A New Species of the Extinct Genus Schizolepis from the Jurassic Daohugou Flora, Inner Mongolia, China with Special Reference to the Fossil Diversity and Evolutionary Implications   总被引：1，自引：0，他引：1  

ZHANG Jianwei  Ashalata D''ROZARIO  YAO Jianxin  WU Zhenjie  WANG Lijun 《《地质学报》英文版》2011,85(2):471-481

Schizolepis daohugouensis sp. nov. is described from the Jurassic sediments of Daohugou flora, from Ningcheng County, Inner Mongolia Autonomous Region, China. The female cone is slender, cylindrical in shape, seed scale complexes are loosely and helically arranged on the cone axis at intervals of 3–5 mm. The seed scales are bilobed and divided almost from the base; the scales have no evident petiole but an articulation at the region of attachment to the cone axis. Each lobe of the seed scales is oval in shape, widest at the lower middle part; lobes are obtusely pointed with entire margins. Bract scale is fan shaped. Based on the records of Schizolepis, this is the first report of the occurrence of female cone of Schizolepis with the seed scales, the winged seeds and vegetative branches preserved together in the Jurassic deposits. The new discovery provides evidence that confirms the phylogenetic position of Schizolepis to the extant Pinaceae.  相似文献   

云南罗平生物群产出层位沉积微相及其化石富集规律          下载免费PDF全文

白建科尹福光  张启跃 《中国地质》2011,38(2):393-402

云南罗平上石坎剖面是产出罗平生物群的代表性剖面。参考Wilson的标准微相模式,从产化石层位识别出6种沉积微相:灰泥灰岩、生屑粒泥灰岩、粪球粒-生屑泥灰岩、纹层状泥晶灰岩、生屑泥粒灰岩和砾屑灰岩。通过在化石采掘现场对化石富集层位的统计,将产化石层位细分为生物群上层段UFH(Upper Fossil Horizon)和生物群下层段LFH(Lower Fossil Horizon),并进一步探讨了每个层段中沉积微相与化石富集规律的关系,发现化石富集程度高的层段主要发育灰泥灰岩、生屑粒泥灰岩、粪球粒-生屑泥灰岩、纹层状泥晶灰岩等4种沉积微相。这种沉积微相组合主要发育在深水、低能的台内盆地环境中,环境水体的滞留、缺氧给生物埋藏提供了良好的条件。  相似文献   

Two New Fossil Sawflies (Hymenoptera, Xyelidae, Xyelinae) from the Middle Jurassic of China   总被引：1，自引：1，他引：0  

WANG Mei  Alexandr P. RASNITSYN  and REN Dong 《《地质学报》英文版》2014,88(4):1027-1033

Two new genera with two new species of sawflies, Cathayxyela extensa gen. et sp. nov. and Aequixyela immensa gen. et sp. nov., from the Middle Jurassic Jiulongshan Formation of southeastern Inner Mongolia, China, are assigned to the subfamily Xyelinae （Hymenoptera, Xyelidae）. Cathayxyela gen. nov. can be distinguished by the third antennal article longer than the head; mesoprescutum and mesoscutellum nearly equal in length; the forewing with Sc meeting C before the junction of 1-M and 1- Rs; a weak and narrow pterostigma; and 3-Cu at least 1.5 times longer than the lm-cu. Aequixyela gen. nov. is characterized by the third antennal article nearly as long as the head; the forewing with Rs＋M approximately equal to 2-Rs in length; 2m-cu inclined toward the wing base and nearly reaching the middle of cell 3rm; lm-cu as long as the 2-Cu and 3-Cu; and the cell 2cua of regular hexagonal shape.  相似文献   

