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红色文学作品中《红岩》的思政教育解读 被引量:4
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作者 徐兴灵 《语文建设》 北大核心 2015年第10X期45-46,共2页
长篇小说《红岩》由作家罗广斌、杨益言创作,描写的是全国解放前夕,重庆地下共产党员和国民党反动派作斗争的故事,以"中美合作所"管制下的"渣滓洞"和"白公馆集中营"为主要活动场所,记载了一大批革命者在... 长篇小说《红岩》由作家罗广斌、杨益言创作,描写的是全国解放前夕,重庆地下共产党员和国民党反动派作斗争的故事,以"中美合作所"管制下的"渣滓洞"和"白公馆集中营"为主要活动场所,记载了一大批革命者在监狱中同敌人做顽强斗争的故事,塑造了一系列共产党员的光辉形象。由于作者本人也因为学生运动被国民党逮捕关进集中营,小说的人物大多是根据真人真事描写的,使这部小说既有小说的特点,又有人物传记的真实感。这部小说自问世以来就广受欢迎,影响了几代人,在今天仍然具有重要意义。 展开更多
关键词 《红岩》 江姐 成岗 刘思扬
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Petrogenesis of Mesozoic granitoids and volcanic rocks in South China: A response to tectonic evolution 被引量:732
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作者 Xinmin Zhou Tao Sun +2 位作者 Weizhou Shen Liangshu Shu Yaoling Niu 《Episodes》 SCIE 2006年第1期26-33,共8页
This paper summarizes the new results on the petrogenesis of Mesozoic granitoids and volcanic rocks in South China. The authors propose that these rocks were formed in time and space as a response to regional tectonic... This paper summarizes the new results on the petrogenesis of Mesozoic granitoids and volcanic rocks in South China. The authors propose that these rocks were formed in time and space as a response to regional tectonic regime change from the continent-continent collision of the Indosinian orogeny within the broad Tethyan orogenic domain in the Early Mesozoic (T1-T3) (Period Ⅰ) to the largely extensional setting as a result of the Yanshanian orogeny genetically associated with the NW-WNW-ward subduction of the paleo-Pacific oceanic lithosphere in the Late Mesozoic (J2-K2) (Period Ⅱ). Of the Period I Indosinian granitoids, the early (T1-T2^1) ones are syn-collisional, and formed in a compressional setting; the late (T2^2-T3) ones are latecollisional, and formed in a locally extensional environment. During the Period Ⅱ Yanshanian magmatism, the Early Yanshanian (J2-J3) granitoid-volcanic rocks, which are distributed mainly in the Nanling Range and in the interior of the South China tectonic block (SCB), are characteristic of rift-type intraplate magmatism, whereas the Late Yanshanian K1 granitoidovolcanic rocks are interpreted as genetically representing active continental margin magmatism. The K2 tholeiitic basalts interlayered with red beds are interpreted as genetically associated with the development of back-arc extensional basins in the interior of the SCB. The Yanshanian granitoid-volcanic rocks are distributed widely in South China, reflecting extensional tectonics within much of the SCB. The extension-induced deep crustal melting and underplating of mantle-derived basaltic melts are suggested as the two principal driving mechanisms for the Yanshanian granitic magmatism in South China. 展开更多
关键词 SOUTHEASTERN CHINA CRUSTAL EVOLUTION JAPANESE ISLANDS GEOCHEMISTRY MAGMATISM ASIA ND CONSTRAINTS SUBDUCTION ACCRETION
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Use of X-ray computed tomography to study structures and particle contacts of granite residual soil 被引量:15
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作者 SUN Yin-lei TANG Lian-sheng 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第4期938-954,共17页
A small problem about soil particle regularization and contacts but essential to geotechnical engineering was studied.The soils sourced from Guangzhou and Xiamen were sieved into five different particle scale ranges(d... A small problem about soil particle regularization and contacts but essential to geotechnical engineering was studied.The soils sourced from Guangzhou and Xiamen were sieved into five different particle scale ranges(d<0.075 mm,0.075 mm≤d<0.1 mm,0.1 mm≤d<0.2 mm,0.2 mm≤d<0.5 mm and 0.5 mm≤d<1.0 mm)to study the structures and particle contacts of granite residual soil.The X-ray micro computed tomography method was used to reconstruct the microstructure of granite residual soil.The particle was identified and regularized using principal component analysis(PCA).The particle contacts and geometrical characteristics in 3D space were analyzed and summarized using statistical analyses.The results demonstrate that the main types of contact among the particles are face-face,face-angle,face-edge,edge-edge,edge-angle and angle-angle contacts for particle sizes less than 0.2 mm.When the particle sizes are greater than 0.2 mm,the contacts are effectively summarized as face-face,face-angle,face-edge,edge-edge,edge-angle,angle-angle,sphere-sphere,sphere-face,sphere-edge and sphere-angle contacts.The differences in porosity among the original sample,reconstructed sample and regularized sample are closely related to the water-swelling and water-disintegrable characteristics of granite residual soil. 展开更多
