期刊文献+
共找到5,199篇文章
< 1 2 250 >
每页显示 20 50 100
Provenance and Paleoclimate of the Triassic to Middle Jurassic Adigrat Sandstone,Blue Nile Basin,Central Ethiopia
1
作者 Bekele BARSISA Ayalew DEREJE +2 位作者 Kidanemariam GILAMICHAEL Atnafu BALEMWAL Raphaël PIK 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第4期1007-1020,共14页
Mineralogical and geochemical studies have been undertaken on the Triassic to Lower Jurassic Adigrat Sandstone of the Blue Nile Basin of central Ethiopia to infer its source rock type,paleoweathering,and paleoclimatic... Mineralogical and geochemical studies have been undertaken on the Triassic to Lower Jurassic Adigrat Sandstone of the Blue Nile Basin of central Ethiopia to infer its source rock type,paleoweathering,and paleoclimatic history.The Adigrat Sandstone occurs at the basal section of the Mesozoic sedimentary formation and unconformably overlays the Neoproterozoic–Paleozoic crystalline rocks,or locally,the Karroo sediments in the northern Blue Nile Basin.A mineralogical study reveals that quartz(Q),feldspars(F),and lithic fragments(L)are the framework grains of the sandstone.On the QFL diagram,the plot of the modal composition of the sandstone mainly falls within the feldspathic arenite and quartzose arenite fields.The geochemical data of the lower section of the sandstone mainly falls within the arkose and subarkose fields,whereas the upper section data falls within the quartzose and sublithic arenite fields.Mineralogical and geochemical weathering indices indicate that the provenances of the Adigrat Sandstone were exposed to pronounced weathering intensity,where the lower part of the sandstone was controlled by arid to semi-arid conditions,whereas the upper section was linked to humid to semi-humid(tropical to subtropical)climatic conditions.Mineralogical and geochemical data also indicate that mafic to intermediate basement rocks were the primary source rocks of the sediment.Perhaps the sediment was assumed to have been reworked by multi-cyclic sedimentary processes.The discriminant function diagram,the REE pattern,La/Th vs.La/Yb,and the Th–Hf–Co plot are consistent.A comparison of provenance studies for the Adigrat Sandstone in the Blue Nile Basin and the Mekele outlier of northern Ethiopia indicates that the sediment of the former is highly sorted,experienced higher weathering intensity,and compositionally derived from mafic to intermediate crystalline rocks.On the other hand,the sediment of the latter is essentially a weathering product of felsic rocks. 展开更多
关键词 mineralogical geochemical PALEOWEATHERING humid provenance Adigrat Sandstone
下载PDF
Provenance of colorless and brown volcanic glass in late Pleistocene tephra layers in the Western Philippine Sea
2
作者 Fuqing JIANG Zhishun ZHANG +6 位作者 Zhaohui ZHANG Guoliang ZHANG Peng HUANG Xiaojing ZHOU Zhifang XIONG Congying LI Tiegang LI 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第5期1438-1449,共12页
Tephra layers in the western Philippine Sea,characterized by abundant volcanic glass shards,may provide crucial evidence on the eruption history of volcanoes and tectonic evolution of the western Pacific.A 220-ka sedi... Tephra layers in the western Philippine Sea,characterized by abundant volcanic glass shards,may provide crucial evidence on the eruption history of volcanoes and tectonic evolution of the western Pacific.A 220-ka sediment core from the Benham Rise in the western Philippine Sea offers new insights into the provenance of four intercalated tephra layers(T1–T4,in chronological order)containing either colorless or brown glass shards.Relative to primitive mantle,all glass shards are enriched in large-ion lithophile elements,such as Rb,Cs,and Pb,and depleted in high field-strength elements,such as Th,Nb,and Ta,indicating a subduction-related origin.The colorless glass shards are characterized by high SiO_(2)(>78%)and light rare earth element(LREE)contents as well as high La/Sm ratios(>9),low FeO and MgO contents(<1%),low Sr/Y(<15)and high Ba/Th ratios(>100),pointing to a rhyolitic composition and a medium-K calc-alkaline serial affinity.In contrast,the brown glass shards are characterized by lower SiO_(2)(<63%)and LREE contents,higher FeO,MgO,and CaO contents,lower La/Sm(<6)and Ba/Th(<75),and similar Sr/Y ratios(<15),indicating derivation from medium to high-K calc-alkaline andesite magma.Brown glass shards from layers T3(152 ka)and T4(172 ka)were correlated with volcanic deposits from the Taal and Laguna Caldera in the Maccolod Corridor,respectively,while the colorless glass shards from layers T1(36.5 ka)and T2(61.2 ka)were likely sourced from the Irosin Caldera in the Bicol Arc.Establishing the provenance of late Pleistocene tephra layers in the western Philippine Sea is helpful to complement a Philippine volcanic history and establish a regional tephrochronostratigraphy. 展开更多
关键词 volcanic glass provenance chemical composition Philippine Sea late Pleistocene
下载PDF
Mineralogy and whole-rock geochemistry of the Oligocene Barail Group of rocks of Belt of Schuppen,Northeast India:Implications for tectono-provenance and paleo-weathering
