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1.
Seven coleoid jaws recovered from Santonian to lower Campanian (Upper Cretaceous) strata in Hokkaido, Japan were taxonomically studied. Based on the comparison with the jaws of modern and fossil coleoids, six of the seven jaw fossils are referred to the following two genera and three species, including one possible new species: Nanaimoteuthis jeletzkyi and N. yokotai of the order Vampyromorpha, and Paleocirroteuthis sp. nov. (?) of the order Cirroctopodida. The other single lower jaw is seemingly similar to those of modern octopods and teuthids with respect to the shape of the inner lamella, but its order-level assignment could not be determined because of its imperfect preservation. N. jeletzkyi has been described in the Upper Cretaceous fore-arc basin deposits in Hokkaido (Yezo Group) and Vancouver Island, Canada (Nanaimo Group), whereas N. yokotai occurs only in the Yezo Group. These findings, complemented by previous reports of coleoid jaws, gladii, and phragmocones from the Yezo and Nanaimo Groups, demonstrate that a highly diversified, non-belemnitid coleoid fauna including large teuthids had already appeared during the post-Albian Late Cretaceous, in the North Pacific region.  相似文献   

2.
Vertebrate remains from the Upper Cretaceous (Santonian) Ajka Coal Formation (Bakony Mountains, western Hungary) are described. Macro- and microfossils collected from two boreholes and from isolated chunks of sediment/matrix dumped on spoil heaps of the Jókai Mine represent pycnodontiform and lepisosteiform fishes, bothremydid turtles, the mosasauroid Pannoniasaurus inexpectatus, the crocodyliforms cf. Theriosuchus, Iharkutosuchus makadii and cf. Allodaposuchus, as well as ankylosaurian and theropod dinosaurs. This unit was deposited in a swampy lacustrine environment, in contrast with the neighbouring and contemporaneous floodplain deposit of the vertebrate-bearing Csehbánya Formation at Iharkút. Despite significant environmental differences, the faunal composition of the Ajka Coal Formation assemblage completely overlaps with that of the Csehbánya Formation, suggesting the occurrence of the same semi-aquatic and terrestrial species in both settings. The ankylosaurian remains further strengthen the previous view that ankylosaurus preferred wetland habitats such as fluvial systems and coastal regions.  相似文献   

3.
Breakage-induced shell repair and drilling were studied in 548 shells belonging to 24 species of gastropod from the Ripley Formation (latest Campanian-Maastrichtian) of the south-eastern U.S.A. Frequencies of repair are high even by Recent standards. These is no relationship between the frequency of shell repair and shell architecture. Repair increases in frequency with increasing shell length. Drilling, which is less common in Ripley gastropods than in most warm-water Tertiary species, decreases in frequency with increasing shell length.  相似文献   

4.
5.
Remapping the Chalk of the Central Chalk Mass of the Isle of Wight between Carisbrooke (Newport), Calbourne and Shalcombe, including the Bowcombe Valley, has identified a complex series of tectonic ‘rolls’ and ‘flats’ in a region that has been interpreted to be a relay ramp between the Needles and the Sandown faults. A major new WNW trending fault at Cheverton throws the Chalk down by >50 m to the SW in a 80-100 m wide zone of faulting within which some chalk blocks have near vertical dips. The fault location and trend closely follows the edge of the Cranbourne-Fordingbridge High and could also reflect, for the first time, the surface expression of part of the Needles Fault, a major inversion reverse fault. Located along this fault zone deep Quaternary weathering of the Chalk and Quaternary gravel deposits are present. The trend of the Cheverton Fault brings it towards Gotten Leaze where a groundwater pumping station is located and groundwater springs regularly cause flooding on the Brighstone-Calbourne Road. Analyses of the jointing in the Chalk show that stratabound fracture patterns typical of the Chalk formations elsewhere in Southern England are present in the Central Mass. In addition, there are numerous small faults along which valleys have formed. Tectonic structure and lithology have had a profound influence on the geomorphology and groundwater flow in the Chalk in the Central Mass.  相似文献   

