS, BiPbCuS). The gangue is represented by quartz (quartz 1, quartz 2 and quartz 3), feldspars, sericite, chlorite, yellowish brown clay minerals, and hematite. The textural relationships between sulphides, quartz and alteration products show that the mineralization is essentially syn- to late-D2 and suggest that syenitic country rock and dextral shear zones have played an important role in the metallogenesis of these veins. This mineralization shows characteristics for copper-bearing calc-alkaline deposits, but differs from these by its more extensive alteration and its abundance in hematite. Substitutions of Al(IV) by Si(IV) in sericite associated with the sulphide mineralization and cataclastic deformation suggest that the temperature of trapping of the fluids is between 230&#176;C and 275&#176;C. 展开更多
关键词 Guider pan-african Syenitic Intrusion QUARTZ and Quartz-Feldspar VEINS SULPHIDE Mineralization
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稀土-PAN配合物的近红外发光研究 被引量:5
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作者 孟建新 陈大志 +3 位作者 李景娆 冯德雄 李敬辉 谢国伟 《发光学报》 EI CAS CSCD 北大核心 2002年第1期49-52,共4页
金属指示剂 1 ( 2 吡啶偶氮 ) 2 萘酚 (PAN)对Ln3 + (Ln3 + =Yb3 + ,Nd3 + 和Er3 + )的近红外发光有不同的敏化作用 ,不论在固体还是在溶液中 ,PAN分子都可显著地敏化Yb3 + 离子的发光 ,对Er3 + 离子的发光也有一定的敏化作用 ,但... 金属指示剂 1 ( 2 吡啶偶氮 ) 2 萘酚 (PAN)对Ln3 + (Ln3 + =Yb3 + ,Nd3 + 和Er3 + )的近红外发光有不同的敏化作用 ,不论在固体还是在溶液中 ,PAN分子都可显著地敏化Yb3 + 离子的发光 ,对Er3 + 离子的发光也有一定的敏化作用 ,但不能敏化Nd3 + 离子的发光。溶剂的种类对配合物溶液的近红外发光强度有非常明显的影响。根据配体三重态能级与Ln3 + 的发射能级匹配的原理和浓度猝灭效应 ,对不同条件下Ln 展开更多
关键词 pan 镧系离子 近红外发光 镧(Ⅲ) LN^3+ 稀土配合物 1-(2-吡啶偶氮)-2-苯酚
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1-(2-吡啶偶氮)-2-萘酚(PAN)修饰碳糊电极测定Co(Ⅱ)的研究 被引量:1
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作者 史兴旺 张国荣 《化学传感器》 CAS 2003年第3期42-49,共8页
该文研制了1-(2-吡啶偶氮)-2-萘酚(PAN)碳糊修饰电极(CMCPE),并且建立了微分脉冲伏安法测定Co(Ⅱ)的方法。分析过程包括一在搅拌条件下开路富集步骤,然后是在0.1mol·L^(-1)NaOH溶液中将富集在电极表面的Co(Ⅱ)氧化,最后利用微分脉... 该文研制了1-(2-吡啶偶氮)-2-萘酚(PAN)碳糊修饰电极(CMCPE),并且建立了微分脉冲伏安法测定Co(Ⅱ)的方法。分析过程包括一在搅拌条件下开路富集步骤,然后是在0.1mol·L^(-1)NaOH溶液中将富集在电极表面的Co(Ⅱ)氧化,最后利用微分脉冲阴极伏安法获得分析峰,测定下限约为5.9×10^(-9)mol·L^(-1)。只有较少的物质如V~Ⅱ、Ce~Ⅲ、EDTA等发生干扰,这些干扰很容易消除。电极应用于人发中Co(Ⅱ)的分析。 展开更多
关键词 1-(2-吡啶偶氮)-2-萘酚 pan 碳糊修饰电极 测定 Co(Ⅱ) 微分脉冲阴极伏安法 钴离子
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1-(2-吡啶偶氮)-2-萘酚(PAN)修饰碳糊电极测定痕量铋
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作者 周益辉 易师 +1 位作者 匡云飞 何定庚 《Journal of Chemistry and Chemical Engineering》 2008年第11期38-44,共7页
该文研制了1-(2-吡啶偶氮)-2-萘酚(PAN)修饰碳糊电极(CMCPE),并且建立了溶出伏安法测定Bi(III)的方法。在1.0X10^-4mol/L HCl底液中,从-0.6V~0.6V进行阳极化扫描,在0.2V左右出现一灵敏的铋溶出峰,其二次导数峰电流和Bi(II... 该文研制了1-(2-吡啶偶氮)-2-萘酚(PAN)修饰碳糊电极(CMCPE),并且建立了溶出伏安法测定Bi(III)的方法。在1.0X10^-4mol/L HCl底液中,从-0.6V~0.6V进行阳极化扫描,在0.2V左右出现一灵敏的铋溶出峰,其二次导数峰电流和Bi(III)浓度在6.0X10^-1mol/L~2.0X10^-5mol/L范围内呈良好的线性关系,其线性言和为ip=0.0225c+0.0619(ip为μA,c为10^-6mol/L),相关系数R为0.9985,检出限达1.0X10^-7mol/L。方法应用于胃叶中痕量Bi(III)的测定,实验结果满意。 展开更多
关键词 1-(2-吡啶偶氮)-2-萘酚(pan) 碳糊修饰电极 溶出伏安法
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PAN-蛋白质络合物的极谱吸附波及其应用
