青海省西宁市大墩岭黄土剖面元素组分变化与第四纪古气候演化     

王永明  侯元才 《青海国土经略》2001,(Z1)

根据黄土剖面中古土壤系列与砂质黄土中常量元素氧化物含量基本特征,主要地质特征、黄土堆积与古土壤形成古气候环境、演化过程与主要元素组分特征、关系进行了讨论,结合孢粉测年等资料,1.19MaB.P.黄土形成以来的气候演变过程与元素组分变化关系。  相似文献   

Meltwater and the global ocean conveyor: northern versus southern connections     

Dan Seidov  Eric Barron  Bernd J. Haupt 《Global and Planetary Change》2001,30(3-4)

The sensitivity of the ocean circulation to changes in North Atlantic surface fluxes has become a major factor in explaining climate variability. The role of the Antarctic Bottom Water in modulating this variability has received much less attention, limiting the development of a complete understanding of decadal to millennial time-scale climate change. New analyses indicate that the southern deepwater source may change dramatically (e.g., experience a decrease of as much as two thirds during last 800 years). Such change can substantially alter the ocean circulation patterns of the last millennium. Additional analyses indicate that the Southern Hemisphere led the Northern Hemisphere changes in some of the glacial cycles of Pleistocene, implying a seesaw-type oscillation of the global ocean conveyor. The potential for melting of sea ice and ice sheets in the Antarctica associated with global warming can cause a further slowdown of the southern deepwater source. These results demand an assessment of the role of the Southern Ocean in driving changes of the global ocean circulation and climate. Systematic model simulation targeting the ocean circulation response to changes in surface salinity in the high latitudes of both Northern and Southern Hemispheres demonstrate that meltwater impacts in one hemisphere may lead to a strengthening of the thermohaline conveyor driven by the source in the opposite hemisphere. This, in turn, leads to significant changes in poleward heat transport. Further, meltwater events can lead to deep-sea warming and thermal expansion of abyssal water, that in turn cause a substantial sea-level change even without a major ice sheet melting.  相似文献   

Distributions of fatty acids in a stalagmite related to paleoclimate change at Qingjiang in Hubei,southern China   总被引：5，自引：0，他引：5  

XIE Shucheng  HUANG Junhua  WANG Hongmei  YI Yi  HU Chaoyong  CAI Yanjun & CHENG Hai . 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  Geophysics  University of Minnesota  MN  USA 《中国科学D辑(英文版)》2005,48(9):1463-1469

~~Distributions of fatty acids in a stalagmite related to paleoclimate change at Qingjiang in Hubei,southern China1. Dorale, J. A., Edward, R. L., Ito, E. et al., Climate and vegetation history of mid-continent from 75 to 25 ka: A speleothem record from Crevice Cave, Missouri, USA, Science, 1998, 282(5395): 1871-1874. 2. Li, B., Yuan, D., Qin, J. et al., Oxygen and carbon isotopic char- acteristics of rainwater, drip water and present speleofhems in a cave in Guilin area, and thei…  相似文献   

白垩纪“温室”气候与海洋   总被引：11，自引：1，他引：10       下载免费PDF全文

胡修棉 《中国地质》2004,31(4):442-447

白垩纪典型的"温室"气候和海洋一直是地学界关注的焦点之一.与现今地球"冰室"状态相比,温室状态下的气候和海洋遵循着不同的运行模式.本文在近年来取得的大量同位素、古生物以及气候和海洋模拟实验数据的基础上,评述了白垩纪古气候和古海洋研究中取得的重要进展.化石氧同位素数据揭示白垩纪全球平均气温比现今高3～10℃,海洋纬向温度梯度仅0.15～0.3℃/1°,全球海洋结构和大洋环流可能与现今完全不同,大洋环流的驱动很可能是盐度变化而不是温度差异.白垩纪深水沉积显示出从早白垩世碳酸盐台地相、含黑色页岩夹层、黑色页岩和大洋红层大规模出现一直到晚白垩世整体以大洋红层为主的转变.对该沉积转变机制及其与古海洋、古气候关系的研究正是IGCP463/494的主要科学目标.  相似文献   

湖泊沉积生物硅的测定与应用:以湖光岩玛珥湖为例   总被引：14，自引：1，他引：13  

王文远  刘嘉麒  彭平安 《地球化学》2000,29(4):327-330

在国外实验方法基础上,初步建立了湖泊沉积生物硅实验室测定方法,硅胶模拟实验表明,该方法准确可靠,沉积样品重复测试显示测量平均偏差小。利用此方法,首次分析了我国雷州半岛湖光岩玛珥湖Ｂ孔部分岩芯生物硅含量,结果显示,生物硅敏感地记录了末次冰消期古季风气候的变化,揭示了快速变化的ＢΦｌｌｉｎｇ－ＡｌｌｅｒΦｄ－Ｙｏｕｎｇｅｒ Ｄｒｙａｓ气候事件,表明了低纬度湖泊沉积生物硅也是一个理想的古气候替代指标。  相似文献   

STABLE ISOTOPES DISTRIBUTION IN CORE Ck6 AND VARIATIONS OF PALEOCLIMATE OVER QARHAN LAKE REGION IN QAIDAN BASIN, CHINA     

黄麒  陈宜崧  韩风清  陈践发  王先彬 《中国海洋湖沼学报》1997,(3)