6.
New theropod remains with abelisaurid affinities from the Upper Cretaceous (Anacleto Formation, lower Campanian), NW Patagonia, Argentina, are here described. The specimen (MPCN-PV 69) consists of a partial premaxilla, fragmentary vertebrae, proximal portion of both humeri, distal portion of the pubis, and an incomplete pedal ungual. Characters linking with Abelisauridae are a premaxilla with a subquadrangular body, externally ornamented, and paradental plates with a striated surface; and humerus with bulbous proximal head, conical internal tuberosity, and reduced greater tubercle. The humerus is similar to those of Carnotaurus and Aucasaurus, due to the presence of a bulbous head and a discontinuity between the head and the internal tuberosity, but also differs from both taxa in the more distal location of the greater tubercle with respect to the internal tuberosity. Aucasaurus also comes from Anacleto Formation, but differences in the humeri suggest that MPCN-PV 69 is a different taxon. The phylogenetic analysis performed supports the affiliation to Abelisauridae, but fails to determinate a more precise relationship with others abelisaurids. However, a majority rule consensus of the analysis shows a position within Brachyrostra. Despite being fragmentary, MPCN-PV 69 probably represents a new abelisaurid from the Anacleto Formation, thus increasing the knowledge and diversity of Late Cretaceous South American abelisaurids.  相似文献   

7.
Site 549 recovered a Lower Cretaceous succession which has been shown to include parts of the Barremian and Albian stages. Forty-four species of Ostracoda are illustrated and their stratigraphic distribution used to recognise three major facies units. An high diversity inner shelf facies earlier in the Barremian gives way to a low diversity, outer shelf facies, higher in the succession. The early Albian appears to indicate a return to an inner shelf fauna. The faunas recovered have been compared to similar faunas elsewhere in N. W. Europe.  相似文献   

8.
A new gigantic sauropod, Huabeisaurus allocates gen. et sp. nov., about 20 m in length and 5 m in height, was discovered in the Upper Cretaceous Huiquanpu Formation, Tianzhen County, Shanxi Province. It is notably different from Diplodocidae, Titanosauridae and Nemegtosauridae in the following aspects: the teeth are strong, peg-like with a length ratio of the tooth crown to tooth root at about 3 to 1; the cervical vertebrae are long with forked spines; the spines in dorsal vertebrae are relatively high, unbifiarcated; the caudal vertebrae are amphicoelous, with anterior neural spines and unbifurcated spines and chevrons; the femur is straight and long, narrow and flat and the tibia and fibula are long and flat. These characters show that the described genus should represent a new family, Huabeisauridae fam. nov. The discovery enriches the sauropod dinosaur record in China, and is quite significant to the study of the taxonomy, evolution, migration, extinction and palaeobiogeographic provincialism of the  相似文献   

9.
Facies evolution and vertical changes within the Late Cretaceous sequence of the Bohemian Cretaceous Basin reveal fluctuations of intra- and extrabasinal circumstances. Evidence of periodic oscillations is recognized and two categories of aperiodic event indications are distinguished according to their significance and lateral persistence. Several lithoevents may be related to eustatic changes, while others indicate the independent evolution of the basin, influenced by epeirogenetic movements of segments of the Bohemian Massif.  相似文献   

10.
A synsacrum fragment and an incomplete ilium of the giant bird Gargantuavis philoinos are described from the upper Campanian/lower Maastrichtian Montplo-Nord locality at Cruzy (Hérault, southern France). The ilium provides new information about the pelvic morphology of Gargantuavis. Both the synsacrum and ilium are extensively pneumatised. This extensive pneumatisation may be a plesiomorphic feature, but may also have had a weight-reduction function in a large flightless bird.  相似文献   

