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1.
Phosphatic nodules are abundant in the Glauconitic Marl (Cretaceous, Cenomanian) of south-east England, particularly where the sequence is condensed. Some of the nodules are derived from the underlying Upper Greensand, and are phosphatic fossil fragments, fossil moulds, and calcareous concretions. Concretions in particular show signs of a complex history of multiple phases of boring, encrustation, phosphatisation, and glauconitisation. Phosphate and glauconite are both replacements after fine-grained carbonate sediment and cement. The majority of the phosphates are whole and fragmentary moulds of fossils. The origin of theses nodules involved: (1) infilling of shells, (2) burial, (3) prefossilisation-cementation of fossil infillings. probably by high magnesian calcite, (4) dissolution of aragonitic shell material, (5) disinterment and exposure of moulds on the sea floor, followed by (6) phosphatisation. boring. and enerustation by various organisms, and sometimes glauconitisation. Many nodules bear evidence of several cycles of cementation, exposure, mineralisation, boring and enerustation.
The closest Recent analogues to the Glauconitic Marl phosphates appear to be the phosphatic crust and nodules forming today off the coast of southern California. The features described and processes inferred from the Glauconitic Marl occurrences appear to have been widespread in nodular phosphatic facies.  相似文献   

2.
The sedimentary features and fossils within the Wadi Hasa Marl Formation coupled with optical luminescence chronology indicate alternating wet and dry periods have occurred on the Jordanian plateau since the last interglacial. The Jurf Ed Darawish Member rests unconformably on the Maastrichtian Muwaqqar Chalk Marl Formation and is composed predominantly of poorly sorted, clast-supported conglomerate. Palaeocurrents and clast composition indicate provenance from Cretaceous sedimentary rocks and Tertiary basalts to the west and southwest of the study site and the facies suggest a flashy alluvial depositional environment probably similar to the modern wadis. The overlying Burma Member consists of bedded grey-green clayey silts and marls with calcrete profiles, up to 1.2 m thick, and isolated gravel lenses. The fine-grained sediments contain charophytes, ostracods, bivalves and various species of gastropod indicating normal freshwater lacustrine conditions. The calcretes contain a poorly preserved fauna suggesting lacustrine deposition followed by subaerial exposure and pedogenesis. Three optical luminescence ages have been obtained from the Burma Member which suggest that the member ranges in age from >111 ka through to <40 ka. The facies variations are indicative of climatic fluctuations in Jordan during this period and human artefacts are found embedded in the sediments. This preliminary study suggests that the Late Quaternary central Jordan sedimentary record may preserve valuable evidence of complex climatic variation which will supplement the data from the Jordan Valley where tectonic activity complicates the sedimentary record.  相似文献   

3.
The Middle Miocene Kingshill Marl of St. Croix, Virgin Islands, affords an opportunity to reconstruct ancient island-margin calcareous plankton communities and to determine their contribution to the accumulation of island-slope sediments. Because of the present outcrop pattern of this unit, both lateral and vertical changes in organism/sediment relationships may be investigated.Subsidence of a NE-SW trending grabenal structure on St. Croix during the latest Early Miocene produced the Kingshill Seaway, which was flanked on the northwest and southeast by island masses of Cretaceous volcanogenic sediments, and on the northeast and southwest by the insular shelf edges. Hydrographic conditions in the shallow Seaway promoted high rates of pelagic biogenic skeletal production, resulting in the accumulation of thick pelagic calcareous oozes composed of a framework of calcitic planktonic foraminiferal tests in a matrix of calcareous nannoplankton, planktonic foraminiferal debris and fine aragonite needles. Minor siliceous components included diatom frustules and sponge spicules. Turbidity currents and debris flows transported terrigenous detritus and reef-tract skeletal rubble into the Seaway from the shallow basin margins.Comparison of the pelagic chalks and marls of the Kingshill Marl with modern sediments accumulating on the northwest St. Croix island slope establishes valuable guidelines to infer the total biogenic composition of the original ooze accumulating on the Kingshill Seaway floor. Comparison of the diagenetic processes affecting island-slope calcareous oozes with those affecting their deep-sea counterparts underscores the necessity of considering the range and intensity of differential solution as a factor in the ooze → chalk diagenetic continuum. The major diagenetic event in the Kingshill Marl ooze → chalk process was the solution of aragonitic skeletal sediment, probably during flushing by fresh water.  相似文献   

