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1.
Autoassociation is a computer method of comparing a sequence of nonnumeric elements, e.g., of rock types. The sequence is slid past a replicate of itself. At each position of overlap the number of matching elements is noted and statistics of goodness-of-match are computed. The method allows several properties to be coded at each position in the sequence. It also allows unknown, missing, or not applicable elements. Reverse matches also are performed, i.e., with the duplicate sequences reversed in direction. Autoassociation is used to detect partial repetitions in stratigraphic sequences and to compare regressive and transgressive phases of cyclothems.  相似文献   

2.
This paper analyses the meeting between the international petroleum industry and two local communities. The building of an oil terminal in a local community is both a major event, and a generator of processes on the local level. Three different angles is used to enlighten these processes; categorised as as place, people and mind. The place analysis consentrates on the effects on population and workforce development, the people analysis look at the institutional and planning processes, and the mind analysis the effects on the feeling of local identification. The paper demonstrates that local factors are of crucial importance even for the international petroleum industry.  相似文献   

3.
The term environment has been used in various and inconsistent ways by scientists from many disciplines and can frequently be regarded as an empty formula. The author argues that this term has an ascertained meaning only within the concept of ecology. Therefore, any attempt to use the relative term environment in an absolute way and apart from this context must necessarily lead to its hypostatization, giving it the character of an entity of its own. The different aspects of the ecology concept — here called dimensions — should rather be defined according to the specific approaches of particular empirical studies. The paper briefly discusses the meaning of those dimensions which are interrelated and form a multidimensional space. Depending on the position of a particular approach within this multidimensional concept, a specific, ontologically neutral definition of environment may be developed, whose meaning (in accordance with the scale of reflections) can now be specified.This text is the enlarged and altered version of a lecture given on 1979-08-27 at the Third Vienna International Meeting on Human Ecology (Vienna, 1979-08-27–1979-08-31).  相似文献   

4.
Zusammenfassung Die Bildung des Spateisensteinganges von Grube Neue Haardt schließt an die Hauptfaltung an. Der Gang ist aus einer Abschiebung entstanden und wird von der Geisweider Überschiebung abgeschnitten.Es wird nachgewiesen, daß auf dieser Überschiebung nach Zeit und Richtung unterschiedliche Bewegungen stattgefunden haben.  相似文献   