3
作者 Manash Pratim Gogoi Yunpeng Dong +6 位作者 Pradip Borgohain Devojit Bezbaruah Arvind Pandey Yadav Krishna Gogoi Garima Konwar Gautam Raj Bawri Bubul Bharali 《Acta Geochimica》 EI CAS CSCD 2024年第5期904-932,共29页
The petrographic and geochemical attributes of the Oligocene Barail Group of rocks are used to decipher the likely source area(s)or tectonic domains,as this sequence of rocks was deposited in a foreland basin governed... The petrographic and geochemical attributes of the Oligocene Barail Group of rocks are used to decipher the likely source area(s)or tectonic domains,as this sequence of rocks was deposited in a foreland basin governed by orogenic domain,namely the North-east Arunachal Himalayas.The river system that gave rise to the Brahmaputra River(Yarlung-Tsangpo),which flowed through several tectonic domains of the Himalayan ranges,primarily from BomiChayu,Gangadese Granitoid,Higher Himalayan Leucogranites,and Namche Barwa into the proto Bengal Basin now a part of Assam Arakan Basin and Naga Schuppen Belt,was the main source of the sandstone formation of the Barail Group.The purpose of sandstone petrography,which combines modal analysis with XRF(Major Oxides)and HR-ICPMS(Trace&Rare Earth Elements)research,is to identify the type of source rock(s),their weathering pattern,and its paleo-environmental circumstances.These sandstones were formed from recycled orogen and include lithic and sublithic arenite variants with advanced texture and chemical maturity.The sediments were felsic(Th/Co:1.38,Cr/Th:9.78,La/Lu:11.58,Th/Sc:0.99,Eu/Eu*:0.66,La/Sc:3.05,La/Co:4.18),with contributions from intermediate source rocks and low-rank metamorphics deposited in an active continental margin to a continental island arc setting.Climatic conditions impacted the sediments of Barails,characterised by being warm and semi-humid to humid which resulted in moderate to a high degree of chemical weathering,as shown by weathering indices like CIA(79.14),PIA(85.47),CIW(86.9),WIP(32.50),ICV(0.71),and Th/U(6.03),which were further additionally supported by C-Value(1.01),PF(1.20),Sr/Cu(2.04),and Rb/Sr(0.97). 展开更多
关键词 Belt of Schuppen Barail Group Sandstone PETROGRAPHY Geochemistry provenance Tectonic setting
下载PDF
Provenance of Conglomerate and Sandstone from Early Permian Shoushangou Formation in Xi Ujimqin,Inner Mongolia:Implications for Understanding Paleo-Asian Ocean Subduction
4
作者 ZHANG Yingli GUO Xianqing MA Shouxian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第1期10-31,共22页
During the Late Carboniferous to Early Permian,a rift was formed by post-collisional extension after ocean closure or an island arc-related basin formed by Paleo-Asian Ocean(PAO)subduction in the Xi Ujimqin area.Never... During the Late Carboniferous to Early Permian,a rift was formed by post-collisional extension after ocean closure or an island arc-related basin formed by Paleo-Asian Ocean(PAO)subduction in the Xi Ujimqin area.Nevertheless,the closure time of the PAO is still under debate.Thus,to identify the origin of the PAO,the geochemistry and U-Pb age of zircons were analyzed for the extra-large deep marine,polymict clastic boulders and sandstones in the Shoushangou Formation within the basin.The analyses revealed magmatic activity and tectonic evolution.The conglomerates include megaclasts of granite(298.8±9.1 Ma)and granodiorite porphyry(297.1±3.1 Ma),which were deposited by muddy debris flow.Results of this study demonstrated that the boulders of granitoids have the geochemistry of typical I-type granite,characterized by low Zr+Nb+Ce+Y and low Ga/Al values.The granitoid boulders were formed in island arc setting,indicating the presence of arc magmatism in the area that is composed of the Late Carboniferous to Early Permian subduction-related granitoid in southern Xi Ujimqin.Multiple diagrams for determining sedimentary provenance using major and trace elements indicate that Shoushangou sediments originated from continental island arc-related felsic rocks.Detrital zircon U-Pb age cluster of 330–280 Ma was obtained,indicating input from granite,ophiolite,Xilin Gol complex,and Carboniferous sources to the south.The basin was geographically developed behind the arc during the Early Permian period because the outcropped intrusive rocks in the Late Carboniferous to Early Permian form a volcanic arc.The comprehensive analyses of source areas suggest that Shoushangou sediments developed in a backarc basin in response to the northward subduction of the PAO.The backarc basin and intrusive rocks,in addition to previously published Late Carboniferous to Early Permian magmatic rocks of arc unit in Xilin Gol,confirm the presence of an Early Permian trencharc-basin system in the region,represented by the Baolidao arc and Xi Ujimqin backarc basin.This study highlights the importance and potential of combined geochemical and geochronological studies of conglomerates and sandstone for reconstructing the geodynamic setting of a basin. 展开更多
关键词 provenance analysis backarc basin Shoushangou Formation Early Permian Central Asian Orogenic Belt
