检索结果-南通市图书馆

Cosmogenic ^(21)Ne concentrations and exposure ages of summit bedrocks in the Grove Mountains,Antarctica

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2010年第4期53卷 518-521页

作者： KONG Ping1,2,DING Lin2,LAI QingZhou2 & HUANG FeiXin3.1 Key Laboratory of the Earth’s Deep Interior,institute of geology and geophysics,{3. academy of Sciences,beijing 100029,china 2 Key Laboratory of Continental Collision and Plateau Uplift,institute of Tibetan Plateau Research,{3. academy of Sciences,beijing 100085,china 3.institute of Mineral Resources Research,china Metallurgical geology Bureau,beijing 100025,china Key Laboratory of the Earth’s Deep Interior Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China institute of Mineral Resources Research China Metallurgical Geology Bureau Beijing China

Various sources of 21Ne and 22Ne exist in surface rocks:cosmogenic,in situ nucleogenic from internal U and Th,trapped crustal nucleogenic and trapped *** paper reports the first measurement,in china,of cosmogenic 21Ne and 22Ne in surface *** developed a unique sample pre-treatment procedure that effectively removed inclusions inside quartz grains,and thus maximally reduced nucleogenic contributions of 21Ne and ***-heating experiments show that concen-trations of cosmogenic 21Ne and 22Ne in summit bedrock samples R9202 and R9203.from Grove Mountains,Antarctica,are(3.83.0.87)×108 and(5.22±0.51)×108 atoms/g,*** corresponding minimum exposure ages are 2.2±0.5 and 3.0±0.3.*** indicates that the ice sheet in East Antarctica was uncovered the crest of Mount Harding,a typical nunatak in Grove Mountains,since at least mid-Pliocene.

关键词： 21Ne cosmogenic nuclide exposure age Antarctica Grove Mountains

Comparison of two end-member styles of epithermal Au-(Cu)deposits

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 212-213页

作者： FAN Hongrui and XIE Yihan institute of geology, chinese {3. of Sciences,{4., china institute of geology Chinese Academy of Sciences Beijing 100029 China

EPITHERMA Au-(Cu) deposits occur largely in volcano-plutonic arcs (island arcs as well as continentalarcs) associated with subduction zones, with ages similar to those of volcanism. These deposits form atshallow depth,<1 km, and are hosted mainly by volcanic rocks. Modern volcanic-hydrothermal systems provide an analogue to the environment for the ancient intrusion-related and volcanic epithermal deposits. Recent studies also indicate that the volcanic epithennalore deposits are formed from magmatic fluids, although the magmatic signatures have been largely erasedby meteoric water. At depth (fig. 1), the magmatic fluid from the high-level intrusive magma will result in the formation of intrusion-related deposits (e.g. porphyry Cu, Au, Mo deposits). Detailed studies of fluid inclusions and stable isotopes indicate that the hydrothermal system that form these deposits are initially

关键词： epithermal Au(Cu) deposit mineralization ore-forming fluid.

The onset and advance of the Asian summer monsoon

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2006年第1期51卷 80-88页

作者： Lü Junmei1,2,4. ZHANG Qingyun1, TAO Shiyan1 & JU Jianhua3.1. State Key Laboratory of Numerical Modeling for Atmospheric Sci- ences and Geophysical Fluid Dynamics, institute of Atmospheric Physics, chinese academy of Sciences,{3., china 2. Department of Atmospheric Sciences, Yunnan University, Kunming 650091, china 3. china Meteorological Administration Training Centre, beijing 100081, china 4. Graduate School of chinese academy of Sciences, beijing 10003., china State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Department of Atmospheric Sciences Yunnan University Kunming China Graduate School of chinese academy of Sciences Beijing China china Meteorological Administration Training Centre Beijing China

