检索结果-南通市图书馆

Chengdeite-A New Mineral of Ordered Natural Iron-iridium Alloy

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1996年第1期70卷 27-32,108页

作者： Yu Zuxiang institute of geology, chinese academy of geological sciences, beijing

Chengdeite occurs in chromite orebodies in dunite as well as in placers in their neighbourhood. The mineral occurs as granular aggregates in association with inaglyite and in some cases occurs as graphic intergrowths with native iridium. It is opaque with a metallic lustre, colour steel-black, streak black,HM = 5.2, VHN50=452 kg/mm2, cleavage not observed, fracture not observed, strongly magnetic. Its reflection colour is bright white with a yellowish tint. It has no internal reflection, bireflectance or pleochrism, and shows *** chemical analyses were carried out by means of the electron microprobe. The mean percentages of the data obtained in the 13.analyses ares S 0.001, Fe 7.9, Ni 0.03. Co 0.03. Cu 0.83. As 0.02, Rh 0.19, Pd 0.00, Os 0.06, Ir 88.5, Ft 2.2 and Pb 0.00. The simplified formula is Ir3.e, which requires Ir 91.17 and Fe 8.83. the total being 100.00 (% ).Five strongest lines of X-ray powder diffraction (hkl, d, I)are: 111, 2.18 (80);200, 1.89 (60); 220, 1.3. (70);3.1, 1.142 (100);222,1.094 (80).Through indexing of the X-ray powder diffraction data, the mineral has been determined to be cubic with Pm 3., a = 0.3.92(5)nm, V = 0.05453.m and Z = 1.

关键词： new mineral chengdeitc chromite ore

A Study of Mesoproterozoic Iron Cosmic Micro-spherules from 1.8 Ga and 1.6 Ga Old Strata in the Ming Tombs District,beijing

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4期81卷 649-657页

作者： SONG Tianrui HE Zhengjun WAN Yusheng and LIU Yanxue institute of geology,chinese academy of {3. sciences,beijing 10003. institute of geology Chinese Academy of Geological Sciences Beijing 100037

Numerous iron cosmic micro-spherules have been discovered from Mesoproterozoic strata including the Changzhougou Formation （1.8 Ga） and the Dahongyu Formation （1.6 Ga） of the Ming Tombs district, beijing. There are 1 to 3. grains of cosmic spherules per 2 kg of a sandstone sample taken from the bottom of a coarse sandstone bed of the Changzhougou Formation and 56 grains per 3.69 kg of a rock sample from silicified carbonate rocks of the Dahongyu Formation. The surface textures of cosmic spherules analyzed by means of the secondary electron imagery are identical with those reported from references either domestic or abroad. So far the geo-ages of 1.8 Ga and 1.6 Ga of cosmic spherules from the Changzhougou and Dahongyu formations might be older than those reported in the world. Table 1 gives the electron probe analysis data of cosmic spherules for 3. spherule grains and 44 testing points as follows （%）： FeO, 80-95; Cr2O3. 0-9.56; NiO, 0-0.78; CoO, 0-0.46; indicating that the Cr2O3.content is higher and FeO content lower in the Changzhougou Formation than in the Dahongyu Formation. The helium isotopic data of cosmic spherules as well as their host rocks vary greatly between the Changzhougou and the Dahongyu formations as shown in Table 2. The data of cosmic spherules of the Changzhougou Formation vs the Dahongyu Formation are 57.5/1.23.in ^3.e/^4He （10^-8）; and 55.54/809.60 in ^4He （10^-6cm^3.TP/g）; those of coarse sandstone of the Changzhougou Formation vs silicified carbonate of the Dahongyu Formation are 3.3./2.59 in ^3.e/^4He （10^-8） and 4.56/2.3. in ^3.e （10^-6cm^3.TP/g）. The ratio of analytic data of helium isotopes are different for cosmic spherules and their host rocks; for example, the ^3.e/^4He （10^-8） values are 16.96 and 0.48, and the ^4He （10^-6 cm^3.TP/g） are 12.18 and 3.5.98 for the Changzhougou and Dahongyu formations respectively. It was reported that the world＇s oldest micrometeorites had been found in the Meso-Proterozoic Satakunta Formation, Finland

关键词： Proterozoic cosmic spherule helium isotopes extraterrestrial material carbonaceous chondrite

A New Genus of Psittacosauridae (Dinosauria: Ornithopoda) and the Origin and Early Evolution of Marginocephalian Dinosaurs

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2003年第1期77卷 15-20页

作者： YOU Hailu institute of geology, chinese academy of geological sciences, beijing 10003.XU Xing and WANG Xiaolin{3. of Vertebrate Paleontology and Paleoanthropology chinese academy of sciences, beijing 100044 institute of geology Chinese Academy of Geological Sciences Beijing 100037

An almost complete juvenile dinosaur skull with lower jaw was discovered fromthe Early Cretaceous Yixian Formation in Beipiao, Liaoning Province, china. Here, the specimen isdescribed and a cladistic analysis is performed in order to find its phylogenetic relationships. Theresult shows that this specimen represents a new genus of Psittacosauridae, Hongshanosaurus houi,gen. et sp. nov., and confirms the monophyletic status for Ceratopsia and Marginocephalia. However,Heterodontosaurus is found to be the sister taxon to Marginocephalia, rather than a basalOrnithopoda.

