检索结果-南通市图书馆

Science China Chemistry 1990年第2期33卷 235-245页

作者：刘秀铭许同春刘东生 Institute of Geology Academia Sinica Beijing 100011 PRC Institute of Geology Scate Seismological Bureau Beijing 100011 PRC

Anisotropy of magnetic susceptibility is used in the present study to reveal thedepositional fabric on the original (windblown) loess and secondary (redeposited) loess. The two kinds of sediments mentioned above can be distinguished in terms of their susceptibility anisotropy, e.g. anisotropy degree, magnetic foliation and lineation parameters. On this basis the magnetic fabric of the Pliocene red soil underlaying the loess is studied, and compared with the results of a typical residue-deposited red clay in South China. Considering its geological features, the red soil in Xifeng is regarded probably as aeolian in origin also.

关键词： anisotropy of magnetic susceptibility magnetic fabric loess paleosol red soil.

The summer monsoon evolution recorded by carbon isotope of organic matter from the Yuanbao loess section during the Last Interglaciation

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2002年第15期47卷 1289-1291页

作者： Yong He Dahe Qin Jiawen Ren Fengxia Li Chinese Acad Sci Cold & Arid Regions Environm & Engn Res Inst Lanzhou 730000 Peoples R China

Based on the carbon isotope record of organic matter from the Yuanbao loess section, northwestern China, five enhanced summer monsoon events were observed at this area during the Last Interglaciation. Such events were also recorded by the paleosol layers, pollen assemblage and magnetic susceptibility. It is suggested that the enhanced summer monsoon leads to the shift of vegetation type, which results in the change of δ13C value of organic matter in the paleosol layer. It appears that the δ13C of organic matter is a good indicator for the summer monsoon variation. Among these five events, the first, second and the fifth reached their maximum smoothly, but the other two had experienced a less cold stage before reaching their peaks, which suggests that the mechanisms of such events may be different.

关键词： Chinese Loess Plateau paleosol carbon isotope of or-ganic matter summer monsoon.

Variation of summer monsoon intensity on the Loess Plateau of Central China during the last 130 000 a——Evidence from Rb and Sr distribution

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第6期42卷 473-476页

作者： Chen, J Qiu, G Lu, HY Ji, JF Department of Earth Sciences Nanjing University Nanjing China Xi’an Laboratory of Loess and Quaternary Geology Chinese Academy of Sciences Xi’an China

THE loess-paleosol sequences from China potentially provide one of the best terrestrial records of past climates. Studies have shown that magnetic susceptibility in the sequences represents a proxy climate index closely related to changes of summer monsoon intensity. Some interpretative models have been advanced to account for these magnetic variations, although unanimity of opinion has not been reached. Recent geochemical studies of chemical

关键词： paleomonsoon loess paleosol Rb and Sr geochemistry.

A climatic reversal at the last interglacial-last glacial transition recorded in the loess section at Zhaitang, Beijing

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第6期44卷 571-575页

作者： Shangfa Xiong Dongsheng Liu Zhongli Ding Chinese Acad Sci Inst Geol Beijing 100029 Peoples R China

A weakly developed paleosol was identified at S1-L1 transition of the loess section of Zhaitang, Beijing. This paleosol may represent a climatic reversal which is associated with the strengthening in summer monsoon and correlated well with the climatic regression event documented in the paleoclimate records from Greenland ice, marine sediments and European pollen at the last interglacial-last glacial transition.

关键词： last interglacial period last glacial period loess paleosol climatic reversal.

CHANGES OF QUATERNARY CLIMATE OF LOESS DISTRICT IN CHINA

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 1989年第1期32卷 96-105页

作者：王永焱 Department of Geology Northwest University Xi'an

On the basis of the data of sporo-pollen analysis, the weathering index of loess and paleosol layers and the climatic differences between the periods of the formation of loess and paleosol as reflected by intensities of natural remanent magnetization of loess and paleosol, it may be confirmed that the loess layers represent the climate of glacial stages, while paleosol was formed during interglacial stages. The climatic changes in the loess area of China have undergone 23 cycles which were combined with the paleomagnetic dating. TL ages of paleosol layers and the average ages of termination could be excellently correlated with the δ^(18)O stages of deep sea core V_(28-239). Thus, it may be recognized that the Luochuan and Xi'an loess-paleosol sequences are the typical climatostratigraphy in China and even in the world.

关键词： loess paleosol paleoclimate.

