检索结果-南通市图书馆

Paleo-Mesoarchean sedimentary record in the Dharwar Craton,India:Implications for Archean ocean oxygenation

Geoscience Frontiers 2024年第1期15卷 126-154页

作者： G.Harshitha C.Manikyamba M.santosh Cheng-Xue Yang A.Keshav Krishna V.V.sesha sai I.Panduranga Reddy CsIR-National Geophysical Research Institute(NGRI) Uppal RoadHyderabad 500007India Department of Geology Osmania UniversityHyderabad 500007India school of Earth science and Resources China University of GeosciencesBeijing 100083China Department of Earth science University of AdelaideAdelaide SA5005Australia Yonsei Frontier Lab Yonsei UniversitySeoul 03722Republic of Korea geological survey of India State UnitNagpurIndia

The early Archean oceans were marked by significant redox changes which have su.s.quently shaped the Earth’s *** chemical sediments of banded Iron and Manganese formations provide important geochemical proxies for these historical shifts in the redox conditions and to trace the ancient sedimentation patterns and *** this study,we investigate the proto-ore of the Archean Mn-formations of the sandur,Chitradurga and shimoga greenstone belts of Dharwar Craton of southern Peninsular India,which is geochemically characterised as quartz arenites,Mn-arenites,Fe-arenites,Mn-argillites and *** geochemical systematics suggest their deposition in shallow to deeper shelf in the Archean *** detrital zircon u-Pb systematics of Mn arenites and argillites indicate their maximum depositional age of 3230±52 Ma representing the oldest onset of sedimentation during the Paleo-Mesoarchean timeframe in the Chitradurga Group of Dharwar *** detrital influx proxies suggest variations in sedimentation rates associated with the Archean transgressive-regressive cycles and fluctuating hydrodynamic conditions,together reflecting an increasing trend in the contributions of recycled sediment from sandur to Chitradurga and shimoga greenstone *** available detrital zircon ages of the Mn arenites and argillites from these greenstone belts indicate a~600 Ma prolonged period of Mn deposition for which high-T hydrothermal fluids from Archean mid-oceanic ridges supplied the *** trace element compositions of the concordant detrital zircons suggest 3.3-3.1 Ga Dharwar basement TTG/granitoid source which is corroborated by the zircon crystallization temperatures of 690-820℃.The source-normalisedα-dose rates of the detrital zircons signify greater degrees of sediment transport and multi-cycle nature which correspond to the earliest episode of crustal growth in the Indian sub-continent associated with the Mesoarchean ur supercontinent.T

关键词： Mn-arenites-argillites Dharwar Craton Zircon u-Pb geochronology Passive margin sediments Ocean oxygenation

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

Coseismic landslide sediment increased by the“9.5”Luding earthquake,sichuan,China

引用

Journal of Mountain science 2023年第3期20卷 624-636页

作者： XIONG Jiang CHEN Hua-yong ZENG Lu.s. Feng-huan GONG Ling-feng TANG Chen-xiao Key Laboratory of Mountain Hazards and Earth surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China Chengdu geological survey Center China Geological SurveyChengdu 610081China

The"9.5"Luding earthquake(Ms 6.8),which occurred on september 5,2022,has triggered thousands of landslides,and caused coseismic landslide sediment in the mountain basin to increase *** the Luding earthquake,landslide sediment may continue to divert to channels,and increase the activity of debris ***,the formation of debris flows can pose a major threat to infrastructure,lives and *** better understand the landslide sediment that increased by the"9.5"Luding earthquake and its impact on the activity of debris flows,we mapped the coseismic landslide database using satellite images.A total of9142 landslides with an area of 49.51 km^(2),covering4.81%of the whole basin,were triggered by the Luding *** coseismic landslides induced by this earthquake are dominated by shallow landslides and are densely distributed in the combined zone of the Xianshuihe fault and the Daduhe *** 333.31×10^(6)m^(3)(error:111.43×10^(6)m^(3)/-70.73×10^(6)m^(3))of coseismic landslide sediments were induced by the earthquake in the epicenter,and the landslide materials were concentrated downstream of the *** *** than 13986.45×10^(4)m^(3)(error:4675.67×10^(4)m^(3)/-2967.92×10^(4)m^(3))of landslide sediment may supply for debris flow ***,the small basins that are distributed near Moxi,Detuo and the junction of the Xianshuihe fault and Daduhe fault are more susceptible to debris flows when rainstorms hit these ***,prevention and mitigation measures,early warning,and land use planning should be adopted in advance in these ***,from the perspectives of landslide scale and the degree of landslide-channel coupling,the activity or active intensity of debris flows in the Luding earthquake area may be lower than that in the epicenter area of the 2008 Wenchuan earthquake.