下载PDF
Exploring emerald global geochemical provenance through fingerprinting and machine learning methods
5
作者 Raquel Alonso-Perez James M.D.Day +4 位作者 D.Graham Pearson Yan Luo Manuel A.Palacios Raju Sudhakar Aaron Palke 《Artificial Intelligence in Geosciences》 2024年第1期202-219,共18页
Emeralds-the green colored variety of beryl-occur as gem-quality specimens in over fifty deposits globally.While digital traceability methods for emerald have limitations,sample-based approaches offer robust alterna-t... Emeralds-the green colored variety of beryl-occur as gem-quality specimens in over fifty deposits globally.While digital traceability methods for emerald have limitations,sample-based approaches offer robust alterna-tives,particularly for determining the geographic origin of emerald.Three factors make emerald suitable for provenance studies and hence for developing models for origin determination.First,the diverse elemental chemistry of emerald at minor(<1 wt%)and trace levels(<1 to 100’s ppmw)exhibits unique inter-element fractionations between global deposits.Second,minimally destructive techniques,including laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS),enable measurement of these diagnostic elemental signatures.Third,when applied to extensive datasets,machine learning(ML)techniques enable the creation of predictive models and statistical discrimination with adequate characterization of the deposits.This study em-ploys a carefully selected dataset comprising more than 1000 LA-ICP-MS analyses of gem-quality emeralds,enriched with new analyses.This dataset represents the largest available for global emerald deposits.We con-ducted unsupervised exploratory analysis using Principal Component Analysis(PCA).For machine learning-based classification,we employed Support Vector Machine Classification(SVM-C),achieving an initial accu-racy rate of 79%.This was enhanced to 96.8%through the use of hierarchical SVM-C with PCA filters as our modeling approach.The ML models were trained using the concentrations of eight statistically significant ele-ments(Li,V,Cr,Fe,Sc,Ga,Rb,Cs).By leveraging high-quality LA-ICP-MS data and ML techniques,accurate identification of the geographical origin of emerald becomes possible.These models are important for accurate provenance of emerald,and from a geochemical perspective,for understanding the formation environments of beryl-bearing pegmatites and shales. 展开更多
关键词 BERYL provenance LA-ICP-MS Machine learning Multivariate analysis Trace elements
下载PDF
Variation, heredity and selection of effective ingredients in Magnolis officinalis of different provenances 被引量:4
6
作者 童再康 曾燕如 斯金平 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第1期7-11,82,共5页
Bark samples of Magnolis officinalis were collected from a 7-year-old trial plantation with 13 provenances in Jingning County of Zhejiang Province on June 25, 2000. The contents of magnolol and honokiol of M. officina... Bark samples of Magnolis officinalis were collected from a 7-year-old trial plantation with 13 provenances in Jingning County of Zhejiang Province on June 25, 2000. The contents of magnolol and honokiol of M. officinalis were analyzed by the method of HPLC (High Performance Liquid Chromatogram). The results showed that such qualitative traits as the content of magnolol, content of honokiol, total content of key phenols, and the ratio of magnolo to honokiol differ significantly between the provenances. The provenances with a sharpened leaf tip from the western part of Hubei Province has a highest content of phenols, and that with a concave leaf tip from the Lushan Mountain has a lowest content of phenols. All these four qualitative traits were genetically controlled, with a heritability between 0.8342 and 0.9871 in terms of provenance. In addition, both longitudinal and latitudinal geographical variations could be found, with longitudinal variations being dominant. As a result, 3 superior provenances from Wufeng, Enshi and Hefeng of the western part of Hubei as well as 10 high-quality individuals were selected. 展开更多
关键词 Magnolia officinalis provenance trial MAGNOLOL HONOKIOL Geographical variation provenance selection
下载PDF
Genetic variations of wood properties and growth characters of Ko-rean pines from different provenances 被引量:4
7
作者 王慧梅 夏德安 +1 位作者 王文杰 杨书文 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第4期277-280,337,共4页
Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatom... Totally 26 provenance stands of 17-year-old Korean pine were selected for investigating wood properties and growth characters in Mao抏rshan Experimental Forest Farm of Northeast Forestry University in 1999. The anatomical property indexes, including tracheid length, tracheid diameter and wall-indiameter ratio, and the physical property indexes, such as growth ring width, late wood percentage and growth ring density, were measured for wood properties. Growth character indexes, including tree height and diameter at breast height, were also measured. The analytical results showed that there exited obviously dif-ference in wood property indexes between different provenances, which is suggested that wood properties are controlled by their genetic differences. The growth character indexes of Korean pines presented significant difference and they might also be controlled by their genetic differences. Most parameters of wood properties mainly varied in the direction of longitude, but the parameters of growth characters varied in the direction of latitude. 展开更多
