检索结果-南通市图书馆

Oxygen and hydrogen isotopic compositions of coexistent minerals of the Tasigake alkali granite pluton,northern Xinjiang:constraints upon the cause of ^(18)O-D depletion and the ^(18)O/^(16)O exchange kinetics

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第12期44卷 1086-1093页

作者： LIU Wei, ZHAO Zhenhua ZHANG Fuqin Research Center of Mineral Resources Exploration, Institute of geophysics , Chinese academy of sciences , {3. 100101, china Guangzhou Institute of Geochemistry, Chinese academy of sciences , Guangzhou 510640, china Research Center of Mineral Resource Exploration Institute of Geophysics Chinese Academy of Science Beijing China Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China

Oxygen and hydrogen isotopic compositions have been determined of three coexistent mineral triplets of alkali feldspar, quartz, arfvedsonite of 11 samples collected from the Tasigake alkali granite pluton, Ulungur River region, northern Xinjiang. Isotopic exchange with meteoric water during subsolidus cooling caused strong 18O-D depletion and the remarkable nonequilibrium 18O/16O relation between coexistent minerals. 18O/16O exchange kinetic effects of the three minerals are simultaneously and consistently modelled. Exsolution and microtextural reorganization of alkali feldspar, and infiltration of water have been mutually facilitated by each other. Shallow intrusion, and circulation of meteoric water throughout the pluton cool it effectively. As a result, the "heat engine" is rapidly extinguished, and the nonequilibrium 18O/16O relation is frosen.

关键词： 18O-D depletion isotopic exchange kinetics alkali granite Ulungur.

Megaripples from the Mesoproterozoic of the Kimberley region,northwestern Australia and its geological implications

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2012年第1期1卷 15-25页

作者： Lan Zhongwu 1,2,3.,Zhong-Qiang Chen 2,4,1.State Key Laboratory of Lithospheric Evolution,Institute of geology and geophysics,Chinese academy of {3.,beijing 10002.,china 2.School of Earth and Environment,The University of Western Australia,Australia 3.Key Lab of Petroleum Resources Research,Institute of geology and geophysics,Chinese academy of {3.,beijing 10002.,china 4.State Key Laboratory of Biogeology and Environmental geology,china University of Geo{3. (Wuhan),Wuhan 43.074,china State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China School of Earth and Environment The University of Western Australia Australia Key Lab of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China State Key Laboratory of Biogeology and Environmental geology China University of Geosciences (Wuhan) Wuhan 430074 China

Large ripples are described from the Mesoproterozoic Hilfordy Formation in the Kimberley region,northwestern *** ripple index (RI) and ripple symmetry index (RSI) suggest the Kimberley ripples were likely generated by storm *** wave height is up to 15 23.cm and wave length is up to 70 90 *** features,incorporated with other morphological characteristics such as symmetry,steepness,ripple spacing,and compositions,agree well with the megaripples previously reported from the intertidal-nearshore settings of modern seas and the geological *** Mesoproterozoic ripples were likely generated by the storm-induced *** survey of the global record of megaripples reveals that such structures have occurred through the geological past from the Archean to present *** were particularly common in the Neoproterozoic and had the largest ripple length and ripple height among the modern and geological *** is probably because extreme storms prevailed at that *** frequent occurrence in present day beach is probably due to the prevalence of extreme storms caused by the monsoon or tsunami/earthquake influenced climatic regimes.