4.
The gliding reptiles of the Upper Permian   总被引:1,自引:0,他引:1  
The skeleton of a long-ribbed reptile from the Upper Permian Marl Slate of north-east England is described. The animal is assigned to the genus Weigeltisaurus , previously recorded from the Kupferschiefer of West Germany. Long-ribbed reptiles from the Upper Permian of Madagascar are also considered. Daedalosaurus Carroll, 1978 is a junior synonym of Coelurosauravus Piveteau, 1926. The European and Madagascan genera can be accommodated within a single family Coelurosauravidae, Infraclass Eosuchia. The skull is diapsid with an incomplete lower temporal arcade. Comparison with the modern Draco and the Upper Triassic kuehneosaurids supports the conclusion that the coelurosauravids were effective gliders.  相似文献   

5.
A new exposure at Oborne, Dorset has yielded a rich fossil assemblage of the Lower Bajocian ammonite Kumatostephanus from the Laeviuscula and Humphriesianum zones. The principal bed containing this ammonite, the Green Grained White Marl is locally diachronous; it is an important local marker horizon and it is herein proposed as a formal stratigraphical unit. The specimens obtained allow a better understanding of the evolution of the genus Kumatostephanus and its relationships to the other stephanoceratids, notably Stemmatoceras.  相似文献   

6.
《Biotechnology journal》2007,2(11):1447-1447
Edited by Dr. Stefan Nordhoff, Marl, Germany Highlight articles: – Sustainable production of biofuels – Coupled production in biorefineries – Biodegradation of fuel oil hydrocarbons – Biobutanol: an attractive biofuel – Sustainable biobased energy, fuels and materials – Renewable resources in the chemical industry – breaking away from oil? – Using waste from olive oil industry for fuel production – Economic impacts of bio-refinery and resource cascading systems – Agricultural raw materials – energy or food? ... and much more: Read the next issue of BTJ!  相似文献   

7.
Food vs Fuel     
Cover illustration: This special issue of BTJ, edited by Dr. Stefan Nordhoff (Marl, Germany), highlights the potential but also the drawbacks of biotechnology in energy production. What are the economics behind sustainable energy production? How can we face the competition for the use of biomaterials for food or for mobility? What are new developments in the field? How much agricultural land can be converted and where should water for irrigation come from? What are alternative solutions to the world's energy problem? Cover images © Corbis Digital Stock and Brand X Pictures.  相似文献   

8.
The present paper deals with the paleoecological significance of the clay-mineral and faunal content of the Shiranish Formation which is exposed at the core Gabal Sinjar, northern Iraq.The paleoecology and environmental conditions which prevailed during sedimentation of the Shiranish Formation are revealed by the interpretation and correlation of the faunal content, and the microfacies fabrics together with the clay-mineral facies. The study shows that sediments of the Shiranish Formation have been deposited under shallow marine, moderately energetic, and weakly oxidizing alkaline conditions. Such environmental condition are easily correlated with the Middle Sharawna Marl (Maestrichtian) of Gabal Oweina, Upper Egypt. Also it was noticed that the sedimentation of the Shiranish Formation in the studied section is cyclic.  相似文献   

