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1.
The Jurassic successions represent a wide distribution in North of the Kerman province. These successions include Ab-Haji, Badamu, and Hojedk formations. The Hojedk Formation contains the plant fossils. The Lenjan section is one of the suitable areas for paleontological studies on the Hojedk Formation. The study section is mostly composed of green sandstone and shale with several interbedded coal veins with different thicknesses. The thickness of the Hojedk Formation is about 200 m in the Lenjan section. In this study, seven genera and 13 species of macro plant fossils were identified and described, including Nilssonia undulata, Nilssonia bozorga, Nilssonia berriesi, Nilssonia sp., Klukia cf. exilis, Klukia exilis, Cladophlebis antarctica, Coniopteris lobata, Coniopteris murrayana, Elatocladus confertus, Podozamites sp., Equisetites sp., and Coniopteris sp. The Bajocian–Bathonian can be attributed to the Lenjan section based on the recognized flora.  相似文献   

2.
Dam failure constitutes a grave threat to human life. However, there is still a lack of systematic and comprehensive research on the loss of life (L) caused by dam break in China. From the perspective of protecting human life, a new calculation method for L occurred in dam break floods is put forward. Fourteen dam failure cases in China are selected as the basic data by three-dimensional stratified sampling, balancing spatial, vertical elevation and temporal representations, as well as considering various conditions of the dam collapse. The method includes three progressive steps: Firstly, some impact factors of loss of life (IFL) are selected by literature survey, i.e., severity of dam break flood (S F), population at risk (P R), understanding of dam break (U B), warning time (T W) and evacuation condition (E C). And the other IFL of weather during dam break (W B), dam break mode (M B), water storage (S W), building vulnerability (V B), dam break time (T B) and average distance from affected area to dam (D D) are also taken into account to get a more comprehensive consideration. According to disaster system and disaster risk, these eleven IFL are divided into four categories. Through the improved entropy method, eight key IFL are further selected out of the eleven. Secondly, four L modules are built based on four categories, which are L-causing factor module (M 1), L-prone environment module (M 2), affected body module (M 3) and rescue condition module (M 4). Eventually, by using two methods of multivariate nonlinear regression and leave-one-out cross-validation in combination with coupled four modules, the calculation method for L is established. Compared with the results of Graham method and D&M method, the result of the proposed one is much closer to the actual value and performs better in fitting effect and regional applicability. In the application, L calculation and consequence assessment are carried out in the example of Hengjiang reservoir that has already broken down. At the same time, L calculation and risk prediction are used in the analysis of Yunshan reservoir, which is under planning. The proposed method can not only be applied to estimate L and its rate (f L ) under various types of dam break conditions in China, but also provide a reliable consequence assessment and prediction approach to reduce the risk of L.  相似文献   

3.
The surroundings of Solothurn (NW Switzerland) have been known for their fossil marine turtles since the beginning of the nineteenth century. In more recent history, access to the fossil bearing layers i.e. the Rätschenbank (Kimmeridgian, Late Jurassic) has not been possible until 1986 when one of the old quarries in the area re-opened. A series of excavations from 1986 to 1989 provided new material and a unique opportunity to re-investigate the fish fauna of the Solothurn Turtle Limestone that has not been dealt with since Agassiz (1833–1844). Examination and classification of the Solothurn specimens, mainly jaw fragments and teeth, furnished 11 species in 6 major groups: chimaeras (Ischyodus), selachians (Hybodus, Paracestracion, Asteracanthus), semionotids (Lepidotes), pycnodontids (Gyrodus, Proscinetes), caturids and oligopleurids (Caturus, Callopterus, Ionoscopus), and aspidorhynchids (Belonostomus).  相似文献   