关键词： megaripples palaeohydrodynamics extreme storms Mesoproterozoic Hilfordy Formation Kimberley northwestern Australia

Modeling the climate effects of different subregional uplifts within the Himalaya-Tibetan Plateau on Asian summer monsoon evolution

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2012年第35期57卷 4617-4626页

作者： ZHANG Ran 1,JIANG DaBang 1,2,3.LIU XiaoDong 4 & TIAN ZhiPing 2,5 1 Climate Change Research Center,Chinese academy of sciences,beijing {3.,china 2 Nansen-Zhu International Research Centre,Institute of Atmospheric Physics,Chinese academy of sciences,beijing {3.,china 3.Key Laboratory of Regional Climate-Environment Research for Temperate East Asia,Chinese academy of sciences,beijing {3.,china 4 State Key Laboratory of Loess and Quaternary geology,Institute of Earth Environment,Chinese academy of sciences,Xi’an 710075,china 5 Graduate University of Chinese academy of sciences,beijing 100049,china Climate Change Research Center Chinese Academy of Sciences Beijing China Nansen-Zhu International Research Centre Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Key Laboratory of Regional Climate-Environment Research for Temperate East Asia Chinese Academy of Sciences Beijing China State Key Laboratory of Loess and Quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate University of Chinese academy of sciences Beijing China

Considering the different uplifting time of different subregions of the Himalaya-Tibetan Plateau(TP),a series of numerical simulations have been conducted with the Community Atmosphere Model(CAM4) developed at the National Center for Atmospheric Research to explore the effects of the phased tectonic uplift of the Himalaya-TP on the evolution of Asian summer *** results show that the uplifts of the Himalaya and northern TP significantly affect the evolutions of South Asian summer monsoon and northern East Asian summer monsoon *** is,the tectonic uplift of the Himalaya intensifies the South Asian summer monsoon circulation and increases the precipitation in South Asia,whereas the uplift of the northern TP intensifies the northern East Asian summer monsoon circulation and increases the precipitation in northern East *** with previous simulations,current comparative analyses of modeling results for different subregional uplifts within the Himalaya-TP help deepen our understanding of the evolutionary history of Asian monsoons.

关键词：青藏高原隆升喜马拉雅亚洲季风高原气候夏季季风次区域隆起演化建模

A New SHRIMP Age of the Xiamaling Formation in the North china Plate and Its Geological Significance

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2007年第6期81卷 1103-1109页

作者： GAO Linzhi~(1,*)ZHANG Chuanheng~2 SHI Xiaoying~2 ZHOU Hongrui~2 WANG Ziqiang~2 SONG Biao~(1,3. 1 Institute of geology,Chinese academy of Geological sciences,{3. 10003.,china 2 china University of Geosciences({3.),{3. 100083.china 3.{3. SHRIMP Central,10003. {3.,china Chinese Acas Geol Sci Inst Geol Beijing 100037 Peoples R China beijing SHRIMP Cent Beijing 100037 Peoples R China china Univ Geosci Beijing 100083 Peoples R China

Setting up the hypostratotype of late Precambrian is the main aim of the research on the Meso-and Neoproterozoic in North *** chronostratigraphic position is the key in this study. However,many key horizons have not been calibrated with the high-quality isotopic *** the reported new U-Pb age with the Sensitive High-Resolution Ion Microprobe（SHRIMPⅡ）,a zircon U- Pb age was obtained of the ash bed in the Xiamaling Formation in North china Plate,yielding a weighted mean;Pb/;U age of 13.8±12 *** is the first SHRIMP U-Pb age from the Xiamaling Formation in the North china Plate,and represents the depositing time of the middle part of the Xiamaling *** zircon age plays an important role to understanding geological evolution of the North china Plate during Meso-and Neoproterozoic.

关键词： SHRIMP U-Pb Dating Mesoproterozoic Xiamaling Formation North china Plate

Genesis of ^(23.)Th excess in basalts from mid-ocean ridges and ocean islands:Constraints from the global U-series isotope database and major and rare earth element geochemistry

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth sciences 2010年第10期53卷 1486-1494页

作者： ZHANG GuoLiang1,2 & ZENG ZhiGang1 1 Key Laboratory of Marine geology and Environment,Institute of Oceanology,Chinese academy of sciences,Qingdao 266071,{3. 2 Graduate University of Chinese academy of sciences,beijing 100049,{3. Key Laboratory of Marine geology and Environment Institute of Oceanology Chinese Academy of Sciences Qingdao China Graduate University of Chinese academy of sciences Beijing China

