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1.
V. S. Markevich A. V. Mozherovskii E. P. Terekhov 《Stratigraphy and Geological Correlation》2012,20(5):466-477
A spore-pollen assemblage was established for the first time in the sediments of the Malokuril??skaya Formation (Khromova Bay, Shikotan Island, Lesser Kuril Range, Kuril island arc system). This find enabled dating of the sediments of the uppermost part of the Malokuril??skaya Formation, which, based on this data, are referred to the Maastrichtian-Danian boundary. The assemblage of radiolarian species was identified for the entire section of the Malokuril??skaya Formation. In sediments of the lower part of the section, members of the Inoceramus group were described. These findings add new information to the paleontological characteristics of the Malokuril??skaya Formation. Moreover, our work allowed detailed correlation of the palynological assemblage studied with coeval palynological assemblages of adjacent areas. The similarity of Cretaceous-Paleogene sections of the Ust-Palanskaya (West Kamchatka), Uchir (Sakhalin Island) and Malokuril??skaya Formations, the Upper Cretaceous basement and the Cenozoic cover of the underwater Vityaz Ridge support the shared history of the development of the entire transition zone from the marginal Sea of Okhotsk to the Pacific at the Maastrichtian-Danian boundary. 相似文献
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Klochkova V. G. Miroshnichenko A. S. Panchuk V. E. Tavolzhanskaya N. S. Yushkin M. V. 《Astronomy Reports》2022,66(5):429-440
Astronomy Reports - The optical spectra of the B-supergiant LS III +52°24 (IRAS 22023+5249) obtained at the 6-m BTA telescope with a resolution $${\text{R}} \geqslant 60{\kern 1pt} {\kern 1pt}... 相似文献
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Please refer to the attachment(s) for more details. 相似文献
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Pyroclastic materials dispersed in recent volcanic eruptions in Northern Patagonia were analysed in order to characterize the volcanic provenance by the geochemical fingerprint. The volcanic products studied were dispersed by eruptions of volcanoes Calbuco in 1961, Chaitén in 2008, and Cordón Caulle Volcanic Complex (CCVC) in 1960 and 2011. The geochemical characterization was based on the determination of 35 major and trace elements by Instrumental Neutron Activation Analysis, including geochemical tracer such as Rare Earth Elements (REE). The study of the pyroclastic products also included the morphological analysis by petrographic and scanning electron microscopy, and the mineralogical characterization by X-ray diffraction.Geochemical tracers determined in the glass fraction of the dispersed pyroclastic materials allowed a clear discrimination of the three volcanoes that gave origin to the tephras, the three of them with different evolution degree. Tephras from 1960 and 2011 CCVC eruptions showed the same geochemical signature. The geochemical parameters providing the differential characterization are the normalized REE and multi-element patterns, the Eu anomaly, the heavy to light and medium to light REE normalized ratios, and the Cs, Sc, Rb, Ta and Th concentrations. The bulk glassy fraction showed the same composition for each volcanic eruption in samples collected even in distant sites (from 100 to 220 km in Chaitén, 2008, and from 80 to 650 km in CCVC 2011), attesting to be the most reliable material for correlation purposes.According to the mineralogy, cristobalite was found in volcano Chaitén tephra as an indicator of such origin. Arsenic, an element of environmental interest, exhibited concentrations ranging from 6 to 16 μg g−1, with the highest values corresponding to Puyehue–Cordón Caulle and Chaitén products. 相似文献
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Simone Fontana Fadi H. Nader Sadoon Morad Andrea Ceriani Ihsan S. Al-Aasm 《Arabian Journal of Geosciences》2010,3(4):351-368
