A comparative analysis of time–depth relationships derived from scientific ocean drilling expeditions     

Sauermilch  Isabel  Mateo  Zenon Richard P.  Boaga  Jacopo 《Marine Geophysical Researches》2019,40(4):635-641

Marine Geophysical Research - Time–depth relationships (TDR) are required for correlating geological information from drill sites with seismic reflection profiles. Conventional...  相似文献   

Contrasting Phytoplankton Structure and Morphologically Based Functional Groups of Reservoirs That Differ in the Adjacent Surrounding          下载免费PDF全文

Elżbieta Wilk‐Woźniak  Judita Koreivienė  Jūratė Karosienė  Agnieszka Pociecha  Magdalena Strzesak  Wojciech Mróz 《洁净——土壤、空气、水》2016,44(6):638-647

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Estimation of the Eddy thermal diffusivity coefficient in water     

Mr. A. Bartzokas 《Meteorology and Atmospheric Physics》1985,33(4):401-405

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A simplified analysis of interface failure under compressive normal stress and monotonic or cyclic shear loading     

Zenon Mrz  Marcin Bia&#x;as 《国际地质力学数值与分析法杂志》2005,29(4):337-368

Interface damage and delamination is usually accompanied by frictional slip at contacting interfaces under compressive normal stress. The present work is concerned with an analysis of progressive interface failure using the cohesive crack model with the critical stress softening and frictional traction present at the contact. Both monotonic and cyclic loadings are considered for anti‐plane shear of an elastic plate bonded to a rigid substrate by means of cohesive interface. An analytical solution can be obtained by neglecting the effect of minor shear stress component. The analysis of progressive delamination process revealed three solution types, namely: short, medium and long plate solutions. The long plate solution was obtained under an assumption of quasistatic progressive growth of the delamination zone. In view of snap back response, the quasistatic deformation process cannot be executed by either traction or displacement control. The states of frictional slip accompanied by shake down or incremental failure are distinguished in the case of cyclic loading, related to load amplitude and structural dimensions. The analysis provides a reference solution for numerical treatment of more complex cases. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

On the propagation of pressure-patterns: Part I     

Mr. R. W. James 《Pure and Applied Geophysics》1953,25(1):101-113

Summary The propagation speed of sinoidal troughs and wedges in a steady state flow is determined from consideration of the mass transport due to the bodily motion of the system. Fundamental propositions are established regarding the mutual motion of wind-, pressure-, temperature-, and density-fields.It is found that in a frictionless barotropic general flow, all perturbations are propagated with the same speed—the speed of the general current. In a baroclinic general flow a perturbation will only be propagated without dispersion if it has a specific (sinoidal) horizontal structure.When a sinoidal perturbation is embedded in a baroclinic general flow-field, it will be propagated as though by a barotropic flow with the sameeffective speed. The effective speed can be computed when the vertical structure of the perturbation and of the mean flow are known.It is frequently assumed that the speed of mean flow at some particular level (500 mb is often assumed) gives the «steering» of the surface perturbation by a baroclinic general flow, that is to say, a baroclinic flow steers a perturbation with the speed of an equivalent barotropic field. The present paper provides a rational basis for the concept of an equivalent barotropic flow, but it is to be remembered that the «steering level» does not depend uniquely on the vertical structure of the mean flow-field, but varies from perturbation to perturbation, being lower for shallow perturbations than for (vertically) deep ones.  相似文献   

The problem of the extension of the Siberian anticyclone towards Southeast Europe,and its relation to atmospheric circulation anomalies over the Northern Hemisphere     

Dr. T. J. Makorgiannis  Mr. B. D. Giles  Dr. A. A. Flocas 《Meteorology and Atmospheric Physics》1981,30(3):185-196

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A note on estimating the direct and diffuse components of global radiation     

Dr. J. D. Kalma  Mr. P. M. Fleming 《Theoretical and Applied Climatology》1972,20(2):191-205

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Late Pleistocene glaciation of Páramo de La Culata,north-central Venezuelan Andes     

Dr. Carlos Schubert  Mr. Sam Valastro 《International Journal of Earth Sciences》1974,63(2):516-538

