检索结果-南通市图书馆

Elevational distribution of forests and its spatiotemporal dynamics in subtropical China from 2000 to 2019

Science China earth Sciences 2024年第8期67卷 2563-2582页

作者： Zhencan ZHENG Liuwen ZHUANG Guofang MIAO Han LIU Zhiqiang CHENG Wenyu LI Rong SHANG Peng GONG Jing Ming CHEN Institute of Geography Fujian Normal University key laboratory of Humid Subtropical Eco-Geographical Process (ministry of Education) Fujian Normal University School of Geographical Sciences Fujian Normal University National land Consolidation Center Ministry of Natural Resources key laboratory of land Consolidation and Rehabilitation Ministry of Natural Resources key laboratory of Digital Mapping and land Information Application Ministry of Natural Resources Department of Geography & Planning University of Toronto Department of Geography The University of Hong Kong

The subtropical region of China possesses abundant forest resources and features a mountainous *** the implementation of policies such as natural forest protection,the Grain for Green Project,and other initiatives since the beginning of the 21st century,coupled with climate change,the forest resources in this region have undergone significant changes compared to historical *** addition,forest resources distributing mainly in mountainous areas also implies that these changes may vary significantly with *** explore the spatiotemporal dynamics of forest distribution in subtropical China since 2000,especially the trend of changes with elevation,we analyzed the data from two land cover products focusing on forest cover and forest *** used a hierarchical approach,in which coarse-classification forest cover data with relatively small uncertainties impose constraints on forest type data with larger uncertainties,to achieve a reasonable balance between obtaining more details and reducing data *** first divided the forest cover data into‘unchanged'and‘changed'*** the constraints by the forest cover results,we further analyzed the‘unchanged'and‘changed'forest *** results indicated that,since the implementation of ecological engineering and management policies,54%of the area in the subtropical region had maintained unchanged forest cover attributes over the past 20 years,which implied the good state of ecological *** results also showed that dynamic conversions existed in the long term between forests and lands for essential production needs like *** elevational variations of forest cover suggested that the dominant changes came from the conversion between forests and croplands in low-elevation regions below 700 m,the conversion between forests and shrublands in mid-elevation regions of 700–1500 m,and the conversion between forests and grasslands in high-elevation regions above 2000 *** the regio

关键词： Subtropical China land cover Forest cover Forest type Elevational distribution

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

Transient Fluvial Incision in the Central Segment of the Lancang River Orogenic Belt,Yunnan Province,SW China

引用

Acta Geologica Sinica(English Edition) 2020年第5期94卷 1728-1730页

作者： SHI Xiaohui LI Tingting PEI Lixin WANG Qingtao HUI Bo CHENG Chao State key laboratory of Continental dynamics Department of GeologyNorthwest UniversityXi’an 710069China key laboratory of deep-earth dynamics of ministry of Natural resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China Chengji Middle School Jingning CountyPingliangGansu 743409China

Objective Geomorphology has played a central role in the study of active orogenic *** tectonic deformation associated with the collision of the Indian and Eurasian plates has occurred in the southeastern margin of the... 详细信息

关键词： Eurasian southeastern Plateau

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

Iron isotope fractionation during fenitization:a case study of carbonatite dykes from Bayan Obo,Inner Mongolia,China

引用

Acta Geochimica 2022年第5期41卷 789-793页

作者： Zongyi Wu Jian Sun Xiaowei Li Xiangkun Zhu Institute of Geology MNR Key Laboratory of Deep-Earth DynamicsChinese Academy of Geological Sciences MNR Key Laboratory of Isotope Geology100037 BeijingPR China State key laboratory of Geological Processes and Mineral resources School of Earth Science and ResourcesUniversity of Geosciences100083 BeijingChina