This diagenetic study (including fieldwork, petrographic, fluid inclusion, and stable isotope investigations) deals with the outcrop of Upper Permian–Lower Triassic carbonate rocks, which are equivalent to the Khuff Formation. The studied succession, which outcrops in the Ras Al Khaimah region, northern United Arab Emirates, comprises three formations, including the Bih, the Hagil, and the Ghail formations. The study focuses on unraveling the conditions and fluid compositions encountered during diagenesis of the succession. Emphasize is also made on linking diagenesis to major stratigraphic surfaces and to highlight reservoir property evolution and heterogeneity of the studied rocks. The evolution of fluids and related diagenetic products can be summarized as follows: (1) formation of near-surface to shallow burial, fine-crystalline dolomite (dolomite matrix) through pervasive dolomitization of carbonate sediments by modified marine pore waters; (2) formation of coarse-crystalline dolomite cement by highly evolved marine pore waters (13–23 wt.% NaCl eq.) at elevated temperatures (120–208°C), and (3) calcite cementation by highly saline fluid (20–23 wt.% NaCl eq.) at high temperature (170–212°C). A final calcite cement generation has been formed by the percolation of meteoric fluids during uplift. Fracture- and vug-filling diagenetic minerals are mainly restricted to the mid-Bih breccia marker level, suggesting preferential focused fluid flow through specific stratigraphic surfaces as well as along tectonic-related structures. Reservoir properties have been evolved as result of the interplay of the original sedimentary texture and the diagenetic evolution. Porosity is higher in the Bih Formation, which is dominated by dolomitized packstones and grainstones, than in the Hagil and Ghail formations, consisting mainly of dolomitized mudstones and wackestones. Image analyses were used to quantify the visual porosity in thin sections. The highest porosity values were measured in the Bih Formation, which is characterized by significant amounts of vug- and fracture-filling cements. This feature is attributed to the increase of porosity owing to substantial dissolution of abundant intergranular and vug-filling cements. In contrast, the Hagil and Ghail formations, which consist of finer-grained rock than the Bih Formation, were less cemented, and thus, the porosity enhancement by cement dissolution was insignificant. 相似文献
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Jean Labasse 《GeoJournal》1991,2(1):61-64
Since a 1921 law the harnessing of the Rhône River from Lyon to the Mediterranean has been directed by a national company composed of the public sector (fromthe valley) as well as of various consumers or distributors of current such as the SNCF or the EDF. This company, the National Company of the Rhône (CNR), was a precursor to the establishment of the TVA in the United States, although it did not begin operations until aftetr the TVA due to prolonged technical negotiations and to the difficulties involved in locating financial support in a period of economic crisis. Even though the utilization of hydraulic power constitutes the prime aim of the CNR, it has also focused on navigation, irration and other agricultural uses from the outset.This article will not further discuss the hydro-electric stations on the Rhône which usually supply more than 22% of French hydro-electric output from thirteen stations now in operation (total power is 2,350 MW and annual average output is 13,000 GWh). This paper will treat the question of the nature and importance of the side effects of the harnessing of the Rhône apart from its essential energy function. 相似文献
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The fossil taxa of the Cenomanian continental flora and fauna of São Luís Basin are observed primarily in the bone bed of the Laje do Coringa, Alcântara Formation. Many of the disarticulated fish and tetrapod skeletal and dental elements are remarkably similar to the chronocorrelate fauna of Northern Africa. In this study, we present a summary of the continental flora and fauna of the Laje do Coringa bone-bed. The record emphasizes the existence of a trans-oceanic typical fauna, at least until the early Cenomanian, which may be interpreted as minor evolutionary changes after a major vicariant event or as a result of a land bridge across the equatorial Atlantic Ocean, thereby allowing interchanges between South America and Africa. The paleoenvironmental conditions in the northern Maranhão State coast during that time were inferred as forested humid areas surrounded by an arid to semi-arid landscape. 相似文献
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The faunal composition of stalked echinoderms in the Brazilian Devonian is still largely unknown despite the great abundance of crinoids in the shallow epicontinental seas of the Paleozoic. The first Devonian crinoids of Brazil, recorded in the literature in 1875 and 1903, were from the sedimentary rocks of the Ererê Formation in the Amazon Basin. Since then, the echinoderms of this formation have not been studied. This study, based on isolated pluricolumnals and columnals, described and identified Botryocrinus meloi n. sp., the first record for this genus in Brazil. In addition to this species, two other morphological patterns were identified: Tjeecrinus sp. and Morphotype AM/Er-01. The form of occurrence of the crinoid material and the paleoautoecology of B. meloi allow preliminary characterization of the habitat as a moderately deep water with weak to moderate currents and soft substrate. The similarity between B. meloi and Botryocrinus montguyonensis and of Tjeecrinus? sp. and T. crassijugatus, from the Devonian of the Armorican and Rhenan Massif, represents new evidence for the existence of contact between the faunas of the Amazon Basin with those of northern Gondwana and Armorica during the Middle Devonian. 相似文献