关键词： Dinosauria Marginocephalia Hongshanosaurus houi, gen. et sp. nov. Yixian Formation Liaoning Province

Ages and Compositions of the Precambrian High-grade Basement of the Qilian Terrane and Its Adjacent Areas

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4期75卷 375-384页

作者： WAN Yusheng, XU Zhiqin, YANG Jingsui and ZHANG Jianxin institute of geology, chinese academy of geological sciences, beijing 10003. institute of geology Chinese Academy of Geological Sciences Beijing 100037 [?]2Wan Yusheng Born in 1958 graduated from china University of Geosciences in 1981 received the Ph.D. degree in 1993 now senior geologist at the institute of geology Chinese Academy of Geological Sciences engaged in the study of geochemistry. Tel: 010–683.8411 e-mail: wanysh@***

Based on geological, chronological, geochemical and Nd isotopic studies of the high-grade basement of the Qilian terrane, the authors have drawn the following main conclusions: (1) the high-grade basement of the Qilian terrane consists mainly of meta-argillo-arenaceous rocks and granites and its bulk part was formed in the period of 0.8–1.0 Ga (the Jinningian period); (2) most of the meta-argillo-arenaceous rocks and granitic rocks have strong negative Eu and Ba anomalies (Eu/Eu*= 0.47–0.71 and Ba/Ba*=0.16–0.64), with fDM and ENd (1.0 Ga) ranging from 1.87 to 2.26 Ga and from ?8.54 to ?4.06 respectively, showing relatively high maturity; and (3. the Jinningian granitic rocks are a typical product of continent-continent collision, being probably related to the formation of the supercontinent Rodinia. These studies, combined with the study of high-grade basement rocks near the Qilian terrane, suggest that before the Jinningian period, the Qilian-Qaidam northern-margin terrane and Dunhuang-Alxa terrane were separated from each other, belonging to different plate systems of the North china craton and Yangtze platform respectively. The Qilian orogenic belt was the same as or similar to the Qiling orogenic belt in terms of the geological evolution history at least before the Jinningian period.

关键词： Qilian terrane chronology Nd isotope geochemistry Precambrian basement

Tectonic Evolution of the Himalayan Collision Belt

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1997年第2期71卷 133-143页

作者： Cui Junwen institute of geology, chinese academy of geological sciences, beijing institute of geology Chinese Academy of Geological Sciences Beijing [?]Cui Junwen Born in 193. graduated from the specialty of geological structure Department of Geology and Geography Peking University in 1965. Now he is research professor at the Institute of Geology Chinese Academy of Geological Sciences and mainly undertakes the study of deformation dynamics of the lithosphere and deep tectonics.

This paper discusses the tectonic divisions of the Himalayan collision belt anddeals with the tectonic evolution of the collision belt in the context of crustal accretion in thefront of the collision belt, deep diapirism and thermal-uplift extension and deep material flow-ing of the lithosphere-backflowing. Finally it proposes a model of the tectonic evolution-progressive intracontinental deformation model-of the Himalayan belt.

关键词： Himalayan collision belt thermal-uplift spreading thermal-uplift extension backflowing progressive intracontinental deformation at model

Geochemical Characteristics of Granitoids in the Eastern Sector of the Northern Tianshan Mountains in Xinjiang

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1期64卷 55-67页

作者： Wang Bixiang Li Zhaonai Zhao Guangzan Wang Fubao Zhang Shuizhe Fei Wenheng institute of geology, chinese academy of geological sciences, beijing institute of geology Chinese Academy of Geological Sciences Beijing

The granitioids in question are located in the geosynclinal fold belt of the Northern Tianshan Mountains.The magmas are intruded into a Carboniferous marine volcanic-sedimentary rock series. forming a contempo-raneous. intermediate-basic to acid. composite intrusion. With a whole-rock Rb-Sr isochron age of 3.5.7 Ma. itis considered to be of middle Heicynian age. The granitoids have a SiO_2 content of 48-78%, a calc-alkali indexof 60 and silica-alkali indices ρ=2.2-2.4 and σ=1.5-2. From basic to acid compositions, the total REE con-tent increases from 3. to 143.ppm. δEu ranges from 0.47 to 0.86 and the Eu anomalies are negative. Thenormalized curves of REE of various rock types are very similar. These coupled with the characteristics of traceelement geochemistry show that the intrusion is an island arc-continental margin, calc-alkaline one. Theδ^(18)O values range from 5.8 to 8.9‰ and the ^(87)Sr/^(86)Sr initial ratio is 0.705. The materials of the intrusion arecomposed of a mixture of the magmas at the top of the upper mantle and in the lower crust, This indicates thatthe rocks might be consanguineous. differentiated and evolved products and possess the characteristics of Ⅰtype granites.

