检索结果-南通市图书馆

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

同方期刊数据库

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, {2. {3. of {4. Sciences, Beijing Panxi {4. 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

Early-Middle Permian Reef Frameworks and Reef-building Models in the Eastern Kunlun Mountains

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2001年第2期75卷 115-125页

作者： TIAN Shugang institute of geology, {2. {3. of {4. Sciences, Beijing 10003.and FAN Jiasong institute of geology and Geophysics, {2. {3. of Sciences, Beijing 10002. chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China

Reef frameworks and building models of the Early-Middle Permian in the eastern Kunlun Mountains have been verified through studies of reef-building communities, palaeoecology and carbonate facies. The eastern Kunlun reefs are built mainly by 6 reef-building communities, which include 11 major categories of frame-building organisms and 6 categories of reef-associated organisms. Eight types of reef-frames have been distinguished and eleven kinds of rocks identified to belong to 6 reef facies. Three sorts of reefs classified by previous researchers, namely mudmounds, knoll reefs and walled reefs, are well developed in the study area. Such reef-facies association and reef distribution show that there are 4.models of reef growth and development, i.e. the tidal-bank knoll-reef model, the plateau-margin wall-reef model, the composite wall-reef model and the deep-water mudmound model. The reefs are mainly constructed by calcareous sponge and calcareous algae, which are similar to all Permian reefs in other area

关键词： reef model Early-Middle Permian eastern Kunlun reefs

A New Fauna——Qinghezhen Fauna——from the Northern Margin of the North china Platform

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1990年第4期64卷 443-459,468-470页

作者： Liu Xiaoliang Wang Dongfang Shenyang institute of geology and Mineral Resources, {2. {3. of {4. Sciences Yue Zhao Shenyang institute of geology and Mineral Resources Chinese Academy of Geological Sciences

In the Inner Mongolia axis and Jiaoliao anteclise along the northern margin of the North china *** has been found that the strata formerly considered as Archaean and Proterozoic are in fact an ophiolite suitesimilar to the Early Palaeozoic Ondor Sum Group in the Northern Geosyncline region of china. The stratahave been named in northern Liaoning as the Qinghezhen Group. The emphasis of this paper is on the discus-sion of the simall shelly fossils found in the siliceous rocks in the upper part of the Qinghezhen Group. Thisophiolite suite stretches in an E-W direction for about 1000 km along the northern margin of the North chinaPlatform. in which 15 fossil localities with stable stratigraphic horizons have been discovered. In this paper. 4.ypes. 7 genera (including 5 new ones) and 10 species (including 8 new ones and 1 new subspecies) aredescribed, which are collectively referred to as the Qinghezhen Fauna. The characteristics of these fossils are:shell form simple. the maximum length not exceeding 4.mm. with obvious shell wall and wall ornaments. TheQinghezhen Fauna is comparable in shell structure of some genera and species with the Meishucun Fauna inSouth china, but differs from the latter in having only monotonous fossil groups developed in a distinctly va-ried ecological environment. The two faunas may belong to the same evolutionary stage of the Early Cambrianbut have developed parallelly in different regions. The existence of the Qinghezhen Fauna represents an impor-tant biological event in the Early Cambrian in the Northern Geosyncline region of china. The discovery of theQinghezhen Fauna will bring new knowledge and profound influence to a series of problems on basic geologyand mineral deposit prospecting such as the Cambrian faunas. biogeographical povincialism in china and thegeotectonic features of the northern margin of the North china Platform.