As a powerful tracer in high-temperature geochemistry,Fe isotopes have been studied for their behaviour during fl uid exsolution and evolution related to felsic magma system,but that for carbonatite magma system remains *** we study the Fe isotope fractionation behaviour during fenitization–processes that widely occur associated with carbonatite or alkaline *** fenite/carbonatite samples from carbonatite dykes at Bayan Obo area are analyzed for their Fe isotope compositions as well as elemental *** with previous reported carbonatite δ^(56)Fe data,the results show that carbonatites range from-0.35‰to 0.28‰,with an average of-0.10‰in δ^(56)Fe values,while fenites range from-0.17‰to 0.30‰,with an average of 0.11‰in δ^(56)Fe *** indicates that fenitizing fl uids exsolved from carbonatite melts are enriched in heavier Fe *** a Fe isotope fractionation trend is diff erent from that for fl uid exsolution from felsic magmatism.δ^(56)Fe values in fenites are negatively correlated with indicators of fenitization intensity such as(Na+K),Ti,Ba,Th,Nb,U or Pb abundances,likely refl ecting that Fe isotopes fractionate during the evolution of the fenitizing fl ***,Fe isotopes are a valuable tool for tracing fl uid exsolution and evolution relevant to carbonatite magmatism and related metal mineralization.

关键词： Iron isotopes Fenitization Fluid exsolution Carbonatite Bayan Obo

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

Zircon U-Pb Ages and Tectonic Implications of Late Paleozoic Volcanic Rocks in the Western Tianshan,North Xinjiang,China

引用

Journal of earth Science 2022年第3期33卷 736-752页

作者： Zaili Tao Jiyuan Yin Wen Chen Yuelong Chen Jingbo Sun Zhihua Xu School of earth Sciences and resources China University of GeosciencesBeijing 100083China key laboratory of deep-earth dynamics of ministry of Natural resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China Limited Liability Company TBEA DUSHANBE Mining IndustryChangji 831100China

The Late Paleozoic volcanic rocks are widespread in the Western Tianshan,and mainly consist of basalt,trachyte,trachy-andesite,andesite and ***,the formation timing and tectonic implications of the volcanic rocks remain *** obtain a comprehensive dataset with adequate spatial coverage,we collected the published zircon U-Pb age data of the Late Paleozoic volcanic rocks in the Western Tianshan,and mapped the temporal and spatial distribution of these volcanic *** compiled dataset indicates that the volcanic rocks in the Western Tianshan were formed in two major stages:Late Silurian-Early Carboniferous and Late Carboniferous-Middle *** southward subduction of the Northern Tianshan Ocean formed a large number of Late Silurian-Early Carboniferous volcanic *** flare-up of Late Carboniferous to Middle Permian magmatism in the NTOB was considered to be the response of the slab-roll back of the northern Tianshan ***,arc magma assemblage and spatial-temporal distribution are of great significance to identify the dynamic mechanism transformation of subduction zone.

关键词： volcanic rocks zircon Western Tianshan tectonic transformation slab-roll back

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

Eocene Basins on the SE Tibetan Plateau: Markers of Minor Offset along the Xuelongshan–Diancangshan–Ailaoshan Structural System

引用

Acta Geologica Sinica(English Edition) 2020年第4期94卷 1020-1041页

作者： LIAO Cheng YANG Tiannan XUE Chuandong LIANG Mingjuan XIN Di XIANG Kun JIANG Lili SHI Pengliang ZHU Wenbin WAN Liangchun TANG Jing YU Jing WU Pinglei key laboratory of deep–earth dynamics of ministry of Natural resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China School of earth and Space Sciences Peking UniversityBeijing 100871China Faculty of land Resource Engineering Kunming University of Science and TechnologyKunming 650093China China University of Geosciences Beijing 100083China

