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1.
山东东部诸城晚白垩世王氏群大面积、高密度集群埋藏的恐龙化石是近年研究的热点,但其沉积物源与精确沉积时限目前尚不明确。本文通过对山东诸城王氏群恐龙化石层中6个砂岩样品的碎屑锆石U-Pb定年表明,样品090414-24-D中最年轻的单颗粒锆石年龄(YSG)为77.3 Ma,应代表王氏群恐龙化石层的最大沉积时限(下限),结合前人对王氏群红土崖组的年代学研究表明,其沉积时限应老于73.5 Ma(上限),也说明赋存恐龙化石层的王氏群上部红土崖组为Campanian期沉积;碎屑锆石定年揭示物源的锆石年龄组成分布在100~130 Ma之间,6个样品的年龄主峰值多在110 Ma或120 Ma左右,与下伏的早白垩世青山群火山岩年龄主峰较为吻合。王氏群恐龙化石层砾岩的砾石成分和古水流研究显示,其中3组砾石统计表明砾岩层砾石成分主要由火山岩或火山碎屑岩组成,3组古水流数据表明,诸城地区王氏群红土崖组砾岩层的古流向以南和南东方向为主,尚有1组显示古流向为向北,表明王氏群物源主要来自盆地北侧莱阳和北西侧沂沭断裂带的青山群火山岩,其次为盆地南缘。本研究为诸城王氏群化石层沉积时限的限定和沉积物源的判断,以及胶莱盆地王氏群时期古地理格局的恢复等提供了重要的依据。  相似文献   

2.
近年来四川盆地不断发现恐龙化石,引起人们极大关注。本文以四川省安岳县最新发现的恐龙动物群埋藏特征,初步探讨其环境意义。一、安岳恐龙化石埋藏特征已发现的安岳恐龙化石均埋藏在侏罗系上统上部地层中(图1)。我们重点对顶部马蹄寺和隆家崖化石点进行了发掘。  相似文献   

3.
Doklady Earth Sciences - A caudal vertebra of a dinosaur (Iguanodontia indet.) is described from Upper Cretaceous (lower Campanian) coastal marine deposits of Izhberda Quarry near Orsk (Orenburg...  相似文献   

4.
Tumors are thought rare in dinosaurs, previously limited in distribution to a single family – hadrosaurs. Here we recognized two different neoplastic lesions, osteoma and hemangioma, in a single caudal vertebra of a titanosaur dinosaur from the Upper Cretaceous of Brazil, diagnosed on the basis of macroscopic, radiological and histological analysis. This is the first occurrence of neoplasia in a non-hadrosaur dinosaur. Therefore, neoplasia is not restricted to hadrosaur dinosaurs, as previously suggested.  相似文献   

5.
Doklady Earth Sciences - A nearly complete and articulated dinosaur skeleton from the Upper Cretaceous (Cenomanian–Santonian) Bayinshire Formation at Bayshin Tsav locality in Gobi Desert...  相似文献   

6.
Eighty two dinosaur trackways were newly discovered in Upper Cretaceous lacustrine deposits on islands in the vicinity of Yeosu, Korea. Most dinosaur tracks occur in marginal lake deposits with polygonal desiccation cracks. The dinosaur tracks at the Yeosu site include 65 ornithopod trackways, 16 theropod trackways and one sauropod trackway. The prevalence of ornithopod tracks and the limited occurrence of sauropod tracks at the Yeosu site evidently reflect decreased sauropod diversity in the Upper Cretaceous. All ornithopod trackways represent bipeds, and most of the ornithopod tracks are similar to Caririchnium from other sites of the Korean peninsula. All fossil wood specimens collected in the study area represent conifers (three species of cupressaceous and two species of taxodiaceous conifers, and a new species) except for one, which is a discotyledon. It is thus inferred that the southwestern part of the Korean Peninsula was primarily covered with mesic forests with taxodiaceous trees during the Late Cretaceous. The K–Ar age of the Yeosu tracksite is determined as 81–65 Ma (Camapnian to Maastrichtian). It indicates that the Yeosu track site contains the last records of dinosaurs living in Asia. Consequently, semi-arid palaeoclimatic conditions, together with a large lake as a persistent water source and rich vegetation of gymnosperm trees as food, resulted in the preservation of abundant dinosaur tracks in the Upper Cretaceous on the Korean Peninsula.  相似文献   