4.
The Campanian-Lower Paleogene successions exposed at the Kharga Oasis contain well-preserved gastropods. Nineteen gastropod species are identified and described in detail. Two new species are established: Gisortia khargaensis from the lower Eocene El Rufuf Formation and Ornopsis? barisensis from the lower Paleocene Kurkur Formation. In addition to, Turritella (Torquesia) derbesi Coquand is recorded herein for the first time from Egypt. The studied gastropods belonging to four clades: Sorbeoconcha (Metacerithium abictiforme (Wanner), Mesalia hofana Mayer-Eymar, Mesalia sp., Turritella (Torquesia) derbesi Coquand, Turritella (Torquesia) forgemoli Coquand, Turritella kaserensis Hewaidy and Azab, Turritella sp.), Littorinimorpha (Cypraedia bullina Oppenheim, Gisortia khargaensis nov. sp., Natica farafrensis Wanner, Aporrhais schweinfurthi (Quaas), Drepanocheilus bicarinatus Abbass, Drepanocheilus? sp., Anchura? unicarinatus (Abbass), Epitonium sp.), Neogastropoda (Ornopsis? barisensis nov. sp., Rostellana daniensis (Quaas), Vouta sp.), and Heterobranchia (Avellana cretacea Quaas).  相似文献   

5.
Micofloral study of Lameta sediments and associated sauropod coprolites in the Nand-Dongargaon basin in Maharashtra was conducted to understand the diet and habitat of sauropods. The study revealed the presence of pollen, spores, algal and fungal remains, well-preserved cuticles of Poaceae, and testate amoebae. Vegetation during Lameta included tall arboreal taxa, such as conifers (Podocarpus and Araucaria), Cycads (Cycas), Euphorian and Barringtonia and herbs and shrubs, such as Cheirolepidiaceae (Classopollis), Arecaceae (Palmaepollenites), Poaceae (Graminidites), Asteraceae (Compositoipollenites), Caryophyllaceae (Cretacaeiporites and Periporopollenites), and Acanthaceae (Multiareolites). Data suggest that the sauropods ate soft tissues of angiosperms and gymnosperms. The intake of testate amoeba, algal remains, sponge spicules, and diatoms might be through water intake.  相似文献   

6.
Upper Cretaceous pelagic deposits outcropping in the Maçka (Trabzon) region include radiolarians and pelagic foraminifera. The Çatak Group represented by the volcano-sedimentary successions consists of three formations having different properties. Two sections, ÇTK1 and ÇTK2, are selected from the Çe meler and Elmalι Dere formations, respectively, establishing the biostratigraphy of outcropping sedimentary units. A total of 17 species of Whiteinella, Helvetoglobotruncana, Marginotruncana, Dicarinella, Praeglobotruncana, Archaeoglobigerina and Hedbergella demonstrating the early Turonian–Coniacian are established in the ÇTK1 stratigraphic section. The early Turonian radiolarian fauna consisting of Halesium sexangulum Pessagno, 1971, Crucella cachensis Pessagno, 1971, Stichomitra communis Squinabol, 1903 is also defined in the same section. A total of 30 species of Crucella, Halesium, Pessagnobrachia, Patulibracchium, Alievium, Archaeospongoprunum, Dicyomitra, Stichomitra, Diacanthocapsa, Dactiyliodiscus, Amphipydax, Pseudoaulophocus, Acaeniotyle, Archaeodictyomitra, Actinomma, Xitus, Neosciadocapsidae characterizing the early and late Turonian, as well as the Coniacian–early Santonian are recognized from red-coloured pelagic limestones of the ÇTK2 section. Also, planktonic foraminifera species of Marginotruncana, Hedbergella, Heterohelix, Globotruncana, Globotruncanita, Archaeoglobigerina, Dicarinella characterizing the Coniacian–Santonian are described in the thin sections of the same samples. The age of red-coloured limestones is identified as the Coniacian–Santonian benefit from radiolarians and pelagic foraminifera. Consequently, radiolarians and pelagic foraminifera within sedimentary successions of the investigation area are distributed in two intervals that coincide with the early Turonian–Coniacian and Coniacian–Santonian intervals.  相似文献   