关键词： A New Fauna from the Northern Margin of the North china Platform

The Erupting-Flow Model and Erupting-Flow Types in Yangbajain Geothermal Field in china

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1989年第3期63卷 313-323页

作者： Hu Xunsen and Zheng Zhuohua institute of Hydrogeology and Engineering geology, {3. {4. of geological Sciences, Zhengding, Hebei Province institute of Hydrogeology and Engineering geology Chinese Academy of Geological Sciences Zhengding Hebei Province

Erupting-flow types of geothermal wells in the Yangbajain geothermal field, china, are proposed based on internal energy of geothermal fluids and hydrogeologic-dynamic conditions of wellbore. An erupting-flow model, w... 详细信息

关键词： well The Erupting-Flow Model and Erupting-Flow Types in Yangbajain Geothermal Field in china Flow

SHRIMP U-Pb dating and Hf isotopic analyses of Middle Ordovician meta-cumulate gabbro in central Qiangtang, northern Tibetan Plateau

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2010年第5期53卷 657-664页

作者： ZHAI QingGuo1 WANG Jun1, LI Cai2.& SU Li3.1 institute of geology, {2. academy of geological Sciences, Beijing 10003., china 2.College of Earth Sciences, Jilin University, Changchun 13.061, china 3.The geological Laboratory Center and State Key Laboratory of geological Processes and Mineral Resources, china University of Geo- sciences, Beijing 100083. china institute of geology Chinese Academy of Geological Sciences Beijing China College of Earth Sciences Jilin University Changchun China The geological Laboratory Center and State Key Laboratory of geological Processes and Mineral Resources China University of Geosciences Beijing China

Metabasites consisting of metamorphic ultra-mafic rocks, cumulate gabbro, gabbro (diabase), basalt, and plagiogranite are exposed at the Taoxinghu area in central Qiangtang, northern Tibetan Plateau. Zircon SHRIMP U-Pb dating for the cumulate gabbro yields a weighted mean age of 4.7±4.Ma, which is the oldest and most reliable magmatic age in this area. Zircon 176Hf/177Hf ratios range from 0.2.2.15 to 0.2.2.57, with εHf(t) values of 5.02.0.2., indicating that the cumulate gabbro was mainly derived from the depleted mantle. In addition, geochemical data of metabasites suggest that they have similar characteristics to those in the mid-ocean ridge basalts (MORB). The Taoxinghu metabasites may represent the fragment of Early Paleozoic ophiolite in the "Central Uplift" of the Qiangtang, northern Tibetan Plateau.

关键词： Qiangtang cumulate gabbro SHRIMP dating Hf isotope

Discovery of a pterodactylid pterosaur from the Yixian Formation of western Liaoning,china

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2001年第13期46卷 1112-1117页

作者： WANG Xiaolin & LU Junchang1. institute of Vertebrate Paleontology and Paleoanthropology, chinese {2. of Sciences, Beijing 10004.,{3. 2. College of Earth Sciences and Resources,{3. University of Geo-sciences, Beijing 100083.{3. 3. Department of geological Sciences, Southern Methodist University, Dallas, TX 752.5, USA institute of Vertebrate Paleontology Chinese Academy of Sciences Beijing 100044 China

A well-preserved pterosaur with nearly complete skull is described from the Lower Cretaceous Yixian Formation at Sihetun in western Liaoning. It is characterized by a low and long crestless skull, slender and pointed teeth, long metacarpal, nearly equal length of metatarsals I -III and short pedal digit V. It is referred to a new genus and species of the family Pterodactylidae: Haopterus gracilis gen. et sp. nov. This is the first pterosaur with a nearly complete skull from the Jehol Biota; it also represents the first non-controversial fossil record of Pterodactylidae in Asia. Haopterus is more derived than Pterodactylus from the Late Jurassic Solnhofen in Germany. This discovery extends the distribution of the family Pterodactylidae from Europe and Africa to Asia and its latest occurrence from the Late Jurassic to the Early Cretaceous. The discovery of Haopterus gracilis provides further evidence for the study of the originand radiation of the Jehol Biota; it also sheds new light on the evolution and

关键词： western Liaoning Early Cretaceous Yixian Formation Pterodactylidae.

