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1.
Mn-activated cathodoluminescence can be used in several fields of carbonate petrography. It may, for instance, be possible to recognize
  1. cement sequences and their correlation (Tab. 1, Figs. 1, 2, 4; Tab. 2, Fig. 1)
  2. growth fabrics of skeletons (Tab. 2, Figs. 2, 3, 4; Tab. 3, Figs. 1, 2)
  3. dolomitisation processes and problems (Tab. 1, Figs. 1, 2; Tab. 4, Fig. 2)
  4. transformation paths from Mg-calcite to calcite and from aragonite to calcite (Tab. 2, Fig. 1; Tab. 3, Figs. 3, 4; Tab. 4, Fig. 1)
  5. growth structures in certain types of ooids (Tab. 1, Fig. 4; Tab. 3, Fig. 3; Tab. 4, Fig. 1)
  6. reworked skeletal particles (Tab. 3, Fig. 4)
  7. phantom grains and fossil-outlines in a micro- or macrocrystalline groundmass (Tab. 4, Figs. 2, 3)
  8. healed fissures crossing micro- or macrocrystalline carbonate rocks (Tab. 4, Fig. 4).
These are, however, no general luminescence criteria indicating the depositional environment. Luminescence of calcite and dolomite requires 20–40 ppm Mn, with the equipments used in this study. Aragonite is not yet investigated systematically. Zonal luminescence in carbonate cements may indicate changes of the chemical composition of the aquifer and may be used for “cement stratigraphy”. In skeletons it rather indicates physiological changes. While aragonitic skeletons lose their luminescence Zonation during replacement by calcite, Mg-calcite skeletons may keep parts of it, because their replacement preserves the original crystal fabric. Blotchy luminescence developes in Mg-calcitic particles during their adjustment to lower Mg-calcites by dissolution-precipitation processes in solutions with changing Mn/Fe-ratios.  相似文献   

2.
Systematic natural hazard mapping in Japan was started after WW II using aerial photographs. Analysing the interaction between disaster occurrence and land conditions is the most useful method for establishing the disaster prediction system for three types of disaster, flood disaster, mass-movement disaster, and earthquake disaster, which are strongly related to land conditions. A series of maps on natural hazards were established based on the results analysed. In our opinion, the following problems of natural hazard mappings remain so far unsolved:
  1. No clear distinction is made between natural hazard mapping and land classification.
  2. Organization of information for natural hazard prevention is not yet established.
  3. There is no established earthquake disaster prevention map.
  4. Utilization of new machines and tools is inadequate.
  5. Effect of human activity is not estimated.
  相似文献   

3.
Problems of landscape and resource protection resulting from the intensification of land-use can be mastered only by intersectoral planning and a land management considering (landscape-)ecological principles right from the beginning. In the district of Leipzig ecological studies in the '80ies have focussed on:
  1. Determination of the regional pattern of atmospheric immissions;
  2. Registration of heavy metals in soil and vegetation;
  3. Soil compaction, soil erosion;
  4. Study of stress indicators in the aeration zone and in the top-most aquifer in order to examine barrier effects in the percolation process.
First results are discussed.  相似文献   

4.
Prior experimental work has shown that in the laboratory the mineralogy of eclogites is sensitive to the ratio of CaO ∶ MgO ∶ FeO and that the reaction pyroxene + kyanite?garnet + quartz proceeds to the right at high pressures in rocks rich in magnesium and to the left in rocks rich in calcium and iron. Typical basalts crystallized at high pressure never contain kyanite. The chemistry and mineralogy of a large number of naturally occurring eclogites show they belong to three classes.
  1. Kyanite-free magmatic eclogites, rich in magnesium, from:
  2. kimberlites
  3. dunites and serpentinites.
  4. Kyanite-bearing eclogites and grosspydites rich in CaO and low in FeO with intermediate MgO from:
  5. kimberlites
  6. gneisses.
  7. Kyanite-free eclogites of metamorphic origin rich in iron with low magnesium and intermediate amounts of calcium from:
  8. glaucophane schists
  9. gneisses.
  相似文献   

5.
The following facts have supported the origin of the Araguainha circular structure in Central Brazil by a meteoritic impact:
  1. the almost circular contour
  2. the impact-morphologic sequence including a central uplift, ring walls and a basin rim of escarpments
  3. outcrops of suevites and mixed breccias
  4. the evidence of shock metamorphism
  5. the presence of shatter cones, and
  6. negative anomalies of the total intensity of the magnetic field at the center of the ring structure.
  相似文献   

