The Elbe Fault System in North Central Europe—a basement controlled zone of crustal weakness     

Magdalena Scheck  Ulf Bayer  Volker Otto  Juliette Lamarche  Dirk Banka  Tim Pharaoh 《Tectonophysics》2002,360(1-4):281-299

The Elbe Fault System (EFS) is a WNW-striking zone extending from the southeastern North Sea to southwestern Poland along the present southern margin of the North German Basin and the northern margin of the Sudetes Mountains. Although details are still under debate, geological and geophysical data reveal that upper crustal deformation along the Elbe Fault System has taken place repeatedly since Late Carboniferous times with changing kinematic activity in response to variation in the stress regime. In Late Carboniferous to early Permian times, the Elbe Fault System was part of a post-Variscan wrench fault system and acted as the southern boundary fault during the formation of the Permian Basins along the Trans-European Suture Zone (sensu [Geol. Mag. 134 (5) (1997) 585]). The Teisseyre–Tornquist Zone (TTZ) most probably provided the northern counterpart in a pull-apart scenario at that time. Further strain localisation took place during late Mesozoic transtension, when local shear within the Elbe Fault System caused subsidence and basin formation along and parallel to the fault system. The most intense deformation took place along the system during late Cretaceous–early Cenozoic time, when the Elbe Fault System responded to regional compression with up to 4 km of uplift and formation of internal flexural highs. Compressional deformation continued during early Cenozoic time and actually may be ongoing. The upper crust of the Elbe Fault System, which itself reacted in a more or less ductile fashion, is underlain by a lower crust characterised by low P-wave velocities, low densities and a weak rheology. Structural, seismic and gravimetric data as well as rheology models support the assumption that a weak, stress-sensitive zone in the lower crust is the reason for the high mobility of the area and repeated strain localisation along the Elbe Fault System.  相似文献   

Die Faziesentwicklung der Reichenhaller Schichten und die Tektonik im Süden des Achensees,Tirol     

Volker Schenk Dipl.-Geol. 《International Journal of Earth Sciences》1967,56(1):464-473

Zusammenfassung Im östlichsten Karwendel setzen sich die oberostalpinen, unteranisischen Reichenhaller Schichten aus einer mächtigen Folge mariner dolomitischer Kalke, sandiger Mergelkalke sowie sedimentärer Brekzien zusammen, die mehr oder weniger tektonisch überprägt sind.Die Brekzien treten in mehrfachem rhythmischem Wechsel zwischen Mergelkalken auf und erreichen erst im obersten Drittel der Schichtserie, die das gesamte Hydasp umfaßt, größere Mächtigkeiten. Ihr polymikter Komponentenbestand wird sowohl aus skythischen Gesteinen als auch aus Aufarbeitungsmaterial der besprochenen Serie gebildet. Ein rein tektonischer Charakter der Brekzien scheidet aus.Relativ rascher, z. T. periodischer Fazieswechsel deutet veränderliche paläogeographische Verhältnisse an.Der tektonische Bau erwies sich einfacher, als früher angenommen wurde.An die Hauptstörungszonen (Inntaleinheit über Lechtaleinheit) sind besondere tektonische Körper gebunden.

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In the extreme eastern Karwendel Range the subanisian Reichenhall Layers (Oberostalpin) are composed of an imposing sequence of initially marine dolomitic limes, sabulous marlaceous limes and sedimentary breccias more or less tectonically marked. The breccias appear in multiple rhythmic alternation between marlaceous limes. A purely tectonic character of the breccias is ruled out.

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Résumé Dans la partie la plus à l'est du Karwendel les couches anisiennes inférieures de Reichenhall (Oberostalpin) se composent d'une énorme masse d'abord de calcaires marins des Dolomites, puis de calcaires de marnes sablonneuses ainsi que de brèches sédimentaires qui sont plus ou moins structurées. Les brèches apparaissent par périodes régulières entre les calcaires de marne. Il est exclu que les brèches aient un caractère purement tectonique.

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Reichenhaller Achensee (). , , .