5.
SummaryNumerical Analyses of Deformability Tests in Jointed Rock — Joint Perturbation and No Tension Finite Element Solutions Sound design of structures in or upon rock requires a thorough knowledge of the rock mass deformability. Field test data interpretation has generally relied upon analytical or Finite Element linear elastic solutions. However, when testing in jointed rock, these can no longer be readily used since the medium cannot resist the tension induced upon loading. Accordingly, other solutions are required. If the discontinuities of the rock mass can all be mapped and their surface properties determined, the Finite Element model will use a Joint Perturbation solution where the joint elements have variable stiffnesses to account for movements along the fractures. If the discontinuities cannot be satisfactorily mapped, a global approach is provided by a No Tension analysis of the stress transfer type. The two techniques are compared in the case of bore hole jack deformability tests and found to agree remarkably well, indicating an appreciable difference from results of linear elasticity.
ZusammenfassungNumerische Analyse von Verformungsversuchen in geklüfteten Fels — Lösungen mittels Kluft-Perturbation und No Tension Analysis auf Grund der Methode der Finiten Elemente Der Entwurf von Bauwerken in oder auf Fels erfordert eine genaue Kenntnis des Formänderungsverhaltens der Felsmasse. Im allgemeinen basiert die Interpretation der Ergebnisse von Feldversuchen auf den Lösungen des zugehörigen Randwertproblems der linearen Elastostatik mittels klassischer analytischer Methoden oder der Methode der Finiten Elemente. Wenn die Versuche aber in geklüftetem Fels durchgeführt werden, müssen die theoretischen Methoden modifiziert werden, da das Medium keine Zugspannungen aufnehmen kann. Zwei Fälle können unterschieden werden. Erstens: die Kluftflächen der Felsmasse können geometrisch erfaßt und ihre Oberflächeneigenschaften können bestimmt werden; in diesem Falle kann die Finite-Elemente-Lösung eine Kluft-Perturbations-Methode verwenden, in welcher spezielle Kluft-Elemente verschiedener Steifigkeiten normal und tangential zu den Kluftflächen die Bewegungen entlang derselben bestimmen. Zweitens: die Diskontinuitäten der Felsmasse können nicht hinreichend beschrieben werden; für diesen Fall ist vorgekehrt durch die Finite-Element-Analyse vom Typ der Spannungsumlagerung unter Ausschaltung der Zugspannungen (No Tension Analysis), um das globale Verhalten der geklüfteten Felsmasse zu erfassen. Die Lösungen dieser beiden Methoden wurden für den Fall der Bohrloch-Verformungs-Tests verglichen; der Vergleich zeigt ausgezeichnete Übereinstimmung, im Gegensatz zu den Lösungen als lineares Elastizitätsproblem.
RésuméLa méthode des Eléments Finis appliquée aux résultats d'essais de vérins cylindriques dans les roches fissurées — solutions dites Joint Pertubé et Sans Traction La construction de structures sur ou dans des roches nécessite une connaissance approfendie de la déformabilité du massif rocheux. L'analyse des résultats d'essais en place se fait généralement à l'aide de solutions analytiques ou par Eléments Finis, qui supposent une élasticité linéaire du milieu. De fait, dans les roches fissurées, ces solutions sont inadéquates puisque le milieu ne peut résister aux sollicitations de traction. Il s'agit donc d'utiliser d'autres méthodes d'analyse. Lors qu'il est possible de déterminer la géométrie et les propriétés de toutes les discontinuités, l'on pourra utiliser une solution par Eléments Finis, dite Joint Perturbé dans laquelle la rigidité de surface du joint (ou fissure) peut varier lorsque des movements prennent place au niveau du joint. Si cela est impossible, il faudra utiliser une approche globale dite Sans Traction qui redistribue les contraintes de traction et les dissipe. On compare ces deux types de solutions dans le cas des essais de vérins cylindriques unidirectionnels. Leurs résultats sont identiques et ont nettement différents de ceux obtenus avec une solution élastique linéaire.

Research supported by the National Aeronautics and Space Administration — Contract NAS 8-21432.

With 8 Figures  相似文献   

6.
Laterites occur extensively in the lowlands of Sri Lanka whereas these are observed as localized outcrops in the uplands and the highlands. In lateritis weathering profiles, Al-rich zones are found between and beneath harder Fe-rich layers. The processes of lateritisation and bauxitisation have produced residual products enriched in both Fe2O3 and Al2O3. In the lowlands and uplands the lateritisation processes have prevailed and the bauxitisation trend is more pronounced in the highlands.
Résumé Les gisements latéritiques s' observent largement dans les lowlands du Sri Lanka. Mais dans les uplands et highlands les affleurements latéritiques sont rares. Aux profils d'altération les zones riches en Al se trouvent entre ou sous les zones plus dures mais riches en Fe. Les deux processus de latéritisation et bauxitisation ont donné lieu aux produits résiduels riches en Fe2O3 ainsi qu'en Al2O3. Il a été observé que le processus de latéritisation se produit plus souvent dans les lowlands et uplands tandis que la bauxitisation est plus repandue aux highlands.
  相似文献   

7.
    
