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1.
在对杏104井,杏1—丁3—检323井和塔3井等3口优选井的介形类化石鉴定的基础上,通过对3口优选井涉及研究层位的87块介形类化石样品进行统计分析和编制介形类主要种的地层分布延限图、开展介形类生物地层学研究,建立松辽盆地晚白垩世嫩江组一段介形类化石带7个,包括新建介形类化石带1个,修订介形类化石带1个,并详细描述这7个介形类化石带。  相似文献   

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本文简要报道了发现于伊朗卡尚地区古近系的介形类,计16属6种、8比较种、9未定种及1亲近种。根据介形类化石组合面貌,并结合钙质超微、沟鞭藻和有孔虫化石组合,认为含介形类化石的地层时代为始新世至渐新世,推测其沉积环境为正常浅海大陆架环境,而且为温暖浅海内陆架。  相似文献   

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本文首次报道了南京附近中三叠统中的海相介形类化石共4属7种,其中1新种Judahella longtanensis和2未定属种Gen.et sp.1及Gen.et sp.2;与介形类化石共生的还有海相瓣鳃类化石Myophoria(Costatoria)goldfussi mansuyi Hsü.此介形类动物群与贵州郎岱中三叠统关岭组的非常相似。  相似文献   

4.
松辽盆地白垩纪介形类生物地层学特征   总被引:8,自引:0,他引:8  
本文详细论述了松辽盆地白垩系介形类属、种数量及壳饰变化在纵向上的分布规律和介形类组合特征的生物地层学意义。认为介形类属的分布是岩石地层组划分的重要依据,种的分布控制了岩石地层段的划分,并可将萨尔图油层、葡萄花油层和高台子油层进一步细分。同时指出松辽盆地介形类的盛衰与湖盆的发育关系密切,介形类的演化周期与湖盆的发育、收缩和沉积旋回相一致,在湖盆最发育的时期,也是介形类繁盛的高峰,湖盆发育的初期和末期,往往是介形类的发生和衰退期。  相似文献   

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西藏改则盆地新生代陆相康托组地层发育,记录了青藏高原腹地始新世气候变化和隆升历史。本文通过对改则盆地中南部改则县嘎热村康托组剖面进行系统的采样和室内处理,获得363个介形类个体,共鉴定11属27种(包括1个未定种)。通过研究区介形类动物群的特征分子Heterocypris igneus及与东濮、渤海、华北、江汉等地区介形类动物群对比研究,认为康托组上部的沉积时代应为晚始新世。本文首次报道了改则盆地康托组的介形类动物群面貌,据介形类组合厘定了康托组沉积时代,为研究青藏高原腹地新生代地层提供了基础资料。  相似文献   

6.
四川盆地白垩纪介形类组合   总被引:1,自引:0,他引:1  
本文描述了四川盆地中江地区城墙岩群之上、嘉定群之下古店组的介形类化石,计7属3亚属、9种2亚种,其中4新种和2新亚种。通过这些化石的研究,并在笔者《川南、黔北嘉定群的介形类》(1982)及《四川盆地城墙岩群的介形类》(待刊)的基础上,将四川盆地白垩系红层的介形类划分为五个组合。自上而下为(一)  相似文献   

7.
湖南湘乡上泥盆统佘田桥组介形类   总被引:2,自引:1,他引:1  
本文首次报道了湖南湘乡上泥盆统佘田桥组介形类化石,共有18属35种及未定种,其中包括11新种。通过与国内外泥盆纪和早石炭世介形类进行比较表明,它们与下伏的中泥盆统棋梓桥组介形类组合和上覆的上泥盆统锡矿山组介形类组合均有明显的差别,该介形类动物群的发现,为佘田桥组的地质时代的确定及地层的划分对比提供了新的古生物依据,并对研究介形类动物群的演化增加了新的资料。  相似文献   

8.
海南岛中、新生代某些淡水介形类和古气候   总被引:3,自引:0,他引:3  
本文应用数理统计的方法,描述了介形类5属10种,其中5新种,对含化石层的时代作了讨论。本文还从介形类的分布、大小变异方面论述了古气候。  相似文献   

9.
松辽盆地嫩江组一段富含介形类化石,是系统研究Santonian期陆相介形类的理想层位。论文对中央坳陷区D80井嫩一段的介形类化石进行了系统的分类、生物地层和壳体特征分析。鉴定出介形类化石11属30种,划分出6个介形类化石带,并与前人的研究结果进行了对比;描述了该段介形类化石的壳体结构,共识别出4种壳饰类型,8种壳形结构,基于介形类壳体特征和其他证据,初步探讨了该时期湖盆湖平面的变化特征,显示出嫩一段时期松辽湖盆湖平面经历了由深逐渐变浅的过程。  相似文献   

10.
介形类不仅是鱼类的天然饵料,还是监测水域环境污染的指示生物,尤为研究地层对比及沉积环境具有重要意义的化石介形类的参考材料。研究现今生活的介形类的生活环境,更可为深入研究化石介形类的古生态及古地理等,提供重要的科学依据。化石介形类的研究与我国地质学、古生物学和油、气田的勘察、钻探、开发都有密切关系。四川省的介形类Brehm(1923)只报道了一个亚种,陈受忠(1982)记述了6种。作者经过最近数年的采集调查,在收集到的标本中已鉴定出1科11属18种。(见表),其中普通泥介虫、棘列泥介虫、角突泥介虫、青春腺状介虫、半球腺状介虫、…  相似文献   

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It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.  相似文献   

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Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.  相似文献   

18.
Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.  相似文献   

19.
肝癌中HBV和HCV基因和抗原的分布及意义   总被引:1,自引:0,他引:1  
采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细  相似文献   

20.
For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.  相似文献   

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