关键词 Korean pine provenance trial Wood properties Geographical variation Genetic variation
下载PDF
Geographic variation and provenance selection for bamboo wood properties in Bambusa chungii 被引量:3
8
作者 杨秀艳 傅懋毅 +1 位作者 谢锦忠 李正才 《Journal of Forestry Research》 SCIE CAS CSCD 2009年第A3期261-267,287,共9页
Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed... Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed by the methods of Analysis of variance and correlation coefficient to reveal the geographic genetic variation situation. The results showed that there are significant differences between fiber length, fibrin and 1% NaOH extraction contents of B. chungii from 8 provenances; moreover, the fiber length and fiber length/width ratio had a decreasing change pattern with geographic variation from the south to the north in altitude (from high to low in elevation). The heritabilities for fibrin, fiber length, 1% NaOH extractive, lignin and fiber length/width ratio were 0.7, 0.84, 0.54, 0.38 and 0.13, respectively. A significant negative correlation was found between 1% NaOH extraction, benzo-alcohol extraction contents and bamboo culm yield, whereas there was a significant positive correlation between fibrin contents and bamboo wood yield. Besides, a close correlation was detected between fiber dimensions indices and bamboo growth or bamboo wood yield. Finally, three provenances with high qualities and culm yield, i.e. Huaiji, Xinyi and Guilin, were selected as superior sources based on principal component analysis. 展开更多
关键词 Bambusa chungii bamboo wood property pulp-bamboo geographic variation provenance selection
下载PDF
Comparison Experiment of Root Cutting to Castanopsis tibetana Hance between Different Provenances at Seedling Stage
9
作者 王勇 黄宁 +2 位作者 刘雄盛 蒋雨桐 蒋燚 《Agricultural Science & Technology》 CAS 2016年第8期1956-1962,共7页
Castanopsis tibetana of five different provenances (Jinxiu, Longsheng, Ziyuan, Hezhou and Leye) were selected as experimental materials to investigate the effects of treatments combining different root lengths and c... Castanopsis tibetana of five different provenances (Jinxiu, Longsheng, Ziyuan, Hezhou and Leye) were selected as experimental materials to investigate the effects of treatments combining different root lengths and contents of rooting agent on the growth of C. tibetana after transplanting of seedlings. The results showed that, there were significant differences in the preserving rate of C. tibetana seedlings between different provenances and different treatments. Among the 5 treatments, the seedlings of Hezhou provenance showed the maximum annual increment of ground diameter, and the seedlings of Ziyuan provenance exhibited the maximum annual increment of seedling height. Therefore, the germplasm from Hezhou provenance might be better than those from other provenances. 展开更多
关键词 Castanopsis tibetana Different provenances INCREMENT Root cutting
下载PDF
Photosynthetic Characteristic Variation of Different Provenances of Liriodendron chinense Sarg. at Seedling Stage
10
作者 惠利省 徐立安 王章荣 《Agricultural Science & Technology》 CAS 2010年第1期122-125,共4页
[Objective]The aim was to study photosynthetic characteristic variation of different provenances of Liriodendron chinense Sarg. at seedling stage and provide the theoretical basis for work of provenance selection,pare... [Objective]The aim was to study photosynthetic characteristic variation of different provenances of Liriodendron chinense Sarg. at seedling stage and provide the theoretical basis for work of provenance selection,parent selection of hybridizing breeding,genetic resource conservation of L.chinense Sarg.. [Method]With 13 provenances 1-year-old L.chinense Sarg. seedlings as tested materials,the photosynthetic characteristic variation of different provenances were studied. [Result]The L.chinense Sarg. seedlings of different provenances had the significant difference on net photosynthetic rate (Pn),stomata conductivity (Gs) and water use efficiency (WUE). The Pn of the highest provenance was 2.36 times the lowest. Majority seed sources light saturation point (LSP) were in 800-1 200 μmol photons/(m2·s). Gs,transpiration rate (Tr) and Pn were significantly positively correlated,and the three had a significant positive correlation with the light compensation point (LCP). Pn,LSP and WUE were negatively correlated. [Conclusion]The photosynthetic characteristics of L.chinense Sarg. had significant variation among provenances. Maybe Gs is the important factor leading to difference in Pn of L.chinense Sarg. seedlings. L.chinense Sarg. seedlings still need higher light intensity and more water. 展开更多