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Erweitertes Manuskript eines Vortrags, gehalten auf der 56. Jahrestagung der Geologischen Vereinigung in Wien am 26. Februar 1966.  相似文献   

Geosynklinaler Vulkanismus in den oberen penninischen Decken Graubündens (Schweiz)     

Volker Dietrich Dipl.-Geol. 《International Journal of Earth Sciences》1967,57(1):246-264

Zusammenfassung Die oberpennimsche Platta-Decke im südöstlichen Graubünden (Schweiz) wird im wesentlichen aus Ophiolithen aufgebaut. Daneben finden sich die zugehörigen Sedimente, d. h. Radiolarite, Kalk- bis Kieselschiefer sowie flyschartige Mergelund Tonschiefer, deren Alter zwischen oberem Jura und Kreide liegt. Unter Ophiolithen verstehen wir Gesteine, die als basische bis ultrabasische Magmen, an Bruchund Schwächezonen gebunden, meist in die wenig mächtigen unverfestigten Tiefseesedimente eines eugeosynklinalen Ablagerungsraumes eindrangen.So handelt es sich bei diesen alpinen Ophiolithen um ehemalige Basalte, Peridotite, Pyroxenite und Gabbros. Für diese Vorkommen trifft auch die TrilogieSteinmanns (1926) zu, jedoch konnten keine Primärkontakte zwischen ultrabasischen und basischen Ophiolithen erkannt werden. Mögliche Kontakte wurden durch eine intensive Schuppentektonik, deren Abscherungshorizont meist mit Serpentinmassen ausgefüllt sind, vollkommen verwischt. Ferner wurden diese Ophiolithe während der alpinen Gebirgsbildung schwach metamorph überprägt.Bedingt durch die Vielfalt dieser Probleme, wollen wir die ultrabasischen Glieder weglassen. Vergleiche mit einigen gut bearbeiteten Beispielen submariner Basalte (Monti Iblei, Sizilien und Quadra Island, Britisch Kolumbien) ließen innerhalb der einzelnen Platta-Schuppen Abfolgen submariner basischer Extrusionen und Intrusionen erkennen: Basal-Breccien, Pillow-Laven, Pillow-Breccien (jetzt Meta-Hyaloklastit-Breccien) und Meta-Hyaloklastite s. str.Petrographisch handelt es sich bei diesen Vulkaniten heute natürlich um Diabase, die sowohl einen basaltischen als auch spilitischen Chemismus besitzen.Vom Hangenden zum Liegenden läßt sich innerhalb der Platta-Decke in den Gesteinen eine fortschreitende metamorphe Überprägung vom anchimetamorphen zum epimetamorphen Bereich verfolgen.Die guten Aufschlußverhältnisse erlaubten, je nach dem Grad der Metamorphose, Veränderungen der ursprünglichen Vulkanitstrukturen zu erkennen. So konnten Pillow-Laven, Breccien und Meta-Hyaloklastite durch den Grünschiefer-Fazies-Bereich hindurch bis in den Bereich der Prasinitisierung verfolgt werden. Dies brachte eine gewisse Klärung in die Problematik der alpinen Grünschiefer.Mit Hilfe der Vulkanitstrukturen, der vulkanischen Abfolgen und der Sedimente, konnte die Schuppentektonik innerhalb der Platta-Decke weitgehend geklärt werden.

