检索结果-南通市图书馆

Mantle-derived magmas:intraplate,hot-spots and mid-ocean ridges

Science Bulletin 2015年第22期60卷 1873-1900页

作者： David H.Green Trevor J.Falloon earth sciences School of Physical Sciences University of Tasmania

Primary or parental magmas act as probes to infer eruption and source temperatures for both mid-ocean ridge （MOR） and‘hot-spot＇ magmas （tholeiitic picrites）. The experimental petrogenetic constraints （＇inverse＇ experiments） argue for no significant temperature differences between them. However, there are differences in major, minor and trace elements which characterise geochemical, not thermal, anomalies beneath ‘hot-spots＇. We suggest that diapiric upwelling from interfaces （redox contrasts） between old subducted slab and normal MOR basalt source mantle is the major reason for the observed characteristics of island chain or ‘hot-spot＇ volcanism. Intraplate basalts also include widely distributed volcanic centres containing lherzolite xenoliths, i.e. mantle-derived magmas. Inverse experiments on olivine basalt, alkali oli- vine basalt, olivine basanite, olivine nephelinite, olivine melilitite and olivine leucitite （lamproite） determined liquidus phases as a function of pressure, initially under anhydrous and CO2-absent conditions. Under C- and H-absent conditions, only tholeiites to alkali olivine basalts had O1 ＋ Opx 4-Cpx as high-pressure liquidus phases. Addition of H20 accessed olivine basanites at 2.5-3 GPa, ,- 1,200 ℃, but both CO2 and H20 were necessary to obtain saturation with O1, Opx, Cpx and Ga at 2.5-3.5 GPa for olivine nephelinite and olivine melilitite. The forward and inverse experimental studies are combined to formulate a petrogenetic grid for intraplate, ‘hot-spot＇ and MOR magmatism within the plate tectonics paradigm. The asthenosphere is geochemically zoned by slow upward migration of incipient melt. The solidus and phasestabilities of lherzolite with very small water contents （〈3,000 ppm） determine the thin plate behaviour of the oceanic lithosphere and thus the earth＇s convection in the form of plate tectonics. There is no evidence from the parental magmas of MOR and ‘hot-spots＇ to support the ＇deep mantle thermal plume＇ hypothesis. The preferr

关键词： experimentsMantle-derived magmas ·High-pressureC-H-O · Asthenosphere - Hot-spotsPlate 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

Radiative Effects on Torrential Rainfall during the Landfall of Typhoon Fitow(2013)

引用

Advances in Atmospheric sciences 2016年第1期33卷 101-109页

作者： Lingyun LOU Xiaofan LI school of earth sciences Zhejiang University

Cloud microphysical and rainfall responses to radiative processes are examined through analysis of cloud-resolving model sensitivity experiments of Typhoon Fitow（2013） during *** budget analysis shows that the increase in the mean rainfall caused by the exclusion of radiative effects of water clouds corresponds to the decrease in accretion of raindrops by cloud ice in the presence of radiative effects of ice clouds,but the rainfall is insensitive to radiative effects of water clouds in the absence of radiative effects of ice *** increases in the mean rainfall resulting from the removal of radiative effects of ice clouds correspond to the enhanced net *** increases（decreases） in maximum rainfall caused by the exclusion of radiative effects of water clouds in the presence（absence） of radiative effects of ice clouds,or the removal of radiative effects of ice clouds in the presence（absence） of radiative effects of water clouds,correspond mainly to the enhancements（reductions） in net *** mean rain rate is a product of rain intensity and fractional rainfall *** radiation-induced difference in the mean rain rate is related to the difference in rain *** radiation-induced difference in the maximum rain rate is associated with the difference in the fractional coverage of maximum rainfall.