关键词 Liriodendron chinense Sarg. provenance Photosynthetic characteristics
下载PDF
Evaluation of Drought Resistance of Olive Varieties from Different Provenances
11
作者 李勇杰 张艳丽 +5 位作者 宁德鲁 贺娜 陈芳 耿树香 陈海云 毛云玲 《Agricultural Science & Technology》 CAS 2014年第11期1905-1907,共3页
In order to study olive’s drought resistance in Yunnan province, different varieties of olive trees from Albania, Italy, Spain and Greece were cultured, and leaves from these trees in drought season and rainy season ... In order to study olive’s drought resistance in Yunnan province, different varieties of olive trees from Albania, Italy, Spain and Greece were cultured, and leaves from these trees in drought season and rainy season were col ected and determined by physiological indices, such as proline content, relative electric con-ductivity, binding water/free water, relative water content and malon-dialdehyde in leaves. The evaluation of drought resistance with subordinate function showed that:There were no significant differences among drought resistances of varieties and provenances. The change of physiological indices in different varieties showed differ-ent ranges. The drought resistance of seven varieties decreased in order as fol ows:Koroneiki〉 Picual〉 Berat〉 Kaliniot〉 Frantoio〉 Coratina〉 Arbequina. 展开更多
关键词 provenance Olive Physiological indices Drought resistance
下载PDF
WSN中基于逐级重建的Provenance增量压缩
12
作者 王昌达 徐芹宝 +1 位作者 宋泽 毛健 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2018年第4期736-743,777,共9页
在无线传感器网络(WSN)中,一般使用溯源(Provenance)对基站(BS)接收的数据进行可信性评估。针对当前的Provenance分段传输方法平均压缩比较低,并且只有当获取所有Provenance分段后才可以解码Provenance等问题,提出了一种基于逐级重建的P... 在无线传感器网络(WSN)中,一般使用溯源(Provenance)对基站(BS)接收的数据进行可信性评估。针对当前的Provenance分段传输方法平均压缩比较低,并且只有当获取所有Provenance分段后才可以解码Provenance等问题,提出了一种基于逐级重建的Provenance增量传输方法,即在WSN多级分簇基础上,运用整数素因子分解具有唯一性这一性质,首次传输最粗粒度的Provenance,其余每次只传输各个粒度之间的增量信息,实现了在解码Provenance时BS能够按粒度从高到低逐级重建Provenance,因此有效克服了上述现有Provenance分段传输方法平均压缩比低、在未获得全部Provenance分段前不能解密等问题。理论分析与实验数据显示,与传统的Provenance分段传输方法相比,本方法在Provenance压缩比、鲁棒性以及能耗方面均优于当前存在的Provenance分段传输方法。 展开更多
关键词 无线传感网络 多级分簇 溯源 增量传输 逐级重建 分段传输
下载PDF
The role of provenance in the diagenesis of siliciclastic reservoirs in the Upper Triassic Yanchang Formation,Ordos Basin,China 被引量:16
13
作者 Ding Xiaoqi Han Meimei Zhang Shaonan 《Petroleum Science》 SCIE CAS CSCD 2013年第2期149-160,共12页
A better understanding of the controls on reservoir quality has become essential in the petroleum exploration in recent years. Determining the original composition of tile sediment framework is important not only for ... A better understanding of the controls on reservoir quality has become essential in the petroleum exploration in recent years. Determining the original composition of tile sediment framework is important not only for paleogeographic reconstructions, but it is also vital tbr predicting the nature of physical and chemical diagenesis of the potential reservoirs. Depositional setting and diagenesis are important factors in controlling the type and quality of most siliciclastic reservoirs. We studied the Upper Triassic Chang 8 and 6 members, where the relationship between sediment provenance and diagenesis was examined. The study attempts to clarify sediment provenance and post-depositional diagenetic modifications of the sandstones through systematic analytical methods including petrographic macro- and microscopic analysis of grain and heavy mineral types, and measurements of the palaeocurrent direction of the Yanchang Formation sediments in the outcrops in order to determine the provenance of the studied sediments. Furthermore, the relationship between framework grains, pore types and diagenesis of the sediments was analyzed by thin section petrographic characterization using a polarizing microscope. Additionally, a JEOL JSM-T330 scanning electron microscope (SEM) equipped with a digital imaging system was used to investigate the habits and textural relationships of diagenetic minerals. On the basis of our results, we believe that sediment provenance is a significant factor which controls the type and degree of diagenesis which may be expected in sandstones. In the Chang 8 and 6 members, tile formation of chlorite rims and laumontite cement was observed where volcanic rock fragments constitute a large part of the framework grains. Furthermore, high biotite content provides abundant iron and magnesium and enables the tbnnation of chlorite rims due to biotite hydrolysis. In addition, ductile deformation of biotite leads to strong mechanical compaction of the sediments. Conversely, high feldspar content diminishes the degree of mechanical compaction, however the dissolution of feldspar minerals in sandstones is commonly observed. Apart from feldspars, quartz and other rigid fi'amework grains highly control the degree of mechanical compaction during the initial stage of burial (0-2 km). 展开更多
关键词 provenance DIAGENESIS tight sandstones Yanchang Formation Ordos Basin
下载PDF
