检索结果-南通市图书馆

Science china Earth Sciences 2006年第11期49卷 1135-1146页

作者： LIN Fangcheng1,2.& PAN Guitang2.1. Geoscience College, Chengdu University of Technology, Chengdu 610059, china 2. Chengdu institute of {2. and mineral resources, Chengdu 610082. china 1. Geoscience College Chengdu University of Technology Chengdu 610059 China 2. Chengdu institute of geology and {2. resources Chengdu 610082 China

A number of lead-zinc sulphide deposits have been discovered in recent years in dolo- mitic rocks of the Upper Sinian Dengying Formation in the Dadu River valley region, Sichuan Province, china. The lead-zinc mineralization is closely associated with a black siliceous exhalite that has been traced over 50 km of strike. This makes Dadu River valley the most extensive stratiform non-ferrous sulphide horizon having been discovered to date in china. In a previous study by the first author (LIN), these deposits were recognised as belonging to the broad spectrum of lead-zinc sedimentary exhala- tive (SEDEX) deposits. In this paper, seismites and seismogenetic structures occurring in close association with the Dadu River valley mineralized zone are described. The close spatial and temporal relationship between the seismites and mineralization provides strong evidence for the hypothesis that the lead-zinc SEDEX deposits formed in direct response to earthquake activities around the Sinian-Cambrian boundary. The earthquakes are postulated to be an effective dynamic mechanism for triggering the upward migration of deep circulating ore fluids along synsedimentary growth faults and their exhalation onto the sea-floor to form the extensive deposits of stratiform lead-zinc sulphide ore.

关键词： seismites, earthquake, lead-zinc deposit, hydrothermal exhalation, Upper Sinian Dengying Age.

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 resources, Nanjing 2.0016, china 3. Tianjin institute of geology and mineral resources, Tianjin 300170, china 4. The 2.d Regional Geological Investigation Party, Xinjiang Bureau of geology and mineral resources, 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 {2. resources Nanjing 210016 China 3. Tianjin institute of geology and {2. resources 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.

Changes of infrared absorption wave number of aromatic-ring C=C bond of vitrinite and their significance

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第12期43卷 1048-1050页

作者： XIAO Jianxin 1 and CHEN Shanqing 2.1. china University of Geosciences, Beijing 100083, china 2. Yichang {2. of geology and mineral resources, Yichang 443003, china china University of Geosciences Beijing China Yichang institute of geology and {2. resources Yichang China

The humilith series of lignite, longflame coal, gas coal, fat coal, coking coal, lean coal, meagre coal and anthracite are measured by FIR1600 infrared spectrophotometer. The variation curve between the infrared absorption wave number of aromaticring C--C bond of vitrinite and its reflectance values are gained, which shows the shift of infrared absorption wave number of aromaticring C--C bond of humic coals towards lower wave number with the increase of coalification. It is believed that the coal rank of humilith series can be determined and more evolutional information about coal composition and structure can be obtained by the infrared spectroscopic method.

关键词： aromatic_nucleus C--C bond infrared absorption wave number vitrinite humic coal.

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 2.0093, china 2. Yichang {2. of geology and mineral resources, Yichang 443003, china 3. Hainan Bureau of geology and mineral resources, Haikou 5702.6, 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 (K2.=2.9%―5.1%, K2./Na2.=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―0.7142. 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 2.2.7 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. 2.7- 2.8 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.

Metallogenic characteristics of epithermal gold deposits in china

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 1999年第S2期44卷 136-138页

作者： FENG Jianzhong~1 and WANG Jingbin~2.1. Department of geology, Peking University, Beijing 100871, china 2. Beijing {2. of geology For mineral resources, Beijing 100012. china Department of geology Peking University Beijing 100871 China Beijing institute of geology for {2. resources Beijing 100012 China