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L. G. Bragina 《Stratigraphy and Geological Correlation》2016,24(2):141-166
A scheme of radiolarian zonal subdivision is proposed for the upper Albian–Santonian of the Tethyan regions of Eurasia. The upper Albian contains one zone: Crolanium triangulare; the Cenomanian contains three zones: Patellula spica (lower Cenomanian), Pseudoaulophacus lenticulatus (middle Cenomanian), and Triactoma parva (upper Cenomanian); the Turonian contains four zones: Acanthocircus tympanum (lower Turonian (with no upper part)), Patellula selbukhraensis (upper part of the lower Turonian), Phaseliforma turovi (middle Turonian (with no upper part)), and Actinomma (?) belbekense (upper part of the middle Turonian–upper Turonian); the Coniacian contains two zones: Alievium praegallowayi (lower part of the Coniacian) and Cyprodictyomitra longa (upper part of the Coniacian); the Santonian contains three zones: Theocampe urna (lower Santonian), Crucella robusta (middle Santonian–lower part of the upper(?) Santonian), and Afens perapediensis (upper part of the upper Santonian). The biostratigraphic subdivisions are correlated with biostrata in the schemes proposed previously for the Tethys and Pacific. A new species Patellula selbukhraensis Bragina sp. nov. is described. 相似文献
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Hydrodynamic characteristics of the western Doñana Region (area of El Abalario), Huelva,Spain 总被引：1，自引：1，他引：0
The Doñana region, in southwestern Spain, comprises a large and important nature reserve, the wetlands of which are affected by human activity. Planting of an extensive eucalyptus forest in the 1950s and, more recently, the use of aquifers for irrigation and water supply for some coastal tourist resorts, have altered the natural groundwater-flow system. The area of the study is the western sector of the region, called El Abalario, which is a gentle topographic elevation between the Atlantic coast and La Rocina Creek (Arroyo de la Rocina). Underneath a variable layer of eolian sands with high dunes near the coast, thick Plio-Quaternary detritic strata, mostly fine silica sands, overlie marls. Near the base there is a variable, deltaic-origin layer of coarse sands and gravels. The dome-shaped water table, inside the sands, is close to the surface everywhere except beneath the dune belt, and small, temporary, shallow lagoons are numerous. The coarse sand and gravel layer conditions groundwater flow and behaves as a semiconfined layer between sands. A cross section through the area was simulated with a model to check the validity of the conceptual groundwater-flow pattern and its sensitivity to the hydraulic parameters. The model was calibrated using parameter values obtained by pumping tests and multilevel piezometric data, and checked against the estimated groundwater discharge into La Rocina Creek. Groundwater flows peripherally to the sea coast, to La Rocina Creek, or directly east and southeastward into the Doñana marshlands, in the Guadalquivir River delta. The average net aquifer recharge rate was calculated to be between 100 and 200 mm year–1 for the area covered by brush, but is remarkably lower in the areas of eucalyptus trees. The transient-state model shows that recharge varies spatially and is not clearly proportional to annual precipitation. Phreatic evapotranspiration plays an important role in decreasing the net value of aquifer recharge to approximately 0.4–0.6 of that calculated with a soil-balance model. The cross section model was used to study the effect of groundwater abstraction on water-table depth by subtracting the contribution of vertical flow, calculated by a well-hydraulics formula, to the semiconfined deep aquifer. The result was a decrease in phreatic evapotranspiration, flow into La Rocina Creek, and lagoon-inundation frequency. Replacement of the eucalyptus forest with native vegetation may raise water-table levels and even reactivate old tributaries to La Rocina Creek.