关键词 X-ray computed tomography granite residual soil RECONSTRUCTION REGULARIZATION particle contact
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Attacks on adult females with infants by non-resident males in the Franois langur 被引量:2
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作者 Qi-Hai ZHOU Bang LUO Cheng-Ming HUANG 《Zoological Research》 CAS CSCD 北大核心 2013年第1期I0014-I0017,共4页
Infanticide by males is a common phenomenon in mammals, especially primates, as lactation lasts much longer than gestation in many species. Usually, infanticidal episodes occur soon after group takeovers, and are trad... Infanticide by males is a common phenomenon in mammals, especially primates, as lactation lasts much longer than gestation in many species. Usually, infanticidal episodes occur soon after group takeovers, and are traditionally considered a male reproductive strategy (i.e., support the sexual selection hypothesis, Hrdy, 1974). To verify the validity of this conception, we observed one group of Franqois' langurs in the Nonggang Nature Reserve, China, between August 2003 and July 2004. During the study period, a Francois' langur female with the youngest infant in the group was attacked three times by immigrating males, and later disappeared by the third day after the final attack. We suggest that these attacks on the female-infant dyad represent infanticide attempts by males, and may be the cause of the adult female and her infant's disappearance. Presumably, that female dispersed with her infant to avoid infanticide and was not killed. Though these observations do not completely verify the sexual selection hypothesis, they are not inconsistent with it. 展开更多
关键词 INFANTICIDE Reproductive tactics Franqois' langur (Trachypithecusfrancoisi)
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Cu and Zn Speciation in an Acid Soil Amended withAlhalline Biosolids 被引量:3
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作者 LUO YONGMINGInstitute of Soil Science, the Chinese Academy of Sciences, Nanjing 210008 (China) 《Pedosphere》 SCIE CAS CSCD 2002年第2期165-170,共6页
Fractionation of metals in acid sandy loam soil amended withalkaline-stabilised sewage sludge biosolids was conducted in order toassess metal bioavailability and environmental mobility. Soilsolution was extracted by a... Fractionation of metals in acid sandy loam soil amended withalkaline-stabilised sewage sludge biosolids was conducted in order toassess metal bioavailability and environmental mobility. Soilsolution was extracted by a centrifugation and filtration technique.Meal speciation in the soil solution was determined by a cationexchange resin method. Acetic acid and EDTA extracting solutions wereused for extraction of metals in soil solid surfaces. Metaldistribution in different fractions of soil solid phase wasdetermined using a three-step sequential extraction scheme. 展开更多
关键词 alkaline-stabilised sewage sludge chemical speciation Cu granite soil
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Particle Size Distribution of Kaolinite and Halloysite in Weathering Products of Granite and Its Implications for Pedogenesis
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作者 WANGYONGJIN等 YANGHAO 《Pedosphere》 SCIE CAS CSCD 1997年第3期211-218,共8页
The kaolins collected from a profile of weathered granite at Yichun County, Jiangxi Province have been subjected to particle size fractionation by the conventional sedimentation method and examined by XRD,SEM and TEM.... The kaolins collected from a profile of weathered granite at Yichun County, Jiangxi Province have been subjected to particle size fractionation by the conventional sedimentation method and examined by XRD,SEM and TEM. All of them exhibit a mixture phase of poorly crystallized kaolinites and halloysites (0.7 nm) occurring as the main clay minerals. Electron micrographs reveal that plate kaolinites are the principal constitution in the coarse fraction, and more tubular and curled halloysite (0.7 nm) in the fine fraction. Both of them show normal probability curves in particle size distributions. The ratios of kaolinite and halloysite (0.7 nm) in different size fractions are examined by X-ray diffraction with a series of X-ray patterns characterized by three main peaks at d(001), d(002) and d(020),varying in intensity. Therefore, an index Qhm, expressed as (Id(001) + Id(002))/(2×Id(020)), is designed to indicate relative ratios of the two clay minerals in a number of mixture phases. Because kaolinite and halloysite (0.7nm) commonly occurred, respectively, in low and medium leaching microenvironment, the index Qhm can be used to indicate weathering and pedogenic.conditions of a weathering crust. 展开更多