关键词： radiative effects rainfall maximum rainfall rain intensity fractional rainfall coverage net condensation hydrometeor change

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

Temporal and spatial variation of fish community and their nursery in a tropical seagrass meadow

引用

Acta oceanologica Sinica 2018年第12期37卷 63-72页

作者： DU Jianguo WANG Yanguo PERISTIWADY Teguh LIAO Jianji MAKATIPU Petrus Christianus HUWAE Ricardo JU Peilong LOH Kar Hoe CHEN Bin Third Institute of oceanography Ministry of Natural Resources Bitung Marine Life Conservation Research Center for Oceanography Indonesian Institute of Sciences College of ocean and earth sciences Xiamen University Institute of ocean and earth sciences University of Malaya

Fish species composition and spatio-temporal variability of the community were studied in a tropical seagrass meadow located in a lagoon in the eastern part of North Sulawesi. The diversity of fish community in the seagrass meadows was relatively high, with the Shannon-Wiener index ranging from 1.57 to 3.69. The family Apogonidae was the most dominant in abundance(8.27 ind./(100 m2)) and biomass(28.49 g/(100 m2)). At the species level,Apogon lateralis and Sphaeramia orbicularis were the most dominant species in abundance and biomass,respectively. For spatial distribution on species, the end, middle and mouth of the lagoon clustered together as a whole, which may be due to the substrate types found in those zones. The fish species, fish abundance and fish biomass were greater in the dry and wet seasons than in the transition season, which is explained by the strong monsoon, which provides a more suitable environment and food for the fish. The maximum length of 93.10% of the captured species was less than their length at maturity, indicating that seagrass meadows are nursery habitats for many fishes. Therefore, protection of the seagrass meadows is essential for fisheries and sustainable resource utilization.

关键词： seagrass meadows fish assemblages nursery function North Sulawesi

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

Models of the earth's plasmapause position

引用

Science China earth sciences 2016年第4期59卷 871-872页

作者： FU SuiYan SUN WeiJie school of earth and Space sciences Peking University

The plasmasphere is a region of relatively dense （-10-10000 cm^-3） plasma, surrounding the earth and ex- tending to distances of about five earth radii （RE）. It is filled with large amount of cold （-1 eV） plasma originated from the earth＇s ionosphere and co-rotating with the earth due to the large scale co-rotation electric field. The outermost boundary of the plasmashere is called the plasmapause.

关键词：等离子体层地球半径模型位置旋转电场等离子体源电离层距离

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

Geochemical characteristics of REE in the Late Neo-proterozoic limestone from northern Anhui Province, China

引用

Chinese Journal Of Geochemistry 2014年第2期33卷 187-193页

作者： CHEN Song GUI Herong SUN Linhua school of earth sciences and Engineering Suzhou University school of Resource and earth Science CUMT

Ten representative limestone samples [six from Wangshan Formation(WL) and the other four from Gouhou Formation(GL)] were collected from outcrops of the northern Anhui Province, and REE concentrations in limestone were measured by ICP-MS. The depositional environment and source of the REE were analyzed, and the results implys that the total REE of samples are low compared with the recent marine sediments, which range from 9.61 to 54.18 mg/kg and an average of 22.93 mg/kg. The PAAS-normalized REE+Y patterns of limestone are characterized by(1) light REE depletion in WL and enrichment in GL with the values of(Nd/Yb)SN ranging form 0.65 to 0.91 and 1.12 to 1.46, respectively;(2) light negative Ce anomaly(0.85–1.02) and positive La anomaly(0.92–1.27); and(3) both Eu(0.91–1.23) and Y(1.42–2.38) expressing light positive anomaly. The character indicated that the depositional environment was oxygenated, with infection by the hydrothermal activity and contamination of detritus.