Evaluating the Provenance of Metasedimentary Rocks of the Jiangxian Group from the Zhongtiao Mountain Using Whole-Rock Geochemistry and Detrital Zircon Hf Isotope 被引量:16
14
作者 LI Qiugen CHEN Xu +4 位作者 LIU Shuwen WANG Zongqi ZHOU Yingkui ZHANG Jian WANG Tao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2009年第3期550-561,共12页
In this study, whole-rock geochemical and Nd isotopic data, as well as detrital zircon Hf isotopes of Palaeoproterozoic metasedimentary rocks from the Jiangxian Group are presented to evaluate the characteristics of t... In this study, whole-rock geochemical and Nd isotopic data, as well as detrital zircon Hf isotopes of Palaeoproterozoic metasedimentary rocks from the Jiangxian Group are presented to evaluate the characteristics of their provenance and the tectonic history. The major and trace element compositions are comparable to Post-Archean upper continental crust (PA-UCC), but have slight enrichment in the LILE, with the exception of Cs and Sr, and a slight depletion in ferromagnesian elements, HFS elements, such as Nb and Ta, and some major elements, such as CaP and Na2O. The geochemical data reveal that the collected metasedimentary rocks have experienced intermediate source weathering with chemical index of alteration values ranging from 72 to 78, varying degrees of K- metasomatism, and post-depositional loss of Na, as well as negligible sorting, and are derived from the weathering of mostly felsic and non-mafic rocks. The selected Lu-Hf isotopic analysis on detrital zircon points to both the Trans-North China Orogen and Eastern Block of the north China craton as the most likely sources for the metasedimentary rocks of the Jiangxian Group. However, a contribution of detritus from the Western Block of the north China craton can be ruled out. The sediments were probably deposited in a back-arc basin within an active continental margin setting. 展开更多
关键词 Paleoproterozoic metasediment geochemistry provenance tectonic setting JiangxianGroup north China craton
下载PDF
The Impact of the Linked Factors of Provenance,Tectonics and Climate on Potash Formation:An Example from the Potash Deposits of Lop Nur Depression in Tarim Basin,Xinjiang,Western China 被引量:20
15
作者 LIU Chenglin JIAO Pengcheng +5 位作者 Lü Fenglin WANG Yongzhi SUN Xiaohong ZHANG Hua WANG Licheng YAO Fojun 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第6期2030-2048,共19页
Potash deposits commonly accumulate in highly restricted settings at the final stage of brine evaporation. This does not mean that potash deposits are formed simply as a result of the evaporation concentration of seaw... Potash deposits commonly accumulate in highly restricted settings at the final stage of brine evaporation. This does not mean that potash deposits are formed simply as a result of the evaporation concentration of seawater or lake water, but rather as a coupling result of particular provenance, tectonics and climate activities. In this paper, we focus on the formative mechanism of the potash deposits of Lop Nur depression in Tarim Basin to interpret the detailed coupling mechanism among provenance, tectonics and climate. In terms of the provenance of Lop Nur Lake, the water of the Tarim River which displays "potassium-rich" characteristics play an important role. In addition, the Pliocene and Lower-Middle Pleistocene clastic beds surrounding Lop Nur Lake host a certain amount of soluble potassium and thus serves as "source beds" for potash formation. During the late Pliocene, the Lop Nur region has declined and evolved into a great lake from the previous piedmont and diluvial fan area. Since the mid Pleistocene, the great-united Lop Nur Lake has been separated and has generated a chain system consisting of Taitema Lake, Big Ear Lake and Luobei Lake which has turned into the deepest sag in Lop Nur Lake. Dry climate in Lop Nur region has increased since the Pliocene, and became extreme at the late Pleistocene. The study implies that potash formation in Lop Nur Lake depends on the optimal combination of extreme components of provenance, tectonics and climate during a shorter-term period. The optimal patterns of three factors are generally characterized by the long-term accumulation and preliminary enrichment of potassium, the occurrence of the deepest sub-depression and the appearance of an extremely arid climate in Lop Nur region. These factors have been interacting synergistically since the forming of the saline lake and in the later stages strong "vapor extraction" caused by extremely arid climate is needed to trigger large scale mineralization of potash deposits. 展开更多
关键词 Potash formation coupling mechanism provenance TECTONICS CLIMATE Lop Nur Tarim basin
下载PDF
Geochemical-geomorphological Evidence for the Provenance of Aeolian Sands and Sedimentary Environments in the Hunshandake Sandy Land, Eastern Inner Mongolia, China 被引量:14
16
作者 LIU Ziting YANG Xiaoping 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2013年第3期871-884,共14页
