检索结果-南通市图书馆

Unstable evolution of railway slope under the rainfall-vibration joint action

Journal of Mountain Science 2024年第4期21卷 1419-1431页

作者： DONG Haoyu WANG Jiading ZHANG Dengfei LI Lin XU Yuanjun state key laboratory of continental dynamics Department of GeologyNorthwest UniversityXi’an 710069China

Understanding the unstable evolution of railway slopes is the premise for preventing slope failure and ensuring the safe operation of ***,as two major factors affecting the stability of railway slopes,few scholars have explored the unstable evolution of railway slopes under the joint action of *** on the model test of sandy soil slope,the unstable evolution process of slope under locomotive vibration,rainfall,and rainfall-vibration joint action conditions was simulated in this *** comparing and analyzing the variation trends of soil pressure and water content of slope under these conditions,the change laws of pore pressure under the influence of vibration and rainfall were *** main control factors affecting the stability of slope structure under the joint action conditions were further *** with the slope failure phenomena under these three conditions,the causes of slope instability resulting from each leading factor were ***,according to the above conclusions,the unstable evolution of the slope under the rainfall-vibration joint action was *** test results show that the unstable evolution process of sandy soil slope,under the rainfall-vibration joint action,can be divided into:rainfall erosion cracking,vibration promotion penetrating,and slope instability sliding three *** the process of slope unstable evolution,rainfall and vibration play the roles of inducing and promoting slide *** addition,the deep cracks,which are the premise for the formation of the sliding surface,and the violent irregular fluctuation of soil pressure,which reflects the near penetration of the sliding surface,constitute the instability characteristics of the railway slope *** paper reveals the unstable evolution of sandy soil slopes under the joint action of rainfall-vibration,hoping to provide the theoretical basis for the early warning and prevention technology of railway slopes.

关键词： Rainfall vibration joint action Small scale model tests Unstable evolution process Unstable characteristics Inducing sliding and promoting sliding

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Challenges in applying REE-based thermobarometers: Insights from mafic-ultramafic granulites in Indian southern granulite terrain

引用

Science China Earth Sciences 2024年第11期67卷 3448-3464页

作者： Xiaofei XU Longlong GOU Chengli ZHANG Junsheng LU Yan ZHAO Wenhao AO Yuhua HU Feng ZHOU Faculty of Land Resources Engineering Kunming University of Science and Technology state key laboratory of continental dynamics Department of Geology Northwest University

High-temperature diffusion of major elements may obscure the records of early and peak metamorphic stages in granulites,while trace elements are more likely to preserve these records due to their lower diffusion ***,using calibrated REE-based thermobarometers has proved essential for reconstructing these key stages,drawing considerable attention and application from ***,the precision of these thermobarometers depends on including both major and trace elements from coexisting minerals to define the correlation coefficients（A,B,and D） among mineral pairs,indicating that the elemental composition of these pairs can affect the *** study examines the mafic-ultramafic granulites in the southern granulite terrain,India,employing integrated methods such as petrography,mineral chemistry,phase equilibrium modeling,and REE-based *** aim to determine their metamorphic conditions and evolutionary history and to identify potential challenges in using REE-based *** garnet,clinopyroxene,and orthopyroxene in the mafic-ultramafic granulite samples display homogeneous compositional profiles,with pronounced Fe-Mg diffusion zones at the interfaces between garnet and ***,the profiles of trace elements within garnet and clinopyroxene are better *** into Fe-Mg exchange and randomly selected mineral pairs significantly influence the accuracy of REE-based ***-Mg exchange can increase in coefficient A,while decreasing coefficient B for light rare earth elements（LREEs） and increasing it for heavy rare earth elements（HREEs）,ultimately resulting in overestimations when calculating REE-based *** example,selecting major compositions with an Ex(=(XMgC-XMg0)/XMg0×100%;where XMgCis the value after Fe-Mg exchange,XMg0is the value before Fe-Mg exchange;XMg=Mg/(Fe2++Mg)) value of ～10 for calculation using the REE-in-Grt-Cpx thermobarometer will result in pressures and t

关键词： Granulites REE-based thermobarometer Fe-Mg exchange Randomly selected mineral pairs

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rheology of continental lithosphere and seismic anisotropy

引用

Science China Earth Sciences 2024年第1期67卷 31-60页

作者： Shengsi SUN Yunpeng DONG Yixi LI Yihai YANG Chao CHENG Bo HUI Bin ZHANG Rutao ZANG state key laboratory of continental dynamics Department of GeologyNorthwest UniversityXi’an 710069China Shaanxi Earthquake Agency Xi’an 710068China

