检索结果-南通市图书馆

Tectonic evolution of the Dabieshan orogen: In the view from polyphase deformation of the Beihuaiyang metamorphic zone

引用

science China earth {2. 2005年第7期48卷 886-899页

作者： LIN Wei1, 2. Faure Michel3, WANG Qingchen1 & Arnaud Nicolas4 1. LTE, Institute of Geology and Geophysics, Chinese Academy of sciences, Beijing 10002., China 2. department of earth and planetary sciences,{2., nagoya university, japan 3. ISTO, UMR CNRS 6113, Batiment Géosciences, Orléans Université d’Orléans, 45067 Orléans Cedex 2. France 4. UMR 652. "Magmas et Volcans", 5 Rue Kessler, 63000 Clermont-Ferrand, France LTE Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China department of earth and {2. sciences Graduate School of Science Nagoya University Japan ISTO UMR CNRS 6113 Orléans Université d'Orléans 45067 Orléans Cedex 2 France UMR 652. Magmas et Volcans 63000 Clermont-Ferrand 5 Rue Kessler France

The Beihuaiyang metamorphic zone was formed by the Early Mesozoic collision of the North and South China Blocks. It consisted of the Foziling and Luzhenguan complexes and was thought to have never afforded a deep subduction. A similar feature of the deformation in the Dabieshan UHP metamorphic rocks implies that these different tectonic units share the same geodynamic background. The early stage of deformation can be preserved on account of their relatively shallower subduction than that for UHP rocks. On the basis of an analysis of the geo- logical structure and geochronological results, five deformational stages have been recognized: a D1-Early compressional deformation which represents the continental subduction; a D2.Early exhumation deformation producing a syn-convergence exhumation; a D3-Main deformation, represented by an exhumation deformation with Late Triassic age; a D4-Doming and its margin extensional gravity collapse deformation and finally a D5-regional extensional deformation of Cretaceous that was mostly introduced by the migmatization and plutonism.

关键词： Beihuaiyang metamorphic zone geometry kinematic polyphase deformation tectonic evolution.

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

Carbon isotopic characteristics and their genetic relationships for individual lipids in plants and sediments from a marsh sedimentary environment

引用

science China earth {2. 2005年第8期48卷 1203-1210页

作者： DUAN Yi1, ZHANG Hui1, ZHENG Chaoyang1, WU Baoxiang1 & ZHENG Guodong2.1. Lanzhou Institute of Geology, Chinese Academy of sciences, Lanzhou 730000, China 2. department of {2. & planetary System science, graduate school of science, Hiroshima university, Higashi-Hiroshima 739-85japan Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou China department of earth & {2. System science Graduate School of Science Hiroshima University Higashi-Hiroshima Japan

The carbon isotopes of individual lipids in herbaceous plants and tree leaves in Ruoergai marsh were measured by the GC-IRMS analytical technique in order to understand the inherent relationships of carbon isotopes between sedimentary and plant lipids from typical marsh environment. The analytical results show that the carbon isotopic compositions of n-alkanes in different kinds of plants differ significantly. Mean δ 13C values of n-alkanes in her-baceous plants (?32.2.―?36.9‰) are 3.3‰ lower than those in woody plant (?2..2.― ?35.0‰). The carbon isotopic compositions of fatty acids in organisms (?30.3‰― ?36.2.) are very similar to those of n-alkanes and the δ 13C values for unsaturated fatty acids are within the range of those for saturated fatty acids. The differences in δ 13C values between plant lipids are obvious and range from 2.4‰ to 7.8‰. It is observed that the carbon isotopic compositions of sedimentary lipids are closely related to those of plant lipids. The carbon isotopic compositions (?2..0‰―?36.9‰) of n-alkanes, ≥C16 fatty acids, n-alkanols, sterols and n-alkanones in the sediments are similar to those of plant lipids and the carbon isotopic compositions of short-chain sedimentary lipids are similar to those of long-chain sedimentary homologues. These indicate that the sedimentary lipids are derived from high plants. However, the δ 13C values of C14:0 and C15:0 fatty acids in the sediments are lighter than those of the same carbon number saturated homologues in plants, reflecting the genetic features partially derived from bacteria. These data provide scientific evidence for carbon isotope-applied research of individual lipids.