贵州遵义松林寒武系底部热液喷口及与喷口相关生物群特征   总被引：22，自引：0，他引：22       下载免费PDF全文

杨瑞东  朱立军  高慧  张位华  姜立君  王强  鲍淼 《地质论评》2005,51(5):481-492

贵州遵义寒武系底部黑色页岩中含Mo、Ni、U等重金属的富集层，它们一直被认为与热水沉积作用有关。本文通过对贵州遵义松林小竹一带的寒武系底部地层的系统的岩石、矿物、地球化学研究，认为遵义松林小竹一带寒武系底部黑色页岩中富含Mo、Ni、U等重金属层属于热液（水）喷流沉积，主要依据有：①含大量的黄铁矿、针镍矿、硫钼矿及较多的锑硫镍矿、黄铜矿、闪锌矿、重晶石、石英、石膏等矿物；②具有大量的同生砾屑，砾屑成分为黑色碳质体和碎屑状黄铁矿、针镍矿、硫钼矿等矿石，它们堆积成层状结构，碎屑呈被撕裂状、棱角状、熔蚀港湾状等结构，球状、脸盆状、枕头状等构造，它们类似海底喷流沉积；③硅同位素、锶同位素、Re／Os值、Th／Sc值、Th／U值都表明有深部物质加入；④黑色岩系中夹碳酸盐岩透镜体，碳同位素具有强烈负异常特征，表明有热液作用；⑤超强富集元素Mo、As、Se、Re和T1都属于典型的气相迁移元素，而钼是典型的高温气相迁移元素，暗示了可能存在火山射气作用；而强富集的Ni、U、Au、Ag、PGE元素组合是超基性岩浆活动的产物，表明有热液活动。研究发现在热液（水）喷流沉积形成的富集Mo、Ni、U等重金属硫化物层之上，产出丰度大、分异度低、含大型海绵类、双壳类、菌藻类和少量大型蠕虫化石的生物群，它的特征与现代太平洋海底热喷口附近的生物群类似，因此认为遵义小竹一带寒武系底部生物群属于与海底热喷口相关生物群，这一新发现对研究寒武纪生态和生物爆发具有重要意义。  相似文献   

华北晚侏罗世—早白垩世风成砂沉积及其古地理和古生态学意义^*   总被引：2，自引：1，他引：1       下载免费PDF全文

许欢  刘海  柳永清  旷红伟  刘燕学  彭楠  董超  薛沛霖  徐加林  陈军 《古地理学报》2013,15(1):11-30

华北晚侏罗世—早白垩世风成砂主要分布于鲁西蒙阴盆地上侏罗统三台组、辽西金—羊盆地上侏罗统—下白垩统土城子组、冀西北尚义盆地上侏罗统—下白垩统土城子组/后城组（原阎家窑组）、鄂尔多斯盆地下白垩统志丹群和甘肃下白垩统河口群。各地风成砂岩均具高角度大型—巨型板状、楔状交错层理及平行层理,分选较好—好,磨圆次棱角状—次圆状等沉积特征。对华北晚侏罗世—早白垩世风成砂赋存层位以及风成砂岩形成时代进行了对比,将风成砂主要划分为3个时期,即基末利期—贝利阿斯期、凡兰吟期—欧特里夫期和欧特里夫期—阿普特期,且从鲁西到甘肃风成砂岩形成时代逐渐变新。通过上述5个地区风成砂的古风向研究发现,当时西北风盛行,古地磁研究显示风成砂岩发育于N25°—N45°之间区域。根据当前全球风带分布特征,认为华北晚侏罗世—早白垩世处于西风带上,为行星风系所控制。通过对比南半球同期风成砂岩古风向研究,提出全球南北半球中纬度地区均处于西风带上。结合风成砂及相应层位沉积特征、沉积环境的研究,初步推测晚侏罗世—早白垩世,华北N30°以北地区为干旱寒冷气候,而N30°以南地区则干旱炎热,华北北部整体处于海拔较高的山地环境,山间盆地发育,火山活动频发。燕辽生物群与热河生物群的演替过程与风成砂沉积相耦合,体现了古地理、古环境对生物群发展的制约作用。  相似文献   

Bioconcentration and biomagnification of polybrominated diphenyl ethers (PBDEs) through lower-trophic-level coastal marine food web   总被引：2，自引：0，他引：2  

Kaoruko Mizukawa  Ichiro Takeuchi  Koji Omori 《Marine pollution bulletin》2009,58(8):1217-1224

Bivalves, crabs, fishes, seawater, and sediment collected from the inner part of Tokyo Bay, Japan, were measured for 20 polybrominated diphenyl ether (PBDE) and 5 polychlorinated biphenyl (PCB) congeners. To determine the trophic levels of the organisms, carbon and nitrogen stable isotope ratios (δ¹³C and δ¹⁵N) were also measured. Bioconcentration factors of PBDE and PCB congeners increased as the octanol-water partition coefficient (K_ow) rose to log K_ow = 7, above which they decreased again. Biomagnification of PCBs and several PBDE congeners (BDE47, 99, 100, 153 and 154) up the trophic ladder was confirmed by a positive correlation between their concentrations and δ¹⁵N. Other PBDE congeners showed a negative or no correlation, suggesting their biotransformation through metabolism. The more hydrophobic congeners of both PBDEs (Br = 2-6) and PCBs (Cl = 6-9) were biomagnified more. It thus appears that PBDEs are less biomagnified than PCBs.  相似文献   

