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1.
文章报道四川天全沙坪、芦山双石、宝兴灵关等地的上三叠统须家河组中丰富的双壳类动物群,建立了一个以YunnanophorusPermophorus-Weiyuanella为特征分子的组合带,分析了双壳类化石组合特征,描述双壳类化石5新种(Pachycardiasichuanensis,Yunnanophorusbaoxingensis,Permophorustianquanensis,Waagenopernatumida,Myophoriopislingguanensis)。它的研究对四川盆地西部和西北部须家河组地度的划分和邻区对比以及古地理概况和煤系地层的认识,提供了新的素材。  相似文献   

2.
川北曾家地区二叠纪-早三叠世的生物地层研究表明,该区二叠系有4个生物带:Nankinelalata-Pisolinastaffelinoides组合带,Neoschwagerina-Verbeekinaverbeeki组合带,Codonofusiela-Reichelinachanghsingensis组合带和Pseudotirolites-Chaotianoceras组合带;下三叠统也有4个生物带:Claraiawangi-Ophiceras组合带,Claraiaaurita-Claraiastachei组合带,Eumorphotismultiformis-Entolium组合带和Tirolites组合带。在此基础上,结合火山沉积事件、沉积物注入和分布的明显变化及陆上暴露标志等的研究,建立了该区二叠系-下三叠统层序地层格架,划分出7个层序,并分析了相应的环境演变和不同的构造背景  相似文献   

3.
StudiesoftheSynthesisofBiomarkers(Part15〔1〕)Synthesisof1,3-Eicosanedioland1,3-Octacosanediol*LiTongshuang(DepartmentofChemist...  相似文献   

4.
对Fibonacci数列的一个重要性质:Fn+1Fn-1F^2n=(-1)^n(Cassini)公式进行了推广。由此推广给出Fibonacci数列的另一个重要性质:Fm+n=Fn-1Fm+FnFm+1的新证明,并得到任意两个Fibonacci数的平方和(差的)关系式。  相似文献   

5.
内蒙古巴丹吉林盆地额济纳旗凹陷中生代孢粉组合   总被引:2,自引:1,他引:1  
研究了内蒙古巴丹要盆地额济纳旗凹陷中生代地层的孢粉化石,建立了三个孢粉化石组合(Pinuspollenites-Cycadopites组合、高Classopollis组合、Cicatricosisporites-Classpollis组合)。  相似文献   

6.
介绍了新型反射式Si光电发射材料(Si-Na3Sb-Cs)-O-Cs,(Si-K3Sb-Cs)-O-Cs,(Si-csasb-Cs)-O-Cs和(Si-Na2KSb-Cs)-O-Cs的激活技术.给出了新型Si光电发射材料的逸出功、灵敏度及其稳定性并与Si和Na2KSb(Cs)光电材料的性能进行比较,简要讨论了影响灵敏度和稳定性的一些因素.叙述了为制备新型Si光电发射材料所设计并加工的碱金属源、锑源、氯源及其激活系统.  相似文献   

7.
新汶煤田上石炭统太原组中共含有5层海相灰岩,各层灰岩中均含有较丰富的类化石。经作者研究,根据它们的属种组成和在纵向上的分布规律建立了两个带三个亚带:Ⅱ.Triticitesboshanensis带;Ⅰ.Pseudoschwagerina带,此带又划分出三个亚带:3.Schwagerinavalida-Boultoniasimplicata亚带,2.Triticitesshandongensis-Montiparusthompsonianas亚带,1.Schwagerinaelkoensis亚带。对各带及亚带的类动物群特征进行了阐述,同时,对较低级的类动物群在层位上高于Pseudoschwagerina带的现象进行了探讨。并将本区所建立的化石带与华北部分地区相应的组合带进行了对比。  相似文献   

8.
报道了采自河北省青龙县老岭的5种和1变种河北新记录植物。它们是榛属的长苞榛CorylusheterophylaFisch.exTrautv.var.shenyangensisL.ZhaoetD.Chen,缬草属的黑水缬草ValerianaamurensisSmir.exKomarov,马兰属的马兰Kalimerisindica(L.)sch.-Bip.和裂叶马兰Kalimerisincisa(Fisch.)DC.,灯心草属的乳头灯心草JuncuspapilosusFranch.etSav.以及鸢尾属的玉蝉花IrisensataThunb.  相似文献   