Rheology of rocks controls the deformation of the Earth at various space-time scales,which is crucial to understand the tectonic evolution of continental *** of rock rheology are mainly conducted via high-pressure and hightemperature rheological experiments and multi-scale observations and measurements of naturally deformed *** present,a large amount of data from such kinds of studies have been *** paper first provides an up-to-date comprehensive review of the rheological mechanisms,fabric types and seismic properties of the main rock-forming minerals at different depths of continental lithosphere,including olivine,orthopyroxene,clinopyroxene,amphibole,plagioclase,quartz and ***,progress in high-pressure and high-temperature experiments and natural deformation observations is introduced,mainly regarding the rheological strength and behavior,seismic velocity and anisotropy of lithospheric mantle peridotite,eclogite,mafic granulite,amphibolite and felsic ***,by taking the Tibetan Plateau as an example,the application of rock rheology for quantitative interpretation of seismic anisotropy data is *** combination of mineral deformation fabrics and seismic anisotropy is expected to make an important breakthrough in understanding the rheological properties and structure of continental lithosphere.

关键词： Lithosphere Mineral fabric Rheology Seismic velocity Anisotropy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Structural Geology and Chronology of Shear Zones along the Shangdan Suture in Qinling Orogenic Belt,China:Implications for Late Mesozoic Intra-continental Deformation of East Asia

引用

Journal of Earth Science 2024年第2期35卷 376-393页

作者： Falak Sheir Wei Li Le Zhang Basil Alabowsh Liuqing Jiang Li Liang Sainan Gao Shair Baz Umar Ashraf state key laboratory of continental dynamics Department of GeologyNorthwest UniversityXi’an710069China Institute of Geology University of PunjabLahore45590Pakistan

The Shangdan suture zone(SDZ)in the Qinling orogenic belt(QOB)is a key to understanding the East Asia tectonic *** SDZ gives information about convergent processes between the North China Block(NCB)and South China Block(SCB).In the Late Mesozoic,several shear zones evolved along the SDZ boundary that helps us comprehend the collisional deformation between the NCB and SCB,which was neglected in previous *** shear zones play an essential role in the tectonic evolution of the East Asia *** study focuses on the deformation and geochronology of two shear zones distributed along the SDZ,identified in the Shaliangzi and Maanqiao *** shear sense indicators and kinematic vorticity numbers(0.54–0.90)suggest these shear zones have sinistral shear and sub-simple shear deformation *** quartz’s dynamic recrystallization and c-axis fabric analysis in the Maanqiao shear zone(MSZ)revealed that the MSZ experienced deformation under green-schist facies conditions at∼400–500℃.The Shaliangzi shear zone deformed under amphibolite facies at∼500–700℃.The^(40)Ar/^(39)Ar(muscovite-biotite)dating of samples provided a plateau age of 121–123 *** with previously published data,our results concluded that QOB was dominated by compressional tectonics during the Late Early ***,we suggested that the Siberian Block moved back to the south and Lhasa-Qiantang-Indochina Block to the north,which promoted intra-continental compressional tectonics.

关键词： Qinling orogenic belt Shangdan suture zone shear zone Late Mesozoic intra-continental deformation East Asia tectonics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Thermal History of Cambrian Burgess Shale-Type Deposits:New Insights from the Early Cambrian Chengjiang and Qingjiang Fossils of South China

引用

Journal of Earth Science 2024年第4期35卷 1215-1223页

作者： Yuheng Qiao Linhao Cui Guangyuan Xing Dongjing Fu Chao Chang Robert Gaines Xingliang Zhang state key laboratory of continental dynamics Shaanxi Key laboratory of Early Life and EnvironmentsDepartment of GeologyNorthwest UniversityXi’an710069China Department of Geology Pomona CollegeClaremontCA91711USA

Burgess Shale-type deposits provide a wealth of information on the early evolution of *** that are central to understanding the exceptional preservation of these biotas and the paleoenvironments they inhabited may be obscured by the post-depositional alteration due to metamorphism at depth and weathering near the Earth’s *** over 50 Cambrian BST biotas,the Chengjiang and Qingjiang deposits are well known for their richness of soft-bodied taxa,fidelity of preservation,and Early Cambrian *** alteration via weathering has been well-investigated,the thermal maturity of the units bearing the two biotas has not yet been *** we investigate peak metamorphic temperatures of the two deposits using two independent *** gradient analyses demonstrate that the most fossiliferous sections of the Chengjiang were buried at a maximum depth of∼8500 m in the Early Triassic,corresponding to∼300°C,while the type area of the Qingjiang biota was buried at a maximum depth of∼8700 m in the Early Jurassic,corresponding to∼240°*** geothermometer analyses of fossil carbonaceous material demonstrate that peak temperatures varied across localities with different burial *** two productive sections of the Chengjiang biota were thermally altered at a peak temperature of approximately 300°C,and the main locality of the Qingjiang biota experienced a peak temperature of 238±22°*** results from two independent methods are *** BST deposits for which thermal maturity has been documented,the Qingjiang biota is the least thermally mature,and therefore holds promise for enriching our understanding of BST deposits.