6.
Geologic, petrological and geochemical investigations have been carried out in the western part of the “Zillertaler Alpen”. Important results are:
  1. The premetamorphic material of the Greiner series consists of conglomerates, breccias, arcosic-sandstones or greywackes, bituminous shales, volcanic lavas and tuffs.
  2. The southern part of the “Zentralgneis” shows a differentiation trend from alkaline granite to quarzdiorite with predomination of granodiorite.
  3. Chemical relationships of granodiorite to its restitic inclusions allow the supposition of a palingenetic origin of the granitic rocks.
  4. At least two stages of metamorphism can be differentiated.
  5. Parts of the Greiner series, covered by triassic metasediments, are supposed to be of Permian age. A lower age boundary can not yet be given.
  6. Some vertical, northeast striking faults with throws of more than 1 or 2 kilometers produced southward verging drag folds.
  7. Geodynamic aspects, revealed from regional metamorphism and tectonics, are discussed.
  相似文献   

7.
H. Kenneweg 《GeoJournal》1994,32(1):47-53
The development of inventory activities in the field of forest damage assessment and monitoring during the last decade in Germany and the present state are recorded as far as remote sensing has been involved. Any forest inventory is influenced by external factors, and the resulting difficulties for an introduction of new technologies are described. The following tasks and/or methods are discussed:
  • -global approaches to deforestation monitoring
  • -working experience from local and regional case studies
  • -vegetation and vegetation-damage monitoring in ”urban forestry”
  • -sampling approaches for large areas
  • -the contribution of spectral signatures and satellite remote sensing to damage assessment
  •   相似文献   

    8.
    The paper presents novel information on the Caledonian orogeny in Ireland. A series of Dalradian (Upper Precambrian-Lower Cambrian) metasedimentary rocks occur as an envelope to a granitic igneous complex at Slieve Gamph, Western Ireland. These metasedimentary rocks have been deformed at several distinct times and evidence is shown for the following sequence of events:
    1. formation of major nappe structures and a tectonic slide. The axial-plane traces of the folds probably trended N. E.-S. W.
    2. formation of upright, gently plunging folds with axial-plane traces of the folds trending N. E.-S. W. Emplacement of the components of the Slieve Gamph igneous complex.
    3. formation of a conjugate set of folds:
      1. Open folds with N. N. E.-S. S. W. trending axial-planes which dip to the east,
      2. Open folds with E.W. trending axial-planes which dip to the north.
    4. formation of kink-bands, open and conjugate folds with an axialplane trace trending N. W.-S. E.
    Late phase of faulting. No isotopic dates are available for these structural events.  相似文献   

    9.
    Since 1980, many of the state governments in India have introduced programmes to integrate traditional medical systems (TM) into official health care institutions and services at different administrative levels. One of these schemes is at Primary Health Centres (phcs) in various districts. However, little research has been undertaken to date on relative demand and utilization, or on the extent to which TM is seen or used as a complement, alternative or supplement to biomedical services, in the same phc setting. The consumer assumes an important role in an integrated approach, where illness behaviour is understood to be a decision-making process. From the structuralist aspect also, the needs and decisions (in a given situation) as perceived by the administration are not necessarily the same as subjectively felt needs, wants, or even expressed needs of individuals. It is hoped research into the degree of usage and levels of clinical utilization of the two coexisting services will be useful in planning norms and services, estimation of recurrent expenditures and allocation of resources for effective functioning of the phcs. This paper presents the findings of a questionnaire based on a quota sample of users of phcs. eighty patients in each of the Allopathy and Siddha medicine wings were interviewed in three phcs in Tamil Nadu, a total of 480 respondents. The main issues considered in this paper are:
    1. Socio-economic characteristics of the users.
    2. Treatment patterns: differential preferences for treatment methods for various disease conditions; multiple-usage — interchangeable or concurrently for the same ailment; degree of medical pluralism; spatial patterns of movement.
    3. The reasons for participating in the present treatment.
    4. Behaviour, satisfaction, attitudes, opinions, preferences, experiences.
    5. Conclusions and implications of the study for research and service planning.
    This study, although based on small and not necessarily representative samples, illustrates some of the potentials and shortcomings of an integrated approach at the institutional level.  相似文献   

    10.
    According to Sakai-Ohmoto's theory regarding the evolution of sulfur isotopes in hydrothermal systems, in conjunction of new data on chemical resaction equilibrium constants and equilibrium isotopic fractionation factors as well as on individual ion activity coefficients of aqueous sulfur species, the following lgfo2.-pH diagrams are constructed:
    1. mole fractions of aqueous sulfur species (X i ),
    2. stability fields of some minerals in the Fe-S-O system,
    3. diagram depicting the oxidation-reduction-state ratio for aqueous sulfur species (R′)
    4. isotopic compositions of sulfur compounds ( \(\delta S_1 ^{34} \) ).
      相似文献   