7.
Accurate laboratory measurement of geo-engineering properties of intact rock including uniaxial compressive strength (UCS) and modulus of elasticity (E) involves high costs and a substantial amount of time. For this reason, it is of great necessity to develop some relationships and models for estimating these parameters in rock engineering. The present study was conducted to forecast UCS and E in the sedimentary rocks using artificial neural networks (ANNs) and multivariable regression analysis (MLR). For this purpose, a total of 196 rock samples from four rock types (i.e., sandstone, conglomerate, limestone, and marl) were cored and subjected to comprehensive laboratory tests. To develop the predictive models, physical properties of studied rocks such as P wave velocity (Vp), dry density (γd), porosity, and water absorption (Ab) were considered as model inputs, while UCS and E were the output parameters. We evaluated the performance of MLR and ANN models by calculating correlation coefficient (R), mean absolute error (MAE), and root-mean-square error (RMSE) indices. The comparison of the obtained results revealed that ANN outperforms MLR when predicting the UCS and E.  相似文献   

8.
Fish diets play a critical role in our understanding of aquatic trophic dynamics and are an important component in developing ecosystem-based approaches to fisheries management. Although large nektonic fishes exert top-down predator effects on the food web and typically support viable commercial and recreational fisheries, little is known about the diet of this guild. We evaluated the diets (6327 stomachs) of four nektonic predatory fishes (Pomatomus saltatrix [78–395 mm], Cynoscion regalis [91–520 mm], Morone americana [156–361 mm], and Morone saxatilis [82–785 mm]) in Delaware Bay and in the adjacent ocean. To assess ontogenetic, geographic, and interspecific variation in diets, observations from individual fish stomachs were clustered into species-size class groups, and dietary overlap was estimated using multivariate analyses. A shift in diet composition, as well as diversity, occurred along the estuarine gradient and into the adjacent ocean. Some prey were shared by most predators, including some crustaceans (dominated by Callinectes sapidus, mysids, and Palaemonetes spp.), fundulids (dominated by Fundulus heteroclitus), engraulids (dominated by Anchoa mitchilli), and clupeids (dominated by Brevoortia tyrannus). However, inter- and intra-specific variation in diet was observed as well. In particular, M. americana consumed fewer engraulids and clupeids, and many more and diverse types of invertebrates, while P. saltatrix consumed more clupeids and less invertebrates. The lack of overlap in diet between the four predators evaluated, and between size groups for each predator, supports previous evidence that these groups feed in trophic guilds defined by species and by size within a species. The highly variable diets for these predators suggest high resolution spatial data are necessary in order to quantify their most important prey and their role in coastal ecosystems.  相似文献   

9.
We present a new normalization for the linear density-perturbation spectrum in a multi-parameter model of the Universe. Using the differential mass function for the nearly galaxy clusters obtained from optical data, we have constructed a functional relation between the dispersion of the density contrast σ 8 on the scale 8h ?1 Mpc and the cosmological parameters Ω m , ΩΛ, h, n, f v for each of three theoretical approximations of the mass function: Press-Schechter, Sheth-Tormen and Jenkins. An extended class of models of the Universe with general spatial curvature include four parameters for the matter components: baryons (Ω b ), “cold” dark matter (Ω c ), “hot” dark matter (Ω v ), and the vacuum energy (ΩΛ). It is shown that the most accurate normalization of the power spectrum is achieved with the Sheth-Tormen approximation.  相似文献   

10.
Pore solution salinity has important bearing on engineering behavior of marine sediments as they influence electrochemical stress (A–R) and differential osmotic stress (?π) of the salt-enriched clays. The electrochemical stress (A–R) is contributed by van der Waals (A) attraction and diffuse ion layer repulsion (R), while the differential osmotic stress (?π) is governed by the differences in dissolved salt concentrations in solutions separated by osmotic membrane. The paper examines the relative influence of differential osmotic stress (Δπ) and electrochemical stress (A–R) on the consolidation behavior of slurry consolidated kaolinite specimens, which are known to be encountered in recent alluvial marine sediments. Methods are described to evaluate the magnitudes of these physico-chemical components and their incorporation in true effective stress. Results of the study demonstrate that differential osmotic stress finitely contributes to true effective stress. The contribution from differential osmotic stress enables kaolinite specimens to sustain larger void ratio during consolidation.  相似文献   