Resumen La región de Doñana, situada en el sudoeste de España, incluye una gran e importante reserva natural, cuyos humedales están siendo afectados por la actividad humana. La extensa plantación de eucaliptus en la década de 1950 y el uso más reciente de los acuíferos para riego y para abastecimiento de centros turísticos costeros han modificado el sistema de flujo del agua subterránea en esta zona. Este estudio se ha realizado en el sector occidental, llamado El Abalario. Se trata de una elevación suave situada entre el océano Atlántico y el arroyo de La Rocina. Debajo de un manto variable de arenas eólicas, que forma un alto cordón dunar costero, se encuentran sedimentos detríticos plio-cuaternarios formados por arenas silíceas finas, que hacia la base incluyen una capa de arenas gruesas y gravas de origen deltrico, los que a su vez yacen sobre margas. El flujo de agua subterránea está relacionado con niveles de gravas y gravillas semiconfinadas por las arenas fluvio-marinas que contienen el nivel freático. El nivel freático es somero excepto debajo del cordón dunar. Son frecuentes pequeñas lagunas temporales. Se ha simulado el flujo de agua subterránea en una sección para comprobar el modelo de flujo conceptual y la sensibilidad a variaciones de los parámetros. El modelo fue calibrado usando los valores de los parámetros hidráulicos obtenidos en ensayos de bombeo y datos piezométricos medidos a diferentes profundidades, y la descarga estimada al arroyo de La Rocina. La recarga de agua subterránea drena lateralmente, por un lado hacia la costa y por otro lado a través del arroyo de La Rocina, o directamente hacia las Marismas de Doñana situadas en el delta del río Guadalquivir. Con una lluvia media anual entre 550 y 600 mm, la recarga neta media estacionaria anual del acuífero, considerando periodos de tiempo largos, se estima entre 100 y 200 mm en las zonas de vegetación autóctona, y es notablemente menor en las zonas de plantación de eucaliptos. El modelo transitorio indica que la recarga varia espacialmente y no es claramente proporcional a la precipitación para periodos de un año. La evapotranspiración freática varia espacialmente y juega un papel importante; disminuye el valor neto de la recarga al acuífero para dejarlo en 0,4 a 0,6 de lo que se calcula mediante un balance de agua en el suelo. La sección modelada sirve para estudiar el efecto de la extracción de agua subterránea sobre la profundidad del nivel freático mediante la substracción del flujo vertical, que se calcula mediante una fórmula de hidráulica de pozos para el acuífero semiconfinado profundo. El resultado es una disminución de la evapotranspiración freática, del flujo al arroyo de la Rocina y de la frecuencia de inundación de las lagunas. La substitución del bosque de eucaliptus por vegetación nativa puede elevar los niveles freáticos e incluso reactivar antiguos "caños" tributarios al arroyo de La Rocina.
Résumé La région de Doñana, située dans le sud ouest de l'Espagne, comprend une importante réserve naturelle avec des zones humides, affectée par l'activité humaine. L'exploitation de vastes plantations d'eucalyptus pendant les années 50 et l'usage plus récent des nappes souterraines pour l'irrigation et l'alimentation en eau des centres touristiques côtiers ont modifié le système de flux d'eau souterraine dans cette zone. La présente étude a été réalisée dans le secteur occidental, appelé El Abalario. Ce secteur consiste en une légère élévation située entre l'Océan Atlantique et la ravine de La Rocina. Une couverture variable de sables éoliens, formant une haute crête dunaire côtière, recouvre des sédiments detritiques plio-quaternaires, déposés eux même sur des sables siliceux lesquels reposent à leur tour sur des marnes. Près de la base se trouvent des sables grossiers et des graviers d'origine deltaïque, dont l'épaisseur varie spatialement. Le flux d'eau souterraine est conditionné par l'aquifère semi confinés des graviers et des sables grossiers. Le niveau phréatique de l'aquifère libre des sables fluvio-marins est peu profond, excepté sous les dunes. On y trouve souvent des petites lagunes temporaires peu profondes. Le flux de l'eau souterraine a été simulé dans une section verticale pour vérifier le modèle hydrogéologique conceptuel et la sensibilité aux variations des paramètres. Le modèle a été calé en utilisant d'une part les valeurs des paramètres hydrauliques