检索结果-南通市图书馆

Geochemistry of high-Mg andesites from the early Cretaceous Yixian Formation, western Liaoning: Implications for lower crustal delamination and Sr/Y variations

引用

Science china Earth Sciences 2006年第9期49卷 904-914页

作者： WANG Xiaorui1, GAO Shan1,2, LIU Xiaoming1, YUAN Honglin1, HU Zhaochu1, ZHANG Hong1,3.& WANG Xuance4 1. State Key Laboratory of Continental Dynamics, Department of geology, Northwest University, Xi`an 710069, china 2. State Key Laboratory of Geological Processes and mineral Resources, china University of Geosciences, Wuhan 43.074, china 3. shenyang institute of geology and mineral Resources, shenyang 110032, china 4. Guangzhou institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, china 1. State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi’an 710069 China 2. State Key Laboratory of Geological Processes and mineral Resources China University of Geosciences Wuhan 430074 China 3. shenyang institute of geology and {3. Resources Shenyang 110032 China 4. Guangzhou institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

85 volcanic rocks of the Yixian Formation from the Sihetun type section werecollected and analyzed for geochemical and isotopic compositions. Major element compositionsindicate that the Sihetun volcanic rocks are high magnesium andesites with some basalts occurring atthe bottom of section. The Sihetun high magnesium andesites (SiO_2 = 52.82-59.3. wt%, Al_2O_3.14.15-16.3.wt%) show many characteristics of adakites such as depletion in heavy rare-earth elements(HREE; Yb = 1.03.1.88 μg/g) and Y(12-20 μg/g) and high Sr (620-13.3.μg/g) and Sr/Y(3.-88), withhigh La_N/Yb_N ratio (10-25). They share similar major and trace element characteristics to volcanicrocks from the Xinglonggou Formation except their lower Nd isotope ratios (^(143.Nd/^(144)Nd(13.Ma) = 0.5118-0.5119, ε_(Nd) (13.Ma) = -11.6-13.8, ^(87)Sr/^(86)Sr (13. Ma) = *** were interpreted in a way that eclogite that formed at the base of thickened Archean lowercrust of the North china craton foundered into the convecting mantle and subsequently melted andinteracted with peridotite. However, compared to the Xinglonggou volcanic rocks, the source of theSihetun magma contained more ancient continental crustal material in order to explain its evolved Ndisotopes. The age of the Sihetun Formation was 120 to 13. Ma, and this indicates that delaminationlasted to the early Cretaceous period. The Sr contents and Sr/Y ratios of the Sihetun high-Mgandesites show significant negative correlations with SiO_2 for samples with SiO_2 > 56%. Thesesuggest that the Sr and Sr/Y values were reduced due to fractional crystallization of ***, the effect of crystallization on volcanic Sr and Sr/Y ratio has to be taken intoaccount.

关键词： High-Mg andesite, Adakite, Yixian Formation, North china Craton, delamination.

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

Whole fossil plants of Ephedra and their implications on the morphology,ecology and evolution of Ephedraceae (Gnetales)

引用

Chinese Science Bulletin 2010年第15期55卷 1511-1519页

作者： WANG Xin 1,2 & ZHENG ShaoLin 3.1 Nanjing institute of geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008,china 2 Fairy Lake Botanical Garden,Shenzhen 518004,china 3.shenyang institute of geology and mineral Resources,shenyang 11003.,china Nanjing institute of geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China Fairy Lake Botanical Garden Shenzhen 518004 China shenyang institute of geology and {3. Resources Shenyang 110034 China

Although there are many reports of fossil Ephedraceae,whole plant fossil record remains *** to a lack of trust on partially preserved fossil materials,scholars working on molecular clock proposed a recent origin of Ephedra and cast doubt on the earlier origin time of *** better the understanding on this interesting group,here we report whole plants of Ephedra hongtaoi ***.(Ephedraceae,Gnetales) from the Yixian Formation (Early Cretaceous) in western Liaoning,*** whole plants of Ephedra demonstrate clearly the characters of Ephedra,including shrubby growth habit,decussate branching pattern,and terminal ovuliferous unit with micropylar *** whole-plant preservation of the fossils provides more convincing fossil evidence of Early Cretaceous Ephedra,helps to resolve the controversy over the origin time of Ephedra,and sheds light on the whole plant morphology,growth habit,ecology and evolution of Ephedraceae.