    11.
    Principe is one of the volcanic centres comprising the Cameroun line in West Africa. The volcanic rocks can be divided into two stratigraphic units:
    1. Younger lava series — basanite and nephelinite overlying.
    2. Older lava series — transitional to mildly alkaline basalt and hawaiite.
    These units lie on a basement of palagonite breccias of tholeiitic affinities. The basic lavas are intruded by plugs ranging in composition from tristanite to phonolite and are overlain by phonolite lavas. These rocks form two chemically and mineralogically distinct suites:
    1. Phonolites which evolved by low pressure crystal fractionation of the younger lava series basanitic magma, and
    2. Tristanite — trachyte — trachyphonolite suite which may have evolved by high pressure crystal fractionation of the older lava series magma.
      相似文献   

    12.
    The “South-Italian city” is characterized at four different levels as an independent cultural-genetic city-type:
    1. The characteristics arrangement of the functional areas and the residential areas of different social groups is represented in a model.
    2. From the model, developments and changes in the arrangement of the functional areas can be identified which clearly deviate from those which are derived from the universal city model.
    3. Some of the structural individuality can be directly explained by the peculiar features of the respective social and economic history.
    4. Some of the special features must, however, be traced back to a wider historico-cultural background. Through this run processes which flow through the universal city development in similar forms, to the deviating structure of the “South-Italian city”.
      相似文献   

    13.
    Shijian Liu 《GeoJournal》1994,34(1):47-54
    Debris flow is a natural phenomenon which occurs on steep slopes of mountain regions. Very often morainic material and nonmorainic sediments, such as debris flow material, fluvial and other sediments, are mixed in the marginal mountain systems of the Tibetan Plateau. The study of quartz-grain surface features of debris flow has an important significance for differentiating between different origins of Quaternary sediments. Features of quartz-grain in debris flow will be described as below:
    1. The predominant shapes of quartz grains are irregular.
    2. The degree of roundness of grains is in general are angular to subangular in shape.
    3. The textures of quartz-grains in debris flows are conchoidal fractures, parallel steps and mechanical V-marks. Parallel steps are especially abundant. Their presence is the most characteristic indicator of debris flow sand, aiding in the differentiation between debris flow and glacial sand.
    4. Fresh cleavage planes are extremely flat.
      相似文献   

    14.
    In Hungary loess has long been used for soil reclamation. The main steps of the method are: horizon A and B are removed from a suitable area and their material is stockpiled at the margins of the resulting pit. The loess (horizon C), this way exposed, is excavated and spread over the salt affected soils to be improved then mixed with their upper layer. The pit is named in Hungarian digó (pit). The name of the reclamation process is the digo method or spreading of yellow earth. Digó method is mainly used for the amelioration of salt affected soils with an acid A horizon and its benefits are as follows:
    1. The acidity of the horizon A is eliminated
    2. The soil structure is improved
    3. The amount of calcium (a plant nutrient) is increased
    4. Soil fertility is improved continuously
    5. The soil depth is extended which adds to the relative volume of the ground water table.
      相似文献   

    15.
    Concordant granite sheets from the granulite facies Scourian Complex, N.W. Scotland exhibit the following features:
    1. a common planar fabric with their host pyroxene granulites;
    2. the presence of an exsolved ternary feldspar phase;
    3. a low-pressure, water-saturated minimum composition;
    4. K/Rb ratios (450–1,350) distinctly higher than most upper crustal granites but similar to the surrounding granulites;
    5. low absolute concentrations of the rare earth elements (REEs), light REE enrichment, and large positive Eu anomalies.
    It is proposed that the granite sheets have originated by anatexis of gneisses undergoing granulite facies metamorphism — gneisses that were already essentially dry and depleted in incompatible elements. Their unusual trace element chemistry may be explained by either disequilibrium melting and/or sub-solidus reequilibration of the granite sheets with the surrounding gneisses. Isotopic and trace element data suggest that cross-cutting, potash-rich pegmatites represent reworking of the granite sheets during a later amphibolitization.  相似文献   