The offset of geological bodies provides robust evidence of displacement along a fault or ductile shear zone. The amount of displacement along the Xuelongshan–Diancangshan–Ailaoshan structural system, southeastern Tibetan Plateau, is uncertain because of the lack of offset geological markers. This NNW–SSE-trending system is developed in three isolated metamorphic complexes and interjacent nonmetamorphosed rocks. They are expected to record similar post-Eocene strain, although their structural patterns should be distinct. Geological mapping in the area between the Xuelongshan and Diancangshan metamorphic complexes has revealed a small Eocene basin, the Madeng Basin, located to the west of the structural system. The sedimentary and volcanic successions of the Madeng Basin are comparable to those of the Jianchuan Basin, which is located to the east of the structural system. Zircon U–Pb geochronological and bulk geochemical data demonstrate that the volcanic rocks of both basins formed during 37–34 Ma and share the same geochemical features. These data suggest that the Madeng and Jianchuan basins previously constituted a single basin, with the distribution of high-K volcanic rocks in the basins defining an ENE–WSW-trending volcanic belt that shows a limited dextral offset of ≤20 km across the Xuelongshan–Diancangshan–Ailaoshan structural system. Therefore, the northern segment of the structural system records no evidence of large-scale lateral movement/displacement. The results suggest that the Indochina block, which is bounded by the Xuelongshan–Diancangshan–Ailaoshan structural system to the east and the Sagaing Fault to the west, has not extruded southward as a whole but rather has been deformed by pervasive crustal shortening.

关键词： offset marker Eocene basin Xuelongshan–Diancangshan–Ailaoshan structural system southeastern Tibetan Plateau India–Eurasia collision

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

Spatial distribution prediction and benefits assessment of green manure in the Pinggu District,Beijing,based on the CLUE-S model

引用

Journal of Integrative Agriculture 2016年第2期15卷 465-474页

作者： ZHANG Li-ping ZHANG Shi-wen ZHOU Zhi-ming HOU Sen HUANG Yuan-fang CAO Wei-dong College of resources and Environment China Agricultural University/Key Laboratory of Arable Land Conservation(North China)Minstry of Agriculture/Key Laboratory of Agricultural Land Quality MonitoringMinistry of Land and Resources School of earth and Environment Anhui University of Science and Technology Institute of Agricultural resources and Regional Planning Chinese Academy of Agricultural Sciences

Green manure use in China has declined rapidly since the 1980 s with the extensive use of chemical *** deterioration of field environments and the demand for green agricultural products have resulted in more attention to green *** intervention and policy-oriented behaviors likely have large impacts on promoting green manure ***,little information is available regarding on where,at what rates,and in which ways（i.e.,intercropping green manure in orchards or rotating green manure in cropland） to develop green manure and what benefits could be gained by incorporating green manure in fields at the county *** paper presents the conversion of land use and its effects at small region extent（CLUE-S） model,which is specifically developed for the simulation of land use changes originally,to predict spatial distribution of green manure in cropland and orchards in 2020 in Pinggu District located in Beijing,*** types of land use for planting or not planting green manure were classified and the future land use dynamics（mainly croplands and orchards） were considered in the *** scenarios were used to predict the spatial distribution of green manure based on data from 2011：The promotion of green manure planting in orchards（scenario 1） and the promotion of simultaneous green manure planting in orchards and croplands（scenario 2）.The predictions were generally accurate based on the receiver operating characteristic（ROC） and Kappa indices,which validated the effectiveness of the CLUE-S model in the *** addition,the spatial distribution of the green manure was acquired,which indicated that green manure mainly located in the orchards of the middle and southern regions of Dahuashan,the western and southern regions of Wangxinzhuang,the middle region of Shandongzhuang,the eastern region of Pinggu and the middle region of Xiagezhuang under scenario *** manure planting under scenario 2 occurred in orchards in the middle re

关键词： CLUE-S model green manure spatial distribution prediction benefits assessment

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

Progress and Controversy in the Study of HP-UHP Metamorphic Terranes in the West and Middle Central China Orogen

引用

Journal of earth Science 2010年第5期21卷 581-597页

作者：刘良杨家喜陈丹玲王超张成立杨文强曹玉亭 State key laboratory of Continental dynamics Department of Geology Northwest University College of earth Sciences and land resources Chang'an University Xi'an Institute of Geology and Mineral Resource