关键词：化石植物生态学麻黄形态学进化材料保存早白垩世生长习性

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

Combination of drainage, water supply and environmental protection as well as rational distribution of water resource in Zhengzhou mining district

引用

Science china Earth Sciences 2005年第10期48卷 1768-1779页

作者： WU Qiang1, LI Duo1,2, DI Zhiqiang3. MIAO Ying3. ZHAO Suqi4 & GUO Qiwen5 1. Resource Exploitation Engineering College, CUMT, Beijing 100083. china 2. Shijiazhuang Engineering College, University of Economics, Shijiazhuang 05003., china 3. shenyang {3. of geology and mineral Resources, shenyang 110032, china 4. State Adminstration of Coal Mine Safety, Beijing 100013. china 5. Zhengzhou Coal Mine Company (Group), Zhengzhou 4523.1, china Resource Exploitation Engineering College CUMT Beijing China Shijiazhuang Engineering College University of Economics Shijiazhuang china shenyang institute of geology and {3. Resources shenyang china State Adminstration of Coal Mine Safety Beijing china Zhengzhou Coal Mine Company (Group) Zhengzhou china

The geological condition of coalfield is much complex in china. With increasing in mining depth and drainage amount, the contradiction of drainage, water supply and environ-mental protection is becoming more and more serious. However, the contradiction can be solved by the scientific management of optimizing combination of drainage, water supply and environ-mental protection. The Philip multiple objectives simplex method used in this article has searched for a possible solution at the first step, and then it goes on searching to find out whether there is a weight number that can lead the solution to the biggest. It can reduce the randomness and diffi-culty of traditional weight method which determine the weight number artificially. Some beneficial coefficients are vague and the number is larger in the model of water resource dispatch. So the vague layer analysis method can consider these vague factors fully, combining the qualitative and quantitative analysis together. Especially, this method can quantify the experiential judge-ment of policy decider, and it will turn to be more suitable if the structure of objective factors is complex or the necessary data are absent. In the paper, the two methods above are used to solve the plans of drainage, water supply and optimizing distribution of water resource in the Zhengzhou mining district.

关键词： combination of drainage, water supply and environmental protection, Philip multiple objective simplex method, vague layer analysis method, distribution of water resource.

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

Chronological record of the Early Mesozoic underplating in the northern margin of North china—U-Pb chronometry of zircons in the Late Mesozoic andesite from Western Liaoning

引用

Progress in Natural Science:Materials International 2007年第8期17卷 943-947页

作者： Shao ji'an~(1,2**) Zhang Hongfu~2 Liu Xiaoming~3.Li Zhitong~4 (1.School of Earth and Space Sciences,Peking University,Beijing 100871,china 2.institute of geology and Geophysics and Key Laboratory of {3. Resources,Chinese Academy of Sciences,Beijing 100029,china 3.Key Laboratory of Continental Dynamics,Northwestern University,Xi'an 710069,china 4.institute of geology and {3. Resources of shenyang,shenyang 110032,china) [a]School of Earth and Space Sciences Peking University Beijing China [b]Laboratory of mineral Resources Chinese Academy of Sciences Institute of Geology and Continental Dynamics Beijing China [c]Key Laboratory of Continental Dynamics Northwestern university Xi'an China [d]institute of geology and mineral Resources of {3. Shenyang China

Cathodoluminescence spectroscopic analysis of zircons in the uppermost sanukites of the early Cretaceous Yixian Forma- tion in Western Liaoning reveals zoning structures of the zircons in the volcanic rocks. LA-ICP-MS chronometry shows that the central part of the zircons is remnant zircon with a U-Pb dating of 254 Ma,which is consistent with the age of the Early Mesozoic underplating granulites,and that the periphery is zircon crystallizing out of the host magma with a U-Pb dating of 116 Ma,which is highly consistent with the Ar-Ar dating of the host volcanic *** of the clinopyroxenes xenocrystals in the sanukites are similar to those of the clinopyroxenes in the underplating granulites,indicating that the granulites accreted to the lower crust in the Early Mesozoic have been reformed and disrupted by the upwelling diapers of the asthenosphere and taken part in formation of the sanukites in the Late Mesozoic.