关键词 kaolin-group minerals particle size distribution weathering crust
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Emotional Costs and Self-efficacy as Predictors of Coping Among the Reemployed and Professional Interns
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作者 Katarzyna Slebarska Agata Chudzicka-Czupala 《Sociology Study》 2013年第5期354-362,共9页
The main goal of the study was to investigate the emotional costs experienced by the organizational newcomers during the first period of reemployment and its relation to general self-efficacy CGSE} and coping. The stu... The main goal of the study was to investigate the emotional costs experienced by the organizational newcomers during the first period of reemployment and its relation to general self-efficacy CGSE} and coping. The study was conducted among 123 previous unemployed, involving 88 reemployed and 35 interns. Questionnaires battery was administered in two waves {T1 and T2~ in the first month of reemployment and after three months. In this article, the data from T2 were analyzed, which allows observing the final results and interactions between research variables. The results showed emotional costs and GSE as significant predictors of coping in the work re-entry phase. Additionally, emotional costs partially mediate the effect of GSE on coping. The differences between both groups, the reemployed and interns were also analyzed. 展开更多
关键词 Emotional costs SELF-EFFICACY coping strategies reemployment
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Petrogenesis and tectonic setting of granite porphyry in Keyouzhongqi area,Inner Mongolia 被引量:1
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作者 WU Qing YANG Weihong +3 位作者 HE Zhonghua YANG Deming MA Rui WANG Jianguo 《Global Geology》 2014年第1期24-33,共10页
The authors studied the geochemistry, zircon U-Pb ages, Hf isotope of the granite porphyry and its petrogenesis and tectonic setting in the studied area. The zircon U-Pb dating indicates the formation of the granite p... The authors studied the geochemistry, zircon U-Pb ages, Hf isotope of the granite porphyry and its petrogenesis and tectonic setting in the studied area. The zircon U-Pb dating indicates the formation of the granite porphyry is in Early Cretaceous ( 125.1 ± 1.5 Ma). The granite porphyry has high-SiO2 and alkali-rich features, which belongs to high-K talc-alkaline series rocks ( A/CNK = 0. 95%-1. 25% ). The analyses of trace elements show the characteristics of a swallow-shaped REE distribution pattern with enrichment in LREEs and most of LILEs and HFSEs, depletion in Ba, Sr, Nb, P and Ti, and especially strong depletion in Eu, which indicates the granite porphyry belongs to the aluminous A-type granite. Their εHf(t) range from 5.94 to 8.80 with Hf two-stage model ages (TDM2 ) of 620 Ma to 803 Ma. Combining with the regional tectonic background, we conclude that the source of the rocks is the new crust materials accreted from depleted mantle in Neoproterozoic and is the product of partial melting of middle and lower crustal rocks, which may be suffered from the dual impact of the subduction of the Palaeo-Pacific Ocean and the closure of the Mongol-Okhotsk Ocean. 展开更多
关键词 PETROGENESIS granite prophyry A-type granite zircon U-Pb dating Keyouzhongqi area Inner Mongolia
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Petrogenetic contrastive studies on the Mesozoic early stage ore-bearing and late stage ore-barren granites from the southern Anhui Province 被引量:11
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作者 YAN Jun HOU TianJie +6 位作者 WANG AiGuo WANG DeEn ZHANG DingYuan WENG WangFei LIU JianMin LIU XiaoQiang LI QuanZhong 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第11期1920-1941,共22页