9.
10.
Chaetognaths are transparent marine animals that are ubiquitous and abundant members of oceanic zooplanktonic communities. Their phylogenetic position within the Metazoa, however, has remained obscure since their discovery. Morphology and embryology have traditionally allied chaetognaths with deuterostomes, but molecular evidence suggests otherwise. Two recent multigene expressed sequence tag (EST) molecular phylogenomic studies suggest that chaetognaths are either sister to the Lophotrochozoa (Matus et al. 2006) or to all protostomes (Marlétaz et al. 2006). We have isolated eight Hox genes, one Parahox gene, and Mox, a related homeodomain gene, from the pelagic chaetognath, Flaccisagitta enflata. Although chaetognath central class Hox genes lack the Lox5 or "spiralian" parapeptide, a diagnostic amino-acid motif that has been utilized previously to assign lophotrochozoan affinity, they do possess a central class Hox gene that has a partial "Ubd-A peptide" found in both ecdysozoan and lophotrochozoan Ubx/Abd-A/Lox2/Lox4 genes. Additionally, we report the presence of two distinct chaetognath posterior Hox genes that possess both ecdysozoan and lophotrochozoan signature amino-acid motifs. The phylogenetic position of chaetognaths, as well as the evolution of the Hox cluster, is discussed in light of these data.  相似文献   

11.
Abstract:  The Cambrian trilobite originally described as Bathyurus gregarius by Billings in 1865 is revised in the light of a new collection from what is judged to be its type locality in the Big Gully Marl Member of the Chamberlain's Brook Formation on the Cape St. Mary's Peninsula of south-east Newfoundland. Here assigned to Parasolenopleura gregaria, it is regarded as the senior synonym of Parasolenopleura cristata (Linnarsson, 1877) in the Swedish Paradoxides ( Eccaparadoxides ) insularis and P. ( Plutonides ) pinus zones, and Parasolenopleura lemdadensis Geyer, 1998 in the Moroccan Ornamentaspis frequens-Kymataspis arenosa zonal boundary beds. Among its features, important details of the relationships of the genal caeca to the eye and cephalic borders are given, as well as illustrations of the significant range of biotic and abiotic morphological variation in holaspid growth stages of the cephalon that will have some bearing on the revision of the Solenopleuridae.  相似文献   

12.
The Cenomanian/Turonian boundary event has been fully documented from a series of localities between Flamborough Head in Humberside and Marham in Norfolk. The carbon isotope excursion can be identified and extrapolated to all the studied sections using bed‐by‐bed correlation. Evidence from studies of the isotope data, trace element geochemistry, and the micropalaeontology are presented. The famous “Black Band” is seen to change laterally into a “red” horizon and then a “green” horizon when traced southwards. This appears to represent the “feather‐edge” of the anoxic event when traced towards a palaeo‐high which is located in the region of the Wash. All the events, so‐identified, can be correlated with the A. plenus Marl succession in southern England.  相似文献   

13.
Spatial heterogeneity in soils is often characterized by the presence of resource-enriched patches ranging in size from a single shrub to wooded thickets. If the patches persist long enough, the primary constraint on production may transition from one limiting environmental factor to another. Tree islands that are scattered throughout the Florida Everglades basin comprise nutrient-enriched patches, or resource islands, in P-limited oligotrophic marshes. We used principal component analysis and multiple regressions to characterize the belowground environment (soil, hydrology) of one type of tree island, hardwood hammocks, and examined its relationship with the three structural variables (basal area, biomass, and canopy height) indicative of site productivity. Hardwood hammocks in the southern Everglades grow on two distinct soil types. The first, consisting of shallow, organic, relatively low-P soils, is common in the seasonally flooded Marl Prairie landscape. In contrast, hammocks on islands embedded in long hydroperiod marsh have deeper, alkaline, mineral soils with extremely high P concentrations. However, this edaphic variation does not translate simply into differences in forest structure and production. Relative water depth was unrelated to all measures of forest structure and so was soil P, but the non-carbonate component of the mineral soil fraction exhibited a strong positive relationship with canopy height. The development of P-enriched forest resource islands in the Everglades marsh is accompanied by the buildup of a mineral soil; however, limitations on growth in mature islands appear to differ substantively from those that dominate incipient stages in the transformation from marsh to forest.  相似文献   