Analysis of empirical data considered to be mixtures of a finite number of end members has been a topic of increasing interest recently. The algorithms EXTENDED CABFAC and QMODEL by Klovan and Miesch (1976) represent a satisfactory solution to this problem if pure end members are captured within the data set or if the composition of true end members are known a priori. Where neither condition is satisfied, the composition of external end members can, under certain conditions, be deduced from the structure of the data. Described herein is an algorithm termed EXTENDED QMODEL which defines feasible end members which are closest to the data envelope.This research was supported in part by a grant from the Office of Naval Research (N00014-78C-0698 Code 483).  相似文献   

8.
Coal seams and culm banks associated with mine fires in the anthracite region of eastern Pennsylvania have been burning for decades. Many of the fires may have ignited by spontaneous combustion or by the burning of trash. Minerals associated with the combustion of anthracite form by the condensation of gas exhaled through surficial gas vents or anthracite smokers. A Pressure-Temperature (P-T) stability diagram is constructed for the condensation of orthorhombic sulfur from anthracite gas using Thermodynamic Loop Analysis (TL analysis). This method of analyzing chemical systems incorporates Kirchhoff's Law into a four step procedure structured around a closed thermodynamic cycle or thermodynamic loop. The four steps, referred to us The Four S S of Thermodynamic Loop Analysis, include: (1) Set Up—graphical characterization of the problem. (2) Sum—the application of thermodynamic principles. (3) Substitute—the use of materials data available from the literature, and (4) Solve—computation of one or more variables. The example presented demonstrates that thermodynamic loops can incorporate any number of polymorphic phase transformations. In addition, thermodynamic loop analysis is applicable to any geologic process involving the condensation of minerals from a gas. The stability diagram derived by TL analysis may have applicability in monitoring the release of sulfur gas into the atmosphere.  相似文献   

9.
Metamorphic rocks at Milos are known in small outcrops beneath the volcanic formations, as xenoliths in the Traphores volcanic breccia and as pebbles in the Paleochora Quaternary deposits. These rocks seem to belong to three different metamorphic units which probably have intricate relationships in the basement: — the eclogites unit shows garnetjadeite or garnet-omphacite primary associations, with apparently late crystallization of lawsonite phenoblasts an recrystallization features at relatively low temperatures; — the glaucophane schist unit exhibits Jadeite+quartz or glaucophane+lawsonite primary mineralogy; — the greenschist facies unit shows low-pressure main assemblages, most generally developed after high-pressure events. The two former units involve tholeiitic meta-igneous rocks, having been spilitized before metamorphism; they generally suffered more or less advanced recrystallization features in the low-pressure field of the greenschist facies. The third unit shows only meta-sedimentary rocks, with the sole exception of one single meta-doleritic pebble having calk-alkaline affinities.Petrological and mineralogical studies, based upon 15 bulk-rock compositions and 178 probe-analysed data points, lead to suspect at least 2, perhaps 3, different metamorphic events rather than one single metamorphic evolution, to account for the 3 U distinguished. From the observation of the mineralogical assemblages and their evolution, the former events (stages 1 and 2) could be related to rapid subduction of ocean-floor or back-arc basalts, whereas, during the latter event (stage 3), the rocks experienced crystallization conditions involving both decreasing pressures and increasing temperatures.  相似文献   

10.
Discusses the tragedy of the commons with regard to fish resources in the North Atlantic, and points to the fact that the Atlantic cod has now been so heavily exploited that a strong regulation of fisheries is needed to preserve an exploitable stock. The author argues for exclusive economic zones dividing up the remaining loopholes among coastal nations and individually transferable quotas.  相似文献   

11.
The history of geography needs to be more closely connected with recent revisionist accounts of the history of science. After a brief review of some of the newer historiographic insights that have lately been applied to writings on geography's history, this paper sets out some additional principles that historians of the subject might profitably engage. Chief among these are the consequences of taking seriously the situatedness and contingency of geographical knowledge and practice.  相似文献   