VOLCANIC-SUBVOLCANIC rocks are extensively distributed in china, in which a series of epithermal golddeposits related to volcanism have been discovered. 1 Metallogenic tectonic settings of epithermal gold deposits The epithermal gold deposits are mainly formed under the following tectonic settings: (i) ancient island arc collision, such as Xingxingxia island arc, Armantai island arc, Beishan island arc and Jueluotage island arc, etc. in periphery of Gunggar, Altai, Baishan, etc. in ancient Europe domain; (ii) extension area of continental margin of back arc, such as Fujian, Zhejiang, Jiangsu and Henlongjiang, *** circum-Pacific metallogenic domain; (iii) Mesozoic-Cenozoic island arc, such as the Tethys-Himalayametallogenic domain and Taiwan; (iV) intracontinental faulting depression or intraplate deep-seatedfaults, such as northern Hebei, Liaoning, Inner Mongolia at the north margin of the North china platformand periphery of Taicheng-Loujiang fault.

关键词： metallogenic characteristics gold deposits china.

Comparison of eastern paleo-Tethyan ophiolites and its geodynamic significance--Evidence from Dur'ngoi ophiolite

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2004年第4期47卷 378-384页

作者： CHEN Liang1,2. SUN Yong1,2. PEI Xianzhi2. Feng Tao2.& Zhang Guowei2.1. Open Laboratory of Continental Dynamics, Ministry of Education, Northwest University, Xi抋n 710069, china 2. institute of {2. and Geophysics, Chinese Academy of Sciences, Beijing 10002., china Open Laboratory of Continental Dynamics Ministry of Education Northwest University Xi’an 710069 China institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Nd-Pb isotopic geochemistry of metabasalt from Dur抧goi ophiolite, Qinghai Prov-ince, NW china reveals the presence of DMM mixing with EMII components in its upper mantle source, which is comparable with present Indian MORB. Comparisons indicate that the geo-chemistry, chronology and source characteristics of Dur抧goi ophiolite coincide with Pa-leo-tethyan ophiolites from 揝anjiang?area. Together with evidences from regional geology in adjacent areas, this study proves that independent paleo-tethyan basins evolved contemporarily, the dynamics of which is attributed to the interaction of mantle plume with over-riding lithosphere.

关键词： ophiolite, Paleo-Tethys, DUPAL anomaly, Indosinian movement.

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

在线全文

学校读者我要写书评

暂无评论

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 {2. resources, china University of Geosciences, Beijing 100083, china 3. Tianjin institute of geology and {2. resources, Tianjin 300170, 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 {2. 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.

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 {2. 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 {2. resources 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.

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

在线全文

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 {2. resources, Chinese Academy of Geological Sciences, Tianjin 300170, china 2. Tianjin Centre of Physical and Chemical Techniques, Tianjin 300050, china Tianjin institute of geology and {2. resources 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.

mineralogy and crystal structure determination of Mg-fillowite

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第5期48卷 635-646页

作者： MA Zhesheng 1 , SHI Nicheng 1 & YE Danian 2.1. china University of Geosciences, Beijing 100083, china 2. {2. of geology, Chinese Academy of Sciences, Beijing 10002., china 1. china University of Geosciences 100083 Beijing China 2. institute of geology Chinese Academy of Sciences 100029 Beijing China

Accurate crystal structure determination of complex phosphate Mg-fillowite ? Na2.a(Mn4Mg2.e)7[PO4]6 has been finished. Mg-fillowite occurs in muscovite-pegmatite in the Altay area, Xinjiang, china. It is of the trigonal lattice, with space group R-3, unit cell a=1.5143(3) nm, c=4.3191(2. nm, V=8.5736 nm3, Z = 18. The R-factor of the determination accuracy is R (I > 2. ( I )) = 0.0776. The cationic polyhedra consist of two kinds of structural units: compound col- umn and screw column. In three-dimensional space, they are linked with each other through corner sharing or edge sharing to build the entire structure. There are 45 atoms in an asymmetric unit and 72. atoms in a unit cell. In terms of types and connection manners of the coordination polyhedra, the degree of complicity is rarely seen in all mineral crystal structures. Study of such a structure is significant for the classification of phosphate and the building rule of coordination polyhedra in a complex crystal structure.

关键词： Mg-fillowite, complex phosphate, crystal structure, coordination polyhedron.