检索结果-南通市图书馆

New ancient DNA sequences suggest high genetic diversity for the woolly mammoth (Mammuthus primigenius)

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第4期16卷 379-386页

作者： YANG Shujuan, LAI Xulong, SHI Suhua, CHENG Shenghong, ZHOU Xiugao, YANG Xiujuan and YANG Hong department of Earth Science, China University of Geosciences, Wuhan 4.0074. China department of Life Science, Sun Yat-Sen University, Guangzhou 510275, China Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China Heilongjiang Provincial Museum, Harbin 150001, China department of Sciences and Technology, College of Arts and Sciences, Bryant University, Smithfield, Rhode Island 02917, usa and department of {4. and geophysics, Yale University, New Haven, CT 06520, usa [a]department of Earth Science China University of Geosciences Wuhan China [b]Institute of Zoology Chinese Academy of Sciences Beijing China [c]department of Life Sceince Sun Yat-Sen University Guangzhou China [d]Heilongjiang Provincial Museum Harbin China [e]department of Sciences and Technology College of Arts and Sciences Bryant University Smithfield Rhode Island USA [f]department of geology and geophysics Yale University New Haven CT USA

Partial DNA sequences of cytochrome b gene (mtDNA) were successfully retrieved from Late Pleistocene fossil bone of Mammuthus primigenius collected from the Xiguitu County ( Yakeshi), Inner Mongolia Autonomous Region and from Zhaodong, Harbin of Heilongjiang Province in northern China. Two ancient DNA fragments (109 bp and 124.bp) were authenticated by reproducible experiments in two different laboratories and by phylogenetic analysis with other Elephantidae taxa. Phylogenetic analysis using these sequences and published data in either separate or combined datasets indicate unstable relationship among the woolly mammoth and the two living elephants, Elephas and Loxodonta . In addition to the short sequences used to attempt the long independent evolution of Elephantidae terminal taxa, we suggest that a high intra-specific diversity existed in Mammuthus primigenius crossing both spatial and temporal ranges, resulting in a complex and divergent genetic background for DNA sequences so far recovered. The high genetic diversity in the extinct woolly mammoth can explain the apparent instability of Elephantidae taxa on the molecular phylogenetic trees and can reconcile the apparent paradox regarding the unresolved Elephantidae trichotomy.

关键词： Mammuthus primigenius genetic diversity ancient DNA phylogenetic analysis.

Carbon isotope ratios of C_(4. plants in loess areas of North 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

Science China Earth Sciences 2006年第1期49卷 97-102页

作者： WANG Guoan1,2,3, HAN Jiamao 2, ZHOU Liping3, XIONG Xiaogang4. TAN Ming2, WU Zhenhai5 & PENG Jun6 1. department of Plant Nutrition, China Agricultural University, Beijing 100094. China 2. Institute of geology and geophysics, Chinese Academy of Sciences, Beijing 100029, China 3. College of Environmental Sciences, MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China 4. Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China 5. Northwest Sci-Tech University of Agriculture and Forestry, Yangling 712100, China 6. Network Center, China Agricultural University, Beijing 100094. China 1. department of Plant Nutrition China Agricultural University Beijing 100094 China 2. Institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 China 3. College of Environmental Sciences MOE Laboratory for Earth Surface Processes Peking University Beijing 100871 China 4. Institute of Botany Chinese Academy of Sciences Beijing 100093 China 5. Northwest Sci-Tech University of Agriculture and Forestry Yangling 712100 China 6. Network Center China Agricultural University Beijing 100094 China

Carbon isotope ratios (δ^(13)C) of 89 C_4.plant samples were determined fromthe loess area in North China. δ^(13)C values vary between -10.5per thousand and -14.6per thousandwith a mean of -12.6per thousand. Along a precipitation gradient from the semi-moist area to thesemiarid area, then to the arid area, the δ^(13)C values of C_4.plants show a slight decreasingtrend. The δ^(13)C values of C_4.plants in the dry season are found lower than those in the wetseason. These trends are opposite to those observed for C_3 species.

关键词： C4 plants, carbon isotope ratios, loess area.

