检索结果-南通市图书馆

Acta Geologica Sinica(English Edition) 1991年第3期65卷 271-287页

作者： Zhao Daxian Tang Guangting The Fifth geological party,{2., Simao,yunnan Liu Linqun The Fifth geological party Yunnan Bureau of Geology and Mineral Resources Sirnao Yunnan

Through studies on the element geochemistry, alteration of country rocks, ore-forming fluids and isotopegeochemistry of the Arno tin deposit in the metamorphic rocks of the Upper Proterozoic Ximeng Group, theauthors consider that the concentration of the B-F-Li-Rb-Cs-Sn association is related to acidic magmatism inthe study area. The Fe-Mg-Li tourmaline in the ore is the replaced product of the country rocks byhypothermal fluid. The δ^(18)O values of mineral separates are +2.01- +13.16‰ and their δ^(34)S values, +2.6-+7.2.. The ore-forming materials were derived from hydrothermal fluid of granitic magma. For themineralization, the temperature is 450°-350℃, the pressure, 450-1000×10~5 Pa, and the age, Himalayan(2..5 Ma). According to the geochemical characteristics, a minerogenic model is established: the deposit is ahypothermal cassiterite-quartz vein type tin deposit controlled by the hidden Himalayan granites.

关键词： The Geochemical Characteristics and Minerogenic Model for the Amo Hypothermal Tin Deposit in Ximeng County yunnan Province

Oxygen isotope as a tracer of REE fractionation in water-rock interaction

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 224-226页

作者： DENG Hailin~1, LI Chaoyang~1, ZHOU Yunman~2.and WANG Chongwu~2.1. Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry Chinese Academy of Sciences, Guiyang 550002. China 2. no.1 geological party, yunnan bureau of geology and mineral resources,{2., China Open Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China No. 1 geological party Yunnan Bureau of Geology and Mineral Resources Xundian 655205 China

STABLE oxygen isotope is not only an effective approach to tracing water-rock interactions, but also canprovide much information about ore-forming temperature and source and evolution of ore fluids in thestudy of hydrothermal deposits. The rare-earth elements (REE) can be used to trace the sources ofore-forming materials and can also, to some extent, indicate the physical and chemical properties of fluids in the geochemical processes. The combination of these two aspects of research can effectivelyprobe into the geochemical behavior and evolution of REE in the process of water-rock interaction duringhydrothermal ore deposition. On the other hand, the essence of REE as tracers in hydrothermal mineralization can be better understood. In this note the Lemachang independent Ag deposit in northeastern yunnan is selected for a case study.

关键词： oxygen isotope tracer water-rock interaction REE fractionation.

Aoyitake plagiogranite in western Tarim Block, NW China: Age, geochemistry, petrogenesis and its tectonic implications

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2006年第11期49卷 1121-1134页

作者： ZHANG Chuanlin1,2. YU Haifeng3, YE Haimin2. ZHAO Yu2.& ZHANG Dongsheng4 1. Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 2. Nanjing Institute of geology and mineral {2., Nanjing 2.0016, China 3. Tianjin Institute of geology and mineral {2., Tianjin 300170, China 4. The 2.d Regional geological Investigation party, Xinjiang bureau of geology and mineral {2., Changji 831100, China 1. Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China 2. Nanjing Institute of geology and mineral {2. Nanjing 210016 China 3. Tianjin Institute of geology and mineral {2. Tianjin 300170 China 4. The 2.d Regional geological Investigation party Xinjiang Bureau of Geology and Mineral Resources Changji 831100 China