    16.
    P, T, \(X_{{\text{CO}}_{\text{2}} }\) relations of gehlenite, anorthite, grossularite, wollastonite, corundum and calcite have been determined experimentally at P f =1 and 4 kb. Using synthetic starting minerals the following reactions have been demonstrated reversibly
    1. 2 anorthite+3 calcite=gehlenite+grossularite+3 CO2.
    2. anorthite+corundum+3 calcite=2 gehlenite+3 CO2.
    3. 3anorthite+3 calcite=2 grossularite+corundum+3CO2.
    4. grossularite+2 corundum+3 calcite=3 gehlenite+3 CO2.
    5. anorthite+2 calcite=gehlenite+wollastonite+2CO2.
    6. anorthite+wollastonite+calcite=grossularite+CO2.
    7. grossularite+calcite=gehlenite+2 wollastonite+CO2.
    In the T, \(X_{{\text{CO}}_{\text{2}} }\) diagram at P f =1 kb two isobaric invariant points have been located at 770±10°C, \(X_{{\text{CO}}_{\text{2}} }\) =0.27 and at 840±10°C, \(X_{{\text{CO}}_{\text{2}} }\) =0.55. Formation of gehlenite from low temperature assemblages according to (4) and (2) takes place at 1 kb and 715–855° C, \(X_{{\text{CO}}_{\text{2}} }\) =0.1–1.0. In agreement with experimental results the formation of gehlenite in natural metamorphic rocks is restricted to shallow, high temperature contact aureoles.  相似文献   

    17.
    A method for obtaining quantitative information on palaeoenvironmental evolution from the loess stratum is approached in this paper.
    1. Twelve typical Holocene loess profiles in Loess Plateau have been studied. A quantitative relation was found between the total ferric oxide content (TFOC) of modern surface loess and modern climate conditions. The increase of TFOC by 1% indicates an increase of annual mean precipitation by 246 mm or a rise of mean January temperature by 5.8 C°.
    2. The corresponding relation between the oak(Quercus) forests and the climatic conditions of the Loess Plateau and adjacent mountainous areas to the south has also been studied. A detailed classification of vegetation ecotypes using generic differences in arboreal family differences in herb plants of an oak forest is suggested, which may improve the reliability of palaeoclimatic reconstructions from spore and pollen data.
      相似文献   

    18.
    The Elzevir batholith belongs to a suite of trondhjemitic intrusions emplaced at ca. 1,240 Ma in the Grenville Province of eastern Ontario. New major and trace element data, including REE, combined with isotopic and petrographic data indicate that:
    1. the batholith has calc-alkalic affinities;
    2. the Elzevir parental magma is very similar to that of dacites in the nearby, coeval metavolcanic rocks; the magma formed by partial melting of crustal material at granulite grade;
    3. chemical differences between the plutonic and volcanic rocks can be best explained by accumulation of plagioclase in the plutonic environment;
    4. fractionation was dominated by plagioclase and quartz, with lesser biotite and epidote, and minor zircon and apatite.
    It is suggested that melting of sialic crust took place during the ‘docking’ of a partly-evolved, originally ensimatic arc system against the main cratonic mass to the northwest.  相似文献   

    19.
    Following a tentative evaluation of palynological information from Ladinian and, more particularly, Karnian successions, there seems to be every indication that qualitative and quantitative compositional differences of palynological assemblages could well be applied in testing concepts of Triassic phytogeography and palaeoclimatology. The following implications are emphasized:
    1. There is sufficient palynological evidence that the Mediterranean region includes a domain of mixed northern (Laurasian) and southern (Gondwana) types of floras.
    2. The concept of an essentially arid nature of a wide equatorial climatic belt during Triassic times finds palynological support.
    3. Palynological evidence does not contradict a concept of pronounced decrease in precipitation towards the western part of the Mediterranean region.
    4. In Europe, occurrences of hygrophytic palynofloras and coals within an arid climatic zone can be explained by the water-supply of extensive river-systems.
      相似文献   

    20.
    Laihuite reported in the present paper is a new iron silicate mineral found in China with the following characteristics:
    1. This mineral occurs in a metamorphic iron deposit, associated with fayalite, hypersthene, quartz, magnetitc, etc.
    2. The mineral is opaque, black in colour, thickly tabular in shape with luster metallic to sub-metallic, two perfect cleavages and specific gravity of 3.92.
    3. Its main chemical components are Fe and Si with Fe3+>Fe2+. The analysis gave the formula of Fe Fe 1.00 3+ ·Fe 0.58 2+ ·Mg 0.03 2+ ·Si0.96O4.
    4. Its DTA curve shows an exothermic peak at 713°C.
    5. The mineral has its own infrared spectrum distinctive from that of other minerals.
    6. This mineral is of orthorhombic system; space group:C 2h /5 ?P21/c; unit cell:α=5.813ű0.005,b=4.812ű0.005,c=10.211ű0.005,β=90.87°.
    7. The Mössbauer spectrum of this mineral is given, too.
      相似文献   

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