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The upper-penninic Platta-Decke located in the south-east part of Grisons (Switzerland) consists essentially of ophiolites. These rocks are associated with upper-jurassic radiolarites, cherts and limestones as well as lower-cretaceous flysch-like calcareous shales and schists.Ophiolites are defined as ultrabasic and basic magmas that intruded thin and unconsolidated deep-sea sediments of a eugeosyncline. They were originally basalts, periodotites, pyroxenites and gabbros. These volcanic sequences conform to the trilogy proposed bySteinmann (1926), although we could not find primary contacts between ultrabasic and basic ophiolites. The contacts are masqued by the effect of imbricate thrust-sheets where the tectonic contact zones are now filled with serpentinites.In addition all the ophiolites were transformed into true greenschists during the alpine metamorphism.Only the basic submarine volcanics will be discussed and described in this work. Comparisons with some well studied examples of submarine basalts (Monti Iblei, Sicily and Quadra Island, British Columbia) gave us the key to recognize in the Platta-Decke equivalent suites of sills, flows, pillow-lavas, pillow-breccias and meta-hyaloclasites.Petrographically all these rocks are now diabases with a basaltic or spilitic chemical composition.Within the Platta-Decke we can recognize from the top to the botton a sequence which starts with anchimetamorphic and continues into epimetamorphic rocks.The clear outcrops allowed us to distinguish the original volcanic structures where the intensity of metamorphism had not destroyed them. Thus we could follow the gradual transition from pillow-lavas and meta-hyaloclastites s. l. through the greenschist-facies into the facies of prasinitisation. These observations contributed significantly to the understanding of the alpine greenschists. By thorough investigations of structures and sequences of the eugeosynclinal volcanic and associated sediments, it was possible to demonstrate the structural relationships within the Platta-Decke.

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Résumé La nappe pennique supérieure du Platta dans les Grisons (Suisse) est formée essentiellement d'ophiolithes. Ces roches s'associent étroitement à des sédiments, tels que radiolarites, cherts, schistes calcaires (calcschistes) du Jurassique supérieur, schistes marneux et argileux et quelques microbrèches, qui semblent représenter les avant-coureurs du flysch crétacé. Par ophiolithes nous entendons les produits de magmas basiques et ultrabasiques liés à des zones de fracture et de faiblesse et qui la plupart du temps se sont insérés dans les sédiments géosynclinaux peu épais et encore meubles. Il s'agit donc d'anciens basaltes, péridotites, pyroxénites et gabbros. La trilogie deSteinmann (1926) y est aussi vérifiée, mais des contacts primaires entre ophiolithes basiques et ultrabasiques n'ont pu être reconnus. De possibles contacts ont été détruits par un écaillage intense, dont les horizons de décollement sont remplis de serpentinites. De plus, ces ophiolithes ont été légèrement métamorpbisées lors de l'orogénèse alpine. La multiplicité et la complexité de ces problèmes étant si grandes, nous écarterons les membres ultrabasiques. Des comparaisons avec des exemples soigneusement étudiés de basaltes sous-marins (Monti Iblei, Sicile et Quadra Island, Colombie britannique) ont permis de reconnaître à l'intérieur des écailles du Platta des cycles d'extrusions et d'intrusions basiques sous-marines: brèches de base, lave en coussins, brèches en coussins (maintenant des brèches méta-hyaloclastiques) et des méta-hyaloclastites s. l. Du point de vue pétrographique, ces volcanites sont naturellement des diabases possédant un chimisme basaltique aussi bien que spilitique. La sollicitation métamorphique dans la nappe passe progressivement du degré anchimétarnorphique au toit à un degré épimétamorphique vers la base. Les conditions favorables d'affleurement ont permis de suivre, correspondant à leur degré de métamorphisme, les changements opérés dans les structures volcaniques primitives. Ainsi les laves en coussins, les brèches et les méta-hyaloclastites traversent le « domaine faciel des schistes verts » pour atteindre celui de la « prasinitisation ».Ceci a jeté quelque lumière sur le problème des « schistes verts alpins ». L'étude des structures volcaniques, des cycles et des sédiments, a permis de débrouiller en grande partie l'écaillage tectonique à l'intérieur de cette nappe du Platta.

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- . . . , . . , , - . , , , , . , , , . (Mt. Iblei, Sizilien; Quadra, Island; Kolumbien). , ( , Pillow-Lava, Pillow-Breccien, Meta-Hyaloklastit)

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Die vorliegende Arbeit, die einen Teil meiner Dissertation darstellt, wurde auf Anregung meiner verehrten Lehrer Herrn Prof. Dr. A.Gansser und Herrn Prof. Dr. R.Trümpy unternommen, denen ich. für viele Diskussionen, Hinweise und wertvolle Kritik im Gelände als auch im Institut sehr danke.

