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  • Articles  (2)
  • 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks  (1)
  • Best von Kryptanden, Kryptaten  (1)
  • Springer  (2)
  • Elsevier
  • 1
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    Isotopic evidence for open system processes within the Campanian Ignimbrite (Campi Flegrei–Italy) magma chamber (2009)
    Springer
    Details
    Publication Date: 2017-04-04
    Description: New Sr and Nd isotope data for whole rocks, glasses and minerals are combined to reconstruct the nature and origin of mixing end-members of the 200 km3 trachytic to phonolitic Campanian Ignimbrite (Campi Flegrei, Italy) magmatic system. The least-evolved magmatic end-member shows equilibrium between host glass and the majority of the phenocrysts and is less radiogenic in Sr and Nd than the most-evolved magma. On the contrary, only the Fe-rich pyroxene from the most-evolved erupted magma is in equilibrium with the matrix glass, while all other minerals are in isotopic disequilibrium. These magmas mixed prior to and during the Campanian Ignimbrite eruption and minerals were freely exchanged between the magma batches. Combining the results of the geochemical investigations on magma end-members with geophysical and geological data, we develop the following scenario. In stage 1, a parental, less differentiated magma rose into the middle crust, and evolved through combined crustal assimilation and crystal fractionation. In stage 2, the differentiated magma rose to shallower depth, fed the pre-Campanian Ignimbrite activity and evolved by further open-system processes into the most-evolved and most-radiogenic Campanian Ignimbrite end-member magma. In stage 3, new trachytic magma, isotopically distinct from the pre-Campanian Ignimbrite magmas, rose from ca. 6 km to shallower depth, recharged the most-evolved pre-Campanian Ignimbrite magma chamber, and formed the large and stratified Campanian Ignimbrite magmatic system. During the course of the Campanian Ignimbrite eruption, the two layers were tapped separately and/or simultaneously, and gave rise to the range of chemical and isotopic values displayed by the Campanian Ignimbrite pumices, glasses and minerals.
    Description: Published
    Description: 285-300
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Campanian Ignimbrite ; Radiogenic isotopes ; Mixing process ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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    PAPER (OA)
  • 2
    Electronic Resource
    Electronic Resource
    Titrimetric determinations of cryptands and cryptates (1979)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 298 (1979), S. 358-362 
    Details
    ISSN: 1618-2650
    Keywords: Best von Kryptanden, Kryptaten ; Volumetrie ; HCl, Metall-Standardlösung, Standardzugabeverfahren
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary Using bromocresol green as a visual endpoint indicator solutions of the cryptands [2.2.1] and [2.2.2] can be determined by titration with HCl in the concentration range of 10−1–10−3 M with relative standard deviations of 0.2–0.4 %. If both cryptand and cryptate are present in one solution, then the sum of them can be determined titrimetrically in the same way. It is also possible to determine the contents of [2.2.1] and [2.2.2] by using a calcium or barium standard solution and the unknown cryptand solution as a titrant. By evaluation of the pH-curve thus obtained, the endpoint of the titration can be determined. In the concentration range of 10−1–10−2 M relative standard deviations of about 0.5% are obtained. [2.2.1] cryptand solutions are determined by using the standard addition technique of Gran with a calcium chloride solution. An ion-selective electrode is used as a probe for calcium ions. If this method is applied, the relative standard deviation in the range of 10−2–10−4 M solutions is approximately 3%. With this technique cryptand can be analysed even when cryptate is present in the solution.
    Notes: Zusammenfassung Bei Verwendung von Bromkresolgrün als visueller Endpunktindicator kann man [2.2.1] und [2.2.2] Kryptandlösungen im Konzentrationsbereich 10−1–10−3 M mit relativen Standardabweichungen von 0,2–0,4% mit HCl titrieren. Wenn in einer Lösung sowohl Kryptand als auch Kryptat vorhanden ist, ist die Summe beider Substanzen auf die gleiche Weise bestimmbar. [2.2.1] und [2.2.2] können auch dadurch bestimmt werden, daß eine Calciumbzw. Barium-Standardlösung mit der Kryptandlösung unbekannter Konzentration titriert wird. Die Auswertung der dabei erhaltenen pH-Kurve ergibt den Titrationsendpunkt, wobei hierdurch im Konzentrationsbereich von 10−1–10−2 M Kryptandlösungen relative Standardabweichungen von etwa 0,5% erreicht werden. [2.2.1] Kryptandlösungen werden außerdem mit der Standard-Additionstechnik nach Gran bestimmt, wobei eine calciumselektive Elektrode als Indicatorelektrode dient. Dabei werden im Konzentrationsbereich von 10−2–10−4 M relative Standardabweichungen von etwa 3 % erhalten. Diese Methode kann auch überschüssigen Kryptand neben Kryptat bestimmen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00482014
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