The impact of the Laacher See Tephra on terrestrial and aquatic ecosystems in the Black Forest,southern germany     

A. F. Lotter  H. J. B. Birks 《第四纪科学杂志》1993,8(3):263-276

Late-glacial lake sediments containing the Laacher See Tephra (LST, 11000 yr BP) have been analysed for pollen and diatoms at two sites (Hirschenmoor, Rotmeer) in the montane belt of the Black Forest (southern Germany) in order to detect the possible impact of this major volcanic eruption on terrestrial and aquatic biota. The pollen assemblages at both sites show a minor increase in grasses and sedges following the tephra deposition, whereas the pollen of aquatic macrophytes do not show any consistent pattern. Partial redundancy analysis and Monte Carlo permutation tests suggest, however, that the LST had no statistically significant effect either on the terrestrial or aquatic pollen assemblages at either site when the effects of time and climatic change are allowed for statistically. The diatom assemblages at both sites changed after the deposition of the LST and diatominferred pH estimates suggest a short but non-significant excursion towards lower values. Multivariate analyses of the diatom data indicate a statistically significant impact of the deposition of the LST and associated changes in sediment lithology on the diatom assemblages when the effects of climatic change and time are allowed for statistically. However, owing to the interaction between tephra and lithology it is not possible to conclude if the diatom changes were caused by the deposition of the LST or by lithological changes.  相似文献   

The Würmian Late-glacial in Iowland Switzerland     

B. Ammann  A. F. Lotter  U. Eicher  M.-J. Gaillard  B. Wohlfarth  W. Haeberli  G. Lister  M. Maisch  F. Niessen  Ch. Schlüchter 《第四纪科学杂志》1994,9(2):119-125

A synthesis is provided of Late-glacial (14-9 ka BP) environmental changes in lowland Switzerland (the ‘Swiss Plateau’). The chronology of deglaciation and subsequent developments in vegetation cover in the area are summarised. The sequence of climatic variations experienced in the region during the Late-glacial is then described and a curve representing the main palaeotemperature variations is presented.  相似文献   

European vegetation history: Palaeovegetation maps from pollen data - 13 000 yr BP to present     

Brian Huntley 《第四纪科学杂志》1990,5(2):103-122

Pollen data are the most important source of information with respect to late Quaternary vegetation history. Broad-scale palaeovegetation patterns have been subjectively inferred from mapped pollen data by previous authors. In this study, multivariate classification was applied to European pollen data for the last 13 000 yr. The resulting clusters are mapped at millennial intervals and can be equated with vegetation units. The maps portray the changing vegetation of Europe since the last glacial. They reveal the impermanence of the assemblages of species that ecologists recognise as communities. The dominant patterns in the maps also change through time, indicating important changes in palaeoenvironmental conditions and in the alignment of major environmental gradients. Human impact upon European vegetation history is seen to be relatively unimportant when the vegetation is viewed at a continental scale.  相似文献   

Mid-Holocene Hydrologic Model of the Shingobee Watershed, Minnesota     

Sheryl K. Filby  Sharon M. Locke  Mark A. Person  Thomas C. Winter  Donald O. Rosenberry  John L. Nieber  William J. Gutowski  Emi Ito 《Quaternary Research》2002,58(3):246

A hydrologic model of the Shingobee Watershed in north-central Minnesota was developed to reconstruct mid-Holocene paleo-lake levels for Williams Lake, a surface-water body located in the southern portion of the watershed. Hydrologic parameters for the model were first estimated in a calibration exercise using a 9-yr historical record (1990–1998) of climatic and hydrologic stresses. The model reproduced observed temporal and spatial trends in surface/groundwater levels across the watershed. Mid-Holocene aquifer and lake levels were then reconstructed using two paleoclimatic data sets: CCM1 atmospheric general circulation model output and pollen-transfer functions using sediment core data from Williams Lake.Calculated paleo-lake levels based on pollen-derived paleoclimatic reconstructions indicated a 3.5-m drop in simulated lake levels and were in good agreement with the position of mid-Holocene beach sands observed in a Williams Lake sediment core transect. However, calculated paleolake levels based on CCM1 climate forcing produced only a 0.05-m drop in lake levels. We found that decreases in winter precipitation rather than temperature increases had the largest effect on simulated mid-Holocene lake levels. The study illustrates how watershed models can be used to critically evaluate paleoclimatic reconstructions by integrating geologic, climatic, limnologic, and hydrogeologic data sets.  相似文献   