Yanshanian magmatisms are intensive in the southern Anhui Province and can be divided into early (152-137 Ma) and late (136-122 Ma) stages. A Yanshanian granitic zone was found to crop out along Qingshan to Changg... Yanshanian magmatisms are intensive in the southern Anhui Province and can be divided into early (152-137 Ma) and late (136-122 Ma) stages. A Yanshanian granitic zone was found to crop out along Qingshan to Changgai areas in the Ttmxi district in Field investigation which has a genetic link with molybdenum multiple metal mineralization. To be a representative syenitic granite in the southern Anhui Province, the Huangshan pluton has not been found so far to have any genetic link with mineralization. Zircon LA-ICP-MS dating indicate that the four granitic bodies from the Qingshan-Changgai zone have concurrent formed ages from 140~:4 to 141~2 Ma, belonging to the Yanshanian early stage magmatism. However, the Huangshan granite is dated to be 12912 Ma, belonging to the Yanshanian late stage magmatism. The Qingshan-Changgai granites show high SiO2 and K20 contents, low P205 contents and middle A12O3 contents and are high-K calc-alkaline series metaluminum I-type granite. These rocks are characterized by enrichments in the large ion lithophile elements and light rare earth elements (REE), depletions in the high field-strength elements, and middle degree negative anomalies of Eu, geochemical features of arc or continent crustal derived magma affinities. These rocks have 87Sr/StSr(t) ratios from 0.7120 to 0.7125,εNd(t) values from -7.24 to -4.38 and zircon εHf(t) values of -4.4 to 6.7, similar to that of the coeval ore-bearing granodiorites in the southern Anhui Province. Integrated geochemical studies indicate that the Yanshanian ore-bearing granodiorites were formed by partial melting of the Meso-Neoproterozoic accreted thickened low crust. Meanwhile, the Qingshan-Changgai granites were formed through a AFC process of plagioclase+amphibole+Shangxi Group of magmas that formed the ore-bearing granodiorites. The Huangshan granites are characterized by high SiOz and K2O contents, moderate Al2O3 contents, seagull shape REE distributed pattern and distinct Eu negative abnormities. Comparing with the Qingshan-Changgai granites, the Huangshan granites show more Ba, Sr, P, and Ti negative abnormities with no Nb and Ta depletions and are high-K calc-alkaline series metaluminum A-type granite, εHr(t) values of the Huangshan granites are from -6.6 to -1.2, similar to that of the early stage ore-bearing granodiorites, indicating that they were also formed by anatexis of the Meso-Neoproterozoic accreted crust, but their magma sources might be residual granulitic crust which ever underwent Yanshanian early stage I-type intermediate-acid magma extraction. Comparing studies on the two stages granites indicate that the early stage granites derived from a relative thickened low crust under a lower temperature condition. Their magma sources were Meso-Neoproterozoic accreted crust which enriched in ore-forming materials and further became more enriched through processes of magma AFC evolution. However, the late stage A-type granites originated from relative shallow crust under a higher temperature condition. Their magma source was depleted in ore-forming materials due to the early stage magma extraction and thus had weak ore-forming capacity. From early to late stage, the magmatisms tectonic setting translated from post-orogenic to anorogenic and the later corresponded to a back-arc extensional setting as increase of the slab subducted angle of the Paleo-Pacific plate. 展开更多
关键词 YANSHANIAN Granite Low crust Ore-bearing magmatic rock The south Anhui Province Jiangnan orogenic belt
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Petrogenesis of the concealed Daqiling intrusion in Guangxi and its tectonic significance: Constraints from geochemistry, zircon U-Pb dating and Nd-Hf isotopic compositions 被引量:8
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作者 ZHANG HuaiFeng LU JianJun +3 位作者 WANG RuCheng MA DongSheng ZHU JinChu ZHANG RongQing 《Science China Earth Sciences》 SCIE EI CAS 2014年第8期1723-1740,共18页