11.
During the Late Cretaceous, high global sea‐level meant that most of the NW European craton was flooded by the deep epeiric ‘chalk sea’. The classical paradigm for chalk deposition envisages a quiet rain of minute skeletal debris of coccolithophorid algae and other pelagic organisms deposited as horizontal, flat‐lying pelagic oozes with local redeposition by slumps, slides and debris flows along faults and other structural features. Seismic data from the Danish Basin and elsewhere necessitate a revision of this paradigm. These demonstrate that the chalk sea floor had a considerable relief, commonly of more than a hundred metres amplitude, comprising moats, drifts, mounds and channels. Seismic sections from the Kattegat sea illustrate the development in the Maastrichtian of a deep moat adjacent to a topographic ridge formed over the inverted NW–SE‐trending Sorgenfrei–Tornquist Zone. The moat was up to 120 m deeper than its SW flank which was formed by an internally complex elongate drift, up to 20 km wide with an estimated length of ca 200 km. Smaller mound‐like features, channels and clinoform beds are superimposed on the large‐scale relief. The sea floor relief is interpreted to have formed in response to persistent bottom currents, flowing parallel to bathymetric contours. The initial build‐up of the broad, gently convex‐up sheeted drift was controlled by relatively low‐velocity bottom currents. The region of highest current velocity was gradually shifted NE‐wards towards the inversion zone ridge, resulting in the formation of the deep moat flanked by the elongate drift. The current is interpreted to have flowed from the SE towards NW on the basis of the internal architecture of the elongate drift and the NW‐ward branching and decrease in moat relief. The architecture and morphology of the moat drift and other features of the chalk sea floor are in all aspects similar to contourite systems of modern continental margins. It is accordingly proposed that the fundamental physical oceanographic concept – contour currents and their resulting contourite drifts – is extended to include the deep epeiric seas which covered NW Europe during the Late Cretaceous.  相似文献   

12.
Funiusaurus luanchuanensis gen. et sp. nov. was described on the basis of an incomplete skull from the Upper Cretaceous Qiupa Formation of the Tantou Basin in Luanehuan County, Henan Province. It is the second representative of lizards known from Luanchuan and adds a new member to the Luanchuan Fauna. F. luanchuanensis is a small-sized lizard and systematically assigned to the Polyglyphanodontidae of the Teiioidea because of the presence of a caniniform tooth and an elongate posterior process of the postorbital. It is distinctive in that the heterodont dentition bears 19 teeth in both the upper and lower jaws, the 3^rd maxillary tooth is large and caniniform, the post-caniniform teeth in maxilla and those posterior to the 3^rd dentary tooth are chisel-like in lateral view, the prefrontal possesses a fossa on its lateral surface, the postorbital with an extremely elongate posterior process and the well-developed retroarticular process has a deep fossa on its dorsal surface. In phylogeny, our analysis suggests a close relationship of Funiusaurus to the large-sized Tianyusaurus from the same basin within the Tuberocephalosaurinae. The discovery of Funiusaurus is significant in confirming the status of the Tuberocephalosaurinae, which includes a group of the Asian members of the Polyglyphanodontidae only.  相似文献   

