检索结果-南通市图书馆

A possible Younger Dryas-type event during Asian monsoonal Termination 3

Science China Earth Sciences 2006年第9期49卷 982-990页

作者： CHEN Shitao1, WANG Yongjin1, KONG Xinggong1, LIU Dianbing1, CHENG Hai2.& R.L. Edwards2.1. College of Geography Science, Nanjing Normal university, Jiangsu Key Laboratory of Environmental Change and Ecological Construction, Nanjing 2.0097, China 2. Department of geology and {2., university of minnesota, Minneapolis {4., usa College of Geography Science Nanjing Normal University Jiangsu Key Laboratory of Environmental Change and Ecological Construction Nanjing China Department of geology and geophysics University of Minnesota Minneapolis USA

Seven U-Th dates, 560 δ 18O data and microscopic sequences were measured for sta- lagmites from two high-altitude caves in Shennongjia area, Hubei Province. Variations of the de- cadal-resolution stalagmite δ 18O record from Swan Cave (1600 m elevation) reflect large spatial changes in circulation strength and precipitation of Asian monsoon. The evidence comes from a great similarity among the stalagmite δ 18O records from Nanjing, Jiangsu Province; Libo, Guizhou Province and here studied area during the last deglaciation, including a part interval of Younger-Dryas event and Bolling-Allerod. A 30-year-resolution stalagmite δ 18O record from Yongxing Cave (14.0 m eleva- tion), 70 km away from Swan Cave, reveals a rapid transition of Asian monsoon climate during Ter- mination 3 at about 2.0}±5 kaBP. Based on 3 U-Th dates and about 5000 continuous annual bands, a millennial dry episode has been observed during Asian monsoonal Termination 3 from the Yongxing δ 18O profile. With respect to its structure, duration and transition, the dry reversal, as indicated by our stalagmite δ 18O record, generally agrees with the pattern of the YD event well-expressed in the Chi- nese stalagmite δ 18O records. This YD-type event is characterized by a large decrease in δ 18O value as much as 2.30‰, more than half of the δ 18O excursion between glacial/interglacial periods, and lasts 1371±59 a determined by the annual counting chronology. After this event, the monsoon climate shifted abruptly into the interglacial period within 74.4.a. Our data corroborate the view that the re- peated occurrence of YD-type event was not an “accident”, possibly resulted from the coupling of ice-sheet and oceanic/atmospheric circulations.

关键词： stalagmite, Termination 3, Asian monsoon, YD-type event, Shennongjia, Hubei Province.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

No apparent lock-in depth of the Laschamp geomagnetic excursion: Evidence from the Malan loess

引用

Science China Earth Sciences 2006年第9期49卷 960-967页

作者： ZHU Rixiang1, LIU Qingsong1,2. PAN Yongxin1, DENG Chenglong1, ZHANG Rui1 & WANG Xianfeng3 1. Paleomagnetism and Geochronology Laboratory (SKL of Lithosphere Evolution), Institute of geology and geophysics, Chi- nese Academy of Sciences, Beijing 10002., China 2. Institute of geophysics and Planetary geophysics, {4. of California, Santa Cruz, CA 95064. usa 3. Department of geology and geophysics, university of minnesota, Minneapolis, mn 55455, usa Paleomagnetism and Geochronology Laboratory (SKL of Lithosphere Evolution) Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Institute of geophysics and Planetary geophysics University of California Santa Cruz USA Department of geology and geophysics University of Minnesota Minneapolis USA

The first-order chronological framework of the long-term Chinese loess/paleosol sequences was based mainly on magnetostratigraphy. However, there remain arguments on the lock-in ages of the major geomagnetic reversals. This study systematically compared the stratigraphic locations of the Laschamp excursion and Henrich events (H4.at～39 ka and H5 at～4. ka) recorded by the Luochuan loess profile in the central Chinese Loess Plateau. Results show that the Lascchamp excursion is bracketed well by these two cold events, and the corresponding estimated age is between about 4..7-4..7 ka, which is close to the widely accepted age of ～4.-4. ka for the ***, our new results do not suggest apparent lock-in effects in the last glacial Malan loess.

关键词： Chinese loess, Laschamp excursion, Henrich event, lock-in depth.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

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

引用

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 2.0097, China 2. Department of geology and {2., minnesota university, Mineapolis mn 55455, usa 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 172. 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.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Distributions of fatty acids in a stalagmite related to paleoclimate change at Qingjiang in Hubei,southern China

引用

Science China Earth Sciences 2005年第9期48卷 1463-1469页

作者： XIE Shucheng1,HUANG Junhua1,WANG Hongmei2.YI Yi1,HU Chaoyong1, CAI Yanjun3 & CHENG Hai4.1. Faculty of Earth Science,China university of Geosciences,Wuhan 4.0074.China 2. School of Environmental Studies,China university of Geosciences,Wuhan 4.0074.China 3. SKLLQG,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710075,China 4. Department of geology and geophysics,{4.,mn55455,{12. Faculty of Earth Science China University of Geosciences Wuhan China School of Environmental Studies China University of Geosciences Wuhan China SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an China Department of geology and geophysics University of Minnesota USA