During the past ten years, various types of HP-UHP metamorphic rocks have been discovered in the South Altyn Tagh, the North Qaidam and the North Qinling （秦岭） in the West and Middle Central China orogen. The UHP rocks, as lentoid bodies in regional gneisses, include eclogite （garnet-bearing pyroxenite）, garnet peridotite and various pelitic or felsic gneisses. There are many records of minerals and microstructures of exsolution indicate the UHP metamorphism, such as coesite （or its pseudomorph）, diamond, exsolution of clinopyroxene/amphibole/＋rutile or rutile＋quartz＋apatite in garnet, exsolution of quartz in omphacite and exsolution of kyanite＋spinel in precursor *** discovery of microstructure evidence for the presence of precursor stishovite in typical Alrich gneiss from the South Altyn Tagh reveals continental subduction and exhumation to and from a depth of more than 350 km. It is the petrological record of the deepest subduction and exhumation of continental rock in the world. The in situ zircon U-Pb dating using LA-ICP- MS or SHRIMP methods shows that the metamorphic ages of the HP-UHP rocks in the South Altyn Tagh, the North Qaidam and the North Qinling are 475-509, 420--457, and 485-514 Ma, respectively. The metamorphic ages of HP-UHP rocks in the North Qaidam are 20-80 Ma younger than those in the South Altyn Tagh and the North Qinling, and the metamorphic ages do not systematically increase or decrease from the South Altyn Tagh through the North Qaidam to the North Qinling. The absence of time transgressive variety of the metamorphism in the three regions does not support the hypothesis that the HP-UHP rocks in these re. gions form the same HP-UHP metamorphic zone. And the HP-UHP rocks in these regions can not be simply correlated to the collision between the North China plate and the South China plate. At present, the study of the HP-UHP rocks in the West and Middle Central China orogen faces several key issues or challenges, such as：（1） the c

关键词： HP-UHP metamorphic zone continental deep subduction zircon LA-ICP-MS and SHRIMP dating South Altyn Tagh North Qaidam North Qinling.

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

Origin of Chromitites in the Songshugou Peridotite Massif,Qinling Orogen (Central China): Mineralogical and Geochemical Evidence

引用

Journal of earth Science 2019年第3期30卷 476-493页

作者： Huichao Rui Jiangang Jiao Mingzhe Xia Jingsui Yang Zhaode Xia School of earth Sciences China University of Geosciences Wuhan 430074 China key Laboratoiy of deep-earth dynamics of ministry of Natural resources Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China School of earth Science and resources Chang'an University Xi'an 710054 China

The Songshugou peridotite massif is located in the north of Shangdan suture zone, North Qinling orogenic belt of Central China. The massif is mainly composed of fine-grained mylonitic dunites, coarse-grained dunites, fine- and coarse-grained harzburgites, and minor clinopyroxenites. The coarsegrained dunites as well as parts of the harzburgites host small-scale chromitites? Chromite grains from various textural types of chromitites and dunites pervasively contain primary and secondary silicate inelusions. Primary inclusions are dominated by monophase olivine, with minor clinopyroxene and a few multiphase mineral assemblages consisting of olivine and clinopyroxene. Secondary inclusions, mainly Cr-chlorite and tremolite, show irregular crystal shapes. Besides, Cr2O3 contents (0.08 wt.%-0.71 wt.%) of primary olivine inclusions are remarkably higher than those of interstitial olivine (<0.1 wt.%). Chr0- mites in the Songshugou peridotite massif are high-Cr type, with Cr^# and Mg^# values ranging of 67.5-87.6, and 23.4-41.2, respectively. The Cr-chlorite, formed by reactions between olivine and chromite in the presence of fluid under middle temperature, indicates the Songshugou peridotite massif has undergone alteration/metamorphism process during emplacement. Chromite grains are modified by these processes, resulting in the various degrees of enrichment of Fe2O3, Cr2O3, Zn, Co and Mn, depletion of MgO, A12O3,Ga, Ti and Ni. Due to low silicate/chromite ratios in the massive ores, chromites from them are slightly influenced by alteration/metamorphism and thus preserve the pristine magmatic compositions. The parental magma calculated based on them has 11.17 wt.%-13.57 wt.% A12O3 and 0.15 wt.%-0.27 wt.% TiO2, which is similar to the parental melts of high-Cr chromitites from elsewhere and comparable with those of boninites. Combined with informations from previous studies, major and trace elements geochemistry of chromite, as well as the nature of the parental magma, it can