关键词： the Chengjiang Biota the Qingjiang Biota burial history Raman geothermometer thermal history Burgess Shale-type Lagerstätte

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Rapid growth in a large Cambrian apex predator

引用

National Science Review 2024年第3期11卷 128-136页

作者：吴雨 Stephen Pates Daniel Pauly 张兴亮傅东静 state key laboratory of continental dynamics and Shaanxi key laboratory of Early Life and Environment Department of Geology Northwest University Department of Zoology University of Cambridge Institute for the Oceans and Fisheries University of British Columbia Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences

Despite the importance of ontogenetic data on early diverging euarthropods to our understanding of the ecology and evolution of past life, the data are distinctly lacking, as reconstructing life histories of fossil animals is often challenging. Here we report the growth trajectory of frontal appendages of the apex predator Amplectobelua symbrachiata, one of the most common radiodont arthropods from the early Cambrian Chengjiang biota(c. 520 Ma) of China. Analysis of 432 specimens(9.1–137.1 mm length; 1.3–25.6 mm height) reveals that appendages grew isometrically, with an estimated maximum size of the whole animal of c. 90 cm. Individuals grew rapidly compared to extant arthropods, as assessed using the electronic length-frequency analysis(ELEFAN) approach. Therefore, we show that the Cambrian apex predator A. symbrachiata was an extremely fast-growing arthropod, with an unusual life history strategy that formed as part of the escalatory ‘arms race’ that shaped the Cambrian explosion over 500 Ma.

关键词： stem-group Euarthropoda Radiodonta post-embryonic development growth dynamics Cambrian Explosion

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Primary and Secondary Calcite in Chinese Loess Distinguished by Crystallinity and Implications for Illuviation Depth and East Asian Summer Monsoon Intensity

引用

Journal of Earth Science 2024年

作者： Yan Zhao Kangjun Huang Yuanqiang Guo Pan Zhang Yawen Lu Long Ma state key laboratory of continental dynamics， Shaanxi key laboratory of Early Life and Environment， Department of Geology， Northwest University

The crystallinity has the potential to distinguish the primary and secondary calcite in Chinese loess， which then provides insights into illuviation depth and variations of the East Asian summer monsoon. However， this aspect has been rarely investigated. In this study， we defined the crystallinity of calcite as the Height/Area (H/A) ratio of the diffracted peak at crystal face (1 0 4). The H/A ratio inversely correlates with the average width of the diffracted peak， where a higher H/A ratio indicates higher crystallinity of calcite. Through the mixing and synthetic experiments， we found that the H/A ratio is minimally affected by factors such as calcite content， deposition temperature or rate but significantly influenced by the ionic impurity and the mixing proportion of different calcites. Subsequently， we examined desert samples of loess sources and loess carbonate nodules. Desert samples predominantly consist of primary calcite which inherits characteristics from cryptocrystalline limestone with high levels of ionic impurities resulting in low H/A ratio of 4.30 ± 0.51. In contrast， loess carbonate nodules contain abundant secondary calcite precipitated within soil interstices with low levels of ionic impurities leading to a significantly higher H/A ratio of 7.76 ± 0.82. Consequently， higher H/A ratios during interglacial periods compared to glacial periods are attributed to variations in relative proportions between primary and secondary calcite in loess sequences. The thickness， between the glacial-interglacial boundary and the depth where the H/A ratio starts to increase from the bottom to the top in the loess layer， can be used to indicate the illuviation depth of upper-soil carbonates and the intensity of the East Asian summer monsoon. This proxy can be further applied in long-term loess sequences to uncover the summer monsoon evolution.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The Origin of Mesozoic A-type Granitoids,Fujian Province,Southeast China:Insights from Geochronology,Mineralogy and Geochemistry