关键词： Luding earthquake Landslide sediment Debris flow activity Remote sensing image

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

Predicting intensity of white-tailed deer herbivory in the Central Appalachian Mountains

引用

Journal of Forestry Research 2018年第3期29卷 830-839页

作者： Andrew B.Kniowski W.Mark Ford Department of Fish and Wildlife Conservation Virginia Tech u.s. geological survey Virginia Cooperative Fish and Wildlife Research Unit Virginia Tech

In eastern North America, white-tailed deer(Odocoileus virginianus) can have profound influences on forest biodiversity and forest successional *** to high deer populations in the central Appalachians have resulted in lower forest *** effects in some areas persist even following deer population reductions or declines. This has prompted managers to consider deer population management goals in light of policies designed to support conservation of biodiversity and forest regeneration while continuing to support ample recreational hunting opportunities. However,despite known relationships between herbivory intensity and biodiversity impact, little information exists on the predictability of herbivory intensity across the varied and spatially diverse habitat conditions of the central Appalachians. We examined the predictability of browsing rates across central Appalachian landscapes at four environmental scales: vegetative community characteristics, physical environment, habitat configuration, and local human and deer population demographics. In an information-theoretic approach, we found that a model fitting the number of stems browsed relative to local vegetation characteristics received most(62%) of the overall support of all tested models assessing herbivory impact. Our data suggest that deer herbivory responded most predictably to differences in vegetation quantity and type. No other spatial factors or demographic factors consistently affected browsing intensity. Because herbivory, vegetation communities, and productivity vary spatially, we suggest that effective broad-scale herbivory impact assessment should include spatially-balanced vegetation monitoring that accounts for regional differences in deer forage *** monitoring is necessary to avoid biodiversity impacts and deleterious changes in vegetation community composition that are difficult to reverse and/or may not be detected using traditional deer-density based

关键词： Biodiversity Central Appalachian Mountains Herbivory Odocoileus virginianus Predicting browsing intensity White-tailed deer

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

In situ Rb-sr Dates of Muscovite and sulfur Isotope of Pyrite from the Yangshan Gold Deposit in Western Qinling,China

引用

Acta Geologica sinica(English Edition) 2023年第5期97卷 1475-1489页

作者： HuANG Yong QI Xianmao Wu Qingsong LI Jianzhong REN Minghua DuAN Liu’an XIONG Tao YANG Zhonghu ZHAO Yang CIREN Lamu WEI Wei DuAN Jilin YAN Mengmeng Civil-Military Integration Center of China geological survey Chengdu 610036China China university of Geosciences Wuhan 430074China Department of Geoscience University of NevadaLas Vegas 89154-4010USA Yantai geological survey Center of Coastal Zone China Geological SurveyYantaiShandong 264000China East China university of Technology Nanchang 330013China

Located along the southern part of the West Qinling orogenic belt,the Yangshan gold deposit is one of the largest in *** major gold ores of Yangshan are disseminated in metasedimentary host rocks with minor native gold amounts in stibnite-gold quartz *** and arsenopyrite are the major Au-bearing *** muscovite from gold-bearing quartz veins was dated using the in situ Rb-sr method to determine the formation age of the Yangshan gold *** Rb-sr isochron date of the muscovite yielded 210.1±5.6 Ma(MsWD=1.2).This date is near the lower end of the period of the mineralized granitic dykes(210.49-213.10 Ma).Two stages of gold enriching process are recognized in the gold-bearing pyrite:the first is incorporated with the Co,Cu,As,Ni enrichment;and the second is accompanied by Bi,Co,Ni,Pb,Cu.s. *** in-situ.s.lfur isotopic valu.s.of pyrites show a restrictedΔ34s range of-1.43‰to 2.86‰with a mean value of 0.43‰.Trace-element mapping and in-situ.s.lfur isotopic analysis of pyrite suggest that the sulfur deposits are likely derived from a magmatic source and likely assimilated by sulfur from the sedimentary ***,magmatism plays a critical role in the formation of the Yangshan gold deposit.