11.
The area of investigation was subject to multifactor analysis of the relationship between the maximum amount of mudflow solid sediments (W) and parameters such as the mudflow basin area (S), average channel slope (α), and mudflow channel length (L). They were used to obtain analytical expressions in order to approximate the W(S, L, α) relation based on the mudflow genesis and source height. Statistical data on mudflow manifestations in different basins in the North Caucasus covering more than fifty years were used to obtain the analytical expressions in order to assess the maximum volume of mudflow solid sediments.  相似文献   

12.
Laboratory measurements are required to study geophysical properties of the subsurface because of lacking direct observation of Earth’s crust. In this research, compressional (P) and shear (S) wave velocity measurements have been conducted on cylindrical specimens of Quartz-micaschist cored using rock blocks taken from the zinc and lead Angouran mine, Zanjan, northwest of Iran. Cylindrical rock specimens were prepared from the blocks by coring in 0°, 30°, 45°, 60°, and 90° into the foliation direction. P- and S-wave velocities were measured along the cylindrical specimens with different foliation orientations. Percent variations of the P- and S-wave velocities (Thomsen’s anisotropic parameters ε and γ) and constant dynamic modulus of test results have been determined. Percent variations of the P-wave velocity (ε) increase with an increase of the foliation angle with respect to the propagating waves direction by a parabolic function as it shows P-wave velocity differences up to a maximum value of 50 %. Thomsen’s anisotropic parameter of γ has also the same function with the foliation angle. Meanwhile, foliation orientation has a much greater influence on ε than γ for foliation angle from 45° to 90° as \( \frac{\varepsilon }{\gamma } \) ratio increases with an increase of foliation angle. Values of dynamic elastic modulus (E), Poisson’s ratio (ν), shear modulus (μ), bulk modulus (K), and Lamé’s constant (λ) increase with the increase of foliation angle with the parabolic function. The results show that dynamic elastic modulus, Poisson’s ratio, shear modulus, bulk modulus, and Lamé’s constant have anisotropic behavior in relation with the foliation orientation.  相似文献   

13.
This article describes a complete sedimentary succession of an ancient macrotidal tide-dominated estuarine system based on the detailed outcrop study. The Eocene siliciclastic sedimentary facies of Ameki Group in the south-eastern Nigeria provides a record of the sedimentary response to an initial regression, followed by marine incursion (transgression) into the Niger Delta Basin. These sedimentary successions are analogues to the subsurface petrolific Niger Delta lithostratigraphic units. Seven facies associations (FA 1 to FA 7) are documented in the study area and the sediments are interpreted as fluvial channel, tidally influenced fluvial channel, tidal channel, tidal flats, supratidal, tidal sand bar and estuarine embayment (open estuarine) deposits. The occurrence of low diversity ichnofaunal assemblages and/or localised high-density monospecific ichnofossil assemblages indicates brackish-water condition typical of estuarine settings. The suites of assemblages include Scoyenia, Skolithos, Cruziana, mixed Skolithos-Cruziana, Glossifungites, Psilonichnus and Teredolites ichnofacies. A complete depositional sequence is encountered in the Eocene Ameki Group which consists of the lowstand, transgressive, highstand and falling stage systems tracts. This depositional succession was most probably controlled by relative sea level changes, sediment supply, accommodation and regional tectonics which affected the development of Niger Delta Basin.  相似文献   