关键词： marsh environment, plants, sediments, individual lipids, carbon isotopic compositions, genetic relationships.

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

DISCOVERY OF THE OLIGO-MIOCENE RODENTS FROM WEST japan AND THEIR GEOLOGICAL ANDPALEONTOLOGICAL SIGNIFICANCE

引用

古脊椎动物学报(中英文） 1995年第4期 320-329页

作者： TAKAFUMI KATO(department of earth and {2. sciences, Kyushu university, Fukuoka 812.81,japan)HIROYUKI OTSUKA(Institute of earth sciences, Faculty of science, Kagoshima university, Kagoshima 890, japan)

New rodent fossils found in the Oligo-Miocene sedboents in Kyushu, West japan, are identified to the following four taxa: 1) Castoridae gen. et sp. indet. A, 2. Steneofiber sp. from the Late Oligocene Sasebo Group; 3) Castoridae gen. et sp. indet. B; 4) Diatomys shantungensis from the Early to Middle Miocene Nojdria Group. Studies of two specimens identified to the family Chstoridae gen. et sp. indet. A and B indicate that they are large beavcrs with the skull of nearly same sise as Trogontherium that holds enamel of longitudinally grooved indsors. Resemblance in sise and features of the incisor enamel indicates that these specimens could be of the same genus. Furthermore, it is known that Steneofiber is a cosmopolitan genus, however, it has not been found in the Late Oligocene in East Asia. The occurrence of Diatomys shantungensis, on the other hand, strongly suggests that the late Early Miocene mammls from japan and the East *** to the same faunal province in Easl Asian margin.

关键词： Kyushu japan Late Oligocene-Early Miocene Rodents

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

Almandine megacrysts from Yingfengling Cenozoic basalt in Leizhou Peninsula and their parental magma origin

引用

Chinese science Bulletin 2001年第14期46卷 1215-1219页

作者： YU Jinhai & S. Y. O’Reilly1. National Key Laboratory of Metallogenic Mechanism of Endogenetic Deposits, department of earth {2., Nanjing university, Nanjing 2.0093, China 2. National Key Center of GEMOC, department of earth and planetary {2., Macquarie university, North Ryde, NSW 2.09, Australia National Key Laboratory of Metallogenic Mechanism of Endogenetic Deposits Department of Earth Sciences Nanjing University Nanjing China National Key Center of GEMOC Department of Earth and Planetary Sciences Macquarie University North Ryde Australia

The garnet megacrysts from Yingfengling basalts are characterlzed by high FeO (>2.%), CaO (7.02. -8.16%) and low MgO (5.88%-10.87%). Significant composition variations are observed in these megacrysts, of which Ni, V, Sc, Co, and HREE are positively correlated with their Mg# and Zr, Hf, Ga, Y, Sr, Nb, Zn and LREE-MREE are negatively correlated with Mg#. Megacryst parent magma is a highly evolved residual melt with strongl depletion in Ti, Sr, Hf, Nb and HREE. This parental magma was generated by more than 60% of crystallization fractionation of clinopyroxene, garnet, plagioclase and ilmenite from quartz tholeiitic magma. It has not erupted to the surface, but stayed at the upper mantle and formed the megacrystic cumulate. Megacrysts and their host basalt are in disequilibrium.

关键词： almandine megacryst geochemistry LAM-ICPMS Lei-zhou Peninsula.