关键词： Rb-sr dating trace-element mapping sulfur isotope gold deposit Yangshan Qinling orogenic belt

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

Geochronology, Geochemistry and sr-Nd-Hf Isotopes of Early–Middle Triassic Adakitic Plutons in Central-eastern Jilin Province, NE China: Constraints on the Non-synchronous Closure of Paleo-Asian Ocean

引用

Acta Geologica sinica(English Edition) 2022年第5期96卷 1615-1630页

作者： sHI Chenglong DING Xiaozhong ZHOu Xiaodong NIE Lijun ZHANG Jibiao Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China survey of Regional geological and Mineral Resurce of Jilin Province Changchun 130022China

The Changchun–Yanji suture zone(CYsZ) in NE China is considered as the suture between the North China Craton(NCC) and Central Asian Orogenic Belt(CAOB). The geochronology, geochemistry and sr-NdHf isotopes of Early–Middle Triassic adakitic plutions from the CYsZ, are presented in this paper to discu.s.their petrogenesis and tectonic setting, as well as to constrain the timing and style of the Paleo-Asian Ocean's final closure. In Early Triassic, the Dayushan pluton(ca. 250 Ma) from western CYsZ has negative ε_(Nd)(t) valu.s. bidirectional provenances(NCC and CAOB) of ε_(Hf)(t), which are formed in a collision tectonic setting. In contrast, in eastern CYsZ, the early Triassic samples in Liangshan(ca. 242 Ma) were high Mg~# valu.s. positive ε_(Nd)(t), single provenances(CAOB) of ε_(Hf)(t) resulting from a subduction setting. In the Middle Triassic, the Atype granites in western CYsZ are found in previous studies representing a post-collisional extensional environment, whereas syn-collisional Lianyanfeng granites(ca. 237 Ma) in eastern CYsZ with low Isr and large scale ε_(Nd)(t) and ε_(Hf)(t) valu.s.from bidirectional provenances(NCC and CAOB), represent a collisional setting. The Paleo-Asian Ocean's occurred in a scissor-like fashion along the CYsZ during the Triassic period.

关键词： granitoids tectonic evolution Paleo-Asian Ocean Central Asian Orogenic belt

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

Determination of the early Paleozoic accretionary complex in southwestern Yunnan, China: Implications for the tectonic evolution of the Proto-Tethys Ocean

引用

China Geology 2023年第2期6卷 322-337,I0016-I0041页

作者： Guo-chuan Yan Bao-di Wang Han Liu Juan He Zhi-min Peng Graduate school of Chinese Academy of geological sciences China Geological SurveyMinistry of Natural ResourcesBeijing 100037China Chinese Academy of geological sciences China University of GeosciencesBeijing 100083China China Aero Geophysical survey and Remote sensing Center for Natural Resources China Geological SurveyMinistry of Natural ResourcesBeijing 100083China Chengdu Center of geological survey China Geological SurveyMinistry of Natural ResourcesChengdu 610081China West Yunnan university of Applied sciences Dali 671006Yunnan China

Accretionary complex study provides important knowledge on the subduction and the geodynamic processes of the oceanic plate,which represents the ancient ocean basin extinction ***,there exist many disputes on the age,material source,and tectonic attribute of the Lancang Group,located in southwest Yunnan,*** this paper,the LA-ICP-Ms detrital zircon u‒Pb chronology of nine metamorphic rocks in the Lancang Group was carried *** u‒Pb ages of the three detrital zircons mainly range from 590-550 Ma,980-910 Ma,and 1150-1490 Ma,with the youngest detrital zircons having a peak age of about 560 *** u‒Pb ages of the six detrital zircons mainly range from 440-460 Ma and 980-910 Ma,and the youngest detrital zircon has a peak age of about 445 *** the Lancang Group,metamorphic acidic volcanic rocks,basic volcanic rocks,intermediate-acid intrusive rocks,and high-pressure metamorphic rocks are exposed in the form of tectonic lens in schist,rendering typical melange structural characteristics of“block+matrix”.Considering regional deformation and chronology,material composition characteristics,and the previous data,this study thinks the Lancang Group may be an early Paleozoic tectonic accretionary complex formed by the eastward subduction of the Changning-Menglian Proto-Tethys Ocean,which provides an important constraint for the Tethys evolution.