赤峰地区孢粉分析与先人生活环境初探   总被引：15，自引：5，他引：15  

许清海  杨振京  崔之久  阳小兰  梁文栋 《地理科学》2002,22(4):453-457

从考古孢粉学角度，根据赤峰七锅山剖面孢粉分析，结合赤峰地区古文化遗址的考古资料，探讨了赤峰地区8000aB.P.以来的先人生活环境，以及人类活动和自然环境演变的过程之间的相互关系，结果表明：8400－6200aB.P. 为温暖湿润的草原气候，先人既狩猎捕鱼，也种植作物和放牧；6200－4000aB.P,，随着森林的破坏，环境逐渐恶劣，农业水平下降；4000－2500aB.P.植被以草原为主，气候温干，先人以旱作农业为主，2500aB.P.至现在，植被为典型的蒿草草原，气候温和偏干，农业和畜牧业相对发展，人类活动加剧。  相似文献   

江苏海州湾海区表层沉积物的孢粉研究     

肖霞云  萧家仪  陈晔 《地理与地理信息科学》2002,18(1):83-86

对江苏海州湾近岸海区的表层沉积物进行孢粉分析 ,总结该研究区的孢粉分布规律及成因。笔者认为该区的松花粉主要来自西北部胶东半岛 ;落叶阔叶乔木花粉来源于连云港市云台山 ;草本植物花粉与陆缘植被相应 ,以盐生的蒿、藜科花粉占优势 ,表明花粉沉积与当地及周边地区植被密切相关。蕨类孢子是从陆地由水流携带搬运而来 ,百分含量的高低可能是受补偿率的影响。  相似文献   

北亚热带江淮地区白浆化土壤的发生学特性     

傅桦  丁瑞兴 《地理研究》2001,20(4):431-438

通过孢子花粉、石英砂颗粒和土壤微形态学分析,研究北亚热带江淮地区白浆化土壤的发生学特性。白浆化土壤下部土体经历了暖温带森林草原景观和亚热带草原景观,为高能化学环境。在母质沉积后,经历了褐土化过程或其他物质堆积,经过一定时期的沉积间断后,堆积新物质,随着气候的变化,成土环境演变为现代气候类型,属亚热带森林草原环境。淀积层也源于黄土状物质,风化程度更强,白浆层则为后期堆积物,不具备高能化学环境。淀积层在高能环境下,存在次生粘化和淀积粘化作用。  相似文献   

干旱区石羊河终闾湖泊孢粉组合中云杉圆柏属环境指示意义探讨   总被引：8，自引：3，他引：8  

朱艳  陈发虎  施祺  颉耀文 《中国沙漠》2001,21(2):141-146

河西走廓东段、石羊河终闾湖泊边缘的三角城剖面下部全新世早期至末次冰消期的292-600cm处155个样孢粉组合显示云杉、圆柏属含量极高，两者之和达40%-60%左右，且百分比互为消长，通过对云杉、圆柏属生态习性、传播性能、与其它组分关系、当地特殊的自然地理条件和表土花粉记录的综合分析，笔者认为剖面中高含量的云杉、圆柏属来自流域上游祁连山，是石羊河搬运的结果，两者含量与区域有效湿度关系密切，云杉丰值指示湿润，圆柏丰值指示干旱。  相似文献   

The landscape factor in the formation of pollen records in lake sediments     

J.-M. Punning  T. Koff 《Journal of Paleolimnology》1997,18(1):33-44

Comprehensive paleobotanical and geochemical methods have been used to study the relationship between the spatial scale of landscape development and values of pollen influx to take the bog sediments. The spatial-temporal history of the four lakes and a bog was established in NE Estonia and pollen analyses of thier sediment were made. It was found that the influx of total arboreal pollen directly corresponds with the sizes of the sites studied, and varies with thier expansion or reduction.  相似文献   

我国某些红树植物花粉形态研究及其古环境意义   总被引：3，自引：0，他引：3  

张玉兰  王开发 《海洋地质与第四纪地质》2002,22(4):29-35

对我国11科11属14种（除红树科和海桑属之外）红树植物花粉形态作了光学显微镜的各种数据测定，并在扫描电镜下观察和摄片研究。这14种红树植物花粉是海榄雌，水芫花，水椰，榄李，红榄李，银叶树，小花老鼠勒，老鼠勒，海漆，杨叶肖瑾，玉蕊，桐花树，尖叶卤蕨，卤蕨，红树植物是热带-亚热带海岸潮间带的一种特有的指示植物，根据沉积物中出现的红树植物花粉种类和数量，可推测海滨红树林的演化，海面升降，海岸线变迁，追溯古海流和沉积物来源。  相似文献