Based on the daily outgoing longwave radiation (OLR) data from National Oceanic and At- mospheric Administration (NOAA) satellites, the Cli- mate Prediction Center’s merged analysis of pre- cipitation (CMAP) data and the National Centers for Environmental Prediction/National Center for At- mospheric Research (NCEP/NCAR) reanalysis dataset, the mean intraseasonal variability of the Asian summer monsoon (ASM) is investigated by using power spectrum analysis, band-pass filter, and diagnostic analyses. The processes of the onset and advance of monsoon over the southern part of Indo- china Peninsula, the east coast of Bay of Bengal, the South china Sea and the Indian subcontinent are explored. It is found that there is an abrupt change in OLR, precipitation and zonal wind during the onset and advance of the ASM. It is also indicated that the southern part of Indochina Peninsula and the adja- cent Andaman Sea is the region where the earliest onset of the ASM occurs in the 2nd pentad of May.

关键词： Asian summer monsoon intraseasonal variability onset advance.

Petrology and ^(4.)Ar/^(3.)Ar iso-topic ages of blueschists in Gangmar, central Qiangtang, northern Tibet

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 2001年第5期46卷 423-427页

作者： DENG Xiguang, DING Lin, LIU Xiaohan & ZHOU YongLaboratory of Lithospheric Tectonic Evolution, institute of geology and geophysics, {3. {4. of Sciences, beijing 100029, china Laboratory of Lithospheric Tectonic Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

The petrology and mineral assemblages of blueschists in the Gangmar, central Qiangtang, northern Tibet were examined, which indicates that the metamorphic condition is high-pressure low-temperature. In this note, we reported the 4.Ar/3.Ar dating results of glaucophane from two blueschist samples. Their apparent ages are (275.0±1.3. Ma and (287.6±2.3. Ma and similar isochron ages are (275.0±0.9) Ma and (282.4.0.8) Ma, respectively. These iso-topic datings show the high-pressure metamorphism occurring in Lower Permian. The ages also coincide with the evolution of Palaeo-Tethys ocean in Late Palaeozoic.

关键词： glaucophane blueschist 3.Ar/4.Ar age Palaeo-Tethys Gangmar northern Tibet.

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

在线全文

学校读者我要写书评

暂无评论

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 {3. and geophysics and Key Laboratory of Mineral Resources,chinese academy of Sciences,beijing 100029,china 3.Key Laboratory of Continental Dynamics,Northwestern University,Xi'an 710069,china 4.institute of {3. and Mineral Resources of Shenyang,Shenyang 11003.,china) School of Earth and Space Sciences Peking University Beijing 100871 China Key Laboratory of Mineral Resources Institute of Geology and Geophysics Chinese Acad. of Sci. Beijing 100029 China Key Laboratory of Continental Dynamics Northwestern University Xi'an 710069 China institute of geology and Mineral Resources of Shenyang Shenyang 110032 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

Simulation of the future change of East Asian monsoon climate using the IPCC SRES A2 and B2 scenarios

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 2003年第10期48卷 1024-1030页

作者： BUEH Cholaw LASG, institute of Atmospheric Physics, chinese academy of Sciences,{3.,{4. LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

In this paper, we applied the newest emission scenarios of the sulfur and greenhouse gases, i.e. Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES) A2 and B2 scenarios, to investigating the change of the East Asian climate in the last three decades of the 21st century with an atmosphere-ocean coupled general circulation model. The global warming enlarges the land-sea thermal contrast and, hence, enhances (reduces) the East Asian summer (winter) monsoon circulation. The precipitation from the Yangtze and Huaihe river valley to North china increases significantly. In particular, the strong rainfall increase over North china implies that the East Asian rainy area would expand northward. In addition, from the southeastern coastal area to North china, the rainfall would increase significantly in September, implying that the rainy period of the East Asian monsoon would be prolonged about one month. In July, August and September, the interannual variability of the precipitation enhances evidently over North china, meaning a risk of flooding in the future.