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Ebenso gilt mein Dank Herrn Prof. Dr. F. deQuervain, Zürich, Herrn Prof. Dr. P.Bearth, Basel, Herrn Prof. Dr. M.Vuagnat, Genf und Herrn PD. Dr. Tj.Peters, Bern, die mit ihren reichen Kenntnissen in alpinen Ophiolithen viele mineralogische und petrographische Anregungen, Ratschläge sowie fruchtbare Diskussion vermittelten.

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Herrn Prof. Dr. M.Weibel, Zürich, danke ich bestens für die Anfertigung der chemischen Analysen.

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Für die Altersbestimmung sei Herrn Dr. F. W.McDowell und Herrn Prof. Dr. P.Signer, Zürich, sehr gedankt.

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Den Mitarbeitern des Institutes für Kristallographie und Petrographie der ETH, besonders Herrn E.Schähli und Herrn R.Gubser möchte ich für ihre technische Hilfe in der Dünnschliffanfertigung, Photographie und Röntgenographie danken.  相似文献   

U-Pb and Rb-Sr radiometric dates and their correlation with metamorphic events in the granulite-facies basement of the serre,Southern Calabria (Italy)   总被引：2，自引：0，他引：2  

Volker Schenk 《Contributions to Mineralogy and Petrology》1980,73(1):23-38

An approximately 7 km thick, continuous sequence of granulite-facies rocks from the lower crust, which contains a lower granulite-pyriclasite unit and an upper metapelite unit, occurs in the NW Serre of the Calabrian massif. The lower crustal section is overlain by a succession of plutonic rocks consisting of blastomylonitic quartz diorite, tonalite, and granite, and is underlain by phyllonitic schists and gneisses.Discordant apparent zircon ages, obtained from granulites and aluminous paragneisses, indicate a minimum age of about 1,900 m.y. for the oldest zircon populations. The lower intersection point of the discordia with the concordia at 296±2 m.y. is also marked by concordant monazites. Therefore, the age of 296±2 m.y. is interpreted as the minimum age of granulite-facies metamorphism.Concordant zircon ages were obtained from a metamorphic quartz monzogabbronorite sill (298±5 m.y.) and an unmetamorphosed tonalite (295±2 m.y.); they are interpreted as the intrusion ages.Discordant zircon ages from a blastomylonitic quartz diorite gneiss, situated between the lower crustal unit and the non-metamorphosed tonalite, reveal recent or geologically young lead loss by diffusion. The ²⁰⁷Pb/²⁰⁶Pb ages of the two analysed size-fractions point to an intrusion age similar to that of the overlying tonalite.Rb-Sr mineral ages are younger in the granulite-pyriclasite unit than in the overlying metapelite unit. Feldspars from the granulite-pyriclasite unit yield ages of about 145 m.y. and those from the metapelite unit 176±5 m.y. In the same way, the biotite cooling ages range between 108 and 114 m.y. in the granulitepyriclasite and between 132 and 135 m.y. in the metapelite unit and the tonalite. Some still younger biotite ages are explained by the influence of tectonic shearing on the Rb-Sr systems. A muscovite from a postmetamorphic aplite in the metapelite unit yields a cooling age of 203±4 m.y.The Rb-Sr isotopic analyses from migmatite bands do not lie on an isochron, perhaps due to limited isotopic exchange between the small scale layers during the long cooling period after the peak of metamorphism.In the phyllonitic gneisses and schists a Hercynian metamorphism is indicated by a muscovite age of 268±4 m.y., whereas the biotite age of 43±1 m.y. from the same sample can be correlated with an Alpine greenschist-facies metamorphism.On the basis of the radiometric dates and of the P-T path of the lower crustal section deduced petrologically, the following model is presented: the end of the Hercynian granulite-facies metamorphism was accompanied by an uplift of the lower crustal rocks into intermediate crustal levels and by synchronous plutonic intrusions into the lower crust and higher crustal levels, but essentially into the latter. Substantial further uplift did not occur until after cooling from the temperature of the granulite-facies metamorphism to the biotite closing temperature. This cooling lasted for about 185 m.y. in the lower part and for about 160 m.y. in the upper part of the lower crust section.A comparison between the geologic evolutions of the NW Serre of Calabria and the Ivrea Zone of the Alps demonstrates striking similarities. The activity of deep seated faults in both areas at least since late Hercynian time raises the possibility that a fault precursor of the boundary of the Adriatic microplate already existed at this time.  相似文献   