12.
Summary Anhydrous partial melting experiments on four peridotite compositions have been conducted at 10 kbar providing a relatively internally consistent set of data on the character of primary melts expected from the oceanic upper mantle in the mid-ocean ridge setting. The four peridotite compositions are: MORB pyrolite (considered to be suitable for the production of primitive (Mg#0.68) MORB glasses at 10 kbar), Hawaiian pyrolite (representative of enriched upper mantle), Tinaquillo lherzolite (representative of more depleted upper mantle), and the spinel lherzolite KLB-1 which is a suitable composition for the production of primitive MORB glasses. The equilibrium liquids were determined by sandwich experiments. The primitive MORB glass DSDP 3-18-7-1 was used in experiments using MORB pyrolite and KLB-1, while a calculated 10 kbar liquid composition fromJaques andGreen (1980) was used in experiments with Hawaiian pyrolite and Tinaquillo lherzolite. The results of the experiments are used to test a 10 kbar melt model for the generation of primitive MORB glasses, which are parental magmas to typical MORB compositions. The melt compositions from the four peridotites studied are significantly different from primitive MORB glasses in major element chemistry and plot away from the field of primitive MORB glasses in the CIPW molecular normative Basalt tetrahedron. The results indicate that primitive MORB glasses are derivative compositions lying on olivine fractionation lines from picritic parents, which themselves are primary magmas at pressures greater than 10 kbar. The results of this study are integrated with previous 10 kbar experimental studies.
Wasserfreie partielle aufschmelzung von MORB pyrolit und andere peridotit-zusammensetzungen bei 10 kbar: bedeutung für die entstehung primitiver MORB gläser
Zusammenfassung Vier Peridotit-Zusammensetzungen wurden bei 10 kbar unter wasserfreien Bedingungen partiell aufgeschmolzen, und die Ergebnisse mit möglichen primitiven Schmelzen Mittel-Ozeanischer Rücken verglichen.Die folgenden perioditischen Zusammensetzungen wurden untersucht: MORB pyrolite [mögliche Ausgangszusammensetzung für primitive (Mg# > 0.68) MORB-Glaszusammensetzungen bei 10 kbar], Hawaiian pyrolite (representativ für angereicherten Oberen Mantel); Tinaquillo lherzolite (representativ für verarmten' Oberen Mantel) und spinel lherzolite, KLB-1 (im Gleichgewicht mit primitiver MORB-Glaszusammensetzung). Die Schmelzen im Gleichgewicht mit diesen Ausgangszusammensetzungen wurden mittels Sandwich-Experimenten ermittelt.Die primitive MORB-Glaszusammensetzung DSDP 3-18-7-1 wurde mit MORB pyrolite und KLB-1 equilibriert, während eine Modell-Zusammensetzung vonJaques and Green (1980) in Verbindung mit Hawaiian pyrolite und Tinaquillo lherzolite vermischt wurde. Die Resultate der Experimente werden mit einem 10 kbar Aufschmelzungsmodell zur Entstehung primitiver MORB-Gläser verglichen. Die Schmelzen im Gleichgewicht mit den vier Peridotit-Ausgangszusammensetzungen unterscheiden sich wesentlich von primitiven MORB-Gläsern, sowohl hinsichtlich ihrer Hauptelemente als auch ihrer Plot-Parameter im Basalttetraeder. Primitive MORB-Glaszusammensetzungen stellen keine primären Schmelzen dar, sondern sind durch Olivinfraktionierung von primitiven Magmen abzuleiten. Die Resultate dieser Untersuchungen werden mit früheren 10 kbar Experimenten verglichen.