14.
《Palaeoworld》2020,29(1):151-160
A first and detailed foraminiferal biostratigraphic work on the lower part of the Zongshan Formation (Limestone I and Calcareous Marl I sequence) in the Chaqiela section, Gamba, southern Tibet, allows the recognition of three latest Coniacian to middle Campanian planktic foraminiferal biozones: Dicarinella asymetrica Total Range Zone, Globotruncanita elevata Partial-Range Zone, and Contusotruncana plummerae Interval Zone. The base and top of the Santonian Stage in the Chaqiela section were placed at the lowest occurrence (LO) of Globotruncana linneiana and the highest occurrence (HO) of Dicarinella asymetrica, respectively. The deposition of the latest Coniacian to middle Campanian sediments of the lower Zongshan Formation in the Chaqiela section seems to have been continuous or at least without any major gap based on the planktic foraminiferal biozones and events.  相似文献   

15.
New material of Natchitochia from the Bartonian Archusa Marl Member is described here, including thoracic, lumbar, sacral, and caudal vertebrae, an innominate, proximal femur, and pedal? phalanx. The vertebrae and innominate are similar to those of Qaisracetus and Georgiacetus. The structure of the caudal vertebrae support previous observations that as sacral vertebrae disconnect from the sacrum, they become caudalized, developing hemal processes on the posteroventral margins of the bodies, reminiscent of chevron bones associated with true caudal vertebrae. The innominate of Natchitochia shares an elongate ilium and pubis with Qaisracetus and Georgiacetus, which differ from the innominata of the more apomorphic archaeocetes. Comparison of archaeocete innominata and sacra in a phylogenetic context indicates that the apomorphic sacrum composed of 4 vertebrae (Pakicetus, Ambulocetus, Rodhocetus, Maiacetus) was reduced to 3 (Qaisracetus) to 2 (Protocetus?, Natchitochia) to 0 (Georgiacetus, Basilosauridae), while the innominata remained robust, supporting a large hind limb until the origin of the Basilosauridae. In Georgiacetus, the innominate is large but detached from the vertebral column, preventing the use of the hind limb in terrestrial locomotion. More crownward cetaceans for which the innominate is known display greatly reduced innominata and hind limbs are disconnected from the vertebral column.  相似文献   

16.
Acastid trilobites from Ludlow strata on Gotland include three stratigraphically non-overlapping species ofAcastella Reed:Acastella madidipes n. sp. (Hemse Marl and Eke Beds),A. breviceps (Angelin 1851) (Burgsvik Beds), andA. amatrix n. sp. (Hamra Beds, and probably Burgsvik Beds). Type and other material ofA. breviceps (Angelin) from the Klinta Formation, Scania, is revised. Meraspid and early holaspid material ofAcastella is described. Some characters supportAcaste and allied taxa of mostly Wenlock age as a monophyletic subfamily Acastinae.Acastella as widely recognized is a grade with Devonian species more closely related to Asteropyginae than to the Ludlow type species. Baltic Ludlow-P?00ED;dolí species previously placed inScotiella Delo form a distinct group,Ewacaste n. gen., that includes a species from the uppermost Eke Beds on Gotland.  相似文献   

17.
Sirenian vertebrae and ribs have been recently discovered from two Middle Eocene localities of the Pamplona Basin, Navarre (western Pyrenees). These outcrops correspond to different lower Bartonian lithostratigraphic units: the lower part of the Pamplona Marl Formation (Uztarrotz site) and the upper part of the Ardanatz Sandstone (Ardanatz site). The former represents a deep and low-energy sea floor far away from a deltaic slope; the Ardanatz environment probably corresponds to a semi-closed deltaic bay periodically affected by catastrophic floods (i.e., fluvial hyperpycnal flows). The presence of epibiontic activity suggests that the bones were exposed for a while prior to the burial. The histological structures are well preserved except in the peripheral region, where tubular-like microstructures filled by pyrite and iron oxides probably correspond to microbial bioerosion. The major mineral component of the fossil bones is francolite (carbonate fluorapatite). In the Ardanatz samples there is evidence of secondary francolite due to the late replacement of original carbonate fluorapatite through internal fractures. The Ardanatz and Uztarrotz sirenian fossils do not show any evidence of reelaboration. They have similar sum of rare earth elements (REE) concentrations relative to the host rock, but comparatively lower than in other vertebrate fossil bones. This feature may be due to the dense compact structure of pachyosteosclerotic sirenian bones.  相似文献   