7.
The first detailed stratigraphic succession of the Upper Cretaceous continental record from the Upper Aude Valley (southern France) is presented together with a magnetostratigraphic study. The combined stratigraphy and magnetostratigraphy of the Marnes rouges inférieures Fm (Lower Red Marls), constrained by biochronological markers such as charophyte occurrence and revised dinosaur eggshells, results in a succession of fluvial red beds dated from chron C32n to the top of chron C31r. It implies an earliest Maastrichtian age close to the C32n.1n-C31r reversal for the majority of the dinosaur sites including Bellevue. In contrast, the upper Maastrichtian is likely represented by a short interval within the lacustrine-palustrine Calcaires et argiles de Vignevieille Fm (Vignevieille Limestones), or it might even not be recorded. The proposed age indicates that the marine to continental transition, as a result of the Late Cretaceous transgression, took place earlier in the north Pyrenean basin than in the southern area.  相似文献   

8.
豫南南阳盆地西峡赵营村上白垩统高沟组含有较多的恐龙蛋化石,其中最为著名的是“路易贝贝”胚胎化石。对含化石地层中恐龙蛋的保存特征和古气候重建,可进一步认识白垩纪恐龙灭绝的古环境背景和原因。本文实测赵营村剖面厚约267.8 m,主要由下伏泥盆系南湾组(厚7.9 m)、上白垩统高沟组(厚259.9 m,未到顶)组成。通过地层沉积物结构构造观测和样品采集,在室内进行了元素、碳酸盐碳氧同位素组成、有机质饱和烃生标化合物等测试。结果表明,高沟组沉积物主要源于熊耳山岩浆岩的风化和短距离迁移,恐龙蛋化石主要保存于海拔200~800 m的山麓至平原过渡带的河漫滩环境,以原地埋藏为主。降雨量的变化造成河漫滩与河道频繁变化,从而导致恐龙在山麓与河漫滩之间来回迁栖。生物标志化合物分析表明,含恐龙蛋化石地层有机质主要来源于水生植物、菌藻类和陆生植物,但植被总体不发育。利用地层沉积岩Si/Al、CIA、Rb/Sr比值,以及δ13C、δ18O等环境指标对高沟组古气候重建,该时期发生了较为快速的旋回变化,经历了暖干—暖湿—干旱—暖湿—干旱的古气候演变过程,总体上呈逐渐干旱化的趋势。通过赵营村晚白垩世早期恐龙蛋化石的埋藏、以及地层的古环境重建,说明古气候、古环境状况可能是影响恐龙生存的主要因素,大量恐龙蛋不能完全孵化以及气候的干旱化导致植被恶化可能是恐龙逐渐消亡的原因。  相似文献   

9.
Upper Jurassic and Lower Cretaceous sedimentary layers are represented in the Brazilian Paraná Basin by the fluvio–aeolian Guará Formation and the Botucatu Formation palaeoerg, respectively, overlapped by the volcanic Serra Geral Formation. In Uruguay, the corresponding sedimentary units are named Batoví and Rivera Members (both from the Tacuarembó Formation), and the lava flows constitute the Arapey Formation (also in Paraná Basin). Despite the lack of body fossils in the mentioned Brazilian formations, Guará/Batoví dinosaur fauna is composed of theropod, ornithopod and wide–gauge sauropod tracks and isolated footprints, as well as theropod teeth. In turn, the Botucatu/Rivera dinosaur fauna is represented by theropod and ornithopod ichnofossils smaller than those from the underlying units. The analysis of these dinosaur ichnological records and comparisons with other global Mesozoic ichnofauna indicates that there is a size reduction in dinosaur fauna in the more arid Botucatu/Rivera environment, which is dominated by aeolian dunes. The absence of sauropod trackways in the Botucatu Sandstone fits with the increasingly arid conditions because it is difficult for heavy animals to walk on sandy dunes, as well as to obtain the required amount of food resources. This comparison between the Upper Jurassic and Lower Cretaceous dinosaur fauna in south Brazil and Uruguay demonstrates the influence of aridization on the size of animals occupying each habitat.  相似文献   