9.
NARMAX模型辨识的直交化最小二乘新算法   总被引:1,自引:0,他引:1  
基于实际中常用的CGS(ClassicalGram-Schmidt)、MGS(ModifiedGram-Schmidt)、HT(HouseholderTransformation)及Givens算法,给出了1类改进的直交化最小二乘新算法,分别称之为改进的CGS、MGS、MHT及MGV算法,改善了原算法的数值稳定性.将改进算法用于非线性NARMAX模型辨识,构造出了1种新的模型结构与参数辨识的一体化算法.新算法基于逐步回归进行模型选项并消去模型中的冗余项,保证了最终模型的结构优化,并可给出比Bilings等算法精度更高的参数估计.仿真结果证明了文章中算法的优越性  相似文献   

10.
中国早石炭世的四射珊瑚可划分为六个组合带,自下而上依序为。1)Ceriphyllum elegatum    (MeniscophyllumxinjiAngense带大致与之相当),2)Caninia dorlodoti或Kassinella-  Lophophyllum densum,3)Cystohrentis或Enygmophyllum-Kakwiphyllum qingh-aiense,4)Pseudouralinia 或Siphonophyllia oppressa,5)Thysanophllum asiaticum或Orinastraea haitoutalaensis-Dorlodotia,6)Yuanophyllum.图乃阶和韦则阶的分界  或Orinastraea,6)Yuanophyllum.图乃阶和韦则阶的分界  划在Siphonophyllia oppressa带的顶部.YuAnophyllum带的时代自韦则晚期延伸至纳缪尔早    期。根据珊瑚动物群的特征区分出三个生物地理区,即天山-祁连区、巴颜喀喇-三江区和扬子  区,各区相应的代表分予分别为Siphonphyllia oppr?  相似文献   

11.
文章描述了西藏最西南部札达、噶尔地区双壳类化石2新种和1新亚种,并刊出部分双壳类化石图版。  相似文献   

12.
Chaohu is located in a deep part of carbonate ramp on the Lower Yangtze Block, which belonged to the low-latitude eastern Tethyan archipelago during the Early Triassic. Fossils were very rich in the Lower Triassic of Chaohu. Bivalves, ammonoids, conodonts were very common throughout the Lower Triassic, while fish fossils were generally rich in some beds of the upper part. It is one of the most typical sections for the Early Triassic chronostratigraphy in the world. Although various fossils had been studied in the 1980s and 1990s, recent studies based upon new and more detailed collections from the Lower Triassic of Chaohu showed that the conodont zonation needs revision. We collected Lower Triassic conodont fossils from continuous sections of the West Pingdingshan, North Pingdingshan and South Majiashan, Chaohu, Anhui Province, and updated zonations were made for each section. Eight conodont zones have been distinguished. They are, in ascending order, Hindeodus typicalis zone, Neogondolella krystyni zone, Neospathodus kummeli zone, Neospathodus dieneri zone, Neospathodus waageni zone, Neospathodus pingdingshanensis zone, Neospathodus homeri zone, and Neospathodus anhuinensis zone. The first occurrence of Neospathodus waageni eowaageni of the N. w. eowaageni subzone (i.e. the base of the N. waageni zone) is suggested as the marker to define the Induan-Olenekian boundary.  相似文献   

13.
北羌塘盆地北部晚侏罗世索瓦组地层古生物新资料   总被引:2,自引:0,他引:2  
在北羌塘盆地北部乌兰乌拉湖地区测制了多条晚侏罗世索瓦组剖面,讨论了该区索瓦组的岩性组合特征、沉积环境及空间变化规律.首次系统研究了索瓦组双壳类、层孔虫及珊瑚化石的组合特征及地理分布.建立了一个双壳类生物组合带,一个层孔虫组合和一个珊瑚组合.确定索瓦组的地质时代为晚侏罗世牛津期-基默里奇期.  相似文献   

14.
Based upon the new data of spore-pollen, plant and bivalve fossils, the coal-bearing strata in the Liupanshan Basin, Ningxia Hui Autonomous Region, Northwest China, which were formerly assigned to the Middle Jurassic Yan’an Formation, are divided into two parts in the present study. The major part is assigned to the Upper Triassic and the overlying part remains in the Jurassic. The new division is of significance to the oil-gas exploration of the basin and the interpretation of the sedimentary and tectonic history and the geographic environment of Liupanshan area during the early Mesozoic.  相似文献   