The samples from the hidden Daqiling muscovite monzonite granite, which has recently been recognized within the Limu Sn-polymetallic ore field, have been analyzed for zircon U-Pb ages and whole rock geochemical and Nd... The samples from the hidden Daqiling muscovite monzonite granite, which has recently been recognized within the Limu Sn-polymetallic ore field, have been analyzed for zircon U-Pb ages and whole rock geochemical and Nd-Hf isotopic compositions to discuss its genesis, source, and tectonic setting. LA-ICP-MS zircon U-Pb dating indicates that the granite crystallized in the late Indosinian(224.8±1.6 Ma). The granite is enriched in SiO2 and K2 O and low in CaO and Na2 O. It is strongly peraluminous with the A/CNK values of 1.09–1.20 and 1.4 vol%–2.7 vol% normal corundum. Chondrite-normalized REE patterns show slightly right-dipping shape with strongly negative Eu anomalies(δEu =0.08–0.17). All samples show enrichment of LILEs(Cs, Rb and K) and HFSEs(U, Pb, Ce and Hf), but have relatively low contents of Ba, Sr and Ti. The zircon saturation temperatures(Tzr) are from 711 to 740°C, which are slightly lower than the average value of typical S-type granite(764°C). The granite has negative εNd(t) and εHf(t) values, which change from ?9.1 to ?10.1 with the peak values of ?9.2 to ?9.0 and from ?3.7 to ?12.6 with the peak values of ?6 to ?5, respectively. The C DMT(Nd) and C DMT(Hf) values are 1.74–1.82 Ga with the peak values of 1.73–1.75 Ga and 1.49–2.04 Ga with the peak values of 1.5–1.6 Ga, respectively. These characteristics reveal that the source region of the granite is dominantly late Paleoproterozoic to early Mesoproterozoic crustal materials. Seven inherited magmatic zircons are dated at the age of 248.6±4.3 Ma, which suggests the existence of the early Indosinian granite in Limu area. These zircons have the εHf(t) values of ?6.7– ?2.3, similar to those of the Daqiling granite, implying the involvement of the early Indosinian granite during the formation of the Daqiling granite. Inherited zircon of 945±11 Ma has the εHf(t) and TDM(Hf) values of 8.7 and 1.14 Ga, respectively, compatible with those of the Neoproterozoic arc magmatic rocks in the eastern Jiangnan orogenic belt. Therefore we inferred that Neoproterozoic arc magma might have been involved in the formation of the Daqiling granite, and that the Neoproterozoic arc magma belt and continent-arc collision belt between the Yangtze and Cathaysia Blocks might have extended westsouthward to Limu region. It is proposed that the underplating of mantle materials triggered by crustal extension and thinning resulted in partial melting of crustal materials to form the Daqiling granite in the late Indosinian under post-collisional tectonic setting. 展开更多
关键词 Daqiling concealed granite zircon U-Pb dating Nd-Hf isotopic compositions petrology and geochemistry POST-COLLISION
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Petrogenetic simulation of the Archean trondhjemite from Eastern Hebei, China 被引量:2
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作者 ZHANG ShiWei WEI ChunJing DUAN ZhanZhan 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第5期958-971,共14页
It is generally believed that trondhjemitic rock, an important component of TTG rocks, is the anatectic product of mafic rocks. However, in many TTG gneiss terranes, for instance, the granulite facies terrane in Easte... It is generally believed that trondhjemitic rock, an important component of TTG rocks, is the anatectic product of mafic rocks. However, in many TTG gneiss terranes, for instance, the granulite facies terrane in Eastern Hebei, trondhjemites occur as small dikes, intrusions or leucosomes in tonalitic gneisses, suggesting their origin of in-situ partial melting. Based on the petrological analysis of a tonalitic gneiss sample from Eastern Hebei, in combination with zircon U-Pb dating, we investigated the petrogenesis of trondhjemite through simulating anatectic reactions and the major and trace element characteristics of the product melt at different pressures(0.7, 1.0 and 2.0 GPa). The results indicate that hornblende dehydration melting in a tonalitic gneiss at 0.9–1.1 GPa and 800–850°C, corresponding to the high-T granulite facies, with melting degrees of 5–10wt.% and a residual assemblage containing 5–10wt.% garnet, can produce felsic melts with a great similarity, for instance of high La/Yb ratios and low Yb contents to the trondhjemitic rocks from Eastern Hebei. However, the modelled melts exhibit relatively higher K2 O, and lower CaO and Mg~# than those in the trondhjemitic dikes and leucosomes from Eastern Hebei, suggesting that the leucosomes may not only contain some residual minerals but also be subjected to the effect of crystal fractionation. The zircon U-Pb dating for the tonalitic and trondhjemitic rocks in the Eastern Hebei yields a protolith age of 2518±12 Ma and a metamorphic age of 2505±19 Ma for the tonalitic gneiss. The latter age is consistent with a crystallization age of 2506±6 Ma for the trondhjemitic rock, confirming a close petrogenetic relation between them. 展开更多