obtenus par des essais de pompage et d'après les données piezométriques mesurées à différentes profondeurs, et d'autre part l'apport estimé de la ravine de La Rocina. L'écoulement d'eau souterraine s'effectue par drainage latérale dans trois directions, d'une part vers la côte, d'autre part à travers la ravine de La Rocina et finalement directement vers les Marais de Doñana situés à l'est et sud-est dans le delta du fleuve Guadalquivir. Avec une pluviométrie moyenne comprise entre 550 et 600 mm, la recharge nette moyenne annuelle des nappes, pour des périodes de temps assez longues, est estimée entre 100 et 200 mm dans les aires de végétation autochtone, et elle est nettement inférieure dans les aires plantées d´eucalyptus. Le modèle transitoire montre que la recharge varie dans l'espace et qu'elle n'est pas clairement proportionnelle aux précipitations annuelles. L'évapotranspiration phréatique joue un rôle important et diminue la valeur nette de la recharge des nappes de 0,4 à 0,6 de la valeur calculée avec un modèle de bilan d'eau dans le sol. La section modélisée est utilisée pour étudier l'effet de l'extraction d'eau souterraine sur la profondeur du niveau phréatique en soustrayant le flux vertical, calculé grâce à une formule d'hydraulique des puits, de la nappe profonde semi-confinée. Le résultat de cette extraction est une diminution de l'évapotranspiration phréatique, du flux au niveau de la ravine de La Rocina et de la fréquence d'inondation des lagunes. La substitution de forêts d'eucalyptus par de la végétation autochtone peut permettre la remonté des niveaux phréatiques et même réactiver d'anciens ravins affluents à La Rocina.相似文献
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This paper provides the first palynological data from four Upper Cretaceous localities from the Islands of Hvar and Šćedro (southern Croatia), in the central part of the Adriatic Carbonate Platform. Studied material represents palynomorphs produced by coastal vegetation and transported to the shallow marine platform areas. Determined vegetation includes diverse hygrophilous, understory vegetation, range of evergreen needle trees attributable to Pinaceae and Podocarpaceae, as well as Araucarian conifers; ginkgo, cycads and/or bennettites. Flowering plants were likely represented by herbaceous forms. The palynoflora is generally indicative of a temperate, warm and humid climate. The occurrence of the Normapolles group with the presence of Plicapollis sp. and Pseudoculopollis sp. point to Turonian or probable Turonian–Coniacian age, and represent the southernmost record of occurrence within the Normapolles palynological province. Dominance of angiosperms and low abundance of ferns suggests an early-Late Cretaceous age. These findings are supported by the micropaleontological analyses and previously determined age of the sauropod dinosaur footprints described on the Island of Hvar. Based on the paleobotanical and palynological data, the dinosaur diet probably included araucarian conifers, ginkgo and angiosperms, and ferns to a lesser extent. 相似文献
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YU Wen 《《地质学报》英文版》2014,88(4):1262-1287
Yangtzeconus priscus-Archaeospira ornata, an important earliest Cambrian benthonic Assemblage of the Yangtze micromolluscan fauna, occurs mainly in the Lower Cambrian Zhongyicun and Dahai Members of the Yuhucun Formation in E Yunnan, the Tianzhushan Member （=Huangshandong Member） of the Dengying Formation in W Hubei and the Maidiping Member of the Hungchunping Formation in C Sichuan, China. About 90% of the genera of this Assemblage are unknown from the Nemakit-Daldynian and Tommotian molluscan Assemblages of the Siberian Platform, Russia. About 90% of the Siberian molluscan genera do not occur in the Zhongyicun and Dahai Members in the Meishucun section and in the corresponding beds of the Yangtze Platform, because the Tommotian molluscan Assemblage is characterizedly abundant archaeocyathids. It is clearly indicated that the Yangtze and Siberian molluscan Assemblages represent different bio- and lithofacies and ages. The age of the pre-trilobitic Yangtzeconus priscus-Archaeospira ornata Assemblage is older than that of the Nemakit-Daldynian and Tommotian molluscan Assemblages and referable to the Earliest Cambrian. Two new genera Mcnamaraconus and Zhangwentangoconus are herein proposed. 相似文献