With 10 Figures  相似文献   

13.
An objective replacement method for censored geochemical data   总被引：1，自引：0，他引：1  
Geochemical data are commonly censored, that is, concentrations for some samples are reported as less than or greater than some value. Censored data hampers statistical analysis because certain computational techniques used in statistical analysis require a complete set of uncensored data. We show that the simple substitution method for creating an uncensored dataset, e.g., replacement by3/4 times the detection limit, has serious flaws, and we present an objective method to determine the replacement value. Our basic premise is that the replacement value should equal the mean of the actual values represented by the qualified data. We adapt the maximum likelihood approach (Cohen, 1961) to estimate this mean. This method reproduces the mean and skewness as well or better than a simple substitution method using3/4 of the lower detection limit or3/4 of the upper detection limit. For a small proportion of less than substitutions, a simple-substitution replacement factor of 0.55 is preferable to3/4; for a small proportion of greater than substitutions, a simple-substitution replacement factor of 1.7 is preferable to4/3, provided the resulting replacement value does not exceed 100%. For more than 10% replacement, a mean empirical factor may be used. However, empirically determined simple-substitution replacement factors usually vary among different data sets and are less reliable with more replacements. Therefore, a maximum likelihood method is superior in general. Theoretical and empirical analyses show that true replacement factors for less thans decrease in magnitude with more replacements and larger standard deviation; those for greater thans increase in magnitude with more replacements and larger standard deviation. In contrast to any simple substitution method, the maximum likelihood method reproduces these variations. Using the maximum likelihood method for replacing less thans in our sample data set, correlation coefficients were reasonably accurately estimated in 90% of the cases for as much as 40% replacement and in 60% of the cases for 80% replacement. These results suggest that censored data can be utilized more than is commonly realized.  相似文献   

14.
An understanding of the irregular coordination polyhedra exhibited by the M2 cations in clinopyroxenes is of prime importance in connection with the behaviour of solid solutions and polymorphism in pyroxenes.As shown by unfolding the silica chains in pigeonite, cations with octahedral stereochemistry like Mg++and Fe++ cause kinking of the silica chains, whereas larger cations like Ca++and Na+have an opposite namely straightening effect. This is a probable factor causing immiscibility in the Mg++-Ca++ solid solutions in pyroxenes. In pyroxene structures with kinked silica chains the arrangement of oxygen atoms approaches close packing; consequently different stacking sequences will be energetically possible leading to polymorphism in pyroxenes.When Pauling's electrostatic valence rule is applied to clinopyroxenes, the charge balance will be exceedingly improved if effective coordination number of M2 cation is assigned and if the distortions of M 2 coordination polyhedron is considered.  相似文献   

15.
Continental tholeiites cannot be identified using the Ti-Y-Zr diagram. Two-hundred and thirteen analyses from 16 localities representing 7 continental tholeiitic provinces all plot outside the within-plate basalt field of this diagram.Analyses representing about 50% of the population plot in the ocean-floor basalt field, the rest plots in the calc-alkali basalt field. Therefore problems might arise when attempts are made to classify ancient tectonomagmatic environments using the Ti-Y-Zr diagram.  相似文献   

16.
This paper analyzes the history and consequences of two large scale hydroelectric projects in Amazonian Brazil. The argument makes three points. First, environmental impacts of such projects are inseparable from issues of human rights, regional economic development, and social justice. The implication of this view is that another development, something quite different from the industrial ideal of modernization, is necessary in Amazonia and elsewere.Second, analytical fragmentation of problems into specialist concerns with such topics as ecology (often only meaning wildlife), environment (often concerned only with soil erosion and regional climate), and human rights (sometimes only focusing on the rights of indigenous people, not small farmer migrants tempted to settle in such areas) is mirrored by a fragmented, and therefore weak, resistance to hydroelectric development. The paper traces the early signs of a more unified resistance movement capable of overcoming these special interests and fragmentation.Third, the paper provides data on an economic monstrosity. The Balbina dam was begun in 1981, had cost $ 700 million by 1988, will not be viable withoutanother $ 700 million of design correction, andeven then will not provide enough electricity for Manaus city: this is a monument to an apparent inability to learn from history.Funding provided by the Luce Program in Food, Resources, and International Policy of Hampshire College; The Peggy Howard Fund; Public Service/Social Change Program of Hampshire College; The Explorer's Club; Patrick T. Knight. Special Thanks to Dorothy and Egydio Schwade, Paulinho Paiakan Kaiapo. In Memory of Chico Mendes.  相似文献   