10.
简要报道了新近首次在冀西北张家口尚义地区发现的恐龙足迹。野外地质调查发现,恐龙足迹赋存于尚义晚中生代盆地侏罗系—白垩系后城组顶部。恐龙行迹呈近东西向展布,由数十个足迹构成。初步研究表明,造迹者分别属于兽脚类和蜥脚类恐龙,由西向东行进。足迹中包括兽脚类足迹70余个,组成数个行迹;蜥脚类足迹15个,构成1列行迹。蜥脚类足迹特征显示其可能属于游泳状的行迹。华北北部土城子组/后城组发育于燕辽生物群—热河生物群更替演化时期(晚侏罗世—早白垩世早期),以往在该时期沉积物中罕见脊椎动物骨骼化石。近年来华北北部土城子组/后城组中频繁发现的恐龙足迹表明,燕辽生物群—热河生物群更替演化时期发育着以恐龙为代表的脊椎动物群。该发现将有助于进一步了解土城子组/后城组沉积时期恐龙属种的多样性及其生物古地理环境。晚侏罗世—早白垩世早期沉积古地理和古生态环境及其与恐龙动物群发育的研究有助于揭示陆地生物群更替演化和环境的关系。  相似文献   

11.
中国的恐龙蛋化石埋藏丰富,分布广泛。迄今为止,已报道有14个省(区)发现恐龙蛋化石。尤其在浙江天台盆地、山东莱阳盆地、广东南雄盆地以及河南西峡和淅川盆地等晚白垩世陆相红层中发现大量的恐龙蛋化石,同时也发现大量共生的恐龙等脊椎动物化石。中国恐龙蛋化石具有数量大、种类多、保存好、分布广、时代跨度大等特点,因此恐龙蛋可以作为中国白垩纪陆相地层划分与对比的重要化石之一。本文在建立天台盆地赖家组和赤城山组的岩石地层、年代地层和恐龙蛋生物地层层序框架的基础上,重点对比讨论了我国几个主要含恐龙蛋沉积盆地的恐龙蛋类群组合序列及其对应的地层关系。同时,对我国周边相邻地区如蒙古、韩国和印度以及其他各个大陆发现的恐龙蛋化石进行了初步对比讨论。天台恐龙蛋化石群与我国其他几个主要的恐龙蛋化石群之间存在一定的差距。相比较而言,天台恐龙蛋化石群和南雄恐龙蛋化石群组合特征鲜明,前者主要以网形蛋类和蜂窝蛋类为主,后者以长形蛋类为优势类群,结合天台盆地陆相红层中多个凝灰岩夹层获得的98~91Ma和南雄盆地67Ma的同位素年龄,据此,天台恐龙蛋化石群代表了晚白垩世早期的恐龙蛋组合,而南雄恐龙蛋化石群则代表了晚白垩世晚期的恐龙蛋组合。天台恐龙蛋化石群与莱阳恐龙蛋化石群明显不同,莱阳盆地的主要蛋化石类型——圆形蛋类和椭圆形蛋类在天台盆地至今没有被发现。但莱阳恐龙蛋化石群与南雄恐龙蛋化石群比较相似,如莱阳盆地金刚口组以椭圆形蛋类为主,含有少量的长形蛋类,而南雄盆地以长形蛋类为主,含有少量的椭圆形蛋类,其中金刚口椭圆形蛋、薄皮椭圆形蛋、长形长形蛋和安氏长形蛋等2属4种蛋化石在两个盆地均有发现。此外,在莱阳盆地王氏群中下部的将军顶组还发现了相对原始的网形蛋类。