Identifying the provenance of aeolian sediments in the Hunshandake Sandy Land is of great importance for understanding the formation of the dune fields in the mid-latitudes and for deciphering information about desert... Identifying the provenance of aeolian sediments in the Hunshandake Sandy Land is of great importance for understanding the formation of the dune fields in the mid-latitudes and for deciphering information about desert's responses to global change. By determining the major and trace elements concentrations of aeolian sands in three grain size fractions from the central and western parts of the Hunshandake Sandy Land, we systematically study the provenance and the depositional history of aeolian sands in this desert environment. Our results show that aeolian sands from the Hunshandake Sandy Land are enriched in SiO2 and are depleted in many other elements compared to those of the Upper Continent Crust (UCC). Variations of the immobile elements ratios like Zr/Hf, La/Yb, Th/Nb, La/Nb, LaN/YbN, GdN/YbN are relatively large in the coarse and medium fractions but minor in the fine fractions. Eu anomalies are quite different in the coarse fractions, but mostly positive in the medium fractions and all negative in the fine fractions. Decreasing tendency of Zr concentrations from the west to the east in the Hunshandake Sandy Land is evident in the coarse sands but rather weak in the fine grain size fractions. Our geochemical data indicate that the sources for the coarse and medium fractions of aeolian sands are diverse, influenced by local geology and geomorphology, while the fine sand fractions are more homogenous due to intensive mixture mainly by aeolian processes. Various ratios of immobile elements suggest that these sands should be sourced primarily from the surrounding mountains by fluvial/alluvial processes rather than from any remote territories. Aeolian sands with Ce negative anomalies are widely distributed in the Hunshandake Sandy Land, indicating that aquatic environments have occurred extensively prior to the occurrence of the dune field. 展开更多
关键词 sediment provenance trace element major element REE aeolian process GEOMORPHOLOGY geochemistry DUNE
下载PDF
Thrusting and Exhumation Processes of a Bounding Mountain Belt: Constraints from Sediment Provenance Analysis of the Hefei Basin 被引量:12
17
作者 刘少峰 刘文灿 +2 位作者 戴少武 黄思骥 陆五云 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2001年第2期144-150,共7页
Lithic (or gravel) composition analyses of the Jurassic Sanjianpu Formation and Fenghuangtai Formation in the Hefei basin show that the sediment provenance consists mainly of four kinds of rock units: the basement met... Lithic (or gravel) composition analyses of the Jurassic Sanjianpu Formation and Fenghuangtai Formation in the Hefei basin show that the sediment provenance consists mainly of four kinds of rock units: the basement metamorphic complex, granitic rocks, medium- and low-grade metamorphic rocks, and sandy and muddy sedimentary rocks, which are distributed along the bounding thrust belt. The whole stratigraphic section can be divided into 2 lithic sequences and 7 subsequences. The regular distribution and changes of lithic fragments and gravels in lithic (or gravel) sequences reflect that the bounding thrust belt of basin has undergone 2 thrusting cycles and 7 thrusting events. Lithic (or gravel) composition analyses of the basin fully reveal that the northern Dabie basement metamorphic complex was exhumed on the earth's surface in the Middle and Late Jurassic, and extensive intermediate and acid intrusive rocks were developed in the southern North Huaiyang or northern Dabie Mountains during the basin's syndepositional stage. 展开更多
关键词 northern Dabie Mountains Hefei basin sediment provenance thrusting and exhumation
下载PDF
A heavy mineral viewpoint on sediment provenance and environment in the Qiongdongnan Basin 被引量:10
18
作者 LIU Xiaofeng ZHANG Daojun +5 位作者 ZHAI Shikui LIU Xinyu CHEN Hongyan LUO Wei LI Na XIU Chun 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2015年第4期41-55,共15页
Based on heavy mineral data in core samples from eleven drillings, supplemented by paleontological, element geochemical and seismic data, the evolution of sediment provenance and environment in the Qiongdongnan Basin ... Based on heavy mineral data in core samples from eleven drillings, supplemented by paleontological, element geochemical and seismic data, the evolution of sediment provenance and environment in the Qiongdongnan Basin (QDNB) was analysed. The results show that the basement in the QDNB was predominantly composed of terrigenous sediments. Since the Oligocene the QDNB has gradually undergone transgressions and evolution processes in sedimentary environment from terrestrial-marine transitional to littoral-neritic, neritic, and bathyal roughly. The water depth showed a gradually increasing trend and was generally greater in the southern region than that in the northern region in the same time. With changes in sedimentary environment, provenances of the strata (from the Yacheng Formation to the Yinggehai Formation) showed principal characteristics of multi-sources, evolving from autochthonous source, short source to distant