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作者 郑石英 罗登柏 《分析试验室》 CAS CSCD 北大核心 2010年第3期44-46,共3页
在0.05 mol/L HAc溶液中,PAN-牛血清白蛋白/人血清白蛋白络合物在-0.58 V(vs.SCE)处产生一灵敏吸附还原峰,峰电位较之游离PAN还原峰负约0.28 V,峰电流与牛血清白蛋白、人血清白蛋白浓度在0.1~12 mg/L,0.1~11 mg/L范围内呈线性关系;检... 在0.05 mol/L HAc溶液中,PAN-牛血清白蛋白/人血清白蛋白络合物在-0.58 V(vs.SCE)处产生一灵敏吸附还原峰,峰电位较之游离PAN还原峰负约0.28 V,峰电流与牛血清白蛋白、人血清白蛋白浓度在0.1~12 mg/L,0.1~11 mg/L范围内呈线性关系;检测限均为0.05 mg/L。运用该法测定了人血清样品蛋白质含量。 展开更多
关键词 单扫描极谱法 1-(2-吡啶偶氮)-2-萘酚(pan) 牛血清白蛋白(BSA) 人血清白蛋白(HSA)络合物
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吐温80-PAN分光光度法测定钢样中的镍
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作者 宋官龙 《当代化工》 CAS 2016年第1期205-206,209,共3页
研究了以1-(2-吡啶偶氮)-2-萘酚(PAN)-吐温-80为显色体系,采用分光光度法测定钢样中的镍(Ⅱ)。在氨-氯化铵缓冲溶液体系中,镍(Ⅱ)与PAN形成红色稳定的络合物。其最大吸收波长为568 nm,表面摩尔吸光系数为ε568=4.62×104 L&... 研究了以1-(2-吡啶偶氮)-2-萘酚(PAN)-吐温-80为显色体系,采用分光光度法测定钢样中的镍(Ⅱ)。在氨-氯化铵缓冲溶液体系中,镍(Ⅱ)与PAN形成红色稳定的络合物。其最大吸收波长为568 nm,表面摩尔吸光系数为ε568=4.62×104 L·mol-1·cm-1。镍(Ⅱ)含量在0~15μg/(25 m L)范围内服从比尔定律。采用联合掩蔽剂消除样品中的铁(Ⅲ)、铜(Ⅱ)、钒(Ⅴ)、铅(Ⅱ)、等对镍(Ⅱ)离子的干扰。使用该方法测定了38#、45#钢样中的镍(Ⅱ)含量,其RSD分别为2.60%、0.10%,加标平均回收率分别为101.48%、104.96%。此方法具有良好的准确性、选择性,且操作简便、快捷,结果满意。 展开更多
关键词 pan 吐温-80 分光光度法 钢样 镍(Ⅱ)
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African swine fever virus MGF505-3R inhibits cGAS-STING-mediated IFN-βpathway activation by degrading TBK1 被引量:1
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作者 Mingyang Cheng Jiawei Luo +14 位作者 Yuetong Duan Yu Yang Chunwei Shi Yu Sun Yiyuan Lu Junhong Wang Xiaoxu Li Jianzhong Wang Nan Wang Wentao Yang Yanlong Jiang Guilian Yang Yan Zeng Chunfeng Wang Xin Cao 《Animal Diseases》 2022年第3期154-164,共11页
African swine fever virus(ASFV)is an important pathogen causing acute infectious disease in domestic pigs and wild boars that seriously endangers the global swine industry.As ASFV is structurally complex and encodes a... African swine fever virus(ASFV)is an important pathogen causing acute infectious disease in domestic pigs and wild boars that seriously endangers the global swine industry.As ASFV is structurally complex and encodes a large number of functional proteins,no effective vaccine has been developed to date.Thus,dissecting the mechanisms of immune escape induced by ASFV proteins is crucial.A previous study showed that the ASFV-encoded protein is an important factor in host immunity.In this study,we identified a negative regulator,MGF505-3R,that significantly downregulated cGAS/STING-and poly(dG:dC)-mediated IFN-βand interferon stimulation response element(ISRE)reporter activity and suppressed IFNB1 and IFIT2 mRNA levels.In addition,TBK1,IRF3 and IκBαphosphorylation levels were also inhibited.Mechanistically,MGF505-3R interacted with cGAS/TBK1/IRF3 and targeted TBK1 for degradation,thereby disrupting the cGAS-STING-mediated IFN-βsignaling pathway,which appears to be highly correlated with autophagy.Knockdown MGF505-3R expression enhanced IFN-βand IL-1βproduction.Taken together,our study revealed a negative regulatory mechanism involving the MGF505-3R-cGAS-STING axis and provided insights into an evasion strategy employed by ASFV that involves autophagy and innate signaling pathways. 展开更多
