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1.
山西大同煤田晚石炭世晚期和早二叠世早期植物群   总被引:3,自引:2,他引:3  
陈芬  王京东 《现代地质》1997,11(2):131-136,T002
对山西大同煤田晚石炭世晚期和早二叠世早期植物化石进行了研究,共鉴定植物化石21属48种,划分2个植物组合,讨论了植物群的特征和时代;此外,还论证了本区晚石炭世晚期和早二叠世早期植物群指示的古气候条件  相似文献   

2.
曹洪升 《贵州地质》1992,9(1):26-40
本文详细地报道了贵州省西部晚三叠世火把冲组和二桥组植物群,计有化石植物48属110种。在这个植物群中,苏铁类植物占优势;蕨类植物了很丰富,其中尤以双扇蕨科植物占有重要地位;银杏类植物和松柏类植物有了较大的发展。并在此基础上,对黔西晚三叠世植物群的性质、地质时代以及与国内外同期类似植物群的关系和对比等进行了讨论,确定了黔西晚三叠世植物群的地质时代为诺利克期至端替克朗。  相似文献   

3.
沈树忠  曾勇 《现代地质》1994,8(4):413-419
本文从植物群总体特点入手,结合沉积环境分析和化石埋藏特征对义马组下含煤段植物的古生态进行了研究.根据植物群的生活习性和生境不同,将本区下含煤段植物群划分出二个植物群落──湿地植物群落和低地植物群落,并通过对植物群的组成成分、叶相进行分析和复合分异度、均衡度计算,认为本区植物群当时是一种生活于暧温带──潮湿气候条件下的植物群.  相似文献   

4.
边坡治理中的植物固坡法   总被引:8,自引:0,他引:8  
植物固坡法是近些年来国际上越来越流的一种边坡治理方法。本文阐述了植物固坡法的基本原理和作用机理,介绍了当前国内外植物固坡工程的一般施工流程,对镇江市的边坡治理提出了建议,最后对植物固坡法的应用前景作了分析。  相似文献   

5.
边坡治理中的植物固坡法   总被引:11,自引:2,他引:11  
植物固坡法是近年来国际上越来越流行的一种边坡治理方法。本文阐述了植物固坡法的基本原理和作用机理,介绍了当前国内外植物固坡工程的一般施工流程,对镇江市的边坡治理提出了建议,最后对植物固坡法的应用前景作了分析。  相似文献   

6.
古植代陆地维管植物的多样演化和绝灭   总被引:1,自引:0,他引:1  
李中明 《地质论评》1994,40(3):237-244
本文描述了石炭-二叠纪陆地维管植物在物种,生态和遗传方面的多样性,并根据古生代末这些植物在时空上的演化过程和数量统计数字,确认二叠-三叠纪集群绝灭事件同样在植物中存在,进而还探讨了植物集群绝灭事件发生的原因,笔者认为其直接外部原因,可能是局部地质事件(如:构造活动,火山爆发)引起热带雨林大面积消失,使气候变干埋所致。又根据当今对化石植物生殖生物学的研究结果,认为当时大部分植物(即古植代植物)的生殖  相似文献   

7.
皇甫川流域百里香草原和人工沙棘灌木林的水分利用特征   总被引:7,自引:0,他引:7  
使用LI-6400光合系统测定仪、LI-3000A叶面积仪等,对皇甫川流域百里香草原和中国沙棘灌木林的优势植物进行了光合速率、蒸腾速率测定,同时还测定了植物水分、土壤水分及群落地上生物量。根据所测数据计算得到了这两个群落优势植物光合和蒸腾的日变化特点、光合水分利用效率,分析了两个群落优势植物叶片含水量、自然饱和亏及水势等植物生理水特征。通过群落优势植物种群的蒸腾失水和土壤水分的分析,探讨了由于土地利用方式的不同,产生的这两个群落生态水的一些明显差异。  相似文献   

8.
植物胶作为钻探冲洗液已有多年的历史,主要在第四系覆盖层、松散地层、砂卵石层勘探取心有独特的效果。近年来,随着环境保护意识的加强,野生植物资源的开发受到了极大的限制,急需寻求新的可持续利用的植物胶。从常用植物胶化学组分以及冲洗液的粘度特性入手,研究植物胶的特性和改性效果,并对某种新型植物胶QM的开发与应用前景做了初步探讨。  相似文献   