14.
The crystal structure of mangan-neptunite, a manganese analogue of neptunite, has been refined in two space groups (Cc and C2/c). The mineral is monoclinic, with the correct space group Cc; the unit-cell dimensions are: a = 16.4821(6), b = 12.5195(4), c = 10.0292(3) Å, β = 115.474(1)°, and V = 1868.31 Å3. The crystal structure has been refined to R 1 = 0.0307 (wR 2 = 0.0901) on the basis of 4892 observed reflections with |F hkl | ≥ 4σ|F hkl |. The most plausible acentric model is caused by the Ti- and (Fe, Mn, Mg)-ordering in the structure. Ti-octahedrons are strongly distorted and consist of short bond Ti-O (1.7 Å), one long bond (2.2 Å), and four equal bonds (2.0 Å). Fe-octahedrons are regularly shaped, with all Fe-O bonds being approximately identical.  相似文献   

15.
Measurements of the broadening of pulsar pulses by scattering in the interstellar medium are presented for a complete sample of 100 pulsars with Galactic longitudes from 6° to 311° and distances to three kiloparsec. The dependences of the scattering on the dispersion measure (τ sc(DM) ∝ DMα), frequency (τ sc(v) ∝ v ?γ ), Galactic longitude, and distance to the pulsar are analyzed. The dependence of the scattering on the dispersion measure in the near-solar neighbourhood can be represented by the power law τ sc(DM) ∝ DM2.2±0.1). Measurements at the low frequencies 111, 60, and 40 MHz and literature data are used to derive the frequency dependence of the scattering (τ sc(v) ∝ V ?γ ) over a wide frequency interval (covering a range of less than 10: 1) with no fewer than five frequencies. The index for the frequency dependence, γ = 4.1 ± 0.3, corresponds to a normal distribution for inhomogeneities in the turbulence in the scattering medium. Based on an analysis of the dependence of the scattering on the distance to the pulsar and on Galactic longitude, on average, the turbulence level C n 2 is the same in all directions and at all distances out to about three kpc, testifying to the statistical homogeneity of the turbulence of the scattering medium in the near-solar region of the Galaxy.  相似文献   

16.
New finds and revision of available collections of nonmarine bivalves provided grounds for development of a zonal scale for terrestrial sequences of the Permian System based on species belonging to the genus Palaeomutela Amalitzky, 1891, which are characterized by regular changes in the structure of the shell hinge. The scale includes two parallel zonal successions that are based on the stratigraphic distribution and evolutionary trends of two morphological lineages of the genus. The zonal succession based on development of the P. umbonata group (dwellers of mobile waters and silty-psammitic substrates) includes 11 range zones: stegocephalum, ovatiformis, umbonata, quadriangularis, krotowi, wohrmani, numerosa, ulemensis, keyserlingi, curiosa, golubevi. The zonal succession based on development of the P. castor group (dwellers of calm waters and silty-pelitic substrates) includes eight range zones: larae, castor, olgae, doratioformis, marposadica, fischeri, obunca, amalitzkyi. The proposed zonal units are correlated with scales based on ostracod, fish, and tetrapod fossils. New species Palaeomutela golubevi sp. nov. and P. amalitzkyi sp. nov. are described with the extended diagnosis of the genus Palaeomutela.  相似文献   

17.
We have modeled the magnetic fields of the slowly rotating stars HD 116458 and HD 126515 using the “magnetic charge” technique. HD 116458 has a small angle between its rotation axis and dipole axis (β = 12°), whereas this angle is large for HD 126515 (β = 86°). Both stars can be described with a decentered-dipole model, with the respective displacements being r = 0.07 and r = 0.24 in units of the stellar radius. The decentered-dipole model is able to satisfactorily explain the phase relations for the effective field, Be(P), and the mean surface field, Bs(P), for both stars, along with the fact that the Be(P) phase relation for HD 126515 is anharmonic. We discuss the role of systematic measurement errors possibly resulting from instrumental or methodical effects in one or both of the phase relations. The displacement of the dipole probably reflects real asymmetry of the stellar field structure, and is not due to measurement errors. Using both phase relations, Be(P) and Bs(P), in the modeling considerably reduces the influence of the nonuniform distribution of chemical elements on the stellar surface.  相似文献   