关键词 african swine fever virus MGF505-3R cGAS/STING signaling pathway TBK1 Innate immunity
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Evaluation of the Third 90 of the 90-90-90 Cascade for the Period 2019-2020 in the Central African Republic
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作者 Gilles Stéphane Landry Ngaya Brice Martial Yambiyo +5 位作者 Alain Farra Pulchérie Pelembi Aubin Bere Davy Golongba Steve Kamadom Alain Berlioz-Arthaud 《World Journal of AIDS》 2021年第4期189-198,共10页
<strong>Introduction</strong> In Central-African Republic, according to UNAIDS in 2019, out of approximately 100,000 people living with HIV, 70% (72,000) knew their HIV status and 47,000 (46%) were on ARV ... <strong>Introduction</strong> In Central-African Republic, according to UNAIDS in 2019, out of approximately 100,000 people living with HIV, 70% (72,000) knew their HIV status and 47,000 (46%) were on ARV therapy;however, there is a paucity of data on viral load suppression in people on ARV therapy. The objective of this study was to assess the third 90 of the UNAIDS strategy for the years 2019 and 2020 in the CAR. <strong>Methods</strong> We analyzed the available viral load data extracted from the data base of the medical analysis laboratory (SYSLAM) of the Institut Pasteur of Bangui for the years 2019 and 2020. The viral loads were determined based on plasma collected in an EDTA tube with Cepheid’s GeneXpert<sup><span style="white-space:nowrap;">&#174;</span></sup> 16-module controllers. Viral load data were extracted from SYSLAM, converted to Excel format, and analyzed with STATA version 14 software. The significance threshold for the statistical tests was set at 5%. <strong>Results</strong> This study included 22,895 patients, of who 72% were female. The average age was 40.82 years, and the majority of the patients (80%) came from the city of Bangui. Regarding the virological parameters associated with this study, 66% of the patients had significant viral load suppression according to the WHO recommendations and 34% were in virological failure. Patients over 50 years of age (71.85%) and age group 40 - 49 years (69.25%) recorded significant levels of viral load suppression. On the other hand, 63.45% of patients under 18 years of age had virological failure. All of these results were statistically significant (p < 0.005). <strong>Conclusion</strong> There should be a concerted effort, to make viral load accessible and available to all patients receiving ARV treatment in the CAR and the management of HIV/AIDS infection of children and adolescents should be given special attention. 展开更多
关键词 HIV ARV Viral Load Suppression 90-90-90 Target Central african Republic
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