15.
西藏聂拉木县聂聂雄拉地区,早、中侏罗世地层较发育,地层中化石属 种繁多。地层划分为下侏罗统“普普嘎组”,中侏罗统聂聂雄拉组和拉弄拉组。作者研究了该区旱、中侏罗世的双壳类动物群40多属80多种。描述双壳类化石8新种:Tancredia(T.)nyalamensis,Hiatellasubtrigona,Pronoella(P.)minima,Opis(O.)curvus,Costigeruillia tetracostata,Weyla costalliformisa,Entolium obliquus,E.subfilosus,刊出部分化石图版,简述双壳类化石组合特征。它的研究对该地区旱、中侏罗世地层划分对比,生物地理分区和动物群特征的认识都具有一定的理论与实践意义。  相似文献   

16.
在世界范围内,"贵州三叠纪化石群"是为数不多的三叠纪化石群产地之一。该生物群是海生爬行动物类、海百合类、脊椎动物类、无脊椎动物类、鱼类、植物类等为一体的生物群,世界罕见。为探究该化石群具有的潜在遗产价值,以对比的思想为指导,从化石群的古地理与古生态环境等几个方面为切入点,采用对比分析的方法,与世界范围内有关三叠纪生物群的世界遗产地或重要的、具有可比性的三叠纪生物群进行对比,探究其潜在的世界遗产价值和全球唯一性。结果表明:该地区在古地理上位于特提斯洋的东段,属于西特提斯古地理构架与东太平洋古地理构架的过渡地区,具有特殊性。同时,记录了三叠纪安尼期—卡尼期的连续完整的地质演化史与生物演化过程,代表着中生代古生物演化的重要阶段,在世界自然遗产提名中具有突出普遍价值。  相似文献   

17.
关岭动物群埋藏环境初探   总被引:3,自引:0,他引:3  
对贵州省关岭县新铺乡毛凹剖面上三叠统瓦窑组底部岩性薄片进行了观察,根据生物含量的多少,可以区分出3种岩性:泥晶灰岩、含生屑泥晶灰岩、泥晶生屑灰岩。结合生物群组合面貌分析,认为关岭动物群埋藏于水体较深且宁静、低能、盐度正常、气候温暖的环境下。同时牙形石Paragondolella属、双壳类Halobia属剖面分布暗示了水体还原事件的发生。结合古氧化还原度敏感元素的丰度变化和化石分异度分析,认为动物群得以完美埋藏,有2点是至关重要的因素:(1) 沉积速率慢,岩性结构致密,颗粒细小,使生物能完整沉积;(2) 爬行动物化石层、化石分异度曲线和w(Ce)/w(La)比值大于2,且正向漂移呈现一一对应关系表明,缓慢沉积过程中,水体还原缺氧给生物埋藏提供了必须的氧隔离层,防止死亡生物氧化分解。  相似文献   

18.
An aquatic fern leaf, Flabellariopteris mii Sun gen. et sp. nov. from the Late Triassic of Western Liaoning, China, is described and proposed as the type species of the new morphortaxon of the Marsileaceae. The fossil leaves are preserved as impression. No fertile and rhizomatic materials are found. The leaves attached at a common point on the top of the petiole are composed of two leaflets joined basally in an opposite arrangement. The petiole is slender. The leaflet is fan-shaped or semi-circular, and commonly divided into four wedge-shaped lobes. Terminal margin of lobes is usually incised, incisions shallow or deep, with bluntly rounded or notched apex. The veins are conspicu- ously dichotomous, but anastomoses and marginal vein are absent. The unique morphological features, including two- parted thin leaflets, size, shape, veins and slender petiole, indicate that the present specimen represents an aquatic fern, which is the oldest fossil record and the first megafossil evidence assignable to Marsileaceae from the Triassic floras.  相似文献   

19.
论述二叠纪末生物大灭绝事件后的一次全球性快速海侵。以往认为该海侵发生在三叠系底部,但新的材料表明属二叠纪末期。在国际标准层型剖面浙江长兴煤山地区海侵高潮(海平面快速上升)见于26层黑色页岩,层内含菊石Hypophiceras组合,双壳类Claraia? baoqingensis和二叠纪牙形刺;在浙江黄芝山剖面海侵见于大灭绝层之上的Claraia cf.bioni层,此层也可与克什米尔Guryul Ravine剖面E_1层(Claraia bioni带)对比;在北极区,海侵层相当于Otoceras Concavum 层。还讨论了康滇古陆东缘和华北古陆南缘此次海侵的影响,这些古陆边缘地区陆相沉积(“卡以头段”和石千峰群)中夹的海相层不是三叠纪,而是二叠纪。  相似文献   

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