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  • 1
    Electronic Resource
    Electronic Resource
    Subduction-related Jurassic andesites in the northern Great Caucasus (1995)
    Springer
    International journal of earth sciences 84 (1995), S. 319-333 
    Details
    ISSN: 1437-3262
    Keywords: Andesites ; Plate tectonics ; Great Caucasus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract During the Jurassic the major tectonic units of the Great Caucasus (Bechasyn, Front Range, Main Range and Southern Slope zone) were affected by intensive magmatic activity. Magmatism within the Bechasyn zone, the northernmost unit, which represents the southern part of the Variscan-consolidated Skythian platform is considered here. With the beginning of the Early Jurassic this zone was reactivated by subsidence, accompanied by the deposition of epicontinental shallow water sediments. The Lower Jurassic portion of this sedimentary pile was intruded by numerous sills which display a clear temporal and spatial evolution. The older basic rocks are lower in the profile than the younger, more acidic rocks. A set of 75 samples, representing all exposed sills and their feeder-dikes, was analyzed for major and 21 trace elements. All samples appear more or less affected by alteration under lower greenschist facies conditions. However, these alterations essentially took place on local scales and did not affect the overall chemistry. According to their main element composition the rocks constitute a calc-alkaline series ranging from basaltic—andesitic to rhyolitic. Most of the samples are andesites. Chemically, these andesites closely resemble modern orogenic andesites occurring at convergent plate margins. Altogether, the field evidence and the chemical and mineralogical data obtained show the investigated rocks to be comagmatic and derived from basalt—andesitic initial melts by magmatic fractionation processes. Tholeiitic melts have to be considered as parental magmas, which according to the trace element characteristics of the basalt-andesitic rocks, were generated from an enriched peridotitic mantle source. 87Sr/86Sr isotope ratios and σ18O values confirm the mantle origin of this rock series. The observed compositional evolution can be explained as a result of olivine and clinopyroxene fractionation of the tholeitic melts followed by amphibole and plagioclase separation. 40Ar/39Ar measurements on biotite and plagioclase phenocrysts separated from these rocks vary between 190 and 180 Ma and thereby place the magmatic activity in the late Early Jurassic, in good agreement with the stratigraphic observations. Genetically, the calc-alkaline rocks are related to a subduction zone of the Andean type. Their chemical and isotopic compositions and their age setting corroborate the plate tectonic models for the evolution of the Caucasus orogenic belt during the Jurassic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00260443
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Nierentumorembolisation (1999)
    Springer
    Der Radiologe 39 (1999), S. 783-789 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Nierentumor ; Embolisation ; Pallitive Therapie ; Ethibloc® ; Alkohol ; Kapilläre Okklusion ; Key words Renal carcinoma ; Embolotherapy ; Embolization ; Capillary occlusion ; Ethanol ablation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Today the relevance of renal tumor embolization is not determined only by the technical and clinical success of the method. Progress in diagnosis of early stages of renal carcinomas as well as the improvement of both surgical techniques and anesthetic procedures have lead to a change in the selection of patients for embolization. Preoperative embolization of advanced renal cell carcinomas with tumor thrombus into the vena cava or of T4 tumors is now an established clinical procedure. The complete occlusion of the vascular bed of the tumors leads to a considerable reduction in intraoperative blood loss and to simplification of the surgical preparation. By using Ethibloc for embolization, palliation of a hemorrhage or of tumor-related pain in inoperable patients is usually successful. Although local control of the tumor disease, including complete tumor ablation, is achieved by embolization, the median survival rate of our palliatively embolized patients is only 3.5 months. This short life expectancy in the group of inoperable patients has to be acknowledged individually in patients considered for palliative embolization who are free of symptoms related to the tumor.
    Notes: Zusammenfassung Hintergrund: Der Stellenwert der Nierentumorembolisation wird heute nicht allein vom technischen und klinischen Erfolg der Methode bestimmt. Die Fortschritte sowohl in der Früherkennung von Nierenkarzinomen als auch die Verbesserung der Operationstechniken und der Narkoseverfahren haben zu einer Veränderung in der Patientenselektion zur Embolisation geführt. Präoperative Embolisation: Die präoperative Embolisation von fortgeschrittenen Nierenzellkarzinomen mit Tumorzapfen in der V. cava oder von T4-Tumoren ist ein im klinischen Alltag fest etabliertes Verfahren. Der vollständige Verschluß des Gefäßbetts der Tumoren führt zu einer erheblichen Reduktion des intraoperativen Blutverlusts und einer Vereinfachung der Präparation. Embolisation bei inoperablen Patienten: Bei inoperablen Patienten gelingt durch die Embolisation mit Ethibloc® zuverlässig die Palliation einer Hämaturie oder von Tumorschmerzen. Obwohl durch die Embolisation eine lokale Kontrolle des Tumorleidens bis hin zur kompletten Ablation der tumortragenden Niere möglich ist, liegt derzeit das mediane Überleben unserer pallitiv embolisierten Patienten bei nur 3,5 Monaten. Diese in der allgemeinen klinischen Inoperabilität begründete kurze verbleibende Lebenserwartung muß für jeden bezüglich des Tumors symptomfreien Patienten individuell bei der Indikationsstellung zur palliativen Embolisation berücksichtigt werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050576
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Subduction-related Jurassic andesites in the northern Great Caucasus (1995)
    Springer
    Geologische Rundschau 84 (1995), S. 319-333 
    Details
    ISSN: 0016-7835
    Keywords: Key words Andesites ; Plate tectonics ; Great Caucasus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract. During the Jurassic the major tectonic units of the Great Caucasus (Bechasyn, Front Range, Main Range and Southern Slope zone) were affected by intensive magmatic activity. Magmatism within the Bechasyn zone, the northernmost unit, which represents the southern part of the Variscan-consolidated Skythian platform is considered here. With the beginning of the Early Jurassic this zone was reactivated by subsidence, accompanied by the deposition of epicontinental shallow water sediments. The Lower Jurassic portion of this sedimentary pile was intruded by numerous sills which display a clear temporal and spatial evolution. The older basic rocks are lower in the profile than the younger, more acidic rocks. A set of 75 samples, representing all exposed sills and their feeder-dikes, was analyzed for major and 21 trace elements. All samples appear more or less affected by alteration under low greenschist facies conditions. However, these alterations essentially took place on local scales and did not affect the overall chemistry. According to their main element composition the rocks constitute a calc-alkaline series ranging from basaltic--andesitic to rhyolitic. Most of the samples are andesites. Chemically, these andesites closely resemble modern orogenic andesites occurring at convergent plate margins. Altogether, the field evidence and the chemical and mineralogical data obtained show the investigated rocks to be comagmatic and derived from basalt--andesitic initial melts by magmatic fractionation processes. Tholeiitic melts have to be considered as parental magmas, which according to the trace element characteristics of the basalt-andesitic rocks, were generated from an enriched peridotitic mantle source. 87Sr/86Sr isotope ratios and δ18O values confirm the mantle origin of this rock series. The observed compositional evolution can be explained as a result of olivine and clinopyroxene fractionation of the tholeiitic melts followed by amphibole and plagioclase separation. 40Ar/39Ar measurements on biotite and plagioclase phenocrysts separated from these rocks vary between 190 and 180 Ma and thereby place the magmatic activity in the late Early Jurassic, in good agreement with the stratigraphic observations. Genetically, the calc-alkaline rocks are related to a subduction zone of the Andean type. Their chemical and isotopic compositions and their age setting corroborate the plate tectonic models for the evolution of the Caucasus orogenic belt during the Jurassic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00260443
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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