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  • 1
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    Silicate melts (1997)
    Berlin; Heidelberg : Springer
    Details
    Call number: doi:10.1007/BFb0048731
    Description / Table of Contents: This book focuses on the experimental determination of the physical properties of silicate melts and magmas close to glass transition. Abundant new data are presented. The same type of measurement is performed on a range of melts to test the effect of composition on physical properties; and a range of different techniques are used to determine the same physical properties to illustrate the relationships between the relaxation of the melt structure and the relaxation of its physical properties. This book is of interest to experimental researchers in the discussion of data obtained from both a materials science and a geoscientific point of view.
    Type of Medium: 12
    Pages: VIII, 74 Seiten , Diagramme
    ISBN: 3540631291 , 978-3-540-63129-3 , 978-3-540-69152-5
    Series Statement: Lecture notes in earth sciences 67
    URL: https://doi.org/10.1007/BFb0048731
    DOI: 10.1007/BFb0048731
    Language: English
    Note: Introduction, Pages 1-2 --- Relaxation, Pages 3-16 --- Shear Relaxation, Pages 17-32 --- Volume Relaxation, Pages 33-43 --- Enthalpy Relaxation, Pages 45-62 --- Summary, Pages 63-72
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  • 2
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    Rheology of melts from the colli albani volcanic district (Italy): a case study (2020)
    Springer Berlin Heidelberg
    Details
    Publication Date: 2023-06-23
    Description: In this study the first viscosity measurements in the glass transition range of melts from highly explosive large-volume eruptions from the Colli Albani Volcanic District (CAVD) are presented. The magmas are ultrapotassic, rich in iron and CaO and characterised by a low silica content (〈 45 wt%). Melt compositions range from tephri-phonolitic to foiditic. The Colli Albani eruptions appear anomalous since they produced a large volume of erupted material in spite of their silica undersaturated compositions. The viscosity of the Colli Albani melt changes as the melt composition evolves from the original melt to a country-rock contaminated melt to a crystal-bearing melt with a permanent decrease in liquid viscosity. Conventional estimations of viscosities assume these magmas to have a low viscosity. The presented data show that the melt viscosities are higher than expected. Taking into account further chemical or rheological features of a melt, the investigated CAVD melts are not that striking as assumed in comparison with other large-volume eruptions. Consequently, considering the alkaline-earth to alkaline ratio together with the SiO2 content could provide an alternative when comparing large volume eruptions.
    Description: Deutsche Forschungsgemeinschaft
    Keywords: ddc:552 ; Viscosity ; Anhydrous melts ; Colli Albani ; Foidite ; Glass transition ; Low temperature
    Language: English
    Type: doc-type:article
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    CITATION GEO-LEO
  • 3
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    Viscosity of evolving magmas: a case study of the Glass House Mountains, Australia (2021)
    Springer Berlin Heidelberg
    Details
    Publication Date: 2023-07-20
    Description: The viscosity of the remelted rock compositions of the Glass House Mountains, SE Queensland, Australia, has been determined via micro-penetration in the high-viscosity regime (108–1013 Pa s). The heat capacity of these melts has also been determined from room temperature to above the glass transition. The combination of these two data sets allows the fitting of the viscosity data by the Adam-Gibbs equation using the configurational heat capacity Cpconf(Tg12) and configurational entropy Sconf(Tg12). The resulting fit parameters allow the robust extrapolation of the viscosity data to higher temperature and viscosities of 10–4 Pa s. This data can now be used in the discussion of the emplacement of the magmas of the plugs, laccoliths, sills and dykes that form the Glass House Mountains complex and the plate motion and the plume responsible for the volcano plugs. The large increase in viscosity of the evolving magma and the resulting decrease in discharge rate of the volcanic vents suggest that very little magma appeared as extrusive lavas or pyroclastic material and that the Glass House Mountains are mainly remnants of intrusive bodies exposed by erosion.