SHRIMPP U-Pb zircon age and geochemical and Nd isotopic data are reported for the Aoyitake plagiogranite in western Tarim Block, NW China. The plagiogranite intruded the Middle Pro- terozoic and Lower Carboniferous with an exposure area of ca. 60 km2.and crystallized at 330.7±4.8 Ma. Rock types mainly include tonalite, trondhjemite and minor amounts of diorite and quartz-diorite. Feldspars in the rocks are dominated by oligoclase-andesine, and minor perthite observed locally. The granites are sodic with Na/K ratios (molar) between 4 and 87. Total REE (50-2.0 ppm) show a clear positive correlation with SiO2. There is no LRRE/HREE fractionation (LaN/YbN=0.5-1.5), me- dium negative Eu anomalies (δ Eu=0.3-0.6), high Y content and low Sr/Y ratio (~1.0). These granites exhibit relatively juvenile Nd T2.M model ages of 470 to 580 Ma and positive εNd(331 Ma) values of 6.2. to 7.65. The aforementioned characteristics are similar to those of ocean island or ocean ridge plagiogranites. However, the regional geology, especially its scale, precludes that the plagiogranite pluton was derived directly from fractionational crystallization of mantle-derived basaltic magma. We interpreted that the primary magma of the pluton might be tonalitic in composition generated by ca. 50% partial melting of the juvenile basaltic crust. The primary magma experienced intensive frac- tionational crystallization, and intruded into the middle to upper crusts to form the granite pluton. In combination with the previous regional geological data, it is concluded that the plagiogranite pluton was emplaced within the Tarim Block in respond to the Carboniferous continental rifting along the Tianshan orogenic belt.

关键词： western Tarim, Aoyitake plagiogranite, age, geochemistry, tectonic implications.

Sulfur isotope geochemistry of the Lemachang independent Ag deposit, northeastern yunnan——A concurrent discussion on the mechanism of sulfur isotope equilibrium between barite and freibergite below 300℃

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 227-230页

作者： DENG Hailin~1, LI Chaoyang~1, ZHOU Yunman~2.and WANG Congwu~2.1. Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002. China 2. No.3 Braneh of no.1 geology {2., yunnan bureau of geology and mineral resources, xundian 6552.5, China Open Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China No. 3 Branch No. 1 Geology Party Yunnan Bureau of Geology and Mineral Resources Xundian 655205 China

IN the study of hydrothermal deposits sulfur isotopes bear much information about the source of sulfur,ore-forming temperature, the evolution of ore-forming fluids and the mechanism of metallogenesis. Todetermine whether sulfur isotopes reach equilibrium between fluids and sulfur-bearing minerals precipitated from the former and among the sulfur-bearing minerals is the key to the application of sulfur isotopegeochemistry to {2. problems. As it has been commonly accepted that sulfur isotopic equilibrium could not be reached between sulfate and sulfide below 350℃, little attention has been paid to thepossible mechanism of sulfur isotope equilibrium between sulfate and sulfide below 300℃. However, this note presents an example to show sulfur isotope equilibrium between barite and sulfate

关键词： sulfur isotope Lemachang independent Ag deposit barite freibergite sulfur isotope equilibrium below 300℃.

On the siltation of the middle Yangtze River

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2004年第5期47卷 463-480页

作者： YIN Hongfu1, CHEN Guojin2. LI Chang抋n1 & WEI Yuan3 1. School of Earth Sciences, China University of Geosciences, Wuhan 430074, China 2. Hydrogeological Team, Hubei bureau of {2. and mineral resources, Jingzhou 434100, China 3. geological Survey of Jiangxi Province, Nanchang 3302.1, China China Univ Geosci Sch Earth Sci Wuhan 430074 Peoples R China Hubei Bur Geol & mineral resources Hydrogeol Team Jinzhou 434100 Peoples R China Geol Survey Jiangxi Province Nanchang 3300201 Peoples R China

