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1.
A new pterosaur Archaeoistiodactylus linglongtaensis gen.et sp.nov.is erected based on an incomplete skeleton with a partial skull and lower jaw.The new taxon is characterized by circular tooth sockets of anterior mandibular teeth,the anterior teeth of the upper jaw bearing posteriorly directed crowns,a relatively short metacarpus,and wing phalanges 2 and 3 and the tibia subequal in length.It possesses some plesiomorphic characters such as short metacarpals and circular tooth sockets.The pointed jaw tip present in the new taxon indicates that the expanded jaw tips of later istiodactylids are a derived character state,and the new taxon represents the first istiodactylus-like pterosaur found from the pre-Late Jurassic deposits,which provides a key role in our understanding the origin and evolution of the known istiodactylid pterosaurs.Archaeoistiodactylus is regarded as the ancestor form of the known istiodactylid pterosaur.  相似文献   

2.
The Berezovsk coal mine in western Siberia has yielded the most diverse Middle Jurassic limnic and terrestrial vertebrate assemblage of Asia.The vertebrate remains were recovered by screen washing from flood-plain deposits on top of a thick coal seam of the Bathonian Itat Formation.A total of 29 vertebrate taxa has been recorded so far,including hybodontiform sharks,acipenseriforms,palaeonisciforms,amiiforms,dipnoans,anu-rans,caudates,turtles,squamates,choristoderans,crocodyliforms,pterosaurs,dinosaurs,tritylodontids,and a diverse mammaliaform and mammalian assemblage (eleutherodontids,docodontans,?amphilestids,dryo-lestids,and zatherians).The caudates are among the oldest in the fossil record and the anurans represent the oldest Asian record of this group.Among the mammals,Anthracolestes is the oldest and most basal known mem-ber of Dryolestidae and so far the only record from Asia.The vertebrate assemblage from the Berezovsk coal mine is very similar to that from the British Forest Marble Formation (Bathonian)and suggests a limited provin-cialism in the Middle Jurassic Laurasian landmass.  相似文献   

3.
A new pterosaur Archaeoistiodactylus linglongtaensis gen. et sp. nov. is erected based on an incomplete skeleton with a partial skull and lower jaw. The new taxon is characterized by circular tooth sockets of anterior mandibular teeth,the anterior teeth of the upper jaw bearing posteriorly directed crowns,a relatively short metacarpus,and wing phalanges 2 and 3 and the tibia subequal in length. It possesses some plesiomorphic characters such as short metacarpals and circular tooth sockets. The pointed jaw tip present in the new taxon indicates that the expanded jaw tips of later istiodactylids are a derived character state,and the new taxon represents the first istiodactylus-like pterosaur found from the pre-Late Jurassic deposits,which provides a key role in our understanding the origin and evolution of the known istiodactylid pterosaurs. Archaeoistiodactylus is regarded as the ancestor form of the known istiodactylid pterosaur.  相似文献   

4.
大量茨康类压型化石在鄂尔多斯盆地中侏罗世含煤地层延安组中被发现。本文根据叶外部形态和表皮构造特征,首次发现拟刺葵属的苦戈维尔叶亚属Phoenicopsis ( Culgoweria),并建立了鄂尔多斯拟刺葵(苦戈维尔叶)(新种) Phoenicopsis ( Culgowaria) ordosensis sp.nov。新种代表了该亚属在我国中侏罗世的第一个化石记录,为研究其地质、地理分布提供了新的证据,也为研究该类植物在欧亚大陆中侏罗世的多样性增添了新内容。  相似文献   

5.
The Yixian Formation is a series of volcanic-sedimentary rocks in Biepiao area of Liaoning Province.It is mainly composed of basic and intermediate-basic volcanic lava,pyroclasts and terrestrial sedimentary rocks.Based on the regularity of volcanic activity,the Yixian Formation was divided by the present authors into four members in ascending order:the first member is of basal conglomerate,basic and intermediate-basic volcanic rocks;the second member is of lake phrase sedimentary rocks,or in another word,precious fossil-rich sedimentary beds;the third is of basic volcanic rocks;and the fourth is of upper conglomerate.Field mapping and comprehensive study also indicate that there are abundant vertebrate fossils (mainly of Psittacosaurus) in the first member of the Yixian Formation,and the Jehol Biota (including Sinosauropterxy,Confuciusorns sanctus,Archaefructus,etc.) is yielded in the second member of Yixian Formation.From west to east,the volcanic activity of Yixian Formation changed regularly from early to late,and from basic and intermediate-basic to acid (alkali).  相似文献   

6.
IntroductionArchaefructus ,theoldestknownangiosperms ,werefoundfromtheUpperJurassicJianshangouFormation (i.e .theformerlowerpartofYi  相似文献   

7.
Androecium of the earliest known flowering plant Archaefructus liaoningensis was found from the Upper Jurassic Jianshangou Formation of western Liaoning, China. The androecium consists of numerous stamens bearing in pair on the reproductive axes below conduplicate carpels. The stamens are composed of a short filament and basifixed anther for each. Monosulcate pollen in situ are found from the anthers. The characters of the androecium reveals that Archaefructus are probably protandrous, and the paired stamens and monosulcate pollen appear to indicate that Archaefructus, as primitive angiosperms,might be derived from extinct seed -ferns during the Older Mesozoic. Archaefructus is considered Late Jurassic in age.  相似文献   