Evolutionary Stages of the Earliest Skeletal Fauna and Division and Correlation of the Precambrian-Cambrian Boundary Strata

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1988年第3期1卷 233-248+349页

作者： Yue Zhao institute of geology, {2. {3. of {4. Sciences, Beijing institute of geology Chinese Academy of Geological Sciences Beijing

Through an analysis of the earliest fossils in the Precambrian-Cambrian boundary beds in various parts ofthe world, especially in the Yangtze and Siberia platforms, the author has found that the evolution of the ea-rliest skeletal animals may be divided from older to younger into three stages. The first stage (theAnabarites-Protohertzina fauna) is represented by the Anabarites-Protohertzina zone of the Meishucunian Stagein the Yangtze platform and the A. trisulcatus and P. cristata zones of the Manykayn Stage in Siberia. The sec-ond stage (the earliest orthothecimorphid and mollusc fauna) is represented by the Paragloborilus-Siphogonuchites zone of the Meishucunian Stage and the Aldanocyathus sunnaginicus zone of the TommotianStage. The third stage (the earliest hyolithimorphid and lapworthellid fauna) is represented by the Sinosachiteszone of the Meishucunian Stage and the *** and *** zones of the Tommotian Stage. The threeevolutionary stages can be used as a criterion for worldwide correlation.

关键词： Evolutionary Stages of the Earliest Skeletal Fauna and Division and Correlation of the Precambrian-Cambrian Boundary Strata

Re-Os(ICP-MS)dating of the massive sulfide ores from the Jinchuan Ni-Cu-PGE deposit

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 2005年第10期48卷 1672-1677页

作者： YANG Gang1,2. DU Andao1, LU Jiren3. QU Wenjun1 & CHEN Jiangfeng2.1. National Research Center of Geoanalysis, Beijing 10003.,{3. 2. Laboratory for Earth Material Cycling, School of Earth and Space Sciences, University of Science and Technology of{3., Hefei 2.002.,{3. 3. institute of Mineral Resource, chinese academy of {14. Sciences, Beijing 10003.,{3. National Research Center of Geoanalysis University of Science and Technology of china chinese academy of {2. Sciences

Massive sulfide ore from the Jinchuan Ni-Cu-PGE deposit was dated by Re-Os technique using Carius Tube digestion, Os distillation, Re extraction by acetone and ICP-MS measurement. An isochron giving an age of 83. ± 3. Ma, initial 187Os/188Os ratio of 0.2.9 ± 0.018 (MSWD = 1.7) and γOs = 13. ± 15 is obtained. The Re-Os age obtained agrees, within analytical uncertainties, with previous SHRIMP zircon U-Pb age of 82. ± 8 Ma (n=5, MSWD = 4.3.. The result suggests that the deposit was formed at Neoproterozoic and that the formation of the Jinchuan Ni-Cu-PGE sulfide deposit may be closely related to the plume activity, which were attributed to the breakup of the Rodinia supercontinent. The high γOs of the massive ores sug-gests that crustal material was involved in the formation of the Jinchuan deposit, however, the quantity of the added crustal material is less than 10%.

关键词： Jinchuan Ni-Cu-PGE deposit, Re-Os dating, ICP-MS.

^(4.)Ar/^(3.)Ar Thermochronological Constraints on the Timing of Collisional Orogeny in the Mian-Lite Collision Belt,Southern Qinling Mountains

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1999年第2期73卷 208-215页

作者： LI Jinyi, WANG Zongqi and ZHAO Min institute of geology, {2. {3. of {4. Sciences, Beijing 10003. chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China

Silurian, Devonian and Carboniferous geological bodies in the Mianxian-Lueyang (Mian-Lue) collisional belt (MLB) and its neighbouring areas, southern Qinling Mountains, china, show similar characteristics of having undergone deformation of two stages. The earlier one, which is inferred to be related to collisional orogeny between the Yangtze and Sino-Korean palaeocontinents based on previous geological data, is responsible for large-scale, north-verging recumbent folds and overthrusts, and associated with low greenschist fades metamorphism. 4.Ar/3.Ar dating of three muscovite samples taken from different localities yields plateau ages of {3.6.9±0.9 and {3.9.5±1.4.Ma and an apparent age of 194.5±3.0 Ma. Thus, the late Triassic collision between the Yangtze and Sino-Korean palaeocontinents has been constrained.

关键词： Qinling Mountains Mian-Lue collision belt muscovite 4.Ar/3.Ar dating collisional orogeny