18.
This paper presents the numerical simulation of pile installation and the subsequent increase in the pile capacity over time (or setup) after installation that was performed using the finite element software Abaqus. In the first part, pile installation and the following load tests were simulated numerically using the volumetric cavity expansion concept. The anisotropic modified Cam-Clay and Dracker–Prager models were adopted in the FE model to describe the behavior of the clayey and sandy soils, respectively. The proposed FE model proposed was successfully validated through simulating two full-scale instrumented driven pile case studies. In the second part, over 100 different actual properties of individual soil layers distracted from literature were used in the finite element analysis to conduct parametric study and to evaluate the effect of different soil properties on the pile setup behavior. The setup factor A was targeted here to describe the pile setup as a function of time after the end of driving. The selected soil properties in this study to evaluate the setup factor A include: soil plasticity index (PI), undrained shear strength (S u ), vertical coefficient of consolidation (C v ), sensitivity ratio (S r ), and over-consolidation ratio (OCR). The predicted setup factor showed direct proportion with the PI and S r and inverse relation with S u , C v and OCR. These soil properties were selected as independent variables, and nonlinear multivariable regression analysis was performed using Gauss–Newton algorithm to develop appropriate regression models for A. Best models were selected among all based on level of errors of prediction, which were validated with additional nineteen different site information available in the literature. The results indicated that the developed model is able to predict the setup behavior for individual cohesive soil layers, especially for values of setup factor greater than 0.10, which is the most expectable case in nature.  相似文献   

19.
The Jurassic-Cretaceous (Volgian-Lower Valanginian) boundary deposits in the lower reaches of the Lena River (near the village of Chekurovka and on the Cape Chucha, North Yakutia) are described bed-by-bed. The taxonomic composition of ammonites and bivalves (mainly Buchia) is determined. The species assemblages are biostratigraphically analyzed and biostratigraphic units of the bed and zone ranks are recognized based on by Buchia and ammonites. Analogues of the Buchia Zones (buchiazones) Unschensis, Okensis, Tolmatschewi, Inflata and ammonite zones Exoticus, Okensis, Sibiricus, Analogus, Mesezhnikowi and ? Klimovskiensis are established in this region for the first time. A correlation of the distinguished buchiazones with the buchiazones of the Nordvik Peninsula, New Siberian Islands (Stolbovoy Island), the basin of the Anyuy River, and Northern California is proposed. The ammonite assemblages constantly contain phylloceratids; some stratigraphic intervals also contain lytoceratids; this is probably connected with a Paleo-Pacific influence. Unlike the ammonite assemblages of the same age of the Khatanga depression, the subzones cannot be distinguished in the Sibiricus and Kochi Zones of the Lower Lena due to differences in the stratigraphic ranges of some ammonite species. Hectoroceras in the Kochi zone is very rare and Praetollia predominates here.  相似文献   

20.
Deepwater sections of the Maikop Group (Oligocene-lower Miocene) and overlying lower-middle Miocene sediments are studied near the Perekishkyul Settlement in lower reaches of the Sumgait River, northern Azerbaijan. Several lithological reference levels and the Spiratella (Pteropoda) Beds are used to correlate preliminarily these uniform clayey sections barren of benthic fossils. Based on distribution of the organicwalled and calcareous phytoplankton, spores, pollen and ichthyofossils, the sections are first subdivided in detail and dated. Distinguished in the sections are two regional levels characterizing distortions in the basin hydrological regime during the late Oligocene (level with large Leiosphaeridia and Pterospermella) and Burdigalian (level with dominant dinocysts of the genus Batiacasphaera), and separate intervals with diverse phytoplankton and ichthyofossils. The Tarkhanian sediments are marked by first-appearing oceanic nannoplankton with Sphenolithus heteromorphus and deepwater ichthyofauna with Vinciquerria merklini. The Karaganian is established at the first occurrence level of peculiar endemics (Sardinella karaganica W. Dan. and Mugil karaganicus Swich.) among ichthyofauna.  相似文献   

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