8.
Androecium of the earliest known flowering plant Archaefructus liaoningensis was found from the Upper Jurassic Jianshangou Formation of western Liaoning, China. The androecium consists of numerous stamens bearing in pair on the re-productive axes below conduplicate carpels. The stamens are composed of a short filament and basifixed anther for each. Mo-nosulcate pollen in situ are found from the anthers. The characters of the androecium reveals that Archaefructus are probably protandrous, and the paired stamens and monosulcate pollen appear to indicate that Archaefructus, as primitive angiosperms, might be derived from extinct seed-ferns during the Older Mesozoic. Archaefructus is considered Late Jurassic in age.  相似文献   

9.
A new dinosaur tracksite was discovered in a steeply inclined sandstone layer of the Middle Jurassic Sanjianfang Formation in the Shanshan area of the Turpan Basin. The site is the first record of dinosaur footprints from Xinjiang Province in northwestern China. More than 150 tridactyl theropod dinosaur footprints are preserved as positive hyporeliefs on the lower bedding plane of a fine-grained sandstone body. Most of the footprints are isolated and appear to be randomly distributed. Some show well defined phalangeal pads, heels and rarely indistinct impressions of the distal part of the metatarsus. Two distinct morphotypes are present: a larger type with relatively broad pads shows similarities to Changpeipus and Megalosauripus, and a slightly smaller, slender and gracile type which is similar to Grallator, Eubrontes and Anchisauripus. In both morphotypes, digit III is the longest with a length between 11.4 and 33.6 cm. A single imprint shows prominent scratches, probably formed during slipping of the track maker.  相似文献   

10.
11.
内蒙古雅布赖盆地红柳沟中侏罗统沉积相及沉积环境研究   总被引:1,自引:0,他引:1  
野外考察发现,雅布赖盆地红柳沟发育一套较完整的中侏罗统扇三角洲沉积地层。其中沉积亚相有扇三角洲平原、扇三角洲前缘及前扇三角洲亚相;沉积微相包括辫状河道、天然堤、决口、沼泽、水下分流河道、水下分流河道间、河口坝、席状砂等沉积微相。从沉积构造特征分析可以看出,河道沉积发育于水动力条件较强的沉积环境,扇三角洲前缘河口坝沉积发育于强与弱水动力条件交替出现的沉积环境,而前扇三角洲则在比较稳定的水动力条件下沉积。对野外6个泥岩样品的微量元素化验结果用蜘蛛图解分析处理,得到样品所含微量元素V、Sr、Rb、B相对富集,而Zr、Cr、Ni相对亏损。通过对该地区样品w(Fe2+)/w(Fe3+)及气候指数计算表明,当时为弱氧化、半干旱的沉积环境。  相似文献   

12.
More than 35 species belonging to 22 genera of fossil plants are recognized by the authors from the Shansonggang flora in the 8hansonggang Basin of Jilin, China. Among them, the coexistence of Coniopteris and Cycadocarpidium demonstrates that the present flora possesses the characters of the early assemblage of Early Jurassic floras in Eurasia. Therefore, the age of the Shansonggang flora is considered the Early Jurassic.This study would be beneficial for better understanding the paleoecological and paleoclimatic characteristics of the Shansonggang Basin. Based mainly on the characters of the flora, the authors suggest that the Lower Jurassic coal-bearing strata, the Shansongang Formation, should namely be renewed.  相似文献   

13.
1IntroductionThe Shansonggang Basin, one of the Mesozoic coal-bearing basins in northeastern China, is located in southern Jilin Province, China and covering about 30 km2(Fig.1). The basin is lying in the northwest-ern margin of the Longgang anticline, just opposite to the Yihe Basin which lies in the southeastern margin of the anticline. During 1940s~1970 s, a lot of work on the survey of coal geology was made in the basin, but there has been a little knowledge about the plant fossils…  相似文献   

14.
The Jianchang Basin is one of the main localities of the precious fossils of Jehol Biota in western Liaoning. The fossil-bearing horizons are mainly in the Yixian- and Jiufotang formations. In the Weijialing- Yaolugou of southwest Jianchang Basin, many precious fossils have been found at Luojiagou Bed of the 2nd Member of the Yixian Formation and at Xidian Bed of the 1 st member of the Jiufotang Formation. The geologic setting, sedimentary environment and paleogeography of the precious fossil-bearing beds were also studied.  相似文献   