Fatty acids extracted from a subtropical stalagmite at Qingjiang in Southern China’s Hubei Province were analysed using gas chromatography-mass spectrometry. These n-alkanoic acids range from C14.to C2. in carbon number, maximizing at C16, with a second dominance at C2.. In contrast to the stalagmite analysed, the overlying soils are characterized by the dominance of heavy-molecular-weight homologues (>C2.). The n-fatty acids in the stalagmite were proposed to be contributed by both the soil ecosystems and the microbes harboring in the percolating water and the cave. The ratios of unsaturated to saturated n-fatty acids (C16:1i/C16:0, C18:1/C18:0) appear to show trends comparable with the oxygen isotope records of the stalagmite carbonate, with enhanced values associated with the cold episode such as Heinrich event 1. This paleoclimate-dependent record of the n-fatty acids might reflect microbial changes in physiology and activity in response to the temperature. This record shows somewhat difference from the previous paleoclimate signal extracted from n-alkanols and n-alkan-2.ones of the same stalagmite. The acid record fails to document the well-known Younger Dryas event which was effectively shown by the latter two biomarkers derived from soil ecosystems. This discrepancy might result from the changing biogeochemical impact on different lipid fractions as well as the varied organism populations in different ecosystems.

关键词： biomarker, ecosystem, microbe, speleothem, paleoclimate, Quaternary.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The *** climate abrupt events in the early and middle Holocene:Stalagmite oxygen isotope record from Maolan,Guizhou,China

引用

Science China Earth Sciences 2005年第4期48卷 530-537页

作者： QIN Jiaming1, YUAN Daoxian1, CHENG Hai2. LIN Yushi1, ZHANG Meiliang1, WANG Fuxing1, R. L. Edwards2. WANG Hua1 & RAN Jingcheng3 1. The Karst Dynamic Laboratory, IKG, CAGS, Guilin 54.004. China 2. {2. and geophysics Department, minnesota university, {4., usa 3. The Management of Maolan National Nature Reserve, Libo 5584.0, China The Karst Dynamic Laboratory IKG CAGS Guilin China geology and geophysics Department Minnesota University MN USA The Management of Maolan National Nature Reserve Libo China

The isotope records which range from 3.9 kaBP to 15.7 kaBP with an average resolution of 90 a have been obtained from 4. cm to 193.6 cm of the upper part of D4.stalagmite from Dongguo Cave in Libo, Guizhou, by using system TIMS U-series dating and carbon and oxygen stable isotope *** study indicates that the last cold event, the YD (Younger Dryas) event, of the last glacial period was apparently shown in D4.record, which started from 12.80 kaBP and ended in 11.58 kaBP, with a great range of drop in temperature. The end of the last glacial period was consistent with the termination I in oceanic isotope records and was with time limit of 11.3 kaBP. The three most distinct cold events in the early and middle Holocene occurred respectively in 10.91 kaBP, 8.2. kaBP and 4.75 kaBP, with a range of drop in tem- perature reaching 2.5℃. The climate abrupt events in thousand and hundred years scale re- corded in stalagmite δ O can be compared to those in GISP2.ice cores from Greenland in their 18 happening time and the range of their lasting time. The cold events in 8.2. kaBP and 4.75 kaBP can also be compared to CC3 stalagmite records in Ireland, which indicate that climate changes of short range in China monsoon areas, western Europe and polar regions, have the same driv- ing factor. This has a global significance. In addition, the trend of record curves in some time- stages is apparently different, which reflects probably the difference between environment in monsoon climate areas and in polar regions.

关键词： isotope record, climate event, stalagmite, Libo, Guizhou.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Abrupt climate change of EastAsian Monsoon at 130 kaBP inferred from a high resolu-tion stalagmite δ18O record

引用

Science Bulletin 2005年第23期50卷 2765-2769页

作者： JIANG Xiuyang1, WANG Yongjin1, KONG Xinggong1,WU Jiangying1, SHAO Xiaohua1, XIA Zhifeng1 & CHENG Hai2.1. College of Geography Science, Nanjing Normal university, Nanjing2.0097, China 2. Department of geology and {2., university of minnesotaMinneapolis, mn {4., usa College of Geography Science Nanjing Normal University Nanjing 210097 China Department of geology and geophysics University of Minnesota Minneapolis MN 55455 USA

2.0Th ages and oxygen isotope data of a stalagmite from Shanbao Cave in Hubei Province characterize thEast Asian Monsoon precipitation from 133 to12. ka. Thdecadal-scale high-resolution δ18O record reveals a detailedtransitional process from the Penultimate Glaciation to thLast Interglaciation. As established with 2.0Th dates, the agof the Termination II is determined to be 12..5±1.0 kaBPwhich supports the Northern Hemisphere insolation as thtriggers for the ice-age cycles. In our δ18O record, the glacialinterglacial fluctuation reaches about 4., almost the samlevel as in other Asian Monsoon cave stalagmite δ18O recordThe transition of the glacial/interglacial period in our recordcan be recognized as four stepwise stages, among which, arapid rise of monsoon precipitation follows the stage o“Termination II pause”. The rapid rise is synchronous withthe abrupt change of global methane concentration, whichreflects that an increase in both Asian Monsoon precipitationand tropical wetland plays an important role in the globaclimate changes.