关键词：模拟亚洲东方季风气侯变化大气循环模型

^(14.C measurement of forest soils in Dinghushan Biosphere Reserve

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1999年第3期44卷 251-256页

作者： SHEN Chengde , LIU Dongsheng (LIU Tungsheng) , PENG Shaolin, SUN Yanmin , JIANG Mantao , Yl Weixi , XING Changping , GAO Quanzhou , LI Zhi’an and ZHOU Guoyi Guangzhou institute of Geochemisry, chinese academy of Sciences, Guangzhou 51064.,{3. institute of geology, chinese academy of Sciences , beijing 100029,{3. South{3. institute of Botany, chinese academy of Sciences, Guangzhou 510650,{3. Guannzhou institute of Geochemisry Chinese Academy of Sciences Guanazhou China institute of geology Chinese Academy of Sciences Beijing China South china institute of Botany Chinese Academy of Sciences Guangzhou China

Organic carbon in forest soils of Qingyunsi and Wukesong profiles can be divided into fast and slow components. Δ14. values of these profiles decrease with increasing of depth. The Δ14. values in 3.—4. cm depth int... 详细信息

Organic carbon in forest soils of Qingyunsi and Wukesong profiles can be divided into fast and slow components. Δ14./sup>C values of these profiles decrease with increasing of depth. The Δ14./sup>C values in 3.—4. cm depth interval of Wukesong profile are decreasing sharply until a very low value,showing that a strong geological environment change occurred about 1 560 years ago. The 14./sup>C apparent ages of Wukesong profile show that the coniferous and broad-leaf mixed forests around Wukesong profile have been developing since 4.5 a BP, which is consistent with historical documents. The penetrating depths of "bomb 14./sup>C" in Qingyunsi and Wukesong profiles are 10 and 20 cm, respectively.

关键词： Dinghushan forest soil 14. tracing 14. apparent age.

Differential rotation of geomagnetic field

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2003年第24期48卷 2739-2742页

作者： WEI Zigang & XU Wenyao institute of geology and geophysics, {3. {4. of Sciences, beijing 100029, china Correspondence should be addressed to Wei Zigang (e-mail: magstorm @***) institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 China

The latitudinal dependence of the westward drift in the main geomagnetic field is examined by using the correlation analysis of moving random pattern. The study reveals the characteristics in the differential rotation of the main field. The results show that the global geomagnetic field drifts westward with an average speed of 0.18/a during 1900—2000. The westward drift rate is not symmetrical with re-spect to the equator. The maximum westward drift rate, 0.3./a, occurs at the latitude j = -15? forming a Rapid Westward Drift Belt (RDB) around this latitude. Going northward and southward from this belt, the drift rate de-creases and reaches the minimum (0.12/a) at j = 50?and the minimum (0.14.a) at j = -56? forming a Northern Hemi-sphere Slow Westward Drift Belt (N-SDB) and a Southern Hemisphere Slow Westward Drift Belt (S-SDB). Three phases can be detected in the evolution of the westward drift. In the first phase (1900—194.), the RDB dominates the global drift pattern. The westward drifts in this belt are much faster than those in other areas. In the second phase (194.—1960), the drift rates in the RDB are less than those in the first phase, while the drifts in the N-SDB and S-SDB are relatively large. In this phase, the differential rotation becomes less obvious. In the third phase (1960—2000), the westward drift in the RDB increases again and the differen-tial rotation gradually becomes apparent.

关键词：地磁场赤道快速西移带 RDB

Subduction age of Neo-Tethys oceanic crust in southwest Yunnan, china: Laser micro-area ^(4.)Ar-^(3.)Ar dating

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1999年第23期44卷 2196-2199页

作者： ZHOIMG Dalai, Jl Jianqing and HU Shilinginstitute of geology, chinese {3. of Sciences ,{4., china institute of geology Chinese Academy of Sciences Beijing China

The basic granulite, which is considered to be the MORB based on geochemistry and isotopic characteristics[1], has been discovered recently as the enclaves in the Yingjiang island-arc magmatic suite on the border of Burma and west Yunnan, east of Myitkyina suture in the eastern Burma. The laser micro-area 4.Ar-3.Ar technique is used to date the age of garnet

关键词： laser micro-area 4.Ar-3.Ar dating granulite facies metamorphic oceanic crust relict Neo-Tethys subduction age.