Ukinrek Maars, Alaska, I. April 1977 eruption sequence, petrology and tectonic setting     

Juergen Kienle  Philip R. Kyle  Stephen Self  Roman J. Motyka  Volker Lorenz 《Journal of Volcanology and Geothermal Research》1980,7(1-2)

During ten days of phreatomagmatic activity in early April 1977, two maars formed 13 km behind the Aleutian arc near Peulik volcano on the Alaska Peninsula. They have been named “Ukinrek Maars”, meaning “two holes in the ground” in Yupik Eskimo. The western maar formed at the northwestern end of a low ridge within the first three days and is up to 170 m in diameter and 35 m in depth. The eastern maar formed during the next seven days 600 m east of West Maar at a lower elevation in a shallow saddle on the same ridge and is more circular, up to 300 m in diameter and 70 m in depth. The maars formed in terrain that was heavily glaciated in Pleistocene times. The groundwater contained in the underlying till and silicic volcanics from nearby Peulik volcano controlled the dominantly phreatomagmatic course of the eruption.During the eruptions, steam and ash clouds reached maximum heights of about 6 km and a thin blanket of fine ash was deposited north and east of the vents up to a distance of at least 160 km. Magma started to pool on the floor of East Maar after four days of intense phreatomagmatic activity.The new melt is a weakly undersaturated alkali olivine basalt (Ne = 1.2%) showing some transitional character toward high-alumina basalts. The chemistry, an anomaly in the tholeitic basalt-andesite-dominated Aleutian arc, suggests that the new melt is primitive, generated at a depth of 80 km or greater by a low degree of partial melting of garnet peridotite mantle with little subsequent fractionization during transport.The Pacific plate subduction zone lies at a depth of 150 km beneath the maars. Their position appears to be tectonically controlled by a major regional fault, the Bruin Bay fault, and its intersection with cross-arc structural features. We favor a model for the emplacement of the Ukinrek Maars that does not link the Ukinrek conduit to the plumbing system of nearby Peulik volcano. The Ukinrek eruptions probably represent a genetically distinct magma pulse originating at asthenospheric depths beneath the continental lithosphere.  相似文献   

Coexisting phengite,paragonite and margarite in metasediments of the mittlere Hohe Tauern,Austria     

Volker Höck 《Contributions to Mineralogy and Petrology》1974,43(4):261-273

The assemblages phengite-paragonite, phengite-margarite and phengite-paragonitemargarite are very common in metasediments of a N-S profile in the middle sector of the Hohe Tauern. The Si⁴⁺-content of phengite shows no regular change with increasing temperature from north to south along the profile. The variations in the d ₀₀₂ basal spacings of phengite coexisting with paragonite are not only dependent on the Na⁺ content of phengite but also on the Mg²⁺+Fe²⁺ content of the micas. Neither the sodium content in phengite nor the potassium content in paragonite shows any dependence on temperature. Chemical analyses of coexisting phengite, paragonite and margarite give the extent of the three-phase-region which is characterized by a small amount of margarite in paragonite (4 Mol%), by a large quantity of Na⁺ in margarite (28 Mol% paragonite), and limited miscibility between phengite and paragonite.  相似文献   

Carbonatite magmatism and fenitization of the epiclastic caldera-fill at Gross Brukkaros (Namibia)     

Thomas Stachel  Volker Lorenz  Gerhard Brey 《Bulletin of Volcanology》1995,57(3):185-196