关键词： northern margin of North china Mesozoic volcanic rock U-Pb chronometry of zircon underplating granulite

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

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

引用

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 {3. and mineral Resources, Nanjing 210016, china 3. Tianjin institute of {3. and mineral Resources, Tianjin 3.0170, china 4. The 2nd Regional Geological Investigation Party, Xinjiang Bureau of {3. and mineral Resources, Changji 83.100, 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 Resources Nanjing 210016 China 3. Tianjin institute of geology and mineral Resources Tianjin 300170 China 4. The 2nd 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 3.0.7±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 (50-220 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 T2DM model ages of 470 to 580 Ma and positive εNd(3.1 Ma) values of 6.23.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.

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

NEW LATE SILURIAN OSTRACODE GENERA FROM CENTRAL NEI MONGOL WITH A DESCRIPTION OF A NEW FAMILY, AULACOBAIRDIIDAE

引用

微体古生物学报 1991年第2期 132-140页

作者： Zhang Li-jun (shenyang lnstitute of geology and mineral Resources, Chinese Academy of Geological Sciences,{3.)

Here described are five new genera and nine new species of Ostracoda from the Upper Silurian Xibiehe Formation of the Baorhantu and Bate’ aobao sections in Darhan Muminggan Lianheqi, Nei Mongol. A new family Aulacobairdiidae of Paleozoic marine Ostracoda is proposed in this paper. Damaoqiella bicarinata, Heterobairdia glypta, Aulacobairdia biconvexa, A. sinuosa, Glossoparacypris prolata, G. constricta, Pseudothrallella

关键词： AULACOBAIRDIIDAE NEW LATE SILURIAN OSTRACODE GENERA FROM CENTRAL NEI MONGOL WITH A DESCRIPTION OF A NEW FAMILY NEI

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

Identification of Hercynian shoshonitic intrusive rocks in central Hainan Island and its geotectonic implications

引用

Science Bulletin 2006年第20期51卷 2507-2519页

作者： XIE Caifu1, 2, ZHU Jinchu1, DING Shijiang3. ZHANG Yeming2, FU Tai’an2 & LI Zhihong2 1. State Key Laboratory for mineral Deposits Research and Department of Earth Sciences, Nanjing University, Nanjing 210093. china 2. Yichang institute of {3. and mineral Resources, Yichang 443.03. china 3. Hainan Bureau of {3. and mineral Resources, Haikou 570226, china Department of Otolaryngology University Hospital VU P.O. Box 7057 1007 MB Amsterdam The Netherlands State Key Laboratory for mineral Deposits Research and Department of Earth Sciences Nanjing University Nanjing 210093 China

An identification has been made of some shoshonitic intrusive rocks in central Hainan Island recently. These rocks are K-rich (K2O=2.9%―5.1%, K2O/Na2O=0.95―2.12), distinctly enriched in LILE and LREE, strongly depleted in Nb, Ta, and moder- ately depleted in Sr and Ti, with (87Sr/86Sr)i = 0.70859―0.71425 and ε Nd(t) = (?2.77―?7.49). They were derived from an EMⅡ-type mantle source. The enrichment process is related to metasomatism of depleted mantle caused by a great amount of fluid-melt released from oceanic crust and terri- genous sediments at great depth (eclogite facies) during the subduction of the South china plate under the Indochina-South china Sea plate in the Carbon- iferous–Early Permian. A SHRIMP U-Pb zircon dating yields a crystallization age of 272±7 Ma for the sho- shonitic intrusions, which is coeval with the strongly peraluminous granites found in central Hainan Island. These two kinds of rocks generally possess syn-intrusion ductile deformation structures. Thus they are considered to have been generated during the early stage (syn-thrust phase) of a post-collisional event. The primary magma of shoshonitic rocks was produced at a depth > 80 km by decompression- dehydration melting of previously enriched litho- spheric mantle wedge, phlogopite-bearing garnet peridotite, which was in turn caused by the break-off of a descendent slab and upwelling of a hot as- thenosphere. The rising of melts was accompaniedby crustal contamination and crystallization fractiona- tion (AFC). Combining with other related data, it is proposed that the southwards subduction and amal- gamation of the South china plate with the Indo- china-South china Sea plate took place at ca. 287- 278 Ma, which was a part of the convergence proc- ess of the Pangea supercontinent. The suture zone was probably located along the line of Song Ma-Beibu Gulf-north margin of the Yunkai Moun- tains-Wuyi Mountains.