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: Georg-August-Universität Göttingen (1018)
    Keywords: ddc:552 ; Glass House Mountains ; Viscosity ; Heat capacity ; Entropy
    Language: English
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  • 4
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    Thermal stress, cooling-rate and fictive temperature of silicate melts (2021)
    Springer Berlin Heidelberg
    Details
    Publication Date: 2023-08-08
    Description: The unknown cooling-rate history of natural silicate melts can be investigated using differential scanning heat capacity measurements together with the limiting fictive temperature analysis calculation. There are a range of processes occurring during cooling and re-heating of natural samples which influence the calculation of the limiting fictive temperature and, therefore, the calculated cooling-rate of the sample. These processes occur at the extremes of slow cooling and fast quenching. The annealing of a sample at a temperature below the glass transition temperature upon cooling results in the subsequent determination of cooling-rates which are up to orders of magnitude too low. In contrast, the internal stresses associated with the faster cooling of obsidian in air result in an added exothermic signal in the heat capacity trace which results in an overestimation of cooling-rate. To calculate cooling-rate of glass using the fictive temperature method, it is necessary to create a calibration curve determined using known cooling- and heating-rates. The calculated unknown cooling-rate of the sample is affected by the magnitude of mismatch between the original cooling-rate and the laboratory heating-rate when using the matched cooling-/heating-rate method to derive a fictive temperature/cooling-rate calibration curve. Cooling-rates slower than the laboratory heating-rate will be overestimated, while cooling-rates faster than the laboratory heating-rate are underestimated. Each of these sources of error in the calculation of cooling-rate of glass materials—annealing, stress release and matched cooling/heating-rate calibration—can affect the calculated cooling-rate by factor of 10 or more.
    Description: Georg-August-Universität Göttingen (1018)
    Keywords: ddc:550.78 ; Fictive temperature ; Annealing ; Thermal stress ; Cooling-rate ; Calorimetry
    Language: English
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  • 5
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    Influence of CO2 on the rheology of melts from the Colli Albani Volcanic District (Italy): foidite to phonolite (2021)
    Springer Berlin Heidelberg
    Details
    Publication Date: 2023-08-08
    Description: In this study, the influence of CO〈sub〉2〈/sub〉 on the rheology of silica poor and K-rich melts from highly explosive eruptions from the Colli Albani Volcanic District (Italy) (CAVD) is measured for the first time. The investigated melts range from foidite to tephri-phonolite to tephrite from the CAVD to a phonolite from the Vesuvius (Italy) with CO〈sub〉2〈/sub〉 concentrations up to 0.50 wt%. Viscosity and calorimetric measurements are performed in the glass transition range Tg between 600 and 780 °C. Although nominally anhydrous, the investigated melts contain H〈sub〉2〈/sub〉O concentrations up to 0.23 wt%. The data exhibit a decrease in viscosity of approx. 100.40 Pa s for the phonolitic composition with ~ 0.07 wt% CO〈sub〉2〈/sub〉 and a Tg reduced by approx. 14 °C. For the tephritic composition, Tg is approx. 5 °C lower and has a viscosity reduced by 100.25 Pa s for the sample containing ~ 0.5 wt% CO〈sub〉2〈/sub〉. Calorimetric measurements of the tephri-phonolite show lowered onset of Tg by approx. 6 °C for the melt with ~ 0.11 wt% CO2 and Tg of the foidite appears not to be influenced by a CO〈sub〉2〈/sub〉 concentration of ~ 0.37 wt% CO〈sub〉2〈/sub〉. However, these tephri-phonolitic and foiditic melts foamed during calorimetric measurements preventing a reliable measurement. It would appear that most of this overall drop in viscosity is caused by the small amounts of H〈sub〉2〈/sub〉O in the melts with CO〈sub〉2〈/sub〉 slightly reducing the viscosity or having no effect on viscosity. Additionally, it is shown that the reduction in viscosity decreases with an increasing degree of the depolymerisation for the investigated melts. Consequently, the explosive style of the CAVD eruptions is mainly caused by crystals and bubbles which form and rise during magma storage and ascent which increases the magma viscosity whereas the CO〈sub〉2〈/sub〉 in the melt slightly reduces the viscosity.