关键词： Early Paleozoic Accretionary complex Langcang Group Block+matrix Proto-Tethys Ocean geological survey engineering Eastern margin of Qinghai-Tibet 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

Present-day upper-crustal strain Rate Field in southeastern Tibet and its Geodynamic Implications:Constraints from GPs Measurements with ABIC Method

引用

Acta Geologica sinica(English Edition) 2024年第1期98卷 265-275页

作者： YANG shaohua PAN Jiawei LI Haibing sHI Yaolin Key Laboratory of Continental Dynamics of Ministry of Natural Resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China Jiangsu Donghai Continental Deep Hole Crustal Activity National Observation and Research station DonghaiJiangsu 222300China Key Laboratory of Computational Geodynamics College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China

The Earth’s surface kinematics and deformation are fundamental to understanding crustal *** effective research approach is to estimate regional motion field and deformation fields based on modern geodetic *** the discrete observed velocity field is obtained,the velocity related fields,such as dilatation rate and maximum shear strain rate,can be estimated by applying varied mathematical *** study applied Akaike's Bayesian Information Criterion(ABIC)method to calculate strain rate fields constrained by GPs observations in the southeast Tibetan *** with results derived from other three methods revealed that our ABIC-derived strain rate fields were more *** maximum shear strain rate highlighted the Xianshuihe–Xiaojiang fault system as the main boundary for the outward migration of material in southeastern Tibet,indicating rotation of eastern Tibet material around the eastern Himalaya rather than whole extrusion along a fixed ***,distinct dilatation rate patterns in the northeast and southwest regions of the fault system were *** northeast region,represented by the Longmenshan area,exhibited negative dilatational anomalies;while the southwest region,represented by the Jinsha River area north of 29°N,displayed positive dilatational *** indicates compression in the former and extension in the *** with deep geophysical observations,we believe that the upper and lower crusts of the Jinsha River area north of 29°N are in an entire expanding state,probably caused by the escape-drag effect of *** presence of a large,low-viscosity region south of 29°N may not enable the entire escape of the crust,but instead result in a differential escape of the lower crust faster than the upper crust.

关键词： strain rate differential escape ABIC GPs southeastern Tibet

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

Characterization of rock thermophysical properties and factors affecting thermal conductivity−A case study of Datong Basin,China

引用

Journal of Groundwater science and Engineering 2024年第1期12卷 4-15页

作者： Meng-lei Ji shuai-chao Wei Wei Zhang Feng Liu Yu-zhong Liao Ruo-xi Yuan Xiao-xue Yan Long Li Institute of Hydrogeology and Environmental Geology Chinese Academy of Geological SciencesShijiazhuang 050061China Technology Innovation Center of Geothermal&Hot Dry Rock Exploration and Development Ministry of Natural ResourcesShijiazhuang 050061China China university of Geosciences(Beijing) Beijing 100083China