Indosinian Foreland Fold-and-Thrust Belt Bordering Yunnan and Guangxi, China

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 391-397页

作者： WU Genyao Institute of geology and geophysics, Chinese Academy of Sciences, Beijing 100029 Institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 [?]2Wu Genyao Male born in 1946 graduated from the department of geology Peking University in 1968 obtained a DSc degree in 1985 now a research professor with the Institute of geology and geophysics Chinese Academy of Sciences. His main research interest is regional tectonics and he has been working on the tethysides in South China and adjacent areas since 1987. Tel: (010) 62008118 Fax: (010) 6201084. E-mail: dizhikx@***

Recent discoveries of ophiolites indicate that there must be a Palaeotethyan geosuture zone bordering China and Vietnam, which separates the Vietbac block from the South China subcontinent. The Indosinian foreland fold-and-thrust belt bordering Yunnan and Guangxi provided further evidence for the palaeotethysides. The oceanic crust was subducted southwestwards while the magmatic arc migrated northeastwards, and the continent-arc collision occurred in the Late Triassic with the thrusting being extended towards the north or northeast. The features of thrust-nappe structure are discussed, which proved the continental margin of the Palaeotethyan ocean there to be a complicated one. A face-to-face collision occurred first along the NW-striking segment and then along the ENE-striking segment accompanied by transpression or oblique thrusting occurring along the NW-striking one.

关键词： thrust-nappe structure foreland fold-and-thrust belt palaeotethysides border between Yunnan and Guangxi

High resolution stalagmite δ18O records over the past 1000 years from Dongge Cave in Guizhou

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2005年第10期50卷 1003-1008页

作者： HE Yaoqi1, WANG Yongjin1, KONG Xinggong1 & CHENG Hai2 1. College of Geography Science, Nanjing Normal University, Nanjing 210097, China 2. department of geology and geophysics, Minnesota University, Mineapolis mn 5.455, {4. College of Geography Science Nanjing Normal University Nanjing 210097 China

Based on MC-ICP-MS U-series dating and stable O-isotope analysis results, a 4.5 years resolution monsoon record over the past 1000 years has been estab- lished for two stalagmites from Dongge Cave, Guizhou. The high resolution oxygen isotope record serves as a proxy for variations in rainfall of Asian southwest monsoon over the Yunnan-Guizhou Plateau. A close relation of the δ 18O record with the ?14. record from tree rings largely reflects impact of centennial-scale solar activity on the monsoon climate changes. The conspicuous decrease in the δ 18O value at AD 1720 indicates an abrupt increase in monsoon rainfall, sug- gesting that an atmospheric-oceanic couple over the tropical Indian Ocean plays an important role in rapid increase of the Northern Hemisphere temperature over the last century.

关键词： cave stalagmite oxygen isotope southwest monsoon solar activity Guizhou.

Rheology of Partially Molten Olivine Aggregates under Water-Saturated Conditions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Continental Dynamics 1997年第1期 54-62页

作者： BAI Wuming (Institute of geophysics, Chinese Academy of Sciences, Beijing 100101, China) MEI Shenghua David KOHLSTEDT (department of geology and geophysics, University of Minnesota, mn {4.5, usa)

The influence of basaltic melt and water content on the high-temperature plastic deformation behavior of olivine aggregates was studied by performing a series of high-temperature creep experiments. The specimens, which are the powder of San Carols olivine plus 1, 4. or 7 wt% MORB, with the grain size of 10-20 μm, were hotpressed. Deformation experiments were conducted in a gas-medium apparatus at a confining pressure of 300 MPa and temperature of 1373 K to 14.3 K. Water was supplied by dehydration of TALC near 1073 K. The hy- droxyl concentration in the samples was determined from Fourier-Transform Infrared (FTIR) spectra.

关键词： partial melting water-saturated conditions rheology high pressure and high temperature

Fluid Flow History in Lower Triassic Bulgo　Sandstone,Central Sydney Basin,Australia

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth Science 2000年第1期19卷 49-57页

作者： Bai Guoping John B Keene department of geology and geophysics, University of Sydney, Sydney, Australia 2006

The fluid flow history during diagenesis of the Lower Triassic Bulgo sandstone has been investigated through integrated analyses of petrography, stable isotope and fluid inclusion. Combined application of these techniques was intended to constrain the temperature, timing, chemistry and source of pore fluids during diagenetic cementation events in the Lower Triassic Bulgo sandstone. The diagenesis proceeded in two different flow regimes: early dynamic fluid flow regime and late slow static fluid flow regime. The former was characterized by a slight increase of δ( 18 O) of pore waters form estimated -15×10 -3 to -14.10 -3 with the temperature increasing from ～10 ℃ to ～75 ℃. During early diagenesis, early clays and pore filling carbonates precipitated from the pore waters. The late slow flow/static fluid regime was characterized by a rapid 18 Oenrichment process. δ( 18 O) of pore waters increased from -14.10 -3 to -5×10 -3 with the temperature increasing from 75 ℃ to 110 ℃. During the late diagenesis, kaolin (generation Ⅱ), quartz and illite crystallized. Oil migrated to the sandstones of the Bulgo sandstone during quartz cementation.