9.
黑龙江小西林铅锌矿植物体内铅锌积累机制初步研究   总被引:1,自引:0,他引:1  
本文利用较新的思路,在地处森林沼泽景观的小西林铅锌矿对植物吸收积累元素的机制进行了初步研究,总结出植物对营养元素和有毒元素的不同积累模式。为植物地球化学找矿方法在生产实际中应用指出了一条新路。  相似文献   

10.
植物中汞的研究进展   总被引:9,自引:1,他引:9  
植物生态系统中汞的环境过程是生物地球化学循环过程的重要组成部分,且与整个生态系统中各物种的生存和发展密切相关。本文介绍了植物中汞生物地球化学循环的进展,包括汞对植物的生物毒性、植物中汞的来源、分布与迁移转化、植物大气间汞的交换过程及其研究方法,以及植被在生态系统间汞循环中的重要作用,最后简要介绍今后的研究重点和热点。  相似文献   

11.
抚顺盆地下第三系经系统的采样、分析、鉴定,发现了丰富的孢粉化石,特别是首次在耿家街组内发现了大量的孢粉化石,填补了以往的空白,为本区有争议的地层(耿家街组)的时代讨论提供了重要的化石依据。根据孢粉组合特征,将耿家街组的时代定为始新世中晚期,孢粉植物群表明该组沉积时期本区发育了常绿、落叶阔叶树为主的森林植被,反映温暖湿润的亚热带—暖温带气候特征。  相似文献   

12.
In preparation for an interdepartmental conference on the taxonomy and nomenclature of fossil spores and pollen, a working committee of palynologists met at the Geological Institute of the U.S.S.R. Academy of Sciences in April 1961. There was deep theoretical divergence in the views of the participants on most of the questions discussed. All did agree that both form-taxa and natural taxa must be used in systematizing fossil spores and pollen. However, one group favored recognition of both “organ-genus” and “form-genus,” while another group regarded the “organ-genus” as superfluous and would replace the term “form-genus” by the term “group.” Naumova and Zaklinskaya believed that neither the organ-species nor the form-species should be identified with the species in the biological sense. All other participants considered them to be true plant species in the biological sense. Zaklinskaya, Naumova, and Lyuber believed, in disagreement with other participants, that the name of a fossil genus should not be derived from that of a family of the natural system. The so-called “approximately-natural” system of classification was unanimously rejected, as were Erdtman's taxa “sporotype” and “sporomorph.” Opinion was divided as to acceptance of Potonie's nomenclatural system (1956, 1960). All agreed that the type method should be used. -- D. C. McGregor.  相似文献   

13.
Pollen contained in 22 fossil packrat middens from the Sonoran Desert provides a complementary, but differing, view of the paleoenvironment from that derived by analysis of the associated plant macrofossils. The regional component of the pollen data is in sharp contrast to the locally oriented macrofossils. A total of 84 macrofossil taxa and 47 pollen taxa were identified; only 18 taxa were common to both. The low Index of Similarity, 0.4, indicates that the two sources of fossil information are providing different sets of paleobotanical data. When combined with plant macrofossils and good radiocarbon dating control, the pollen spectra derived from fossil middens are compatable with other paleoenvironmental sequences.  相似文献   

14.
Dissimilarity coefficients measure the difference between multivariate samples and provide a quantitative aid to the identification of modern analogs for fossil pollen samples. How eight coefficients responded to differences among modern pollen samples from eastern North America was tested. These coefficients represent three different classes: (1) unweighted coefficients that are most strongly influenced by large-valued pollen types, (2) equal-weight coefficients that weight all pollen types equally but can be too sensitive to variations among rare types, and (3) signal0to-noise coefficients that are intermediate in their weighting of pollen types. The studies with modern pollen allowed definition of critical values for each coefficient, which, when not exceeded, indicate that two pollen samples originate from the same vegetation region. Dissimilarity coefficients were used to compare modern and fossil pollen samples, and modern samples so similar to fossil samples were found that most of three late Quaternary pollen diagrams could be “reconstructed” by substituting modern samples for fossil samples. When the coefficients indicated that the fossil spectra had no modern analogs, then the reconstructed diagrams did not match all aspects of the originals. No modern analogs existed for samples from before 9300 yr B.P. at Kirchner Marsh, Minnesota, and from before 11,000 yr B.P. at Wintergreen Lake, Michigan, but modern analogs existed for almost all Holocene samples from these two sites and Brandreth Bog. New York.  相似文献   