About 5.2.108 t/a of silts from the upper reach of the Yangtze River are transported through Yichang into the middle Yangtze River. The middle Yangtze itself and its tributaries yield ca. 0.8×108 t silts annually. Of this total 6×108 t/a input of silts, ca. 1.2.108 t/a are deposited within the river artery and lakes, while ca 4.83×108 t/a are at first transported into the lower reach through Datong, and then either deposited along the river and the Yangtze Delta, or output into the sea. Along the middle Yangtze River silting generally exceeds scouring, but the spatial and temporal distributions of scour-and-fill, as well as its distribution in the river valley transections, are uneven. Along the Yichang-Chenglingji and Jiujiang-Datong Segments of the middle Yangtze, scouring exceeds or equals silting. Silting mainly occurs along the Luoshan-Wuhan-Huangshi Segments with Wuhan as the pivotal point, as well as in the Dongting and Poyang Lakes. Even in these silting-dominated areas, there are times and parts of segments that scouring prevails. As to the transections, generally the river channel of main stream is scouring-dominated, forming V-shaped sections to a depth of 2.30 m or more, whereas the floodplains and bar islands are silting-dominated, forming wide and relatively high flats, which are often artificially transformed into protected embankments. Because the Jingjiang Levee separates the Jianghan Plain from Yangtze to the south, little has been deposited in that plain except a few sediments from the Han River—a tributary of the middle Yangtze. This factor plus the tectonic sag of that plain has made the altitude of plain surface several meters lower than that of the levee in most of the areas. Sil-tation along the Luoshan-Wuhan-Huangshi Segments has resulted in the elevation of flood level in this and upstream segments. River channel scouring plus floodplain silting have caused the transections of the middle Yangtze valley typically with deep channel and height

关键词： the middle Yangtze, scour-and-fill, siltation, silt utilization.

Petrogenesis and significance of early Yanshanian syenite-granite complex in eastern Nanling Range

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2005年第7期48卷 912-924页

作者： CHEN Peirong1, ZHOU Xinmin1, ZHANG Wenlan1, LI Huimin2. FAN Chunfang1, SUN Tao1, CHEN Weifeng1 & ZHANG Min1 1. State Key Laboratory of mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 2.0093, China 2. Tianjin Institute of geology and mineral resources, China geological Survey, Tianjin 300170, China State Key Laboratory of mineral Deposits Research Department of Earth Sciences Nanjing University Nanjing 210093 China Tianjin Institute of geology and mineral {2. China Geological Survey Tianjin 300170 China

In the eastern Nanling Range there exists the early Yanshanian syenite-granite assemblage. A representative example is the Pitou-Tabei complex composed of the Tabei syenite pluton and the Pitou syenogranite pluton in southern Jiangxi Province. U-Pb zircon dating yields ages of 188.6±2.2.Ma for the Tabei pluton and 186.3±1.1 Ma for the Pitou pluton. The Tabei syenite is characterized by relatively low SiO2.content (62.40% - 68.75%), high alkalis (K2.+Na2. = 10.56%-11.96%), low percent K2./Na2. ratios (0.56-0.93), metaluminous fea- ture (A/CNK = 0.80-1.00), enrichment in LILE (Rb, Ba, K) and HFSE (Th, U, Nb, Ta, Zr, and so on), weakly negative to positive Eu anomalies (δ Eu = 0.63-1.82., relatively low (87Sr/86Sr)i (0.70412.0.70543), and relatively high ε Nd(t) (3.14-3.52.. The Pitou syenogranite is charac- terized by high silicon content (SiO2.= 71.06%-76.2.%), relatively low alkalis (K2.+Na2. = 8.10%-9.80%), high percent K2./Na2. ratios (1.2.-1.94), metaluminous feature (A/CNK = 0.94-1.07), enrichment in Rb, Th (U), K, depletion in Ba, Nb, Ta, Sr, P , Zr, Ti, high ΣREE (av- eraging 451.03 μg/g), strong negative Eu anomalies (δ Eu = 0.2.-0.33), relatively high (87Sr/86Sr)i (0.70805-0.70912., and relatively low ε Nd( t ) (?5.35-?6.2.). The Tabei syenite and Pitou syenogranite both have the characteristics of A-type granites. The former is considered to be from the asthenosphere mantle, and the latter was the product of the crust-mantle mixture. They both were probably formed in a rifting setting.