关键词： stalagmite high-resolution U/Th age Termination II.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rheology of Partially Molten Olivine Aggregates under Water-Saturated Conditions

引用

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., 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 10-2. 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

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Mineralogy and crystal structure determination of Mg-fillowite

引用

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. Institute of geology, Chinese Academy of Sciences, Beijing 10002., China China university of Geosciences Beijing China Institute of geology Chinese Academy of Sciences Beijing China

Accurate crystal structure determination of complex phosphate Mg-fillowite ? Na2.a(mn4.g2.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=1.514.(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 4. 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.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mesozoic radiolarian chert from the middle sector of the Yarlung Zangbo suture zone,Tibet and its tectonic implications

引用

Science China Earth Sciences 2006年第4期49卷 348-357页

作者： ZHU Jie1,2. DU Yuansheng1, LIU Zaoxue2. FENG Qinglai1, TIAN Wangxue2. LI Jinping2.& WANG Changping2.1. Faculty of Earth Sciences,China university of geology, Wuhan {2.007{2. China 2. Hubei Institute of Regional geology Survey, Wuhan {2.003{2. China Faculty of Earth Sciences China University of Geology Wuhan China Hubei Institute of Regional geology Survey Wuhan China

Three radiolarian fauna, aged as the Middle-Late Triassic, Late Jurassic-Early Creta- ceous and Cretaceous radiolarian fauna, have been recognised in the radiolarian cherts from the middle sector of the Yarlung Zangbo suture zone, southern Tibet, China. The average contents of SiO2.in the radiolarian cherts of the Middle-Late Triassic and Late Jurassic-Early Cretaceous are 90.2.0} and 92.58% respectively, with average ratios of Al/(Al+Fe+mn) as 0.75 and 0.74.respectively, the average ratios of mnO/TiO2.as 0.36 and 1.2.0} the average ratios of Ce/Ce* as 1.15 and 1.03, and the average ratios of LaN/CeN as 0.85 and 0.93. These geochemical features indicate that both of them are biogenic, deposited in a continental margin basin. The SiO2.content of the Early Cretaceous radiolarian chert is 94.12., with the ratio of Al/(Al+Fe+mn) as 0.59, ratio of mnO/TiO2.as 4.30, ratio of Ce/Ce* as 0.60, ratio of LaN/CeN as 1.59, which imply that the chert is biogenic and was deposited in a pelagic basin. The Middle-Late Triassic association of the radiolarian chert and turbidites as well as their geochemical characteristics indicates the existence of a strong rifting marginal basin in the belt of the Yarlung Zangbo River then. The association of radiolarian chert and bedded basalt indicate an initial Tethyan ocean basin in southern Tibet during the Late Jurassic-Early Cretaceous. The early Cretaceous radiolarian chert coexisting with pillow basalt in top of the ophiolite suite represents sediments from the oceanic Tethyan basin.

关键词： radiolarian chert, sedimentary geochemistry, Mesozoic, Yarlung Zangbo suture zone, Tibet.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Origin and age of mn deposits of the Nantuo Formation in the Sinian System

引用

Chinese Science Bulletin 1997年第24期42卷 2072-2075页

作者： YANG Jiedong, WANG Zongzhe, XUE Yaosong, SUN Weiguo, TAO Xiancong and ZHOU Chuanming1. Center of Modern Analysis, Nanjing university, Nanjing 2.0093, China 2. Nanjing Institute of geology and Palaeontology, Chinese Academy of Sciences, Nanjing 2.0008, China Center of Modern Analysis Nanjing University Nanjing China Nanjing Institute of geology and Palaeontology Chinese Academy of Sciences Nanjing China

THE tillites in the Nantuo Formation of the Sinian System is considered contemporary with theVaranger ice age. The manganese deposits in the Nantuo Formation are most suitable to iso-topic dating and may record the precious information on paleo-ocean chemistry. However,there have heen different views and disputations about their origin and age for a long time. The Sinian System in the Yangtze region is divided into 3 formations from base to top:the Nantuo Formation, the Doushantuo Formation and the Dengying Formation. The

关键词： Neoproterozoie ice age mn deposit isotopic age.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：