检索结果-南通市图书馆

Discovery of Cu-Zn,Cu-Sn intermetallic minerals and its significance for genesis of the Mianning-Dechang REE Metallogenic Belt,sichuan Province,china

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第6期49卷 597-603页

作者： XIE Yuling1, HOU Zengqian2, XU Jiuhua1, YUAN Zhongxin2, BAI Ge2 & LI Xiaoyu3.1. Civil and Environmental Engineering School, University of Science and Technology Beijing, Beijing 100083. china 2. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 10003., china 3. The 109th Geological Team, sichuan bureau of mineral exploration,{3., china Civil and Environmental Engineering School University of Science and Technology Beijing Beijing China Institute of Geology Chinese Academy of Geological Sciences Beijing China The 109th Geological Team Sichuan Bureau of Mineral Exploration Chengdu China

Mianning-Dechang Himalayan REE Metallogenetic Belt in sichuan Province lies along the western margin of the Yangtze Craton. We have conducted detailed mineralogical studies on ore minerals collected from Maoniuping and Dalucao, the two largest deposits in the belt. With optical microscope, SEM/EDS, and EPMA, three rare intermetallic minerals, i.e., zinccopperite (Cu2Zn), Sn- bearing native copper, and Cu-bearing jupiter were found to occur in the main ore along with barite, fluorite, apatite, sulfide and bastnaesite. Since the conditions under which zinccopperite and Sn- bearing native copper formed are quite unique, finding of these minerals, for the first time in domestic REE deposits, has significant implications for the genesis of the ore deposits in which they occur. In comparison with Cu-Zn intermetallic minerals in other occurrences, we propose that the formation of this REE metallogenetic belt is associated with fast upwelling of the Himalayan magma from deep source.

关键词： Mianning-Dechang REE metallogenetic belt, Cu-bearing intermetallic minerals, EPMA, genesis significance, deep source magmatic activity.

Assessment of time-dependent seismic hazards on segments of active fault, and its problems

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第23期43卷 1937-1950页

作者： WEN Xueze Seismological bureau of sichuan Province, chengdu 610041,{{3. Seismological bureau of sichuan Province Chengdu China

Assessment of time dependent seismic hazards on segments of active fault is one of the important techniques of long term earthquake forecast for specific locations. It is based on the data from quantitatively seismo geologic investigation in active faults and expresses seismic hazards of a fault segment with both the earthquake occurrence probability, which increases as the elapsed time increases, and the magnitude predicted. Through summing up and analyzing main technical steps in research of the recent decade, some defects in the current theory and model of this technique are pointed out. For instance, the probabilistic models for recurrence interval are based solely on the quasi periodic behavior of earthquake recurrence, ignoring behavior’s diversity that possibly exists. Variability of repeated rupture dimensions in various cycles is considered inadequately in fault segmentation research, etc. It is most important for improving the reliability of the result of seismic hazard assessment to reveal actual earthquake recurrence behavior and its generalities, and to update relevant models for evaluating probabilistic earthquake hazard based on the behavior and generalities.

关键词： active fault rupture segmentation time dependent hazard probabilistic model long term forecast.

在线全文

学校读者我要写书评

暂无评论

筑梦丝路，集智攻关

丝路百科 2024年第8期 29-30页

作者： china Construction Eighth bureau 中建八局

从开罗向东行驶约50千米，一栋栋高耸的大楼在扬起的黄沙中若隐若现，远远望去仿佛海市蜃楼，这是由中国建筑股份有限公司埃及分公司承建的埃及新行政首都中央商务区，其中最引人注目的是被称为“非洲第一高楼”的标志塔。这个项目作为...

从开罗向东行驶约50千米，一栋栋高耸的大楼在扬起的黄沙中若隐若现，远远望去仿佛海市蜃楼，这是由中国建筑股份有限公司埃及分公司承建的埃及新行政首都中央商务区，其中最引人注目的是被称为“非洲第一高楼”的标志塔。这个项目作为“一带一路”倡议下的标志性工程，汇聚了来自中建八局海外公司的一支由“85后”青年组成的国际化机电团队的智慧与汗水。十年来，这支机电青年团队先后参与了阿尔及利亚邮政总部和毛里求斯机场等多个国际高端项目，凭借精湛的工艺和高质量的服务，推动中国建造走向世界，赢得了国际认可。2023.初，这支青年团队获评国资委全国青年文明号荣誉称号。

关键词：

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

青春赋能人才成长共建共赢建筑未来

丝路百科 2024年第9期 27-28页

作者： china Construction Eighth bureau 中建八局

2500多年前，鲁班斫木为器、构物成具，夺天工之精巧，集营造之大成，后世尊为“百工圣祖”。以鲁班为代表的工匠精神，历千百年薪火赓续、衣钵传承，发扬于新中国，光大于新时代。如今，“中国制造”享誉全球、蜚声中外。以中国建筑集...