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Belyaev Yu. R. Panin A. V. Kiryuhina A. D. Koshurnikov A. V. Kramynin A. M. Pavlov M. A. Konstantinov E. A. Kurbanov R. N. Zakharov A. L. Sychev N. V. 《Doklady Earth Sciences》2022,506(1):S84-S93
Doklady Earth Sciences - A complex of works including geomorphological deciphering, field survey, drilling, electric prospecting, and dating of deposits using the radiocarbon method and optically... 相似文献
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Abed Salih Al Dulaymie Bayan Muhie Hussien Moshtaq Ahmed Gharbi Husam Naji Mekhlif 《Arabian Journal of Geosciences》2013,6(3):801-816
This research examined the balneological characteristics of spring waters within the area of Abu-Jir Fault Zone throughout the hydrogeologic aspects explained by the setting of the hydrogeologic units including the water-bearing horizons of Euphrates, Ana, and Baba Formations. The groundwater flow in the hydrogeologic system correlated with the trends of enrichment or depletion case processes of mineralization (spatial distribution maps of TDS and other components) show different phenomena of groundwater source and interconnection, which helps in the classification springs into two potential site. The physicochemical characteristics of the water flow from springs indicate a hydrochemical approach throughout the spatial variation of important parameters (using Rockware software) related to the balneological study. The monitoring network of the spring waters performed by seven field measurements and 33 variables (totaling to 720 detected measurements) in 18 springs approved the after desk study and water point inventory using a GPS apparatus (GARMIN SUMMIT-e TREX). The study examined the integrated hydrogeological aspects and spring water properties for evolutions and the classification of minero-medicinal water. The traditional hydrochemical information of the spring waters and their sediment properties correlated with balneological limits (standards and definitions) are used in the selection of springs characterized by balneotherapeutic applications. A suggested screening and ranking technique has been developed for evaluating preferable springs selected for natural therapy. The application of ranking technique indicates four graded consequent preferable springs for balneotherapeutic investment: first grade spring represented by Kubaiysa spring (S-4); second grade springs represented by Tawila spring (S-12); third grade springs represented by Mamora spring (S-15), Arnab spring (S-10), Zazoe spring (S-5), and Maqtoom spring (S-13); and fourth grade springs represented by Khalidiya spring (S-16) and Layeg spring (S-7). 相似文献
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The Ordovician stratigraphy of southern-central Xizang (Tibet) has been revised based on new conodont data recovered from 43 samples in four stratigraphic units and their integration with existing nautiloid and graptolite data. The Histiodella holodentata and Pygodus serra biozones have been identified respectively in the Alai and Jiaqu formations of the Chiatsun Group exposed near Alai village in Nyalam County within the Himalayan terrane, and the Yangtzeplacognathus foliaceus Subbiozone (lower part of the Pygodus serra Biozone) in the Sangqu Formation exposed at the Guyu section within Zayu County in the Lhasa terrane. Recognition of these biozones has increased the precision of correlation of the middle-upper Darriwilian strata in the region. Regional reassessment of the Ordovician stratigraphy permitted by new biostratigraphic data has allowed revised definitions for the Chiatsun and Keerduo groups and the Sangqu and Xainza formations. The Chiatsun Group is defined herein to include three lithologically distinctive formations in descending order, the Jiaqu, the Alai and the Adang formations. The stratigraphic age for the Jiaqu and Alai formations in the type area ranges from the middle Darriwilian (Histiodella holodentata Biozone) to middle Katian (Hamarodus brevirameus Biozone), but the age of the Adang Formation remains less certain. 相似文献
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Comparative analysis of the composition and formation conditions of the dunite–pyroxenite association of the Guli Pluton and ultramafic vulcanite (meimechite) showed the similarity of their initial melts and the same type of crystallization, demonstrating the cumulative origin of dunite. 相似文献