关键词： SHRIMP U-Pb dating Hercynian shoshonitic intrusive rocks post-collisional event enriched mantle Hainan Island.

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

The species diversity of fusulinaceans and high-frequency sea-level changes in the Carboniferous-Permian boundary section at Xikou, Zhen'an County,Shaanxi Province, china

引用

Science china Earth Sciences 2006年第7期49卷 673-683页

作者： ZHANG Haijun1, WANG Xunlian2, DING Lin1, XIA Guoying3.& WANG Lei2 1. institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, china 2. Faculty of Earth Sciences and mineral Resources, china University of Geosciences, Beijing 100083. china 3. Tianjin institute of geology and mineral Resources, Tianjin 3.0170, china 1. institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China 2. Faculty of Earth Sciences and mineral Resources China University of Geosciences Beijing 100083 China 3. Tianjin institute of geology and mineral Resources Tianjin 300170 China

The study on the interrelation between sea-level changes and biodiversity with its evolu-tion has great significance for understanding the impact of global changes on organic evolution and exploring the inherent laws of life-environment coevolution in geological history. In this paper, the stratigraphic distribution of fusulinacean fauna in the Carboniferous-Permian boundary section at Xikou, Zhen’an County, Shaanxi Province, is analyzed quantitatively, and the relationship between the species diversity of fusulinaceans and relative sea-level changes is discussed. As a whole, the spe-cies numbers of fusulinacean fauna experience a rapid increase and an obvious decline in Xikou, Zhen’an County, from the Late Carboniferous to the Early Permian. There is a significant increase in species diversity around the Carboniferous-Permian boundary, which is one of the biggest bio-events of the fusulinacean fauna, and represents the radiation of Pseudoschwagerininae subfamily in the studied area. Integrated fusulinacean species diversity into sequence stratigraphic framework, de-tailed study suggests that the species diversity of the fusulinaceans is closely related to its relative stratigraphic location, and is essentially controlled by the sea-level changes, especially by the high-frequency sea-level changes. Generally, the species diversity of fusulinaceans is low, and the number of first and last appearance datum is small in the lower unit of high-frequency depositional cycle formed during the quick rise of the sea level; whereas the species diversity of fusulinaceans is high, and the number of first and last appearance datum is large in the upper unit of high-frequency cycle formed during the slow fall of the sea level. Within the third-order depositional sequence, the species diversity of the fusulinaceans at the first flooding surfaces and the maximum flooding surfaces is low, and it increases upward. The fusulinacean species diversity is low within the transgressive syst

关键词： fusulinaceans, species diversity, high-frequency cyclothem, sequence stratigraphy, sea-level changes, Carboniferous-Permian boundary, Zhen'an, Shaanxi.

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

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

引用

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 {3. Resources, Chinese Academy of Geological Sciences Yue Zhao shenyang institute of geology and {3. 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. 4types. 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

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

^(40)Ar/^(3.)Ar dating of shear deformation of the Xianshuihe fault zone in west Sichuan and its tectonic significance

引用

Science china Earth Sciences 2004年第9期47卷 794-803页

作者： ZHANG Yueqiao1, CHEN Wen2, 3.& YANG Nong1 1. institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, china 2. institute of {3., Chinese Academy of Geological Sciences, Beijing 10003., china 3. institute of {3. and Geophysics, Chinese Academy of Sciences, Beijing 100029, china institute of Geomechanics Chinese Academy of Geological Sciences Beijing 100081 China institute of geology Chinese Academy of Geological Sciences Beijing 100037 China institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Based on field geological survey, structural measurements and classical Ar/Ar dating of mica, biotite and K-feldspar, we obtain cooling ages for Miocene left-lateral shear along the Xianshuihe fault zone. The results document two thermal events during the sinistral shear. The early event (12-10 Ma) corresponds to rapid cooling of the Zheduoshan granitic massif from above 700℃ to below 3.0℃. The late event (5-3.5 Ma) corresponds to cooling of granites intruded along the eastern side of the fault zone. These dating results provide important thermochronological constraint on the timing of late Cenozoic eastward extrusion of the Chuan-Dian Block in the SE Tibetan margin.

关键词： Xianshuihe fault zone, Zheduoshan granitic massif, sinistral shear deformation, 40Ar/3.Ar dating, late Cenozoic.

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：