关键词： diagenesis fluid inclusion isotope fluid flow Sydney basin.

Frequency Effects of Fine Thin Layer

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 1994年第1期13卷 92-96页

作者： Zhang Shuangxi(department of geophysics, China University of Geosciences, Wuhan 4.0074.Yuan Tao Zhang Wenxian(Northwest Petroleum geology Bureau, Ministry of geology and Mineral Resources, Xinjiang 830011)Xiong Weigang(department of geophysics, China Uni

One of the most important research task in reservoir engineering now is to resolve the fine thin layer. What are the characteristics of the fine thin layer? This paper gives the answer in frequency domain. The frequency feature of fine thin layer set obtained is grating. The frequence effects of rhythmic thin layer, on the other hand, is different from those of graded thin layer; the grating effect of fine layer is affected by several factors, but the thickness and its inner layer number are the most predominant factors over others affecting grating effect.

关键词： fine thin bed set grating effect frequency response.

Hydrogen isotopic characteristics and their genetic relationships for individual n-alkanes in plants and sediments from Zoigê marsh sedimentary environment

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2010年第9期53卷 1329-1334页

作者： DUAN Yi1, ZHENG ChaoYang2 & WU BaoXiang1 1 Key Laboratory of Petroleum Resources Research, Institute of geology and geophysics, Chinese Academy of Sciences, Lanzhou 730000, China 2 department of geology, Northwest University, Xi’an 710069, China 1. Key Laboratory of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou 730000 China2. Department of Geology Northwest University Xi’an 710069 China

To understand internal relations of their hydrogen isotopic compositions in typical marsh environment, we, using GC-IRMS analytical technique, measured the hydrogen isotopes of individual n-alkanes in the herbaceous plant, woody plant leaf, and sediments from Zoigê marsh in China. The results show significant differences in the hydrogen isotopic compositions of n-alkanes among the different kinds of plants and the different species in the same kind. δD values of n-alkanes in the herbaceous plants (from -254. to -184.) are lighter than those in woody plant leaf ( from -195‰ to -14.‰ ), and the hydrogen isotopic compositions of n-alkanes in K. tibetica P. are lighter than P. pratensis L. The mean δD values of n-alkanes in the sediments from Zoigê marsh reflect that they were derived from herbaceous plants, which is consistent with the peat samples being composed mainly of herbaceous plant remnants. The significant differences in hydrogen isotopic compositions of n-alkanes among the sedimentary samples are caused possibly by environment factors and the difference in input quantity of different herbaceous plants. A certain negative correlation exists between the δ13C and δD values of n-alkanes in the samples, and plant types can be distinguished using the cross plot of δD vs. δ13C values of n-alkanes in the plants. These data and recognitions provide scientific basis for hydrogen isotopic applied research of individual n-alkanes.

关键词： marsh environment plants sediments individual lipids hydrogen isotopes genetic relationship

Vermiform trace fossils from the Precambrian Ruyang Group, western Henan

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第3期42卷 251-254页

作者： HU Jianmin, MENG Qingren and LI Wenhou1 Xi’ an College of geology, Xi’an 710054. China 2. Institute of geophysics, Chinese Academy of Sciences, Beijing 100101, China 3 department of geology, Northwest University, Xi’an 710069, China Xi’an College of geology Xi’an China Institute of geophysics Chinese Academy of Sciences Beijing China department of geology Northwest University Xi’an China

THE origin and evolution of Precambrian lives has been a long-standing controversial problem. It is now generally accepted by most paleontologists that the origin of metazoa can be traced back to more than 1000 Ma, because the Ediacara and latest pre-Ediacara fauna, such as the Huainan fauna, are featured by their diversification of forms, complicated structures

关键词： Precambrian trace fossil Ruyang Group.