关键词：稀土元素灰岩样品地球化学特征安徽省晚新元古代中国 ICP-MS Ce异常

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

Continental drift, plateau uplift, and the evolutions of monsoon and arid regions in Asia, Africa, and Australia during the Cenozoic

引用

Science China earth sciences 2019年第7期62卷 1053-1075页

作者： Xiaodong LIU Buwen DONG Zhi-Yong YIN Robin S.SMITH Qingchun GUO State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of Sciences CAS Center for Excellence in Tibetan Plateau earth sciences College of earth and Planetary sciences University of Chinese Academy of Sciences National Centre for Atmospheric Science University of Reading Department of Environmental & ocean sciences University of San Diego school of Environment and Planning Liaocheng University

Monsoon and arid regions in the Asia-Africa-Australia(A-A-A) realm occupy more than 60% of the total area of these continents. Geological evidence showed that significant changes occurred to the A-A-A environments of the monsoon and arid regions, the land-ocean configuration in the Eastern Hemisphere, and the topography of the Tibetan Plateau(TP) in the Cenozoic. Motivated by this background, numerical experiments for 5 typical geological periods during the Cenozoic were conducted using a coupled ocean-atmosphere general circulation model to systemically explore the formations and evolutionary histories of the Cenozoic A-A-A monsoon and arid regions under the influences of continental drift and plateau uplift. Results of the numerical experiments indicate that the timings and causes of the formations of monsoon and arid regions in the A-A-A realm were very different. The northern and southern African monsoons existed during the mid-Paleocene, while the South Asian monsoon appeared in the Eocene after the Indian Subcontinent moved into the tropical Northern Hemisphere. In contrast, the East Asian monsoon and northern Australian monsoon were established much later in the Miocene. The establishment of the tropical monsoons in northern and southern Africa, South Asia, and Australia were determined by both the continental drift and seasonal migration of the Inter-Tropical Convergence Zone(ITCZ), while the position and height of the TP were the key factor for the establishment of the East Asian monsoon. The presence of the subtropical arid regions in northern and southern Africa,Asia, and Australia depended on the positions of the continents and the control of the planetary scale subtropical high pressure zones, while the arid regions in the Arabian Peninsula and West Asia were closely related to the retreat of the Paratethys Sea. The formation of the mid-latitude arid region in the Asian interior, on the other hand, was the consequence of the uplift of the *** resul

关键词： Cenozoic Monsoon region Arid region Continental drift Tibetan Plateau uplift Climate simulation

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

Model Analysis of Radar Echo Split Observed in an Artificial Cloud Seeding Experiment

引用

Journal of Meteorological Research 2016年第3期30卷 386-400页

作者： MASAKI Shimada KIKURO Tomine KOJI Nishiyama Department of earth and ocean sciences National Defense Academy Faculty of Engineering Kyushu University

An artificial cloud seeding experiment was performed over the Japan Sea in winter to show how massive seeding could be effective to mitigate heavy snowfall *** results showed that 20 min after cloud seeding,a portion of the radar echo beneath the seeding track was weakened to divide the radar echo into two *** order to analyze the results,a numerical simulation was conducted by using the Weather Research and Forecasting model verion *** this simulation,the seeding effects were represented as phenomena capable of changing rain particles by accreting cloud ice and snow to form graupel particles and by changing cloud liquid water to snow *** graupel particles fell rapidly,thus temporarily intensifying the rainfall,which subsequently ***,the weakened radar echo in the field experiment is deemed to have been caused by the increase in rapidly falling graupel particles.

关键词： heavy snowfall artificial cloud seeding numerical experiment

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

The Mid-Pleistocene Climate Transition Recorded in a 1.6 Myr-Period Lacustrine Sediment Sequence from Mazatage, Tarim Basin

引用

Acta Geologica Sinica(English Edition) 2015年第1期89卷 312-313页

作者： LIU Jian WU Li WANG Rujian ZHAO Yue Institute of Geomechanics CAGS school of ocean and earth Science Tongji University

The mid-Pleistocene climate transition （MPT） has been widely reported in worldwide geological events. As a key issue of the Quaternary geology, it has attracted much attention from the paleoclimate community. MPT refers to a period lasting for several hundreds of thousand years, during which the dominant climate periodicity gradually extended from 41 kyr to 100 kyr （Ruddiman et al., 1989）,