关键词： peridotite chromitite chromite trace element parental magma Songshugou Qinling Orogen

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

Crustal thickness and composition in the South China Block:Constraints from earthquake receiver function

引用

Science China earth Sciences 2022年第4期65卷 698-713页

作者： Changxin CHEN Qingtian LÜ Ling CHEN Danian SHI Jiayong YAN Yinshuang AI Chinese Academy of Geological Sciences Beijing 100037China Chinese MNR laboratory of deep earth Sciences and Technology Beijing 100094China key laboratory of deep-earth dynamics of ministry of Natural resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China State key laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China CAS Center for Excellence in deep earth Science Guangzhou 510640China University of Chinese Academy of Sciences Beijing 100049China key laboratory of earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

Crustal thickness and composition are closely related to geology and tectonic evolution of the *** the differences in the crustal thickness and composition of the South China Block(SCB)is important to gain a comprehensive understanding of multi-phase amalgamation,breakup,reworking,and regional geodynamic *** this study,teleseismic data from 135 high-density portable broadband stations from Sino Probe were processed using Common Conversion Point(CCP)stacking and H-κstacking *** Moho depth and P-wave and S-wave velocity ratio(V_(p)/V_(s))were *** results revealed several insights about the tectonic processes in the ***,the crustal structure and V_(p)/V_(s)ratios of the Cathaysia Block,Jiangnan Orogenic Belt,and Yangtze Block were significantly *** average depth of the Moho in the Cathaysia Block was approximately 31 km,and the V_(p)/V_(s)ratios increased from the inland area(1.66)to the coastal area(1.78),indicating the oceanward increase of mafic proportion in the lower crust,which is related to the influence of the Paleo-Pacific Plate westward ***,the crustal thickness of Jiangnan Orogenic Belt deepens from east ca.31 to the west ca.42 km and the V_(p)/V_(s)ratios varied from 1.75 to 1.64,illustrating a relatively felsic crust,which could have been related to the Mesozoic upper crustal thickening under compression followed by the lower crust removal under the extensional ***,the average crustal thickness of the Yangtze Block was 42 km,and the V_(p)/V_(s)ratios ranged from 1.64 to 1.84,presenting a positive correlation between the Moho depth and the V_(p)/V_(s)ratio,which is explained by the relatively thick mafic lower *** on the variations in the crustal structure and V_(p)/V_(s)ratios of the profile,we inferred that the central part of the Jiangnan Orogenic Belt was bounded by the Jiangshan-Shaoxing-Hengyang in the east and the Jiujiang-Shitai-Jishou in the *** small-scale

关键词： P wave receiver function The South China Block Crustal thickness Crustal composition Block boundary

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

Foreword

引用

Journal of China University of Geosciences 2009年第2期20卷 205-208页

作者：杨经绥李海兵 Paul T Robinson key laboratory for Continental dynamics of the ministry of land and Resouces Institute of GeologyChinese Academy of Geological Sciences Department of earth Sciences Dalhousie University

The Qinghai-Tibet plateau is a fast uplifting area that constitutes the world＇s highest and thickest, and newest piece of continental plate which has unusual geometric configurations and landscapes. The Qinghai-Tibet plateau consists of multiple terranes, with a complex geological history, including the evo- lution of the Tethys Ocean basin, the convergence of terranes and island arcs, multiple subductions, multiple collisions and multiple orogens, over a long period of action of continental dynamic processes. Before the Indian and the Asian plates collided, during the Early Paleozoic, it was already a large orogen and terrane collision complex. As a result of the collision of the Indian and Asian plates, the fast uplift of Qinghai- Tibet plateau became the most magnificent event on the earth during the Cenozoic. It formed a vast, seemingly boundless high plateau with borders consisting of mountain chains with very high peaks, and steep gorges.

关键词： Foreword HPM high SiO ICP

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：