source step by step. During the Early Oligocene, the sediments were mainly proximal basaltic pyroclastic source and adjacent terrigenous clastic source, afterwards were becoming distant terrigenous clastic sources, including Hainan Island on the north, Yongle Uplift on the south, Shenhu Uplift on the northeast, the Red River System on the northwest and Indochina Peninsula on the southwest, or even a wider region. The Hainan Island provenance began to develop during the Early Oligocene and has become a main provenance in the QDNB since the Middle Miocene. The provenances from Yongle Uplift and Shenhu Uplift most developed from the Late Oligocene to the Early Miocene and gradually subsided during the Middle Miocene. During the Late Miocene, as a main source of sediments filled in the central canyon, the Red River System provenance added to the QDNB massively, whose impact terminated at the end of the Pliocene. The western Yinggehai Basin (YGHB) provenance derived from Indochina Peninsula had developed from the Pliocene on to the Pleistocene. In addition, the material contribution of marine authigenous source to the basin (especially to the southern region) could not be ignored. 展开更多
关键词 heavy minerals provenance sedimentary environment Qiongdongnan Basin northern South ChinaSea
下载PDF
Genetic variation and selection of introduced provenances of Siberian Pine(Pinus sibirica) in frigid regions of the Greater Xing'an Range,Northeast China 被引量:7
19
作者 Xiyang Zhao Cheng Wang +7 位作者 Shuchun Li Wei Hou Shiqing Zhang Guijie Han Deng Pan Ping Wang Yufei Cheng Guifeng Liu 《Journal of Forestry Research》 SCIE CAS CSCD 2014年第3期549-556,共8页
Siberian Pine (Pinus sibirica) is an ecologically and eco-nomically important species in pristine forests throughout northern Rus-sia. Four provenances of P. sibirica were introduced from Mongolia and Russia to the ... Siberian Pine (Pinus sibirica) is an ecologically and eco-nomically important species in pristine forests throughout northern Rus-sia. Four provenances of P. sibirica were introduced from Mongolia and Russia to the Greater Xing’an Range (the Daxing’anling), northeast China in 1993. The aim of this research was to study genetic variation and selection of the introduced four Pinus sibirica provenances. Heights (H), basal diameters (BD), survival rates (SR) and crown lengths (CL) of different families were measured as primary outcomes in different growth years. Results of data analyses demonstrated high coefficients of phenotypic variation (PCV) and heritability (H2) for H, BD and CL at 18 years after introduction. PCV and H2 increased with age. Correlations of&amp;nbsp;growth traits between any two growth years were all significantly positive, but the correlation coefficient was smaller when the growth year interval was larger. Correlations between H and the original environment factors decreased gradually, indicating that with long-term subsistence in the new environment, the influence of the source environment declined. Colligation of multiple traits to estimate provenances showed that Novosibirsk, Tomsk, and Altai Mountains had higher survival rates and biomass, and proved more suitable for introduction and plantation in the Greater Xing’an Range in China. 展开更多
关键词 Pinus sibirica provenance genetic testing variation SELECTION
下载PDF
Geochemistry of Carboniferous Sandstones (Sardar Formation), East-Central Iran: Implication for Provenance and Tectonic Setting 被引量:7
20
作者 Mohammad KHANEHBAD Reza MOUSSAVI-HARAMI +2 位作者 Asadollah MAHBOUBI Mehdi NADJAFI Mohammad Hosein MAHMUDY GHARAIE 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2012年第5期1200-1210,共11页
Geochemical analysis of sandstones from the Sardar Formation (from two stratigraphic successions) in east-central Iran were used for identification of geochemical characterization of sandstones, provenance and tecto... Geochemical analysis of sandstones from the Sardar Formation (from two stratigraphic successions) in east-central Iran were used for identification of geochemical characterization of sandstones, provenance and tectonic setting. Sandstones in the two lithostratigraphic successions have similar chemical compositions suggesting a common provenance. Bulk-rock geochemistry analysis of Carboniferous sandstones from Sardar Formation indicates that they are mainly quartz dominated and are classified as quartzarenites, sublitharenites and subarkoses, derived from acid igneous to intermediate igneous rocks. Discrimination function analysis indicates that the sandstones of Sardar Formation were derived from quartzose sedimentary provenance in a recycled orogenic setting. Also, major and trace elements in sandstones of Sardar Formation (e.g., K2O/Na2O vs. SiO2 ) indicate deposition in a stable passive continental margin (PM). Chemical index of alteration (CIA) for these rocks (65%) suggests a moderate to relatively high degree of weathering in the source area. 展开更多
关键词 provenance CARBONIFEROUS tectonic setting GEOCHEMISTRY Sardar Formation Iran
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部