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

PALEOMAGNETIC STUDY OF IGNEOUS ROCKS OF GUPIS—SHAMRAN AREA,KOHISTAN ARC, PAKISTAN,NW HIMALAYA

引用

地学前缘 2000年第S1期7卷 120-121页

作者： Mirza Naseer Ahmad, Yoshiki Fujiwara, Lalu Prasad Paudel[WT5,5”BX](department of earth and {2. sciences, graduate school of sciences, Hokkaido university Sapporo, japan)

Kohistan Sequence has been considered as island arc formed during the subduction of oceanic lithosphere at the leading edge of northward moving Indian continent.. Sedimentary sequences indicate that formation of the intra\|oceanic Kohistan arc began in early Cretaceous time. The isotopic data demonstrate the involvement of enriched, DUPAL type mantle, suggesting that Kohistan arc was formed at or south of the present equator (Khan et al., 1997). The Intra oceanic phase of Kohistan lasted until sometime between 102.and 85 Ma, when Kohistan collided with Asia. From this time until collision with India about 50 Ma ago, Kohistan existed as Andean\|type margin. This paleomagnetic study is from the volcanic and plutonic rocks exposed in Gupis\|Shamran area (west of Gilgit) in northern part of the Kohistan arc. According to geochronological data these rocks were formed 61～55Ma ago (Treloar et al., 1989), when Kohistan was existing as Andean\|type margin. Seven to nine samples were collected from nine sites of Shamran volcanics (58±1)Ma and from five sites of Pingal, Gupis, and Yasin plutons (Ar\|Ar hornblende ages ranges from 61～52.a). On the basis of one Rb\|Sr age of (59±2.Ma from these plutons, the above\|mentioned Ar/Ar ages may be regarded as reasonable intrusion ages of these plutons (Searle, 1991).

关键词： Kohistan paleomagnetism tectonics igneous rock Pakis tan

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

POLYPHASE METAMORPHISM AND INVERTED THERMAL GRADIENT IN THE LESSER HIMALAYA OF CENTRAL NEPAL: CONSTRAINTS FROM WHITE MICA COMPOSITIONS

引用

地学前缘 2000年第S1期7卷 51-52页

作者： Lalu Prasad Paudel 1,2., Kazunori Arita 1[WT5,5”BX](1 department of earth and {2. sciences, graduate school of science, Hokkaido university, Kita 10, Nishi 8, Sapporo 060\|0810, japan 2.Central department of Geology, Tribhuvan university

The Lesser Himalaya in central Nepal consists of greenschist\|facies metasedimentary rocks, which are overthrust by the amphibolite\|facies rocks of the Higher Himalaya along the Upper Main Central Thrust (UMCT). Despite a number of works on metamorphism of the MCT zone and the Higher Himalaya, the low\|grade metamorphic rocks to the south of the MCT zone have not been studied *** the present study, an attempt was made to constrain the metamorphic events and thermal structure of the whole Lesser Himalaya by means of white mica (Ms) compositions. About 600Ms grains in 48 metapelitic samples from the Lesser Himalaya were analysed by the EPMA. Compositional zoning in individual Ms grains was checked by means of X\|ray compositional mapping. There exist wide intersample, intrasample and within grain compositional variations in Ms in the samples from the Lesser Himalaya. Sheared Ms phenocrysts in pegmatites and gneisses have compositions very close to that of the ideal muscovite. Detrital Ms show wide variation in phengite content, most of which are poor in phengite content, and are most probably derived from older higher\|grade metamorphic rocks.

关键词： Lesser Himalaya polymetamorphism inverted metamorphism white mica composition

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

Some basic concepts and problems on the petrogenesis of intra-plate ocean island basalts

引用

Chinese science Bulletin 2009年第22期54卷 4148-4160页

作者： NIU Yaoling1,2.3 1 department of earth {2., Durham university, Durham DH1 3LE, UK 2.school of earth {2. and Resources, China university of Geo{2., Beijing 100083, China 3 school of earth and Space {2., Peking university, Beijing 100871, China department of earth {2. Durham University Durham UK school of earth {2. and Resources China University of Geosciences Beijing China school of earth and Space {2. Peking University Beijing China