关键词： Wang Tarim Basin The Mid-Pleistocene Climate Transition Recorded in a 1.6 Myr-Period Lacustrine Sediment Sequence from Mazatage

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

The effects of local variations in conditions on carbon storage and release in the continental mantle

引用

National Science Review 2024年第6期11卷 22-36页

作者： Stephen F.Foley Chunfei Chen Dorrit E.Jacob school of Natural sciences Macquarie University Research school of earth sciences Australian National University State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences China University of Geosciences

Recent advances indicate that the amount of carbon released by gradual degassing from the mantle needs to be revised upwards, whereas the carbon supplied by plumes may have been overestimated in the *** in rock types and oxidation state may be very local and exert strong influences on carbon storage and release mechanisms. Deep subduction may be prevented by diapirism in thick sedimentary packages,whereas carbonates in thinner sequences may be subducted. Carbonates stored in the mantle transition zone will melt when they heat up, recognized by coupled stable isotope systems(e.g. Mg, Zn, Ca). There is no single ‘mantle oxygen fugacity’, particularly in the thermal boundary layer(TBL) and lowermost lithosphere, where very local mixtures of rock types coexist. Carbonate-rich melts from either subduction or melting of the uppermost asthenosphere trap carbon by redox freezing or as carbonate-rich dykes in this zone. Deeply derived, reduced melts may form further diamond reservoirs, recognized as polycrystalline diamonds associated with websteritic silicate minerals. Carbon is released by either edge-driven convection,which tears sections of the TBL and lower lithosphere down so that they melt by a mixture of heating and oxidation, or by lateral advection of solids beneath rifts. Both mechanisms operate at steps in lithosphere thickness and result in carbonate-rich melts, explaining the spatial association of craton edges and carbonate-rich magmatism. High-pressure experiments on individual rock types, and increasingly on reactions between rocks and melts, are fine-tuning our understanding of processes and turning up unexpected results that are not seen in studies of single rocks. Future research should concentrate on elucidating local variations and integrating these with the interpretation of geophysical signals. Global concepts such as average sediment compositions and a uniform mantle oxidation state are not appropriate for small-scale processes; an increa

关键词： lithospheric mantle carbonate melts deep carbon cycle craton destruction continental rifts

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

Revisiting Late Quaternary Slip-rate along the Maqu Segment of the Eastern Kunlun Fault, Northeast Tibet

引用

Acta Geologica Sinica(English Edition) 2016年第2期90卷 486-502页

作者： LI Jian ZHANG Yueqiao LI Hailong XIONG Jinhong LI Jianhua WU Tairan Institute of Geomechanics Chinese Academy of Geological Sciences school of earth and Space sciences Peking University school of earth sciences and Engineering Nanjing University

The Late Quaternary slip rate along the Maqu segment of the eastern Kunlun Fault was estimated using a combination of high-resolution remote sensing imagery interpretation, field observations and differential Global Positioning System（GPS） measurements of offset river terraces, and 14 C dating of snail shells collected from offset risers. The results show that the left-slip rate along the segment is 3–5 mm/a, and that the vertical slip rate is 0.3–0.5 mm/a. Both the horizontal and vertical slips on the segment remain consistent over a distance of ~100 km. It means that no slip gradient as previously suggested occurred along the Maqu segment, and which thus might behave as an independent seismogenic fault. Judging from multiple relationships among young terrace offsets, we infer that co-seismic surface rupture produced by a characteristic earthquake with a magnitude of Ms7.0–7.5 on the Maqu fault could generate a horizontal slip of 4.5–5 m and a vertical slip of 0.45–0.5 m, with a corresponding ratio（Dh/Dv） of about 9. Two surface rupture events must have occurred over the past 3300 years, the latest one possibly between 1485 cal BP and 1730 cal BP.

关键词： eastern Kunlun fault Maqu fault Late Quaternary slip-rate offset terraces paleo-seismicity

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：