关键词 Trondhjemite TTG gneiss Anatexis Phase equilibria modelling Eastern Hebei
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Multiple-aged granitoids and related tungsten-tin mineralization in the Nanling Range, South China 被引量:51
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作者 CHEN Jun WANG RuCheng +2 位作者 ZHU JinChu LU JianJun MA DongSheng 《Science China Earth Sciences》 SCIE EI CAS 2013年第12期2045-2055,共11页
The Nanling metallogenic belt in South China is characterized by well-developed tungsten-tin mineralization related to multi- ple-aged granitoids. This belt is one of the 5 key prospecting and exploration areas among ... The Nanling metallogenic belt in South China is characterized by well-developed tungsten-tin mineralization related to multi- ple-aged granitoids. This belt is one of the 5 key prospecting and exploration areas among the 19 important metallogenic tar- gets in China. Important progress has been made in recent years in understanding the Nanling granitoids and associated miner- alization, and this paper introduces the latest major findings as follows: (1) there exists a series of Caledonian, Indosinian, and Yanshanian W-Sn-bearing granites; (2) the Sn-bearing Yanshanian granites in the Nanling Range form an NE-SW trending aluminous A-type granite belt that stretches over 350 km. The granites typically belong to the magnetite series, and dioritic micro-granular enclaves with mingling features are very common; (3) the Early Yanshanian Sn- and W-bearing granites pos- sess different petrological and geochemical features to each other: most Sn-bearing granites are metaluminous to weakly per- aluminous biotite (hornblende) granites, with zircon tHe(t) values of ca. -2 to -8, whereas most W-bearing granites are peralu- minous two-mica granites or muscovite granites with CHf(t) values of ca. -8 to -12; (4) based on the petrology and geochemis- try of the W-Sn-bearing granites, mineralogical studies have shown that common minerals such as titanite, magnetite, and bio- tite may be used as indicators for discriminating the mineralizing potential of the Sn-bearing granites. Similarly, W-bearing minerals such as wolframite may indicate the mineralizing potential of the W-bearing granites. Future studies should be fo- cused on examining the internal relationships between the multiple-aged granites in composite bodies, the metallogenic pecu- liarities of multiple-aged W-Sn-bearing granites, the links between melt evolution and highly evolved ore-bearing felsic dykes, and the connections between granite domes and mineralization. 展开更多
关键词 Nanling Range tungsten-bearing granites tin-bearing granites mineralizing potential ore-forming peculiarities
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Geochemistry, geochronology, and petro-genesis of the early Paleozoic granitic plutons in the central-southern Jiangxi Province,China 被引量:23
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作者 ZHANG Yuan SHU LiangShu CHEN XiangYun 《Science China Earth Sciences》 SCIE EI CAS 2011年第10期1492-1510,共19页
This paper reports the systematic study on petrology, geochemistry, LA ICPMS zircons U-Pb dating, and in situ Hf isotope geology of the four plutons in the central-southern Jiangxi Province, an important part of the S... This paper reports the systematic study on petrology, geochemistry, LA ICPMS zircons U-Pb dating, and in situ Hf isotope geology of the four plutons in the central-southern Jiangxi Province, an important part of the South China Block. In the outcrops, rocks are gradually changed from wall rock (slate or schist) to pluton (gneissic granite); some residual blocks of sandy rock occur in the margin of pluton, and the foliations of residual blocks are parallel to those of both wail rock and gneissic granite. The thin-section observations show that the four plutons contain peraluminous minerals such as muscovite and sillimanite. The flattened and elongated feldspar and quartz grains are often visible in the gneissic granite, parallel to direction of lineation, suggesting that the granitic rock were subjected to a strong ductile sheafing. Geochemically, the A/CNK values from 13 granitic samples are between 1.03 and 1.37 with an average of 1.16, indicating that the granites are of strongly peraluminous plutons. The REE compositions of the 13 samples are similar, showing higher EREE contents, with enrichment in LREEs, depletion in Eu and REE patterns with