综合以上分析,莱阳恐龙蛋化石群大致介于晚白垩世早期的天台恐龙蛋化石群和晚白垩世晚期的南雄恐龙蛋化石群之间,更接近于南雄恐龙蛋化石群,时代应为晚白垩世中晚期。天台恐龙蛋化石群与西峡恐龙蛋化石群非常相似,在科一级分类单元中,至少有巨型长形蛋类、蜂窝蛋类和棱柱形蛋类等6个蛋科在两个盆地中均有发现,尤其是巨型长形蛋科仅在天台和西峡两个盆地中有化石记录,其中西峡巨型长形蛋这一蛋种同时产于西峡盆地走马岗组、赵营组和天台盆地的赤城山组。西峡盆地发现的其他一些蛋化石也可以归入到天台盆地新建立的一些蛋化石类型中。据此推断,走马岗组和赵营组与赤城山组的层位可能大致相当。虽然我们对西峡盆地已报道的部分恐龙蛋化石进行了初步厘定,但鉴于西峡盆地大量恐龙蛋化石的形态学和分类学尚存在较多的问题,两盆地的详细对比还有待于进一步的研究。天台恐龙蛋化石群与淅川盆地的恐龙蛋化石组合差别很大,相应的淅川盆地的恐龙蛋类群与相邻的西峡盆地的差别也较大,此外,在淅川盆地高沟组发现有树枝蛋类,这一类蛋化石在天台盆地未发现,据此推测淅川盆地的时代应晚于天台盆地和西峡盆地。相比较而言,淅川盆地的蛋化石组合与莱阳和南雄恐龙蛋化石群有一定的相似性,都含有长形蛋类、圆形蛋类和椭圆形蛋类等,因而,淅川盆地的马家村组和寺沟组的层位被认为可能与莱阳盆地的金刚口组和南雄盆地的坪岭组相当。综上分析,我们可以初步建立我国晚白垩世恐龙蛋化石群的组合序列及其对应的地层层序和时代框架,从下至上至少包含了4个恐龙蛋化石群:1)天台恐龙蛋化石群,赋存层位为天台群中上部的赖家组和赤城山组,时代约为晚白垩世早期(塞诺曼期土伦期);2)西峡恐龙蛋化石群,赋存层位为走马岗组、赵营组和六爷庙组,晚白垩世早中期(土伦期桑顿期);3)莱阳恐龙蛋化石群,赋存层位为王氏群中上部的将军顶组和金刚口组,晚白垩世中晚期(科尼亚克期坎潘期);4)南雄恐龙蛋化石群,赋存层位为南雄群园圃组和坪岭组,晚白垩世晚期(坎潘期马斯特里赫特期)。此外,随着研究工作的继续和深入,有望建立起包括早白垩世恐龙蛋化石群在内的白垩纪恐龙蛋化石群的组合特征序列,为进一步划分与对比我国白垩纪地层提供更多的基础资料。  相似文献   

12.
浙江恐龙和蛋化石的时代   总被引:2,自引:1,他引:1       下载免费PDF全文
在浙江省内,有12个白垩纪红层盆地中发现恐龙化石和蛋化石,且多个盆地龙蛋共生。经初步调查,除金衢盆地衢江群下部中戴组发现恐龙化石外,恐龙化石和蛋化石均产于盆地内的中上部地层:即永康群朝川组、方岩组,衢江群的金华组和衢县组,天台群两头塘组和赤城山组。从相关地层的古生物组合时代和火山岩同位素年龄为101~90Ma以及地层的古地磁均为正向极性特征分析,浙江绝大部分恐龙蛋的时代应为晚白垩世,而蜂窝蛋类化石时代则很可能是早白垩世晚期或未期。  相似文献   