13.
The upper Campanian-lower Maastrichtian site of Lo Hueco (Cuenca, Spain) has provided a set of well-preserved partial skeletons in anatomical connection or with a low dispersion of their skeletal elements. One partial skeleton is herein described and a new titanosaurian sauropod is established, Lohuecotitan pandafilandi. This titanosaur is diagnosed by eight autapomorphic features: dorsally and ventrally widened or bifurcated posterior centrodiapophyseal lamina in anterior and middle dorsal vertebrae; short postspinal lamina with a transversely expanded distal end represented by smooth scars in the dorsal vertebrae; anteriormost caudals with the medial spinoprezygapophyseal and medial spinopostzygapophyseal laminae ventrally connected with the prespinal and postspinal laminae, respectively; anterior caudal neural spines with a dorsal projection of the prespinal and postspinal laminae; anterior caudal neural spines bears a “greek-cross”-like cross-section; middle caudal centra having two round and rough structures in the dorsal edge of the posterior articulation, which extends to the dorsal surface of the centrum; the articular ends of the rami of the haemal arches are divided in two articular surfaces; and tuberosity between the anterior and the lateral trochanter of the fibula. The herein performed phylogenetic analysis considered L. pandafilandi as a member of Lithostrotia more derived than Malawisaurus. The known palaeodiversity of the Late Cretaceous Ibero-Armorican titanosaurs is increasing, and further analyses focused on this group will be necessary to better understand the evolutionary history of European titanosaurs and to clarify their relationships within Titanosauria.  相似文献   

14.
Patagonia has yielded the most comprehensive fossil record of Cretaceous theropods from Gondwana, consisting of 31 nominal species belonging to singleton taxa and six families: Abelisauridae, Noasauridae, Carcharodontosauridae, Megaraptoridae nov. fam., Alvarezsauridae, and Unenlagiidae. They provide anatomical information that allows improved interpretation of theropods discovered in other regions of Gondwana. Abelisauroids are the best represented theropods in Patagonia. They underwent an evolutionary radiation documented from the Early Cretaceous through to the latest Cretaceous, and are represented by the clades Abelisauridae and Noasauridae. Patagonian carcharodontosaurids are known from three taxa (Tyrannotitan, Giganotosaurus and Mapusaurus), as well as from isolated teeth, collected from Aptian to Cenomanian beds. These allosauroids constituted the top predators during the mid-Cretaceous, during which gigantic titanosaur sauropods were the largest herbivores. Megaraptorans have become better documented in recent years with the discovery of more complete remains. Megaraptor, Aerosteon and Orkoraptor have been described from Cretaceous beds from Argentina, and these taxa exhibit close relationships with the Aptian genera Australovenator, from Australia, and Fukuiraptor, from Japan. The Gondwanan megaraptorans are gathered into the new family Megaraptoridae, and the Asiatic Fukuiraptor is recovered as the immediate sister taxon of this clade. Although megaraptorans have been recently interpreted as members of Allosauroidea, we present evidence that they are deeply nested within Coelurosauria. Moreover, anatomical information supports Megaraptora as more closely related to the Asiamerican Tyrannosauridae than thought. Megaraptorans improve our knowledge about the scarcely documented basal radiation of Gondwanan coelurosaurs and tyrannosauroids as a whole. Information at hand indicates that South America was a cradle for the evolutionary radiation for different coelurosaurian lineages, including some basal forms (e.g., Bicentenaria, Aniksosaurus), megaraptorans, alvarezsaurids less derived than those of Laurasia, and unenlagiids, revealing that Gondwanan coelurosaurs played sharply differing ecological roles, and that they were taxonomically as diverse as in the northern continents. The unenlagiids represent an endemic South American clade that has been recently found to be more closely related to birds than to dromaeosaurid theropods. Analysis of the theropod fossil record from Gondwana shows the highest peak of origination index occurred during the Aptian–Albian and a less intense one in the Campanian time spans. Additionally, peaks of extinction index are recognized for the Cenomanian and Turonian–Coniacian time spans. In comparison, the Laurasian pattern differs from that of Gondwana in the presence of an older extinction event during the Aptian–Albian time-span and a high origination rate during the Cenomanian time-bin. Both Laurasian and Gondwanan theropod records show a peak of origination rates during the Campanian.  相似文献   