18.
Two types of dinosaur footprint, both belonging to the ichnogenus Anchisauripus, are described from the Triassic (Norian) of South Glamorgan, South Wales. They occur on the surfaces of thin-bedded, graded sandstones which are shown to be of sheet flood origin. Other lithofacies associated with the footprints are temporary lake deposits, soil horizons and ephemeral stream conglomerates and sandstones. The overall environment where these dinosaurs lived was that of the low-lying area (piedmont), adjacent to a mountain range (now the South Wales Coalfield) flanked by alluvial fans and talus slopes, and marginal to the Keuper Marl lake.The preservation of the footprints is for the most part perfect, but others are deformed somewhat or simply vague depressions (squelch marks) where the sediment was very muddy and wet. The footprints have been preserved as a result of (1) their impression into a slightly damp muddy sediment (which imparted the best moulding characteristics); (2) slight desiccation during subaerial exposure which made the surface firm and scour-resistant; and (3) burial of the surface by a thin sheet flood of low turbulence, which quickly covered the footprints, and only locally eroded into them.The nature of the footprint trackways indicates that the animals were bipedal and travelling at a strolling pace. There is no indication that they were carnivores or herbivores, but in either case, there is evidence for a food source being available.  相似文献   

19.
The Süßwasser-Schichten (Freshwater Beds) (Oligocene) in the Mainz Basin are a paleontologically poorly studied formation. A succession of predominantly lacustrine marls from Wolfsheim can be attributed to the Süßwasser-Schichten on basis of a palaeoecological and biostratigraphic analysis of its mammal teeth, fish otoliths, ostracods, mollusks, foraminifera and charophytes. The occurrence of the mammal speciesToeniodus aff.hexalophodus andIssiodoromys minor (primitive form) enables an attribution of the Süßwasser-Schichten to the reference level MP 24 of the eurasiatic mammal biostratigraphic zonation. As the reference fauna of level MP 24 is believed to occur in a lithostratigraphically markedly lower horizon, viz. the basal Cyrenenmergel (Cyrena Marl), a re-examination of its origin is suggested. The mammal age of the so-called Süßwasser-Schichten from the locality Heimersheimer Berg is MP 30. Therefore, we suggest a correlation of Heimersheimer Berg with the Mittlere Cerithien-Schichten (MiddleCerithium Beds). The fish fauna of Wolfsheim shows close biogeographical relationships with the fish fauna of Saint-Martin-de-Castillon in southern France and indicates an age around the Rupelian/Chattian boundary. It cannot be decided at the moment whether the Süßwasser-Schichten are of late Rupelian or early Chattian age.  相似文献   

20.
A total of 462 coprolites from three localities exposing Upper Cretaceous deposits in the Münster Basin, northwestern Germany, have been subjected to an array of analytical techniques, with the aim of elucidating ancient trophic structures and predator–prey interactions. The phosphatic composition, frequent bone inclusions, size and morphology collectively suggest that most, if not all, coprolites were produced by carnivorous (predatory or scavenging) vertebrates. The bone inclusions further indicate that the coprolite producers preyed principally upon fish. Putative host animals include bony fish, sharks and marine reptiles – all of which have been previously recorded from the Münster Basin. The presence of borings and other traces on several coprolites implies handling by coprophagous organisms. Remains of epibionts are also common, most of which have been identified as the encrusting bivalve Atreta. Palynological analyses of both the coprolites and host rocks reveal a sparse assemblage dominated by typical Late Cretaceous dinoflagellates, and with sub‐ordinate fern spores, conifer pollen grains and angiosperm pollen grains. The dinoflagellate key taxon Exochosphaeridium cenomaniense corroborates a Cenomanian age for the Plenus Marl, from which most studied coprolites derive. The findings of this study highlight the potential of a multi‐proxy approach when it comes to unravelling the origin, composition and importance of coprolites in palaeoecosystem analyses.  相似文献   

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