13.
郧县青龙山一带的上白垩统是一套以冲积扇相为主体的红色陆源碎屑沉积,依据岩性变化,可分为上、中、下3个组合.下部组合含多个产恐龙蛋化石的层位.上部组合与毗邻的李官桥盆地胡岗组(K32hg)可以对比.红寨子、青龙山一带的恐龙蛋化石分布集中,藏量丰富,类型较多,埋藏甚浅,保存好,实属举世罕见.据初步研究,蛋壳的显微结构有5种类型,分属于5个恐龙蛋科,即Dendroolithidae,Dictyoolithidae,Faveoloolithidae,Prismatoolithidae和Spheroolithidae,其中以Dendroolithidae分布最广、数量最多.  相似文献   

14.
黑龙江沿岸晚白垩世恐龙生物群化石产地的初步预测   总被引:1,自引:0,他引:1  
李萍 《世界地质》2005,24(2):118-122
根据对黑龙江沿岸孙吴、逊克和嘉荫保兴-炮台店一带晚白垩世地层与嘉荫乌拉嘎、龙骨山等含恐龙化石群的渔亮子组(K2y)等对比及在前三个地区已发现部分恐龙化石的线索,初步预测孙吴北部、逊克东南部和嘉荫保兴-炮台店等三地区可能为较大规模的恐龙化石群产地。预测区含恐龙化石的晚白垩世地层均属河流-湖泊相沉积,除恐龙外,尚可能发现叶肢介、介形类、鱼、龟鳖类、鳄、鸟类及被子植物等伴生化石。上述地区下伏于渔亮子组的太平林场组(K2t)和永安村组(K2yn)等地层,也有含恐龙化石的可能性。  相似文献   

15.
A new theropod dinosaur,Shidaisaurusjinae gen.et sp.nov.,has been described on the basis of an incomplete skeleton.The specimen was found near the base of the Upper Lufeng Formation(early Middle Jurassic)in Yunnan,China.It is the first theropod dinosaur from the Middle Jurassic of Yunnan.Shidaisaurus jinae is distinguishable from other Jurassic theropods by certain features from the braincase,axis,and pelvic girdle.The absence of any pleurocoels in the axis or in any anterior dorsal vertebrae suggests that the new Lufeng theropod is relatively primitive and more plesiomorphic than most of the Middle to Late Jurassic theropods from China.Most Chinese taxa of Jurassic theropod dinosaurs have not been well described;a further detailed study will be necessary for us to determine their phylogenetic relationships with Shidaisaurus jinae.  相似文献   

16.
The North American fossil record of dinosaur eggshells for the Cretaceous is primarily restricted to formations of the middle (Albian–Cenomanian) and uppermost (Campanian–Maastrichtian) stages, with a large gap in the record for intermediate stages. Here we describe a dinosaur eggshell assemblage from a formation that represents an intermediate and poorly fossiliferous stage of the Upper Cretaceous, the Santonian Milk River Formation of southern Alberta, Canada. The Milk River eggshell assemblage contains five eggshell taxa: Continuoolithus, Porituberoolithus, Prismatoolithus, Spheroolithus, and Triprismatoolithus. These ootaxa are most similar to those reported from younger Campanian–Maastrichtian formations of the northern Western Interior than they are to ootaxa reported from older middle Cretaceous formations (i.e., predominantly Macroelongatoolithus). Characteristics of the Milk River ootaxa indicate that they are ascribable to at least one ornithopod and four small theropod species. The taxonomic affinity of the eggshell assemblage is consistent with the dinosaur fauna known based on isolated teeth and fragmentary skeletal remains from the formation, although most ornithischians and large theropods are not represented by eggshell. Relative to the Milk River Formation eggshell, similar oospecies occurring in younger Cretaceous deposits tend to be somewhat thicker, which may reflect an increase in body size of various dinosaur lineages during the Late Cretaceous.  相似文献   