15.
鸡西群城子河组时代的进一步探讨   总被引:9,自引:1,他引:9  
姜宝玉  冯金宝 《地层学杂志》2001,25(3):217-221,240
近年来 ,古生物工作者在鸡西群城子河组及其相当地层的生物化石研究方面取得了巨大的进展。在总结这些新的材料的基础上 ,通过与国外的化石组合进行对比 ,从海相双壳类、植物、孢粉及海相沟鞭藻化石等多方面的证据 ,尤其是根据 Thracia rotundata、Vectianella、Pseudaphrodina ricordeana等欧洲 Aptian阶重要的双壳类化石、被子植物及三沟类被子植物花粉的出现 ,城子河组的时代应为 Aptian期 - Albian期早期  相似文献   

16.
对海南岛乐东盆地白垩系进行了深入研究 ,将原报万组上部一套冲积相划分出来 ,新建长茅组 ;厘订后的报万组限定在长茅组之下 ,为一套河湖相沉积 ,二者为整合接触 ,含孢粉化石 ,时代为早白垩世最晚期到晚白垩世。  相似文献   

17.
石宁 《第四纪研究》1996,16(4):319-328
华北地区的云杉属和冷杉属在早上新世就有大量的发展。榆社盆地在4.4MaBP.时,云杉属在孢粉植物群中的含量达50%一70%,与云杉属同时发现的还有一些喜暖植物。根据化石和孢粉学证据、沉积条件、古地形及欧洲的旁证材料推测,上新世云杉属和冷杉属的生态习性与现代生活在寒冷地带的云杉、冷杉不同,它们是一些可以生长在相对暖湿气候条件下的种类。上新世以森林为主的植被在2.3MaB.P.时转变为疏林草原,亚热带植物基本迁离榆社盆地。云杉属和冷杉属不仅在孢粉植物群中大量减少,在木本植物中也降为次要组分。古植物的演化和迁移历史反映了冰期气候和东亚季风气候发展的历程。  相似文献   

18.
根据孢粉和植物化石组合面貌 ,结合岩性及岩相特征 ,论述焉耆含油气盆地红山地区长期存有争议的侏罗纪地层的时代归属 ,认为该区仅发育了中侏罗世地层 ,包括西山窑组和头屯河组 ,为本盆地的石油勘探提供了地层划分与对比的时代依据  相似文献   

19.
Sediments and fossil pollen of two short cores from Birket Qarun, Egypt, reflect Nile floods, lake levels, and agricultural developments of the last 325 yr, and demonstrate the potential of a long and detailed record from the Fayum Depression. The chronology of these cores is inferred by correlation of historic events with changes in the fossil and sedimentary records.Subangular clay clasts and blocky structure resulting from occasional exposure, drying, and reworking of lake sediments reflect low Nile floods of the mid-1600s. Abundant pollen of shallowwater, rooted aquatic plants provides evidence for continued low lake levels through the 1700s. A high lake level, resulting from the extreme Nile flood of 1817–1818, is recorded by hystrichospheres, reworked by wave action, from Eocene marine sediments exposed on the north shore of Birket Qarun.Political administration, as reflected in agricultural policy, is also recorded in lake history. Changing lake levels are, in part, correlated with canal neglect during Mamluk and Ottoman control, and renewed canal maintenance under the agricultural policy of Mohammed Ali. Increased cattail (Typha) pollen dates from perenial irrigation after 1873. Olive and date pollen, and pollen of newly introduced exotic trees, are abundant after 1930 as a result of accelerated introduction and cultivation of fruit, lumber, fuel, and windbreak trees following World War I. The sequence of introduction of exotic plants is reflected in the pollen of Zea mays, from the New World, followed by Casuarina from Southeast Asia and Australia, and Eucalyptus from Australia.  相似文献   

20.
孢粉聚集速率是描述孢粉产量的一个定量指标。多年冻土区孢粉聚集速率的确定受到冻胀作用的强烈影响。主要体现在两个方面:首先,野外测得的沉积物厚度是冻胀后的数值,显然偏大,因而影响到沉积物沉积速率的计算。其次,样品中分凝冰透镜体的存在,影响到孢粉样品体积的测定。由于孢粉聚集速率是一个包含沉积物沉积速率及孢粉样品体积的多变量函数,因而冻胀作用对孢粉聚集速率的测定产生显著影响。加拿大育空西南部一条冻土钻孔剖面的孢粉资料表明,冰分凝引起的冻胀作用是导致孢粉聚集速率误差的主要因素。  相似文献   

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