关键词： syenite-granite assemblage single zircon U-Pb age rifting environment Nanling Range.

geological - Geophysical - Geochemical Exploration Models of Copper - Iron Deposits in Southeastern Hubei

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1994年第3期68卷 299-309页

作者： Guo XuequanSoutheast Hubei geological party, Hubei {2. of geology and mineral resources, Daye, Hubei Chinese Academy of geological Sciences Beijing

This paper discusses geological-geophysical-geochemical models of such typical deposits as the Tieshan-type Fe-Cu deposit, the Tonglushan-type Cu-Fe deposit, the Yehuaxiang-type Cu deposit, the Jiguanzui-type Cu-Au deposit, and the Tongshankou-type Cu (Mo) deposit. The models were established based on practical data of the polymetallic deposits dominated by copper ore in southeastern Hubei. These models, which are graphically illustrated in the paper, systematically summarize the metallogenic geological conditions and the geophysical-geochemical characteristics of copper deposits in this area. The models are of practical significance for studying copper deposits, predicting {2. resources, choosing exploration methods, and searching for ore deposits based on existing ones in the study area.

关键词： southeastern Hubei copper-iron deposits composite exploration model

Discovery of Fossil Charophytes from the Late Triassic Xujiahe Formation and Early Jurassic Lower Yimen Formation, Sichuan Province, and Its Significance

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1992年第3期66卷 301-309,327页

作者： Liu Junying Chen Zhongliang Institute of geology, Chinese Academy of geological Sciences, Beijing Panxi geological party, Sichuan bureau of geology and mineral resources, Xichang Liu Linqun Institute of geology Chinese Academy of Geological Sciences Beijing China

This paper describes the fossil charophytes collected from the Late Triassic Xujiahe Formation in Dazuand Early Jurassic Lower Yimen Formation in Xichang, Sichuan Province, and their significance. Up to now,papers dealing with fossil charophytes of the Late Triassic, especially of the Early Jurassic, have been rarelypublished. The description of the two new species of Porochara, P. dazuensis and P. xichangensis, and theirfossil assemblage not only provides an important basis for classification and correlation of red beds insouthwestern China but reveals for the first time the features of the charophyte flora of the Late Triassic-EarlyJurassic in the area, thus offering valuable data for the establishment of Triassic and Jurassic charophyte fossilzones in China.

关键词： Sichuan Late Triassic Early Jurassic charophyte fossil

Response to“Discussion on the systematic position of the Early Cambrian priapulomorph worms”

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2006年第2期51卷 250-256页

作者： HAN Jian1 & HU Shixue2.1. Department of geology and Key Laboratory for Continental Dynam- ics of the Education Ministry, Northwest University, Xi’an 710069, China 2. yunnan {2. Institute, Kunming 650011, China Department of geology and Key Laboratory for Continental Dynamics of the Education Ministry Northwest University Xi’an China yunnan geological Institute Kunming China

Due to the combination of complex states of preservation and taphonomies inChengjiang fossils, Huang et al.) expressed different opinions to those of Han et al.) on themorphology and systematic position of the fossil priapulomorph worms (Priapulomorpha) based on theiradditional materials. These diverse opinions are critical in any investigation of the diversity ofthe Introverta in the Cambrian explosion. However, some of their ideas need to be discussed infurther detail.

关键词： Response to Discussion on the systematic position of the Early Cambrian priapulomorph worms

Gymnosperms on the eve of the terminal Permian mass extinction in North China and their survival strategies

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第11期43卷 889-897页

作者： WANG Ziqiang+1 and ZHANG Zhiping+2. 1. Tianjin Institute of geology and mineral {2., Chinese Academy of geological Sciences, Tianjin 300170, China 2. Tianjin Centre of Physical and Chemical Techniques, Tianjin 300050, China Tianjin Institute of geology and mineral {2. Chinese Academy of Geological Sciences Tianjin China Tianjin Centre of Phyhical and Chemical Techniques Tianjin China

Main characteristics of the Permian redbed gymnosperms in North China have been summarized: dominant peltasperms and conifers, numerous enigmatics such as Gigantonoclea and Psygmophyllum, and abundant precursors of Mesozoic gymnosperms. Furthermore, stresses affecting these plants survival are suggested to be paleoatmospheric CO-2.concentration, water stress, wind and fire activities, and fungal infection. Consequently, a preliminary analysis accounts for the ecological strategies of these gymnosperms to the P-Tr event.

关键词： North China Permian gymnosperms mass extinction.