15.
河南淅川盆地的恐龙蛋发现与研究始于1974年,淅川盆地恐龙蛋具有非常高的多样性,共计发现4个蛋科、6个蛋属、6个蛋种,尤其以树枝蛋类最为丰富。近年来,河南地质博物馆对全省地质遗迹调查过程中,在淅川盆地再次有新的恐龙蛋类型的发现,本文对其中的部分标本进行记述,根据壳单元呈多分叉的不规则树枝状,蛋壳厚度为1.62~1.74 mm,锥体间隙明显,壳单元自锥体上部开始出现分枝,蛋壳中部大多具有3~4个分枝,近蛋壳外表面形成融合层,蛋壳具有复杂的气孔系统等特征区别于其他类型的树枝蛋类,建立一新蛋种:大石桥树枝蛋(Dendroolithus dashiqiaoensis oosp. nov.)。通过对淅川盆地恐龙蛋分类与对比、不同类型恐龙蛋在地层中的分布研究,将有助于盆地内白垩纪红层的划分,也将为秦岭东段各盆地中同一时期红层的划分与对比、古地理、古环境和古气候等研究提供更加翔实的古生物学证据。  相似文献   

16.
A new abelisaurid theropod from the Cenomanian of Candeleros Formation (Neuquén Province, NW Patagonia, Argentina) is described. It includes an isolated frontal, partial pelvis, two fused sacral centra, femoral shaft, rib fragments, partial metatarsal II and shaft of metatarsal III. A paleohistological analysis shows that MMCh-PV 69 was somatically mature at time of death. The prevalence of relatively ordered intrinsic fibers in the primary bone indicates a relatively lower growth rate of MMCh-PV 69 compared with other abelisauroids, such as Aucasaurus garridoi. Phylogenetic analysis found MMCh-PV 69 as a basal abelisaurid, sister group of the node formed by Majungasaurinae and Brachyrostra. We estimated the body mass of MMCh-PV 69 in 240 kg, which makes it one of the smallest abelisaurids recorded. This new form adds to the extensive theropod fauna of the Candeleros Formation, probably the most diverse association of meat-eating dinosaurs recorded in a Cretaceous Formation from South America.  相似文献   

17.
红层是古地磁学的重要研究对象之一。以往对河湖相红层的古地磁研究较多,而对于风成红层的研究较少。因 此,对于风成红层剩磁记录是否可靠等基本问题仍然缺乏清晰的认识。文章对江西信江盆地上白垩统圭峰群塘边组风成 红层和河口组河流相红层开展了古地磁研究,并通过对比风成红层与河流相红层的古地磁结果,探究风成红层剩磁记录 的可靠性及不同沉积过程对古地磁记录的影响。逐步热退磁实验结果显示仅有19% 的塘边组风成红层分离出稳定的特征 剩磁,而且其强度衰减曲线为凸形,表明特征剩磁为碎屑赤铁矿携带的原生剩磁。其平均方向为Ds=15.6 °, Is=28.9 °, n= 25, κ=13.0, α95=8.3 °;对应的古地磁极为Latitude=70.7 °, Longitude=245.6 °, A95=6.8 °。该古地磁极与赣州地区河湖相红层 的古地磁极及华南晚白垩世的古地磁极位置一致,表明风成红层的剩磁记录是可靠的。河口组河流相红层绝大部分样品 未能分离出稳定的特征剩磁。磁化率各向异性结果显示塘边组和河口组为沉积组构。岩石磁学结果表明,载磁矿物为赤 铁矿和磁铁矿。通过对塘边组风成红层的薄片观察和红度值比较等进一步研究表明,颗粒粒度和胶结程度可能对红层剩 磁记录的稳定性有一定影响。  相似文献   