Based on 23.Th-23.U disequilibrium and major element data from mid-ocean ridge basalts(MORBs) and ocean island basalts(OIBs),this study calculates mantle melting parameters,and thereby investigates the origin of 23.Th excess.(23.Th/23.U) in global MORBs shows a positive correlation with Fe8,Po,Na8,and Fmelt(Fe8 and Na8 are FeO and Na2O contents respectively after correction for crustal fractionation relative to MgO = 8 wt%,Po=pressure of initial melting and Fmelt=degree of melt),while 23.Th excess in OIBs has no obvious correlation with either initial mantle melting depth or the average degree of mantle ***,compared with the MORBs,higher(23.Th/23.U) in OIBs actually corresponds to a lower melting *** suggests that the 23.Th excess in MORBs is controlled by mantle melting conditions,while the 23.Th excess in OIBs is more likely related to the deep garnet *** vast majority of calculated initial melting pressures of MORBs with excess 23.Th are between 1.0 and 2.5 GPa,which is consistent with the conclusion from experiments in recent years that DU>DTh for Al-clinopyroxene at pressures of >1.0 *** initial melting pressure of OIBs is 2.2-3.5 GPa(around the spinel-garnet transition zone),with their low excess 226Ra compared to MORBs also suggesting a deeper mantle ***,excess 23.Th in MORBs and OIBs may be formed respectively in the spinel and garnet stability *** addition,there is no obvious correlation of K2O/TiO2 with(23.Th/23.U) and initial melting pressure(Po) of MORBs,so it is proposed that the melting depth producing excess 23.Th does not tap the spinel-garnet transition *** and MORBs in both(23.Th/23.U) vs.K2O/TiO2 and(23.Th/23.U) *** plots fall in two distinct areas,indicating that the mineral phases which dominate their excess 23.Th are ***/Yb-Ce curves of fast and slow ridge MORBs are similar,while,in comparison,the Ce/Yb-Ce curve for OIBs shows more influence from *** mechanism

关键词： excess 23.Th clinopyroxene garnet spinel-lherzolite mid-ocean ridge ocean island

On the evolution and histology of some Cambrian protoconodonts, paraconodonts and primitive euconodonts

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2004年第7期47卷 577-584页

作者： DONG Xiping Department of geology, Peking University, beijing 100871, china Laboratory of Palaeobiology & Stratigraphy, Nanjing Institute of Ge-ology and Palaeontology, Chinese {3. of sciences, Nanjing 210008, china Department of geology Peking University Beijing China Laboratory of Palaeobiology & Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China

Previous reports on the morphological evolution of protoconodonts and paraconodonts are reviewed. The evolutionary trends exhibited by species of the protoconodont genus Gapparodus and the paraconodont genus Westergaadodina are discussed. Based on the present study on histology, genus Paibiconus is protoconodont, while genus Yongshunella is paraconodont (fig. 1 (a)). However, the nature of Huayuanodontus has not been fully understood so far. Recently, the transitional form New Gen. Sensu Miller, 1980 of late Late Cambrian has been found in Hunan Province, South china. It is considered as the Sister-Group of Proconodontus. Moreover, another kind of transitional form of middle Late Cambrian and late Late Cambrian between Prooneotodus notundatus and Pnoconodontus, which looks like Prooneotodus notundatus in gross morphology, but has anterior and posterior costae, has also been found in Hunan, South china. This kind of transitional form is believed to be probably the real intermediate link between Prooneotodus rotundatus and Pnoconodontus, and Prooneotodus rotundatus is most probably the ancestor of Proconodontus. The two transitional forms noted above are all euconodonts by the study of their histology. Unlike the euconodonts of Post-Cambrian, the evolutionary relationships among the species of protoconodonts, paraconodonts and the primitive euconodonts could not be made clear without the histological study on them.

关键词： protoconodonts, paraconodonts, evolution, histology, Cambrian.

