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1.
松辽盆地阿尔必期微体浮游植物新属种   总被引:4,自引:3,他引:1  
该文描述了松辽盆地中白垩世阿尔必期泉头组三段的微体浮游植物化石1新属7新种,隶属于微咸水沟鞭藻类2属5新种(含4新亚种),淡水绿藻1属1种和疑源类1新属1新种。并对沟鞭藻 Ngktericysta Bint,1986进行了修订。  相似文献   
2.
The discovery of Foraminifera and Ostracodesin the dark green, sandy-glauconitic marl clay in the Joux Valley (in the Vaudois Jura) suggests to date these sediments Middle and Upper Albian. The Ostracode associations are similar to those found in the Paris Basin, but different from those which characterize the subalpine region.  相似文献   
3.
At least 22 tridactyl dinosaur tracks, poorly preserved in various degrees of expression, have recently been found at an exposure in the Dakota Formation (Lower Cretaceous, Albian) in Jefferson County, Nebraska. These tracks generally have broad, blunt digits and a broad posterior margin. The largest of the tracks measures 57 cm in length and 58 cm in width. All of the tracks lie within a stratigraphic horizon of 40 cm or less, but they do not form a single trackway. We interpret the trackmakers to have been ornithopods.

The Jefferson County tracks are in a well-cemented sandstone with oscillation ripples, at a stratigraphic level between two well-established sequence boundaries. Channel forms and lateral accretion units are common in the stratigraphic interval enclosing the tracks, and the site is interpreted as a bar or sand flat in a tidally influenced river.

The Jefferson County tracks are only the second known occurrence of large Mesozoic tetrapod tracks east of the Rocky Mountain Front-High Plains Margin, including the Black Hills of South Dakota, west of the Atlantic Coastal Plain, and north of the Gulf Coastal Plain. Further, this paper is the first documentation of in situdinosaur fossils from the Nebraska-Iowa area.  相似文献   
4.
Leaflets of Marsileaceae are described from the Albian (Early Cretaceous) strata of Jordan. The fossils are from the Jarash Formation (Kurnub Group) and are found in fluvial sediments along with water lily leaves. The small wedge-shaped leaves have dichotomous veins that anastomose and form a marginal vein. Based on comparisons to living genera, Marsileaceaephyllum mahisensis Hu, Taylor, Brenner et Basha, n. sp., is most similar to Marsilea, in particular, with terrestrial leaflet forms; yet, it is distinct from living and fossil species by its small size and the few dichotomously branched middle veins that have a monopodial course. In addition, a single similar-veined smaller leaf with a retuse apex is thought to be a juvenile leaf of the same species. This is the first megafossil evidence of the family from Africa/Arabian Peninsula.  相似文献   
5.
Spatial distribution patterns of benthic foraminifers in upper Albian sediments from 25 DSDP/ODP sites and 31 onshore sections of the North and South Atlantic Ocean are used to generate paleobathymetric reconstructions and to identify areas of high primary production such as coastal and equatorial upwelling zones. New paleobathymetric estimates are provided for DSDP/ODP sites and onshore locations that are not situated on oceanic crust. Paleobathymetric reconstructions indicate shallow water exchange between the North and South Atlantic but show the existence of a deep-water connection between the western and eastern Tethys (>2500 m) through the Gibraltar Gateway. Strikingly, there is no evidence for a strong latitudinal gradient in deep-water benthic foraminiferal distribution during the late Albian: South Atlantic assemblages show close affinity to North Atlantic and Tethyan assemblages, exhibiting only a minor degree of provincialism. Biogeographic patterns reveal a distinct asymmetry in late Albian paleoproductivity for the North Atlantic. As for the present day, the eastern margins of the Atlantic were generally more productive than the western margins, and a belt of enhanced carbon flux export to the seafloor can be traced around the north African coast, which probably corresponded to a zone of vigorous coastal upwelling. By contrast, assemblage composition in the South Atlantic generally reflects mesotrophic to oligotrophic conditions. Benthic foraminiferal distribution patterns, thus, provide robust proxy data to test predictions from paleocirculation and paleobathymetric models for the mid-Cretaceous Atlantic Ocean and adjacent margins.  相似文献   
6.
The Albian sediments of the Transdanubian Range in Hungary were deposited in non-marine to fully-marine environments. The studied sections revealed diverse benthic ostracod faunas with moderately-preserved specimens. Forty-six taxa are identified and Cypridea zalanyii n. sp. is newly described. The detailed palaeoecological study of these ostracod faunas provided an opportunity to distinguish eight assemblages. The assemblages include limnic, brackish lagoon, shallow marine, reef and low oxygenated semi-enclosed basin environments in the Northern Tethys region we investigated. This work contributes to the knowledge about Albian non-marine faunas from Europe and explores ecological requirements of brackish faunas.  相似文献   
7.