17.
The Zhutian and Dafeng formations (Upper Cretaceous) of the Heyuan Basin in northeastern Guangdong Province, China, have produced thousands of dinosaur eggs. Macromorphological features (egg diameter, egg shape, outer surface texture, and shell thickness) of 461 eggs were analyzed using non-destructive techniques and subjected to statistical analyses in order to assess their diversity and taxonomic affinities. Three types (1, 2 and 3) of eggs were discerned based on shape and outer surface morphology. Type 1 eggs are spherical to ellipsoidal in shape and have a rough surface. Three subtypes (Type 1-A-1, 1-A-2, and 1-B) are apparent from scatter plots and cluster analyses of egg diameters and shell thickness. Type 2 eggs are elongate with linear ornamentation on the surface, and are comparable to eggs that belong to the oofamily Elongatoolithidae. Type 3 eggs are elongate with a smooth surface, and are assigned to the oofamily Prismatoolithidae. Macromorphological features of the various egg types suggest that Type 1 could have been laid by ornithischian, sauropod or therizinosaur dinosaurs, Type 2 by oviraptorids, and Type 3 by troodontids. This study represents the first comprehensive statistical analysis of macrofeatures of dinosaur eggs, and reveals taxonomic diversity in the dinosaurs that were laying eggs in the Upper Cretaceous Heyuan area heretofore unrecognized in skeletal remains.  相似文献   

18.
An almost complete skull, which was collected from the Upper Cretaceous of the Bayan Mandahu area in Inner Mongolia, China by the Sino-Canadian Dinosaur Project, is described and assigned to a new genus of protoceratopsid dinosaur, Magnirostris dodsoni gen. et sp. nov. This new taxon is distinguished from other protoceratopsids by the robust rostral bone and the existence of incipient orbital horn cores. The existence of an additional antorbital fenestra indicates a close relationship between Magnirostris and Bagaceratops.  相似文献   

19.
"路易贝贝"恐龙胚胎化石产于中国河南省南阳市西峡县阳城乡,位于西峡盆地上白垩统高沟组下(底)部,是Macroelongatoolithus xixaensis(西峡巨型长形蛋)的胚胎骨骼化石。西峡盆地上白垩统自下而上划分为高沟组、马家村组、寺沟组。高沟组产有丰富的恐龙蛋化石和少量恐龙骨骼化石,以及少量的双壳类、腹足类、介形类、轮藻、植物孢粉、植物化石碎片和丰富的遗迹化石。依据上述化石的地质时代并结合高沟组与上覆马家村组整合接触关系和寺沟组化石组合情况,以及高沟组与下伏泥盆系南湾组角度不整合接触关系和周边相邻盆地的地层对比,将西峡盆地高沟组地质时代置于晚白垩世中晚期的康尼亚克期(Coniacian)。高沟组下、中部为半干旱温热气候条件下的红色陆相类磨拉石建造的陆源碎屑岩,属间歇性的、以牵引流为主的浑水河流冲积扇沉积物;高沟组上部为冲积扇和辫状河沉积。"路易贝贝"所在层位的古地理环境是冲积扇扇端朝向南的、缓坡状宽阔平坦的冲积扇扇面,可归入冲积扇相-扇端亚相-漫流微相。  相似文献   

20.
A review of the stratigraphy of the continental Cretaceous sequences is given. Conchastracans, ostracods and charophytes have proved useful in biostratigraphy, with additional aid from pelecypods, gastropods, larger plant fossil and, locally, dinosaur remains.The continental Lower Cretaceous deposits are considered to fall into three domains: the Circum-Pacific, the Tethyan and the NW Chinese. The continental Upper Cretaceous sediments occur mainly in the three domains: NW Chinese, SE Chinese and NE Chinese.  相似文献   

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