Interpretation of Dune Genesis from Sedimentogical Data and Ground Penetrating Radar (GPR) Signatures: A Case Study from Ashirmata Dune Field, Mandvi Beach, Gujarat, India

在线全文

学校读者我要写书评

暂无评论

International Journal of Geosciences 2012年第4期3卷 772-779页

作者： Deshraj Trivedi Koravangatt Devi Ilya Buynevich P. Srinivasan K. Ravisankar Vipul Silwal D. Sengupta Rajesh R. Nair Indian Institute of Technology Structural Engineering Research Centre Temple University

The coastal dunes located near the Ashirmata region, south of Mandvi beach lies near the straight coast have been stud-ied by making use of sedimentological information and Ground Penetrating Radar (GPR) data. Sedimentological analy-sis reveals the NNW-SSE trending longitudinal dunes consists of well sorted fine sands with unimodal distribution pos-sibly formed by constant wind gust and also the point out to the origin of sediments from single source;mostly the sediments derived from Indus delta transported to beach by long shore drift and tidal waves, carried inland by local on-shore winds. The radargram confirms, the homogenous sand layers with paleosols at shallow depth slip faces are proba-bly formed due to extreme storm activity of Recent.

关键词： Coastal Dune Ashirmata Region Sedimentogical Analysis Ground Penetrating Radar paleosol

High-resolution multi-proxy records of Asian monsoon activities from terrestrial sediments over the last 75,000 years

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第S1期44卷 223-229页

作者： KazuyoshiYAMADA HitoshiFUKUSAWA ShujiIWATA Department of Geography Graduate School of Science. Tokyo Metropolitan University Hachioji 192-0397 Japan.

Our research group have investigated chronology and sedimentology of terrestrialsediments including loess-paleosols sediments over the last 75 ka at Lanzhou, northwestern China,and over the last 45ka at Tokyo, central Japan. Based on chronology of high resolution dating ofESR, TL, and IRSL and tephrochronology in these sediments, we investigated to reconstructactivities of Asian summer and winter paleomonsoons by using magnetic susceptibility, colorreflectance and eolian dust concentrations over the last 75ka. Relations between standard curves ofdelta 18O in GISP2 and color reflectance in loess-paleosol sediments of Linxia over last 140 kashows that color reflectances are good proxy records indicating Asian summer paleomonsoonactivity in time and are closely related to standard curve of delta 18O in GRIP since the lastinterglacial. Also, relations between standard curve of delta 18O in GISP2 and eolian dustconcentrations over the last 75 ka at Lanzhou shows the Asian winter paleomonsoon activitieshave coincided with climatic changes in North Atlantic by GISP2 ice cores, and suggests thatresponse of winter monsoon was rapid in global cooling stages, but slow in warming stage. Otherresults of our research in terrestrial sediments show as follows; 1) Horizons of Heinrich eventsfrom H1 to H4 in loess-paleosol sequences at Lanzhou. 2) Magnetic susceptibility and MSfrequency dependent are possible to be available as proxy records for pedogenesis of tile KantoLoam in Japan. 3) 8.2ka cooling event was recognized in Holocene loess-paleosol sequences atLanzhou.

关键词： loess paleosol Asian monsoon color reflectance Heinrich Eevents Dansgaard-Oeschger Cycle

CLIMO-ENVIRONMENT CHANGES IN NORTH XINJIANG SINCE LATE PLEISTOCENE

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1988年第13期33卷 1134-1138页

作者：文启忠郑洪汉 Guiyang Institute of Geochemistry Academia Sinica

According to the information on fossil species and sedimentary features of the Late Pleistocene sediments in north Xinjiang, we may successfully learn the history of climatic changes during the past 120,000 yr which provides reasonable scientific evidence of vital importance for predicting the trend of future climate and evolution of environment as well as their influence on production arrangements.

关键词： climatic changes paleosol spore-pollen and 14C age data

Loess geochemistry and Cenozoic paleoenvironments

在线全文

学校读者我要写书评

暂无评论

Loess geochemistry and Cenozoic paleoenvironments

22-Ma eolian deposits in China and long-term climate changes

中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： Zhengtang GUO~(a,*) a Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing,100029,China

Loess-soil sequences are among the best terrestrial records of *** in northern China provide a 22 million-year(Ma) geological history of the Asian deserts(dust sources),winter monsoon(dust carrier) and summer monsoon(moisture carrier) winds,and the regional *** geochemistry represents one of the most dynamic research fields in loess-based *** of the most frequent approaches are reviewed here with emphasis to the loess deposits in China.

关键词： loess geochemistry Cenozoic climate paleosol monsoon

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Acta Geochimica 2006年第S1期 281-281页

作者： William Ruddiman Tungsheng LIU Department of Environmental Science Clark Hall University of Virginia Charlottesville Virginia 22903 USA Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China