引用

Acta Geologica Sinica(English Edition) 2024年第3期98卷 630-640页

作者： XIE Qifeng DONG Yunpeng CAI Yuanfeng ZHAI Mingguo XIAO Aifang ZHANG Hong Zijin School of Geology and Mining Fuzhou UniversityFuzhou 350108China state key laboratory of continental dynamics Northwest UniversityXi’an 710069China state key laboratory for Mineral Deposits Research Nanjing UniversityNanjing 210023China state key laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

The magma sources,origins and precise forming ages of the miarolite from Qishan and Kuiqi intrusions are still *** results reveal that,miarolites from the Qishan and Kuiqi intrusions yield crystallization ages of~101 and~98 Ma,and they have a high formation temperature(~910℃)and low oxygen fugacity value,indicating crystallization condition at low pressure in the upper crust with temperature of 678℃.The Qishan and Kuiqi miarolites are characterized by enrichment in SiO_(2) and high-K alkali,depletion in Ca and Mg,and belong to the high-K weak peraluminous rock *** samples are enriched in HFSEs(i.e.,Ta,Zr and Hf)and LILEs(i.e.,Ba,P and Sr),depleted in Ba and Sr with the negative anomaly of *** the primitive mantle normalized trace element spider diagram,the samples show a right-inclined‘seagull-type’pattern,combined the ratios of(La/Yb)_(N),10000×Al/Ga,Rb/Nb and Nb/Ta etc.,they were proved to be alkaline A-type *** the characterize of the trace elements,they were derived from clay-rich source accompanied pelite melting,and subjected to K-feldspar crystallization *** values of ε_(Hf)(t)and tDM2 are distributed in the range of-2.8 to 3.3 with~1.2 Ga,and-6.0 to 4.0 with~1.2 Ga,revealing that they were generated from the Mesoproterozoic Cathaysia basement *** comprehensive research reveals the Kuiqi and Qishan intrusions derived from crust-mantle mixing and partial melting of the crust,respectively,resulting from lithospheric extension generated by the Paleo-Pacific Plate subducted into the European-Asian Plate.

关键词： A-type granitoid geochronology extension subduction Mesozoic Southeast China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Earthquake potential across the North–South seismic belt of China

引用

Science Bulletin 2024年第2期69卷 179-182页

作者： Yanchuan Li Xinjian Shan Chunyan Qu Guohong Zhang Xiaogang Song state key laboratory of Earthquake dynamics Institute of GeologyChina Earthquake AdministrationBeijing 100029China

The elastic rebound theory,which frames our understanding of earthquakes,suggests that the accumulated elastic strain on faults will ultimately be released through earthquakes[1].As such,identifying the location,rate,and accumulation of slip deficit on faults constitutes a basis for seismic potential assessment[2].Interseismic coupling(ISC)refers to the ratio of the slip deficit rate on a fault to the far-field loading rate,where full and no coupling correspond to 100%and 0%slip deficits,respectively.

关键词： seismic belt fault

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Regulation effect of the grille spacing of a funnel-type grating water–sediment separation structure on the debris flow performance

引用

Journal of Mountain Science 2024年第7期21卷 2283-2304页

作者： LI Shuai GU Tianfeng WANG Jiading WANG Fei LI Pu state key laboratory of continental dynamics/Department of Geology Northwest UniversityXi’an 710069China Chengdu Institute of Mountain Hazards and Environment Ministry of Water Resources&Chinese Academy of SciencesChengdu 610299China

The size of pores or the grille spacing of water–sediment separation structures directly affects their regulation effect on the debris flow performance.A suitable pore size or grille spacing can effectively improve the water–sediment separation ability of the *** new funnel-type grating water–sediment separation structure(FGWSS)combines vertical and horizontal structures and provides a satisfactory water–sediment separation ***,the regulation effect of the grille spacing of the structure on the debris flow performance has not been *** regulation effect of the structure grille spacing on the debris flow performance is studied through a flume test,and the optimal structure grille spacing is *** empirical equation of the relationship between the relative grille spacing of the structure and the sediment separation rate is ***,the influence of the water–sediment separation structure on the regulation effect of debris flows is examined from two aspects:external factors(properties of debris flows)and internal factors(structural factors).The experimental results show that the gradation characteristics of solid particles in debris flows constitute a key factor affecting the regulation effect of the structure on the debris flow *** optimum grille spacing of the FGWSS matches the particle size corresponding to the material distribution curves d85~d90 of the debris *** total separation rate of debris flow particles is related to the grille spacing of the structure and the content of coarse and fine particles in the debris flow.

关键词： Debris flow Water–sediment separation structure Grille spacing Performance regulation effect

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：