建立云南罗平生物群地质公园刍议   总被引：1，自引：0，他引：1       下载免费PDF全文

谢韬  张启跃  周长勇  吕涛  楼雄英  刘伟  孙媛媛 《沉积与特提斯地质》2009,29(3):110-112

云南罗平生物群是继贵州关岭动物群之后的又一新发现。本文结合云南罗平生物群的特点,分析了罗平生物群的科学研究价值、审美学价值及其开发前景,认为建立地质公园具有一定的可行性和必要性。  相似文献   

Current Knowledge of Mesozoic Coleoptera from Daohugou and Liaoning (Northeast China)   总被引：4，自引：1，他引：3  

Alexander G. KIREJTSHUK  Alexander G. PONOMARENKO  Alexander A. PROKIN  CHANG Huali  Georgy V. NIKOLAJEV  and REN Dong 《《地质学报》英文版》2010,84(4):783-792

<正>The present paper is devoted to an overview on fossil Coleoptera studied from Inner Mongolia, Daohugou(Middle Jurassic,Jiulongshan Formation)and Liaoning(Upper Jurassic-Lower Cretaceous,Yixian Formation)deposited in Chinese collections.As a result,species of the tribe Sperchopsini and Hydrophilini from Hydrophilidae,families and subfamilies Silphidae,Syndesinae from Lucanidae,Pleocomidae,Trogidae, Trogissitidae,Pyrochroidae,Diaperinae from Tenebrionidae,and Cerambycidae were first registered in the Mesozoic and some families were defined as new.It was shown that many superfamilies represented in the Recent Fauna were formed within the Middle Jurassic and Lower Cretaceous.The materials examined confirm the hypothesis that Cucujiformian beetles are a younger group than other infraordera of Polyphaga(Staphyliniformia and Elateriformia)and,therefore,they appeared in the fossil record only in the late Mesozoic.It was shown and confirmed that most superfamilies appeared in the fossil records before Cucujoidea.The synonymy of Notocupes Ponomarenko,1964;Sinocupes Lin,1976,syn.nov.;Amblomma Tan,Ren et Liu 2005,syn.nov.;Euryomma Tan, Ren et Shih,2006,syn.nov.,non Stein,1899 and Ovatocupes Tan et Ren,2006,syn.nov.;synonymy of Tetraphalerus Waterhouse,1901 and Odontomma Tan,Ren et Ge 2006,syn.nov.;and synonymy of Priacmopsis Ponomarenko,1966 and Latocupes Tan et Ren,2006,syn.nov.are proposed.Sinorhombocoleus papposus Tan et Ren,2009 is transferred from the family Rhombocoleidae to Schizophoridae.Cervicatinius complanus Tan,Ren et Shih,2007 and Forticatinius elegans Tan,Ren et Shih,2007 are transferred from the family Catiniidae(suborder Archostemata)to superfamily Cleroidea(suborder Polyphaga:first among the family Peltidae and second as a closely related group to the latter family).The family Parandrexidae is transferred from the superfamily Cucujoidea to Cleroidea.The ecological circumstances of the past ecosystems and hypotheses of historical development of the order Coleoptera are discussed.The age of faunas examined is considered.The list of the taxa described from Daohugou and Liaoning is compiled.  相似文献   

黔东北及邻区新元古代陡山沱期岩相古地理特征   总被引：3，自引：0，他引：3       下载免费PDF全文

何明华  喻美艺  王约  袁良军  赵元龙  黄隆辉 《沉积与特提斯地质》2006,26(1):41-46

陡山沱早期,沉积环境自北西向南东可大致分为碳酸盐台地潮上坪-台缘浅滩相和浅海陆棚盆地相;陡山沱晚期,自北西向南东可大致分为开阔台地相区和深水陆棚-次深海相区。庙河型生物群的产出位于晚期开阔台地向深水陆棚-次深海过渡相区中的黑色页岩、硅质页岩中,其沉积环境为最大浪基面以下的宁静、贫氧环境,其沉积方式为悬浮沉积。  相似文献   

Habitat dynamics in the bed sediments of an intermittent upland stream     

Fiona J. McKenzie-Smith  Stuart E. Bunn  Alan P. N. House 《Aquatic Sciences - Research Across Boundaries》2006,68(1):86-99

  相似文献