关键词： Geochemical Characteristics of Granitoids in the Eastern Sector of the Northern Tianshan Mountains in Xinjiang

Zijinshan-Bitian Cu-Au-Mo orefield, SW Fujian——An example of gold-rich PCS zoning

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 134-135页

作者： QI Jianzhong~1, LI Zhaonai~2, ZHANG Dequan~3. FANG Xiheng~4 and XIAO Huiliang~1 1. Nanjing institute of geology and Mineral Resources, chinese academy of geological sciences, Nanjing 210016, china 2. institute of geology, chinese academy of geological sciences, beijing 10003., china 3. institute of Mineral Deposits, chinese academy of geological sciences, beijing 10003., china 4. institute of geology, Ministry of Nuclear Industry, beijing 100013. china Nanjing institute of geology and Mineral Resources Chinese Academy of Geological Sciences Nanjing 210016 China institute of geology Chinese Academy of Geological Sciences Beijing 100037 China institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing 100037 China institute of geology Ministry of Nuclear Industry Beijing 100013 China

THE Zijinshan-Bitian Cu-Au-Mo orefield is spread to north of the Shanghang County, SW *** geological structure it is located at the plunging end of NE-trending Xuanhe anticlinorium, in the NE rim ofthe NW trending Shanghang volcano-sedimentary basin. Orefield basement is composed of the Archean-Middle Proterozoic low-grade metamorphic rock formations, containing marine basic metavolcanic sequenses. Lower Cretaceous subaerial volcanic rocks of andesite-trachy andesite-rhyolite composition fill inthe volcano-sedimentary basin. Pre-mineralization granitic batholith dated 145Ma（Rb-Sr）and 157Ma（U-Pb） occupies the axial part of the plunging anticlinorium, which was regarded as crust-remelting typegranitoids. Mineralization-affiliated subvolcanic dacite porphyrite, co-volcanic granodiorite and quartzdiorite porphyrite （102.2 Ma（Rb-Sr）, Sr1 = 0.708 9） belong to syntactic type in genesis and

关键词： gold-rich porphyre copper system zoning Fujian Zijinshan.

The^(40)Ar/^(3.)Ar age record of formation and uplift of the blueschists and eclogites in the western Tianshan Mountains

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2000年第11期45卷 1047-1052页

作者： GAO Jun, ZHANG Lifei & LIU Shengwei1. institute of geology, chinese academy of geological sciences, beijing 10003.,{3. 2. Department of geology, Peking University, beijing 100871, Chin institute of geology Chinese Academy of Geological Sciences Beijing China Department of geology Peking University Beijing China

The 40Ar/3.Ar ages indicate that the eclogite facies rocks of the Hasiate slice in the western Tianshan Mountains were formed at the early stage of Devonian （401 Ma） and had been uplifted to the greenschist facies tectonic level in the middle stage of Devonian （3.1 Ma）. The formation and uplift of the blueschists of the Akesayi slice are constrained to the late stage of Devonian （3.0-3.4 Ma）. The different tectonic slices in the high-pressure metamorphic belt have experienced the different uplift history.

关键词： western Tianshan Mountains eclogite blueschist 40Ar/3.Ar age.

Northernmost paleo-tethyan oceanic basin in Tibet:Geo-chronological evidence from ^(40)Ar/^(3.)Ar age dating of Dur'ngoi ophiolite

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2001年第14期46卷 1203-1205页

作者： CHEN Liang, SUN Yong, PEI Xianzhi, GAO Ming, FENG Tao, ZHANG Zhongqing & CHEN Wen1. Laboratory of Continental Dynamics, Northwest University, Xi’an 710069, china 2. Department of geology, Northwest University, Xi’an, 710069, china 3.{3., chinese academy of geological sciences, beijing, 10003., china Laboratory of Continental Dynamics Northwest University Xi’an China Department of geology Northwest University Xi’an China institute of geology Chinese Academy of Geological Sciences Beijing China

Whole rock 40Ar/3.Ar age dating has been conducted on a basalt sample from Dur’ngoi ophiolite, Qinghai Province, which was reported to be the northernmost pa-leo-tethyan oceanic basin in Tibet. A high temperature pla-teau age (3.5.3.7.9 Ma) with an isochorn age (3.6.6±7.1 Ma) has been obtained, representing the eruption time of oceanic crust Considering related geological settings, the new age provides constraints on the northernmost pa-leo-tethyan suture zone in Tibet and the tectonic evolution of Paleo-tethys in Northeast Tibet and adjacent areas.

关键词： Dur’ngoi ophlolite 40Ar -3.Ar age Paleo-tethys.