18.
拉萨地体中部上白垩统达雄组的建立及构造隆升意义   总被引:2,自引:0,他引:2  
孙高远  胡修棉 《地质学报》2017,91(12):2623-2637
拉萨地体中部措勤盆地内,呈东西向发育一套厚度巨大(~1800m)的晚白垩世陆相磨拉石沉积建造。通过对研究区内达雄村附近出露较好的虾格子剖面开展详细的测制工作,并将该套地层自底到顶分为5段,依次为中-粗粒砂岩层段、大套砾岩层段、中粒砂岩夹粉砂岩-泥岩层段、大套紫红色与绿色粉砂岩/泥页岩层段以及均质中粒砂岩层段。地层底部与下伏郎山组含圆笠虫灰岩呈沉积不整合关系,顶部被新生代沉积物覆盖。通过岩相组合与沉积结构构造分析研究,认为该套地层形成于冲积扇-辫状河沉积体系。通过地层顶部火山灰夹层和下伏郎山灰岩的圆笠虫化石显示其形成年龄约为98~91 Ma,这与获得的砂岩碎屑最年轻锆石年龄较为一致。砾岩砾石统计结果显示火山岩砾石为其主要成分。砂岩碎屑成分显示以大量火山岩岩屑为主。这些碎屑成分特征表明其主要来自岩浆弧的物源区。结合碎屑锆石U-Pb年代学和Hf同位素数据表明,中拉萨地体上广泛分布的则弄群火山岩可能为其主要的物源区。本文综合该套晚白垩世沉积的时空分布、岩性组合以及物源区特征,将其新命名为"达雄组",并将其与中拉萨地体北侧的竟柱山组对比表明,两者可能共同代表了中拉萨地体在晚白垩世早期(约98~91 Ma)所经历构造隆升,为青藏高原腹地在印度-亚洲大陆碰撞之前隆升提供了地质证据。  相似文献   

19.
红层是古地磁学的重要研究对象之一。以往对河湖相红层的古地磁研究较多,而对于风成红层的研究较少。因 此,对于风成红层剩磁记录是否可靠等基本问题仍然缺乏清晰的认识。文章对江西信江盆地上白垩统圭峰群塘边组风成 红层和河口组河流相红层开展了古地磁研究,并通过对比风成红层与河流相红层的古地磁结果,探究风成红层剩磁记录 的可靠性及不同沉积过程对古地磁记录的影响。逐步热退磁实验结果显示仅有19% 的塘边组风成红层分离出稳定的特征 剩磁,而且其强度衰减曲线为凸形,表明特征剩磁为碎屑赤铁矿携带的原生剩磁。其平均方向为Ds=15.6 °, Is=28.9 °, n= 25, κ=13.0, α95=8.3 °;对应的古地磁极为Latitude=70.7 °, Longitude=245.6 °, A95=6.8 °。该古地磁极与赣州地区河湖相红层 的古地磁极及华南晚白垩世的古地磁极位置一致,表明风成红层的剩磁记录是可靠的。河口组河流相红层绝大部分样品 未能分离出稳定的特征剩磁。磁化率各向异性结果显示塘边组和河口组为沉积组构。岩石磁学结果表明,载磁矿物为赤 铁矿和磁铁矿。通过对塘边组风成红层的薄片观察和红度值比较等进一步研究表明,颗粒粒度和胶结程度可能对红层剩 磁记录的稳定性有一定影响。  相似文献   

20.
大数据时代下美国地质调查局的科学新观   总被引:2,自引:1,他引:2  
杨宗喜  唐金荣  周平  张涛  金玺 《地质通报》2013,32(9):1337-1343
2010年,美国地质调查局为适应社会需求,将以往以学科为主线的组织架构调整为以重大问题为主线,新增了核心科学体系的科学使命,并于2012年制定和发布了《美国地质调查局核心科学体系科学战略(2013-2023)》,作为其今后10年核心科学研究的纲领.该战略是美国地质调查局在“大数据时代”的背景下提出的地球科学研究的新思维,将临界带视为其重点研究对象,按生态系统的内在逻辑构建了模块式科学框架,突出数据密集型科学研究新范式与地球科学研究的结合,以期形成为变化世界服务的科学体系,以增强地质调查满足社会需求的能力和解决复杂的经济-社会问题的能力,也代表了地球系统科学未来发展的一个新方向.  相似文献   

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