Carbon isotope composition and its implications of Lower Cretaceous Aptian-Albian shallow water carbonates in the Cuoqin Basin, North Tibet

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2004年第3期47卷 247-254页

作者： ZHU Jingquan1, LI Yongtie2, JIANG Maosheng1 & CHEN Daizhao1 1. Institute of geology and geophysics, Chinese academy of {3., beijing 10002., china 2. Research Institute of Petroleum Exploration and Development, CNPC, beijing 100083. china Institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 China Res. Inst. Petroleum Explor./Devt. CNPC Beijing 100083 China

The d 13. values of Lower Cretaceous Aptian-Albian platform-type carbonates in the Cuoqin Basin, North Tibet vary between 2.48 and 5.46. The mean value is 3.93. The values are not only provided with positive excursion, but also 1.17 higher than those of con-temporaneous pelagic carbonates which possess pretty high d 13. values. The origin is ap-proached. During the oceanic anoxic events, a great number of organisms were rapidly buried, causing the increase of the d 13. value of oceanic total dissolved carbon (TDC) and generally promoting the values of marine carbonates. After that, owing to the organisms undergoing dif-ferent isotopic fractionation in the paleo-ocean with stratified structure, d 13. values of shallow sea carbonate were obviously higher than those of pelagic carbonates.

关键词： shallow water carbonate, stable carbon isotope, paleooceanography, Aptian-Albian stage, Cuoqin Basin.

Comparison of two end-member styles of epithermal Au-(Cu)deposits

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第S2期44卷 212-213页

作者： FAN Hongrui and XIE Yihan Institute of geology, Chinese academy of sciences,{3., china Institute of geology Chinese Academy of Sciences Beijing 100029 China

EPITHERMA Au-(Cu) deposits occur largely in volcano-plutonic arcs (island arcs as well as continentalarcs) associated with subduction zones, with ages similar to those of volcanism. These deposits form atshallow depth,<1 km, and are hosted mainly by volcanic rocks. Modern volcanic-hydrothermal systems provide an analogue to the environment for the ancient intrusion-related and volcanic epithermal deposits. Recent studies also indicate that the volcanic epithennalore deposits are formed from magmatic fluids, although the magmatic signatures have been largely erasedby meteoric water. At depth (fig. 1), the magmatic fluid from the high-level intrusive magma will result in the formation of intrusion-related deposits (e.g. porphyry Cu, Au, Mo deposits). Detailed studies of fluid inclusions and stable isotopes indicate that the hydrothermal system that form these deposits are initially

关键词： epithermal Au(Cu) deposit mineralization ore-forming fluid.

CENOZOIC COLLISIONAL DEFORMATION AND LITHOSPHERE TECTONIC EVOLUTION OF THE EASTERN HIMALAYAN SYNTAXIS

在线全文

学校读者我要写书评

暂无评论

地学前缘 2000年第S1期7卷 12-13页

作者： Ding Lin, Zhong Dalai, Zhang Jinjiang, Ji Jianqing(Institute of geology and geophysics, Chinese academy of {3., beijing 10002.,china)

The Eastern Himalayan Syntaxis (EHS) is one of the strongest deformation area along the Himalayan belt resulted from the collision between Indian plate and the Eurasian plate since 50～60Ma, and has sensitivity tracked and preserved the whole collisional processes. It should depend on the detail geological investigations to establish the deformational accommodate mode, and the uplift history, to elucidate the deep structure and the crust\|mantle interaction of the EHS. The Namjabarwa metamorphic complex indented into the Gangdise arc along the sinistral Pai shear fault and the dextral Aniqiao shear fault on the both sides of the Great Canyon of Yalung Zangbo river since the collision of the NE corner of the Indian plate and the Eurasian Plate at 60～70Ma [1] . The distance between Yarlung Zangbo suture and Bangong—Nujiang suture is shortened more 120km in the EHS area than that of the Lhasa block.

关键词： Eastern Himalayan Syntaxis collisional deformation Magmatism and high\|pressure metamorphism Lithospheric evolution