Abstract:  Up to now, more than 40 dinosaur sites have been found in the latest Jurassic – earliest Cretaceous sedimentary outcrops (Villar del Arzobispo Formation) of Riodeva (Iberian Range, Spain). Those already excavated, as well as other findings, provide a large and diverse number of sauropod remains, suggesting a great diversity for this group in the Iberian Peninsula during this time. Vertebrae and ischial remains from Riodevan site RD-13 are assigned to Turiasaurus riodevensis (a species described in RD-10, Barrihonda site), which is part of the Turiasauria clade. This is the first time that a taxon is attributed to Turiasaurus genus out of its type site. A Neosauropod caudal vertebra from the RD-11 site has been classified as Diplodocinae indet., supporting the previous attribution on an ilion also found in Riodeva (CPT-1074) referring to the Diplodocidae clade. New remains from the RD-28, RD-41 and RD-43 sites, of the same age, among which there are caudal vertebrae, are assigned to Macronaria. New sauropod footprints from the Villar del Arzobispo Formation complete the extraordinary sauropod record coming to light in the area. The inclusion of other sauropods from different contemporaneous exposures in Teruel within the Turiasauria clade adds new evidence of a great diversity of sauropods in Iberia during the Jurassic–Cretaceous transition. Turiasauria distribution contributes to the understanding of European and global palaeobiogeography.  相似文献   
8.
三水盆地早白垩世白鹤洞组的被子植物花粉*   总被引:3,自引:1,他引:3  
系统描述了区内早白垩世白鹤洞组的被子植物花粉,11属20余种.结合前人研究成果,对一些容易混淆的属种作了区分性的讨论.据所发现的被子植物花粉的组合面貌,将白鹤洞组归人中晚阿尔必期.  相似文献   
9.
Summary During the Late Albian, Early and Middle Cenomanian in the NW part of the Adriatic Carbonate Platform (presentday Istria) specific depositional systems characterised by frequent lateral and vertical facies variations were established within a formerly homogeneous area, ranging from peritidal and barrier bars to the offshore-transition zone. In southern Istria this period is represented by the following succession: thin-bedded peritidal peloidal and stromatolitic limestones (Upper Albian); well-bedded foreshore to shoreface packstones/grainstones with synsedimentary dliding and slumping (Vraconian-lowermost Cenomanian); shoreface to off-shore storm-generated limestones (Lower Cenomanian); massive off-shore to shoreface carbonate sand bodies (Lower Cenomanian); prograding rudist bioclastic subaqueous dunes (Lower to Middle Cenomanian); rudist biostromes (Lower to Middle Cenomanian), and high-energy rudist and ostreid coquina beds within skeletal wackestones/packstones (Middle Cenomanian). Rapid changes of depositional systems near the Albian/Cenomanian transition in Istria are mainly the result of synsedimentary tectonics and the establishment of extensive rudist colonies producing enormous quantities of bioclastic material rather than the influence of eustatic changes. Tectonism is evidenced by the occurrence of sliding scars, slumps, small-scale synsedimentary faults and conspicuous bathymetric changes in formerly corresponding environments. Consequently, during the Early Cenomanian in the region of southern Istria, a deepening of the sedimentary environments occurred towards the SE, resulting in the establishment of a carbonate ramp system. Deeper parts of the ramp were below fair-weather wave base (FWWB), while the shallower parts were characterised by high-energy environments with extensive rudist colonies, and high organic production leading to the progradation of bioclastic subaqueous dunes. This resulted in numerous shallowing- and coarsening-upwards clinostratified sequences completely infilling formerly deeper environments, and the final re-establishment of the shallow-water environments over the entire area during the Middle Cenomanian.  相似文献   
10.
《Geobios》2018,51(6):591-596
The first evidence of the presence of Cycadeoidea marylandica (Order Bennettitales) in the Cretaceous of Eurasia is presented. The single specimen consists of a trunk fragment found in the late Albian deposits of the Utrillas Formation, near the village of Gargallo (NE Spain). It is a cylindrical fragment of a silicified trunk with exceptional preservation of external structures (leaf scars and cones). The characteristics of the cones indicate different states of development. The presence of this taxon in deposits of southwestern Eurasia further supports the hypothesis that floristic exchange occurred between North America and the islands that composed the Iberian Plate during Albian times.  相似文献   
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