The Gross Brukkaros inselberg is a dome structure with a crater-shaped central depression within Precambrian/Cambrian country rocks which was active as a depocenter during the Late Cretaceous. The formation of the structure was due to the intrusion and subsequent intermittent depletion of a shallow magma reservoir. Juvenile material has not been recognized hitherto. This is the first account of juvenile lapilli from within the epiclastic fill of the caldera structure. The lapilli are calciocarbonatites and magnesiocarbonatites in composition, but are characteristically low in elements such as P, Nb, Ba and Sr, otherwise typical of carbonatites. This signature, however, is also characteristic of carbonatites from surrounding volcanic centers and necks. The Brukkaros sediments suffered strong metasomatic-hydrothermal alteration, which introduced in a first stage fluids rich in Fe, Ti, Na, Nb, V, K (Ca?, CO₂?), and in a second stage the Brukkaros sediments were silicified on a large scale and locally enriched in P, Th and Cr. Si is derived from desilication of the wall rocks (basement?, Nama sediments) of the magma reservoir. Cr was probably mobilized during alteration of the abundant doleritic detritus within the Brukkaros depocenter.  相似文献   

Optimizing the Number of Double-Differenced Observations for GPS Networks in Support of Deformation Monitoring Applications     

Volker Janssen 《GPS Solutions》2001,4(3):41-46

Deformation monitoring using GPS is usually carried out by installing and operating a local network of GPS receivers mounted on the deforming body, e. g., the flanks of a volcano. For continuous monitoring applications a near-real-time, epoch-by-epoch solution obtained from multi-baseline processing is desired in order to take into account between-baseline correlations and to detect movements over as short a period of time as possible. In the case of the volcano monitoring application, the sides of the volcano will block out part of the sky, hence the receivers are not likely to track a lot of satellites that are visible from all receiver stations at the same time. If the usual base-station/base-satellite approach is used in the baseline processing, only the common satellites are considered, resulting in the number of possible double-differenced observables being comparatively low; hence a ot of valuable information may be lost. The proposed method, based on the work by Saalfeld (1999), considers satellites that are visible from a small number of network stations only. Thus the number of independent double-differenced observables can be maximized in order to obtain a better solution. A numerical example is given that verifies the improved solutions that can be obtained using this data processing approach. ? 2001 John Wiley & Sons, Inc.  相似文献   

Intercomparison of sediment sampling techniques by means of radionuclide and heavy metal analysis     

Dr. Hartmut Nies  Dr. Horst Albrecht  Volker Rechenberg  Ingo Goroncy  Dr. Henning Dahlgaard  Dietmar Weiß  Prof. Dr. Lutz Brügmann 《Ocean Dynamics》1990,43(1):27-53

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Die Ausbreitung hochfrequenter Hertzscher Felder in Kalilagerstätten     

Dozent Dipl.-Ing. Dr. Volker Fritsch 《Pure and Applied Geophysics》1948,12(1-2):23-52

Zusammenfassung 1) Die Versuche fanden in den Gruben Hannovers, des Werragebietes und des Südharzes statt. 2) Die Untersuchungen erstreckten sich über das ganze praktisch in Betracht kommende Wellenband, angefangen von den Meterwellen bis in den 1000 Meter-Bereich. 3) Im Zuge der Untersuchungen konnten die bisher gr?ssten, unter Tag überhaupt erzielten Reichweiten erreicht werden. Die gr?sste Reichweite wurde zwischen zwei Hannoverischen Gruben erzielt und betrug bei 14 Kilometer. 4) Frequenz und geologische Faktoren sind stets von Einfluss. 5) Die Versuche zeigen, dass unter Kalilagerst?tten Funkmutungsverfahren nach dem Reflexions- und Refraktionsprinzip für gr?ssere Aufschlussteufen m?glich sind. 6) Die Versuche haben alle Voraussetzungen des Grubenfunks so weit gekl?rt, dass dessen praktischer Einführung nichts im Wege steht.

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Summary The purpose of the experiments described in this paper was to investigate the conditions of propagation of a transmitter situated below the surface of the ground. This problem is of interest to both radio engineers and geophysicists. By determination of the extinction and reflection areas of electrical discontinuity may be located. The experiments were carried out in German potassic salt mines. Rocks of potassic salts are known as very bad conductors. Therefore the extinction is but very little. In this area ranges up to 14 kilometres were reached. This is the greatest range obtained up to now under the surface of the ground. The investigations were carried out with different wave lengths from 10 up to 2000 metres. The influence of geological discontinuities, alkaline deposits and disturbed areas was always very great. The author mentions that the above ranges could certainly still be considerably increased by application of all technical means available at present.

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