ImODareNThelast3Oycars'~tilicproductinnofsalts,andnawh,andexpIorationofsaltlakes,haveyboedmuCinfonnationonQarhanInke.Thereisliteraturedetailingthelakebpaleo-dhate,paboenvbonment,paboerelogy,evolution,etC-since5OkaB.P.(ZhengPenShinCtal.,l993,ChenKereoetal.,l986;HuangQiCtal.,l98l),butfewonthebefore5OkaB-P-eventS.CoreCk6thattheFirsttheloghalExplorationTeamoftheQinghaibologicalBu-rmudrilledat9lOmdePthinQarhanLakeyallasetofcontinuouslylacustrinetali-rnentdataveryvaluableforstudyofpabo…  相似文献   

西安刘家坡剖面第1第5层古土壤研究^*   总被引：22，自引：1，他引：21  

赵景波 《地理研究》1991,10(4):51-58

根据对土壤结构、CaCO₃淀积深度、化学成分和孢粉资料的分析,本文得出:西安刘家坡剖面第1层古土壤为棕壤,发育在年平均降水景800mm以上的温暖条件下,第5层古土壤为黄棕壤,发育在年平均降水量850mm以上的北亚热带条件下。  相似文献   

Early postglacial chironomid succession in southwestern British Columbia,Canada, and its paleoenvironmental significance     

Ian R. Walker  Rolf W. Mathewes 《Journal of Paleolimnology》1989,2(1):1-14

Chironomids typical of cold, well-oxygenated, oligotrophic environments are common in late-Pleistocene deposits, but these taxa are rare in Holocene sediments of most small temperate lakes. Hypotheses to explain the demise of these taxa include variations in climate, lake trophic state, lake levels, terrestrial vegetation, and/or sediment composition. In southwestern British Columbia, this demise correlates with palynological evidence for a lodgepole pine decline, and for rapid climatic amelioration, at about 10 000 yr B.P. Faunal changes are poorly correlated with lithological boundaries. The similar timing of the declines among lakes suggests that a regional influence, climate, has possibly been the principal determinant of early chironomid faunal succession.This is the eleventh of a series of papers to be published by this journal that was presented in the paleolimnology sessions organized by R.B. Davis for the XIIth Congress of the International Union for Quaternary Research (INQUA), which took place in Ottawa, Canada in August 1987. Dr. Davis is serving as guest editor of this series.  相似文献   

广西柳桥地区二叠系-三叠系界线附近黏土矿物及古气候特征   总被引：3，自引：3，他引：3  

蒙有言  冯庆来  何卫红  顾松竹  金雨溪  张凡 《地质科技情报》2005,24(4):25-30

对广西柳桥地区深水相二叠系-三叠系界线地层进行了详细的黏土矿物研究,依据黏土矿物种类的质量分数将东攀剖面划分为3个带.质量分数总体较高的蒙脱石和伊利石组合的出现,说明该区当时处于中低纬度温和干湿交替的古气候环境.大隆组绝大部分地层出现质量分数相对稳定的高岭石,表明晚二叠世末具有温暖-炎热潮湿气候的特点.大隆组顶部(第二带)伊蒙混层的剧增,表明火山活动增强.罗楼组(第三带)中高岭石和伊蒙混层消失,主要的黏土矿物为伊利石,表明火山活动明显减弱,气候变成温和干旱.剖面中长石和伊利石呈逐渐增多的趋势,表明相对海平面下降,陆源物注入量逐渐增加,这与沉积相的分析结果相吻合.  相似文献   

The Paleocene and Eocene in the Russian part of West Eurasia     

M. A. Akhmets’ev  V. N. Beniamovski 《Stratigraphy and Geological Correlation》2006,14(1):49-72

Biostratigraphic charts of marine Paleocene and Eocene in the European and West Siberian parts of Russia include the unified zonations of nannoplankton, planktonic and benthic foraminifers, dinocysts, radiolarians, diatoms, and palynomorphs of higher plants. These regional zonations summarize comprehensive data on the Lower Paleogene, which have been obtained by paleontologists and biostratigraphers in the last century. In the content and resolution degree, they represent a solid basis for geological and paleogeographic consideration and characterize the time succession of diverse biotic and abiotic events. On the other hand, the depicted biotic events have been controlled by successive tectonic, paleogeographic, and paleoclimatic events, because organisms determining contents of biostratigraphic zones changed not only in the course of evolution, but also in response to transformation of surroundings. As elements of general communication systems, epicontinental seas of the Paleogene have been interconnected via straits and seaways, which promoted interchange of water masses and biotas belonging to the Tethys, Atlantic or Arctic oceans, and inner seas. Size and configuration of the seas and seaways changed under influence of tectonic processes and eustatic events of epeirogenic or regional origin. Widening, narrowing, and cessation of communication ways have been responsible for different-scale changes in sedimentation and biotic environments. New materials on the Paleogene in a vast territory of Russian sector of West Eurasia offer an opportunity to revise somewhat the dynamics of climatic changes in the Northern Hemisphere during the Early Cenozoic, which characterize the terminal phase of transition from the warm to cold biosphere of the Earth.  相似文献