Late Pleistocene glacial features in the Páramo de La Culata region, north-central Venezuelan Andes, include: 1. depositional features: morainic till and fluvio-glacial deposits (terrace gravels); 2. sculptured features: glaciated valleys, cirques, horns, and arêtes; and 3. erosional features: striation and grooving, polished rock, roches moutonnées and whaleback forms, and erratic boulders. Two main levels of moraines were found, an older one at 2600 m elevation, and a younger one between 3000 and 3500 m. The difference in age is reflected by the higher degree of weathering, erosion, and vegetation cover of the lower level, as compared with the higher level. Radiocarbon dating, and a comparison and correlation of these glacial features with those of adjacent regions, indicates that the lower morainic level (2600 m) is probably the result of the main glacial advance of the Late Wisconsin Glaciation. The main morainic level (3000 to 3500 m) was probably formed by the latest Wisconsin glacial advance. The Late Pleistocene snow-line depression reached approximately 1200 m below the present snow-line (i. e., down to approximately 3500 m).  相似文献   

Seasonal climatic variability over the Southern Oceans     

Mr. N. A. Streten 《Theoretical and Applied Climatology》1977,25(1):1-19

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Geochronology of upper Tertiary volcanic activity in the Andes of north Chile     

Mr. M. C. W. Baker 《International Journal of Earth Sciences》1977,66(1):455-465

25 new K-Ar data are presented for Upper Cenozoic andesites and ignimbrites from the Andes of north Chile between 20° 30 S and 22° 30 S. The original simple volcanic stratigraphy of andesites overlying ignimbrites has been refined. A more complicated stratigraphy, with some andesites predating the ignimbrites, is described. The sequence and timing of volcanic events differ along the length of the north Chilean Andes. Ages of the earliest widespread ignimbrite eruptions range from 21 m. y. to 10 m. y., in different segments of the volcanic chain. The existence of two large acid extrusives of Quaternary age suggests that generation of acid magmas has continued until recently.

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Zusammenfassung 25 neue K-Ar-Daten von känozoischen Andesiten und Ignimbriten der nordchilenischen Anden zwischen 20° 30 S und 22° 30 S werden vorgestellt. Die ursprünglich einfache Stratigraphie — Andesite überlagern Ignimbrite — wurde verfeinert, und eine komplexere Stratigraphie, bei der einige Andesite älter sind als die Ignimbrite, wird beschrieben. Die Reihenfolge und der zeitliche Ablauf vulkanischer Tätigkeit sind in den nordchilenischen Anden komplex. Die ältesten ausgedehnten Ignimbritdecken reichen in den verschiedenen Abschnitten der Vulkanzone von 21 bis 10 Mio. Jahre. Das Vorhandensein von zwei großen sauren quartären Extrusionszyklen läßt vermuten, daß die Bildung von sauren Magmen bis in die Gegenwart andauerte.

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Resumen Se presentan 25 nuevas edades radiométricas de lavas y ignimbritas Cenozoicas de los Andes del Norte Chileno, entre los meridianos 20° 30 S y 22° 30 S. La estratigrafía primera de las rocas volcanicas (las lavas sobre las ignimbritas) se ha refinado. Se describe una estratigrafia mas complicada, en que algunas lavas antedatan las ignimbritas. La sucesión y las edades de los eventos volcanicos diferen a lo largo de los Andes del Norte Chileno. Las edades de las erupciones mas tempranas y extensivas varian entre 21 M. a. y 10 M. a. en segmentas diferentes de la zona volcanica. La existencia de dos grandes derrames acidos de edad cuaternaria sugere que la producción de magmas acidas continuó hasta el tiempo reciente.

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Résumé On présente 25 valeurs nouvelles sur l'âge radiométrique des andésites et des ignimbrites du Cénozoïque supérieur des Andes du nord du Chili entre les latitudes 20° 30 et 22° 30 S. L'ancienne stratigraphie simplifiée où les andésites surmontent les ignimbrites a été révisée, et remplacée par une stratigraphie plus compliquée où quelques andéseites précèdent les ignimbrites. La succession et la chronologie des éruptions volcaniques diffèrent le long des Andes du nord du Chili. Dans les différentes parties de la chaîne volcanique, l'âge des premières grandes eruptions d'ignimbrites varie entre 21 et 10 M. a. La présence de deux grandes coulées acides d'âge quaternaire permet de supposer que des magmas acides continuent à se former.

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