Rock thermal physical properties play a crucial role in understanding deep thermal conditions,modeling the thermal structure of the lithosphere,and discovering the evolutionary history of sedimentary *** advancements in geothermal exploration,particularly the identification of high-temperature geothermal resources in Datong Basin,shanxi,China,have opened new *** study aims to characterize the thermal properties of rocks and explore factors influencing thermal conductivity in basins hosting high-temperature geothermal resources.A total of 70 grou.s.of rock samples were collected from outcrops in and around Datong Basin,shanxi *** property tests were carried out to analyze the rock properties,and the influencing factors of thermal conductivity were studied through experiments at different temperature and water-filled *** results indicate that the thermal conductivity of rocks in Datong,shanxi Province,typically ranges from 0.690 W/(m·K)to 6.460 W/(m·K),the thermal diffusion coefficient ranges from 0.441 mm^(2)/s to 2.023 mm^(2)/s,and the specific heat capacity of the rocks ranges from 0.569 KJ/(kg·℃)to 1.117 KJ/(kg·°C).Experimental results reveal the impact of temperature and water saturation on the thermal conductivity of the *** thermal conductivity decreases with increasing temperature and rises with high water saturation.A temperature correction formula for the thermal conductivity of different lithologies in the area is proposed through linear *** findings from this study provide essential parameters for the assessment and prediction,development,and utilization of geothermal resources in the region and other basins with typical high-temperature geothermal resource.

关键词： Datong Basin Rock thermal conductivity Thermal diffusivity specific heat capacity Influencing factors

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

Discovery of~2.5 Ga zircon u-Pb age from the diabase,Ar Horqin Banner Area,Inner Mongolia:Implications for Neoarchean crystalline basement of Bainaimiao Arc Belt

引用

China Geology 2023年第3期6卷 531-532页

作者： Ji-yu Du Cheng Qian Wen-bin Wu Yu-jin Zhang Chao Zhang Tao Qin Yong-fei Ma Hong-xi You shenyang Center of geological survey China Geological SurveyMinistry of Natural ResourcesShenyang 110034China Northeast geological s&T Innovation Center China Geological SurveyMinistry of Natural ResourcesShenyang 110034China College of Earth science Jilin UniversityChangchun 130061China Liaoning Institute Co.Ltd.of Geology and Mineral Resources Shenyang 110032China

*** The Bainaimiao Arc Belt(BAB),one of the most important units of the southeastern Central Asian Orogenic Belt(CAOB),locates along the northern margin of the North China Craton(NCC).There is a lack of understanding ... 详细信息

关键词： basement Belt zircon

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

Characteristics and dynamic analysis of the February 2021 long-runout disaster chain triggered by massive rock and ice avalanche at Chamoli, Indian Himalaya

引用

Journal of Rock Mechanics and Geotechnical Engineering 2023年第2期15卷 296-308页

作者： Tiantian Zhang Yueping Yin Bin Li Xiaojie Liu Meng Wang Yang Gao Jiawei Wan Kaushal Raj Gnyawali Institute of Geomechanics Chinese Academy of Geological SciencesBeijing100081China China Institute of geological Environment Monitoring China Geological SurveyBeijing100081China College of Geology Engineering and Geomatics Chang’an UniversityXi’an710100China sichuan geological survey Institute Chengdu610081China Natural Hazards section Himalayan Risk Research Institute(HRI)Bhaktapur44800Nepal

A massive rock and ice avalanche occurred on the western slope of the Ronti Gad valley in the northern part of Chamoli,Indian Himalaya,on 7 February 7,*** avalanche on the high mountain slope at an elevation of 5600 m above sea level triggered a long runout disaster chain,including rock mass avalanche,debris avalanche,and *** disaster chain had a horizontal travel distance of larger than 17,600 m and an elevation difference of 4300 *** this study,the disaster characteristics and dynamic process were analyzed by multitemporal satellite *** results show that the massive rock and ice avalanche was caused by four large expanding discontinuity *** disaster chain was divided into five zones by satellite images and field observation,including source zone,transition zone,dynamic entrainment zone,flow deposition zone,and flood *** entrainment effect and melting water were recognized as the main causes of the long-runout *** on the seismic wave records and field videos,the time progress of the disaster was analyzed and the velocity of frontal debris at different stages was *** total analyzed disaster duration was 1247 s,and the frontal debris velocity colliding with the second hydropower station was approximately 23 m/*** study also carried out the numerical simulation of the disaster by rapid mass movement simulation(RAMMs).The numerical results reproduced the dynamic process of the debris avalanche,and the mechanism of long-runout avalanche was further verified by parametric ***,this study discu.s.d the potential causes of disaster and flood and the roles of satellite images and seismic networks in the monitoring and early-warning.

关键词： Rock and ice avalanche Disaster chain Long-runout Entrainment Flood

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

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：