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1.
在东昆仑西端布喀达坂峰地区二叠纪地层中首次发现陆相孢粉与海相疑源类化石一起保存的孢粉—疑源类化石组合。经对两个样品较为丰富的孢粉型化石研究后发现,上部组合以裸子植物花粉占优势,双囊无肋花粉最多,可与塔里木盆地的卡伦达尔组的孢粉组合做粗略的比较,但组合中出现了时代偏晚的Ephedripites及Taeniae-sporites,因此,研究区马尔争组中段复理石地层的时代当为中二叠世—晚二叠世。  相似文献   
2.
Based on a nearly complete lower jaw from the Early Cretaceous of Liaoning Province, a new ctenochasmatid pterosaur: Liaoxipterus brachyognathus gen, et sp. nov. is erected. Liaoxipterus brachyognathus is different from any known pterosaurs with skulls preserved from western Liaoning Province and its peripheral areas in that the anterior part of the mandibular symphysis is expanded, being widest between the fourth alveolus of each side. Liaoxipterus brachyognathus is assigned to Ctenochasmatidae based on the following characters: the rounded anterior end of the lower jaw is spatulated and dorsoventrally flattened and marked heterodonty in the dentition is absent. It differs from other ctenochasmatid pterosaurs in having relatively small number of teeth. Liaoxipterus is distinguished from some ornithocheirids, which have expanded anterior parts of the mandibular symphyses, such as Anhanguera piscator,Coloborhynchus robustus in which the teeth of the new pterosaur are not as variable.  相似文献   
3.
An almost complete juvenile dinosaur skull with lower jaw was discovered from the Early Cretaceous Yixian Formation in Beipiao, Liaoning Province, China. Here, the specimen is described and a cladistic analysis is performed in order to find its phylogenetic relationships. The result shows that this specimen represents a new genus of Psittacosauridae, Hongshanosaurus houi, gen. et sp. nov., and confirms the monophyletic status for Ceratopsia and Marginocephalia. However, Heterodontosaurus is found to be the sister taxon to Marginocephalia, rather than a basal Omithopoda.  相似文献   
4.
The Marattiales is one of the oldest lineages of vascular plants with extensive fossil records dated back to the Carboniferous. Understanding the fossil diversity variation and distribution pattern is helpful for exploring the evolutionary history of this fern group. In this work, the preliminary analysis of diversity change and distribution of the Mesozoic Marattialean fossil records in China are reported covering the Triassic and Jurassic periods based on available published data. In addition, a brief discussion is made regarding to the potential causes for these variation and distribution of this fern group.  相似文献   
5.
正 INTRODUCTION In recent years many Cenozoic fossil vertebrates have been discovered at widely scattered localities. In a previous paper [10] we have already given a  相似文献   
6.
Character, Age and Ecology of the Hezheng Biota from Northwestern China   总被引:4,自引:0,他引:4  
1 Introduction In recent years, field works in the Hezheng area resulted in an explosive growth of new knowledge of Chinese mammalian faunas of the Late Cenozoic. A continuous sedimentary sequence from the Oligocene to the Pleistocene is developed and exposed in the Linxia Basin, Gansu Province, which contains a large number of mammal fossils. The Hezheng area comprises almost the whole Hezheng County, the western half of Guanghe County, the southern half of Dongxiang County, Linxia C…  相似文献   
7.
Three sporopollen assemblages are recognized for the first time from the Cretaceous Yimin Formation in the Hailar Basin of eastern Inner Mongolia. They are (in ascending order): the lmpardecispora-Aequitriradites- Clawttipollenites assemblage; the Triporoletes-Pilosisporites-Asteropollis assemblage; and the Appendicisporites- Asteropollis-Tricolpites assemblage, distributed in Members 1, 2 and 3 of the Yimin Formation respectively. Recognition of this biostratigraphic sequence is very important for the division and correlation of the Yimin Formation in the basin. Meanwhile, the age of the Yimin Formation is considered to be Barremian to Early Albian based on the palynological data.  相似文献   
8.
A new genus and species of the family Tanystropheidae, Dinocephalosaurus orientalis gen. et sp. nov., is described based on a nearly complete skull. This is the first record of the order Protorosauria from China. It also represents the only known occurrence of Tanystropheidae outside Europe, the Middle East and North America. Dinocephalosaurus is quite similar to Tanystropheus from Monte San Giorgio, Switzerland. Primarily it is distinguished from Tanystropheus in the shape of the premaxilla, maxilla, jugal and parietal. Although the family Tanystropheidae is now referred to the order Protorosauria, the new material from China indicates that the archosauromorph affinities of tanystropheids need further investigation. The discovery of Dinocephalosaurus provides new clues for the study of the evolution and radiation of Protorosauria and Tanystropheidae. It is also important for the study of the eastern Tethyan Fauna and the paleobiogeographical relationship between Europe and southern China in the Triassi  相似文献   
9.
晚二叠世末的生物礁出露及其意义   总被引:15,自引:1,他引:15       下载免费PDF全文
贵州紫云长兴期生物礁礁前礁后和礁核的顶部都有白云岩。如下证据说明这种白云岩是潮上萨勃哈环境蒸发交代成因的:①这种白云岩的氧同位素值都比其灰岩原岩明显高得多,②其微量元素Sr、Fe的含量范围与陕甘宁盆地奥陶纪马家沟组马五段蒸发交代成因的泥晶白云岩的很相似,③白云石的晶体都是泥粉晶大小的自形—半自形晶体,④出现在礁体的顶部,⑤含有藻纹层、鸟眼构造、干裂缝等典型的潮坪环境构造。该礁的出露可能是海平面下降造成的。意大利的Dolomites盆地在二叠纪末由中陆架环境变浅到鲕粒滩环境,再到大气水环境。我国下扬子盆地在二叠纪末由碳酸盐补偿面以下的深水盆地变浅到碳酸盐补偿面以上的深水盆地。这些事实都说明,二叠纪末曾经发生全球性的海平面下降。这种大规模的海平面下降可能是引起二叠纪末生物礁集群绝灭的机制的表现之一。  相似文献   
10.
许家窑遗址是中国旧石器时代中期的一处重要考古遗址,按照地层古生物学常规判断,其地层为上更新统下部.许家窑遗址是泥河湾盆地乃至东亚地区发现的上更新统包含古人类及古哺乳动物化石和旧石器时代考古遗物最丰富的一个地层剖面.许家窑遗址的古地磁测年的分析存在重大理念误区,其"早更新世晚期至中更新世早中期"的断代结论令人难以置信.  相似文献   
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