Basaltic magmatism that builds intra-plate ocean islands is often considered to be genetically associated with "hotspots" or "mantle plumes". While there have been many discussions on why ocean island basalts (OIB) are geochemically highly enriched as an integral part of the mantle plume hypothesis, our current understanding on the origin of OIB source material remains unsatisfactory, and some prevailing ideas need revision. One of the most popular views states that OIB source material is recycled oceanic crust (ROC). Among many problems with the ROC model, the ocean crust is simply too depleted (e.g., [La/Sm]PM > 1) OIB. Another popular view states that the enriched component of OIB comes from recycled continental crust (RCC, i.e.; terrigenous sediments). While both CC and OIB are enriched in many incompatible elements (e.g., both have [La/Sm]PM >>1), the CC has characteristic enrichment in Pb and deletion in Nb, Ta, P and Ti. Such signature is too strong to be eliminated such that CC is unsuitable as source material for OIB. Plate tectonics and mantle circulation permit the presence of ROC and RCC materials in mantle source regions of basalts, but they must be volumetrically insignificant in contributing to basalt magmatism. The observation that OIB are not only enriched in incompatible elements, but also enriched in the progressively more incompatible elements indicates that the enriched component of OIB is of magmatic origin and most likely associated with low-degree melt metasomatism. H2. and CO2.rich incipient melt may form in the seismic low velocity zone (LVZ). This melt will rise because of buoyancy and concentrate into a melt rich layer atop the LVZ to metasomatize the growing lithosphere, forming the metasomatic vein lithologies. Erupted OIB melts may have three components: (1) fertile OIB source material from depth that is dominant, (2. the melt layer, and (3) assimilation of the metasomatic

关键词：岩石成因论海洋 OIB 矿物学

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

Structure of a pair of anticyclonic vortices in northern part of the South China Sea in autumn of 1994

引用

Acta Oceanologica Sinica 2002年第2期21卷 203-216页

作者： Fu Gang, Toshio Yamagata1. department of Marine Meteorology, Ocean university of Qingdao, Qingdao 2.6003, China2. department of earth and planetary Physics, university of Tokyo, japan department of Marine Meteorology Ocean University of Qingdao Qingdao 266003 China department of earth and {2. Physics University of Tokyo Japan

A pair of remarkable meso-scale anticyclonic vortices, one formed closely to another, inthe northern part of the South China Sea during the period from the later August to early September of 1994 were documented by the in situ observation data. Their spatial structures were examined in detail from the horizontal and two nearly perpendicular/vertical angles of view. It was shown that the horizontal scales of these two vortices were around 100, 50 km, and their vertical scales were about 500, 1000 m, respectively. Two 'warm core' structures associated with these two vortices were found in their horizontal and vertical analyses. The closer spacing of these two vortices (namely, 60 km), which was smaller than the Rossby radius of deformation, suggested that they might merge with each other during their next evolution stages and form into a larger vortex eventually.

关键词： The South China Sea a pair of anticyclonic vortices warm core Rossby radius of deforma-tion

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

Effects of salinity on methane gas hydrate system

引用

science China earth {2. 2007年第11期50卷 1733-1745页

作者： YANG DingHui1 & XU WenYue2.1 department of Mathematical sciences, Tsinghua {2., Beijing 100084, China 2.school of earth & Atmospheric sciences, Georgia Institute of Technology, Atlanta, GA 30332. USA department of Mathematical sciences Tsinghua University Beijing China school of earth & Atmospheric {2. Georgia Institute of Technology Atlanta USA