15.
The petrogenesis and geodynamic setting of the Late Jurassic Baita porphyry quartz monzodiorite in Xingcheng--Liaoxi area provide information for understanding the Mesozoic tectonic evolution of the northeastern North China Craton. In this paper, geochronological, whole-rock geochemical, and in-situ zircon Hf isotopic analyses of Baita porphyry quartz monzodiorite were investigated to constrain the crystallization age and petrogenesis. Zircons exhibit typical oscillatory zoning in cathodoluminescence images and show relatively high Th/U ratios(0.78--1.62), and U-Pb analyses indicate that these rocks were crystallized during the Late Jurassic(159±1 Ma). Geochemically, they are characterized by high contents of SiO_2(65.21 wt%--65.31 wt%), Al_2O_3(16.29 wt%--16.31 wt%), Sr(521×10~(-6)-539×10~(-6)), and Sr/Y ratio(45.1--47.8) but low Y(10.9×10~(-6)-12.0×10~(-6)), with obvious adakitic geochemical affinities. These above-mentioned findings, combined with their negative ε_(Hf)(t) values(-21.7 to-20.2), corresponding two-stage model age(T_(DM2)) of 2 579--2 484 Ma, as well as low MgO(1.38 wt%--1.39 wt%), Cr(18.5×10~(-6)-19.5×10~(-6)) and Ni(9.45×10~(-6)-9.46×10~(-6)) values, indicate that Baita porphyry quartz monzodiorite may be generated by partial melting of the Neoarchean-Paleoproterozoic thickened basaltic lower crust. Based on the results from this study and pre-vious regional studies, it is concluded that Baita porphyry quartz monzodiorite was spatially related to the westward subduction of the Paleo-Pacific plate.  相似文献   

16.
The Jianchang Basin is one of the main localities of the precious fossils of Jehol Biota in western Liaoning. The fossil-bearing horizons are mainly in the Yixian- and J iufotang formations. In the Weijialing-Yaolugou of southwest Jianchang Basin, many precious fossils have been found at Luojiagou Bed of the 2nd Member of the Yixian Formation and at Xidian Bed of the 1st member of the Jiufotang Formation. The geologic setting, sedimentary environment and paleogeography of the precious fossil-bearing beds were also studied.  相似文献   

17.
In the Middle Jurassic,a large-scale tectonic-magmatic activities and hydrothermal mineralization occurred in the eastern Jilin province.The deposit types consist of the orogenic gold deposit,porphyry molybdenum deposit and skarn gold deposit,etc.,which constitute regional hydrothermal metallogenic series.The magmatic bodies related to mineralization belong to calc-alkaline series,which are characterized by active continental margins.The above-mentioned different types of deposits formed in a uniform tectonic setting,which resulted from the combined processes between the subduction of Pacific plate under the Eurasia plate and the persistent post-collisional convergent forces between the North China plate and the Siberian plate.The mineralizations were happening in the deceleration period,after which Paleo-Pacific plate was strongly subducted under the Eurasia continental block,i.e.transition period from compression to extension.  相似文献   

18.
In recent years,many fossil vertebrates,including feathered dinosaurs,have been discovered at Nanshimenzi village,Gangou Town,Qinglong County,Hebei Province,China.A geological section including the fossil-bearing strata was measured at Nanshimenzi,to determine the exact geological age and sedimentary characteristics of the section,and a new lithostratigraphic unit was named as the Nanshimenzi Bed.The Nanshimenzi Bed is about 56.6 m in thickness,mainly consisting of gray sandstones and siltstones and containing fossil vertebrates and several coal streaks.On the basis of survey and comparison,the Nanshimenzi Bed should be assigned to Tiaojishan Formation and probably to the upper part of the formation.  相似文献   

19.
Middle and Late Cambrian trilobite faunas from the Dama section in western Hunanare are composed of 63 genera and subgenera, 84 species, and two forms of gen. et sp. indetermined. Which include a mixture of cosmopolitan agnostoids and polymeroids. Three new species,Hardyoides damaensis,Meringaspis damaensis and Rhyssometopus (Rodtrifinis) nitidus, are described by present author in 2004. Besides, Erixanium is recognised for the first time in study area, which is significant for biostratigraphical correlation of the Late Cambrian in the Austalo-Asia region. According to distribution regularity vertical, the Middle and Late Cambrian trilobites can be divided into 9 trilobite communities for the Dama section. Based on the trilobite communities analysis, the author concludes that from the east Mt. Lailong to Dama through Fenghuang, further east, reach in Chenxi,the palaeoenvironments were changed from a shallow-water of oxygen-rich (platform margin slope ) into a deep-water of oxygen-poor setting (basin).  相似文献   

20.
Middle and Late Cambrian trilobite faunas from the Dama section in western Hunanare are composed of 63 genera and subgenera, 84 species, and two forms of gen. et sp. indetermined. Which include a mixture of cosmopolitan agnostoids and polymeroids. Three new species, Hardyoides damaensis ,Meringaspis damaensis and Rhyssomelopus (Rodtrifinis ) nitidus, are described by present author in 2004. Besides, Erixanium is recognised for the first time in study area, which is significant for biostratigraphical correlation of the Late Cambrian in the Austalo-Asia region. According to distribution regularity vertical, the Middle and Late Cambrian trilobites can be divided into 9 trilobite communities for the Dama section. Based on the trilobite communities analysis, the author concludes that from the east Mt. Lailong to Dama through Fenghuang, further east, reach in Chenxi.the palaeoenvironments were changed from a shallow-water of oxygen-rich (platform margin slope) into a deep-water of oxygen-poor setting (basin).  相似文献   

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