17.
Zusammenfassung Aus randlichen Teilbecken des Tuz Gölü (Salzsee), Türkei, werden bis zu 40 cm große, über dem Wasserspiegel des Salzbeckens liegende Salzschirme beschrieben, deren einzelne Anwachsstreifen verschiedenen Wasserständen bei der Evaporation des Beckens entsprechen. Die Schirmform kann durch bevorzugtes Horizontal-Wachstum der NaCl-Kristalle in der obersten Wasserschicht bei gleichzeitig sinkendem Wasserspiegel gedeutet werden. Ansatzpunkte für die Schirmbildung sind im Sediment steckende NaCl-inkrustierte Pflanzenstengel, die in das Becken eingeschwemmt wurden.
Occurrence and origin of Salt-umbrellas in the Tuz Gölü (Salt-Lake), Turkey
Salt umbrellas with a maximum diameter of 40 cm are a special form of NaCl growth. They occur above the water surface of evaporating Tuz Gölü (Salt Lake) in Central Anatolia, Turkey. The different growth rims of the umbrella correspond to the different water levels during evaporation of the basin.The umbrella-like shape is best to be explained by the fact that within the uppermost water layer (highest NaCl-concentration) NaCl-crystals grow preferentially in horizontal direction while the water level is steadily sinking.Small plant-stems having been brought into the basin and incrusted by NaCl act as crystallization centers for the formation of the umbrellas.

Herrn R. H. Okan, Direktor der Salzwerke von Yavsan Tuzlasi, sowie Herrn Georg Irion, Heidelberg, danke ich herzlich für die wertvolle Mithilfe bei der Probenahme.  相似文献   

18.
The concept of space is one of the most fundamental of geographical concepts. There is no work in geography that does not certain it. Nevertheless, geography has not as yet formulated an explicit and unambiguous definition of geographical space. This fact has had negative consequences for geographical theory, methodology and application. In the effort of contributing to its elimination we will try to outline the basic connotations of the concept.The concept of geographical space is a relational one. It acquires meaning and sense only when related to other concepts. The concept of space may be conceived as a supplement to things, i.e. substantively conceived objects. Space conceived in this way is the synonym of emptiness. The concept of space may be also conceived in relation ti individual landscape elements as their environments. Space conceived in this way has the character of a field of force. And, finally, space may be conceived also with respect to the totality of landscape elements, i.e. the system expressed by the term synergic. It is only this third variant of space which should be understood as the geographical space in the full menaing of the term. It is only this conception of geographical space as the space filled with qualities in relations and proportions that is considered as one of the basic prerequisites for the formulation of the theory of geography as science capable of prediction and thus also of practical utilization.  相似文献   

19.
Conclusions Considering the admitted facts, nothing allows us to affirm that the glasses studied by N.P. are really genuine glasses arising from an incongruent melting of biotite, and there is no reason not to consider these glasses as being pinite.  相似文献   

20.
In recent years, there have been numerous calibrations of the biotite-garnet Fe-Mg exchange geothermometer. The Eastern Lac Seul region of the English River subprovince, Ontario, provides an excellent field area in which to compare these calibrations.Trend surface analysis using the temperatures obtained from garnet cores and matrix biotites-showed almost identical trends in the eastern Lac Seul region regardless of the calibration used. The absolute temperatures and the precision of each calibration do, however, show large variation. Geothermometers based solely on lnKD were found to give more precise results than the calibrations that attempt to incorporate non-Fe-Mg components. The Perchuk and Lavrent'eva (1983) thermometer yields the most precise and accurate results. If a sufficient number of samples are collected over a region, it can be used to estimate metamorphic temperature trends to ±30° C. Metamorphism and migmatization of the English River subprovince occurred during the Kenoran orogeny, 2.68 b.y. ago. Our results show that a thermal anticline has been preserved, with temperatures of 600° C at the north and south contacts with Uchi and Wabigoon Greenstone belts, increasing to 725 °C at the center of the subprovince. A garnet-cordierite in isograd occurs at 650° C and an orthopyroxene in isogradat 700° C.  相似文献   

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