Using an approximately analytical formation, we extend the steady state model of the pure methane hydrate system to include the salinity based on the dynamic model of the methane hydrate system. The top and bottom boundaries of the methane hydrate stability zone (MHSZ) and the actual methane hy-drate zone (MHZ), and the top of free gas occurrence are determined by using numerical methods and the new steady state model developed in this paper. Numerical results show that the MHZ thickness becomes thinner with increasing the salinity, and the stability is lowered and the base of the MHSZ is shifted toward the seafloor in the presence of salts. As a result, the thickness of actual hydrate occur-rence becomes thinner compared with that of the pure water case. On the other hand, since lower solubility reduces the amount of gas needed to form methane hydrate, the existence of salts in sea-water can actually promote methane gas hydrate formation in the hydrate stability zone. Numerical modeling also demonstrates that for the salt-water case the presence of methane within the field of methane hydrate stability is not sufficient to ensure the occurrence of gas hydrate, which can only form when the methane concentration dissolved in solution with salts exceeds the local methane solubility in salt water and if the methane flux exceeds a critical value corresponding to the rate of diffusive methane transport. In order to maintain gas hydrate or to form methane gas hydrate in marine sedi-ments, a persistent supplied methane probably from biogenic or thermogenic processes, is required to overcome losses due to diffusion and advection.

关键词： methane gas hydrate,solubility,stability of hydrate,salinity,phase equilibrium

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 the Red earth sequence on the northeastern Tibetan Plateau and its implications for regional aridity since the middle Miocene

引用

science China earth {2. 2006年第5期49卷 505-517页

作者： WANG Xianyan1,7, LU Huayu1,2. JI Junfeg3, WANG Xiaoyong1,7, ZHAO Jingbo4, HUANG Baochun5 & LI Zhen6 1. SKLLQG, Institute of earth Environment, Chinese Academy of sciences, Xi’an 710075, China 2. {2. of Urban and Resources sciences, Nanjing university, Nanjing 2.0093, China 3. {2. of earth sciences, Nanjing university, Nanjing 2.0093, China 4. {2. of Geography, Shaanxi Normal university, Xi’an 710062. China 5. Institute of Geology and Geophysics, Chinese Academy of sciences, Beijing 10002., China 6 {2. of Geography, Qinghai Normal university, Xining 810008, China 7. graduate school of the Chinese Academy of sciences, Beijing 100039, China SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an China graduate school of the Chinese Academy of {2. Beijing China department of Urban and Resources sciences Nanjing University Nanjing China department of earth {2. Nanjing University Nanjing China department of Geography Shaanxi Normal University Xi’an China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China department of Geography Qinghai Normal University Xining China

The Red earth deposit around Xining, northeastern Tibetan Plateau, has beenstudied in terms of soil micro-structure, grain-size distribution, major- and trace-elementchemistry and magne-tostratigraphy. Field investigations indicate that the Red earth sequenceconsists of 2. visually definable yellow-brown and weakly-developed soils interbedded with reddishstrongly-developed soils, and has a similar structure to the aeolian Red Clay deposit on the ChineseLoess Plateau. Grain-size analysis shows that the Red earth deposit is very fine-grained with anegligible sand fraction ( > 63 μm). Thin-section observations under light microscopy show that thedeposit has a clayey texture and the coarse fraction ( > 10 μm) mainly consists of quartz,feldspar and micas. Pyroxene and hornblende were also observed. This mineralogical composition ofthe coarse fraction is similar to that of the Quaternary loess. In addition, all of the mineralgrains are semi angular semi-angular and are generally finer than 63 μm. There is a good agreementbetween the major and minor trace element chemistry of loess-soil units and the Red earth *** REE distributions of the loess-soil and the Red earth deposit are similar in shape, withenriched LREE and fairly flat HREE profiles and a clear negative Eu anomaly. The geochemicalcharacteristics of the Red earth deposit are also identical to those of upper continental crust,thus indicating a wind-blown origin. Magnetostratigraphic investigation shows that onset of the Redearth deposition predates 11.4 Ma BP (13.6 Ma at a nearby site). The distribution of the reportedMiocene aeolian loess at Qin''an of the Loess Plateau is still unknown. Our results indicate thatthis aeolian deposit had extended to the northeastern Tibetan Plateau by at least the middleMiocene. The similarity of the element geochemistry between the Red earth deposit and the overlyingloess shows that they may have similar sources and dynamic transport system, and may indicate thatthe

关键词： Red earth deposit, Northeastern Tibetan Plateau, aeolian deposit, aridity of Asia, the middle Miocene.

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：