relative LREE-enrichment and negligible Eu anomalies. They show enrichment in Rb, Th, U and depletion in Ba, Sr, Nb, Ti, belonging to a low Ba-Sr type of granite. Thus, the four bodies should be derived from the same magmatic source. Zircons used as U-Pb dating mostly exhibit euhedral shape and high Th/U values from 0.52 to 1.54 with an average of 1.08, suggesting that most zircons are of magmatic genesis. The zircons from four plutons yielded rather similar 206pb/238U vs. 207Tpb/235U concordia ages: 436.1±5.7 Ma for the Tangwan granite, 440.6±4 Ma for the Jiekou gneissic granite, 435.9±6.2 Ma for the Dongbao gneissic granite, and 441.9±3.1 Ma for the Jinxi K-granite, respectively, corresponding to Silurian Llandovery. Several xenocrysts yielded U-Pb ages around 700 Ma, implying that a breakup event took place during Neoproterozoic in the South China Block. In situ Lu-Hf isotopic analysis shows that all εHf(t) values of zircons are negative and have two-stage Hf model ages (TDM2) from 1.4 to 3.6 Ga, indicating that the Silurian granitic magma came from the re- cycle of Meso-Paleoproterozoic basement and even partly Archean rocks, and had not been effected by mantle magma. Re- searches on regional geology suggest that an intracontinental tectono-magmatic event took place during the early Paleozoic in the study areas, which is characterized by folding and thrusting, leading to crustal shortening and thickening, up to 20 km thickness. The high geothermal temperature from thickening crust and accumulation of producing high-heat radioactive elements gradually softened crustal rocks and caused a partial melting, forming peraluminous granitic magma. Under the post-orogenic extensional and de-pressure condition, these granitic magma rose and was emplaced in the upper crust, leading to development of S-type plutons 展开更多
关键词 granite GEOCHEMISTRY LA ICPMS zircon U-Pb dating Hf isotope early Paleozoic central-southern Jiangxi Province
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Description of Soil Evolution in Southern Mashhad City Using Jenny's and Johnson and Watson-Stegner's Conceptual Models
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作者 Alireza KARIMI Isa ESFANDIARPOUR BORUJENI GHASEMZADEH GANJEHIE 《Pedosphere》 SCIE CAS CSCD 2018年第4期656-665,共10页
Conceptual models are suitable for describing internal relationships of complex systems, including soil. We used conceptual models, the Jenny's and Johnson and Watson-Stegner's models to understand the formation and... Conceptual models are suitable for describing internal relationships of complex systems, including soil. We used conceptual models, the Jenny's and Johnson and Watson-Stegner's models to understand the formation and evolution of soil. We studied 20 pedons in granitic hilly lands, loessial piedmont, and piedmont plain in southern Mashhad, northeast Iran. These soils were characterized by high levels of gypsum, especially in the granitic saprolites, which suggested the importance of the wind in shaping the soil structure. Jenny's model is a developmental and equilibrium model, which only describes the state of the soil formation factors and considers that each bioclimatie zone has a specific climax soil. It focuses on the genesis of the surface soil and is not suitable for buried soils and paleosols. Johnson and Watson-Stegner's model describes soil as a product of progressive and regressive processes due to horizonation or haploidization. Progressive processes during the last interglacial cycle created a well-developed paleosol with an argillic horizon in all landforms, except the piedmont plain. Developmental soil up-building by aeolian addition led to gypsum enrichment of the granitic saprolite. Erosion decreased soil thickness and exposed the argillic horizon. The Last Glacial Maximum led to greater deposition of loess, covering the paleosol. Humidity was higher during the early Holocene than today, leading to the development of a Bk horizon. This horizon was preserved in the stable surfaces of granitic hilly land and in the loessial piedmont, but buried on the piedmont plain via the deposition of alluvial sediments. Jenny's model could be used for current soil formation factors, whereas Johnson and Watson-Stegner's model required morphological characteristics of pedons for interpretation. 展开更多
关键词 landscape evolution LOESS progressive pedogenesis regressive pedogenesis soil formation model
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