2500多年前，鲁班斫木为器、构物成具，夺天工之精巧，集营造之大成，后世尊为“百工圣祖”。以鲁班为代表的工匠精神，历千百年薪火赓续、衣钵传承，发扬于新中国，光大于新时代。如今，“中国制造”享誉全球、蜚声中外。以中国建筑集团有限公司为代表的央企，更是频频刷新世界纪录，不断在“一带一路”沿线创造着中国奇迹。

关键词：

On the siltation of the middle Yangtze River

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 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 43.074, china 2. Hydrogeological Team, Hubei bureau of Geology and {3. Resources, Jingzhou 43.100, china 3. Geological Survey of Jiangxi Province, Nanchang 3.0201, china School of Earth Sciences China University of Geosciences Wuhan 430074 China Hydrogeological Team Hubei Bureau of Geol./Mineral Rsrc. Jingzhou 434100 China Geological Survey of Jiangxi Prov. Nanchang 330201 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 203. 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.

On Deep Structures of the Xikang-Yunnan Axis

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 211-225页

作者： Yuan Xuecheng bureau of exploration Geophysics and Geochemistry,Ministry of Geology and mineral Resources, Beijing Liu Linqun bureau of exploration Geophysics and Geochemistry Ministry of Geology and Mineral Resources Beijing

Through recent study, the author considers that the north-south-trending Kangding-Honghe tectonic belt is not a marginal uplift zone of the Yangtze Platform but a Tethyan-type collisional tectonic belt of which the crust-upper mantle can be structurally divided into three layers. The upper layer is the brittle upper crust, dominated by overthrusting and imbrication; the middle layer is the plastic lower crust and part of the upper mantle, represented by compression and shortening; and the lower layer is the upper mantle, probably belonging to the Yangtze Platform in light of the thickness of the lithosphere.

关键词： On Deep Structures of the Xikang-Yunnan Axis

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

在线全文

学校读者我要写书评

暂无评论

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.{3. 2. Yichang Institute of Geology and mineral Resources, Yichang 443.03.{3. 3. Hainan bureau of Geology and mineral Resources, Haikou 570226,{3. State Key Laboratory for mineral Deposits Research and Department of Earth Sciences Nanjing University Nanjing China Yichang Institute of Geology and mineral Resources Yichang China Hainan bureau of Geology and mineral Resources Haikou 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.

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

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 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 Resources, Nanjing 210016, china 3. Tianjin Institute of Geology and mineral Resources, Tianjin 3.0170, china 4. The 2nd Regional Geological Investigation Party, Xinjiang bureau of Geology and mineral Resources, Changji 83.100, china Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Nanjing Institute of Geology and mineral Resources Nanjing China Tianjin Institute of Geology and mineral Resources Tianjin China The 2nd Regional Geological Investigation Party Xinjiang Bureau of Geology and Mineral Resources Changji 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.

Geochemical characteristics and applications of 18α(H)-neohopanes and 17α(H)-diahopanes

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2000年第19期45卷 1742-1748页

作者： WANG Chunjiang, FU Jiamo, SHENG Guoying, XIAO Qianhua, LI Jinyou, ZHANG Yali & PIAO Mingzhi1. Slate Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences. Guang/hou 510640, china 2. Department of Geosciences, Petroleum University, Beijing 102200, china 3. Institute of Petroleum {3. and Exploitation, Liaohe {3. of Petroleum {3., Panjin 240000, china State Key Laboratory of Organic Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Department of Geosciences Petroleum University Beijing China Institute of Petroleum exploration and Exploitation Liaohe Bureau of Petroleum Exploration Panjin China

Distributions and geochemical significances of 18α(H)-neohopanes and of 17α(H)-diahopanes in oils from west Xialiaohe depression of the Bohai Bay Basin have been studied. Relative abundance of 18α(H)-neohopanes and of 17α(H)-diahopanes can be effectively used as maturity parameters, in a range of medium-high mature stage, based on consideration on sedimentary-organic facies of source rocks. With a dual geochemical significance of maturity and sedimentary-organic facies, neohopane and diahopane parameters can be well used in oil-source correlation and in petroleum population division. Formation, primary concentration and preservation of precursors of rearranged hopanes are closely related to depositional conditions such as Eh-pH and clays content. A series of probable diahopanes (series D) was detected in the oils, which exhibits a similar distribution pattern and geochemical behavior as that of 17α(H)-diahopanes (series B).

关键词： 18α(H)-neohopane 17α(H)-diahopane maturity sedimentary-organic facies.