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: Georg-August-Universität Göttingen (1018)
    Keywords: ddc:550.78 ; Viscosity ; Calorimetry ; Colli Albani ; Carbon dioxide ; Glass transition ; Foidite
    Language: English
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  • 6
    Electronic Resource
    Electronic Resource
    Compressibility of titanosilicate melts (1994)
    Springer
    Contributions to mineralogy and petrology 118 (1994), S. 157-168 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The effect of composition on the relaxed adiabatic bulk modulus (K0) of a range of alkali- and alkaline earth-titanosilicate [X 2 n/n+ TiSiO5 (X=Li, Na, K, Rb, Cs, Ca, Sr, Ba)] melts has been investigated. The relaxed bulk moduli of these melts have been measured using ultrasonic interferometric methods at frequencies of 3, 5 and 7 MHz in the temperature range of 950 to 1600°C (0.02 Pa s 〈 ŋs 〈 5 Pa s). The bulk moduli of these melts decrease with increasing cation size from Li to Cs and Ca to Ba, and with increasing temperature. The bulk moduli of the Li-, Na-, Ca- and Ba-bearing metasilicate melts decrease with the addition of both TiO2 and SiO2 whereas those of the K-, Rb- and Cs-bearing melts increase. Linear fits to the bulk modulus versus volume fraction of TiO2 do not converge to a common compressibility of the TiO2 component, indicating that the structural role of TiO2 in these melts is dependent on the identity of the cation. This proposition is supported by a number of other property data for these and related melt compositions including heat capacity and density, as well as structural inferences from X-ray absorption spectroscopy (XANES). The compositional dependence of the compressibility of the TiO2 component in these melts explains the difficulty incurred in previous attempts to incorporate TiO2 in calculation schemes for melt compressibility. The empirical relationship K∝V-4/3 for isostructural materials has been used to evaluate the compressibility-related structural changes occurring in these melts. The alkali metasilicate and disilicate melts are isostructural, independent of the cation. The addition of Ti to the metasilicate composition (i.e. X2TiSiO5), however, results in a series of melts which are not isostructural. The alkaline-earth metasilicate and disilicate compositions are not isostructural, but the addition of Ti to the metasilicate compositions (i.e. XTiSiO5) would appear, on the basis of modulus-volume systematics, to result in the melts becoming isostructural with respect to compressibility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01052866
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  • 7
    Electronic Resource
    Electronic Resource
    The onset of non-Newtonian rheology of silicate melts (1990)
    Springer
    Physics and chemistry of minerals 17 (1990), S. 125-132 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The viscoelastic behavior of silicate melts has been measured for a range of compositions (NaAlSi3O8, NaCaAlSi2O7, CaMgSi2O6, Li2Si4O9, Na2Si4O9, K2Si4O9, Na2Si3O7, K2Si3O7 and Na2Si2O5) using the fiber elongation method. A1l compositions exhibit Newtonian behavior at low strain-rates, but non-Newtonian behavior at higher strain-rates, with strain-rate increasing faster than the applied stress. The decrease in shear viscosity observed at the high strain-rates ranges from 0.3 to 1.6 log10 units (Pa s). The relaxation strain-rates, έrelax, of these melts have been estimated from the low strain-rate, Newtonian, shear viscosity, using the Maxwell relationship; έrelax=τ −1=(ηs/G∞)−1. For all compositions investigated, the onset of non-Newtonian rheology is observed at strain-rates 2.5+0.5 orders of magnitude less than the calculated relaxation strain-rate. This difference between the non-Newtonian onset and the relaxation strain-rate is larger than that predicted by the single relaxation time Maxwell model. Normalization of the experimental strain-rates to the relaxation strain-rate predicted from the Maxwell relation, eliminates the composition. and temperature-dependence of the onset of non-Newtonian behavior. The distribution of relaxation in the viscoelastic region appears to be unrelated to melt chemistry. This conclusion is consistent with the torsional, frequency domain study of Mills (1974) which illustrated a composition-invariance of the distribution of the imaginary component of the shear modulus in melts on the Na2O-SiO2 join. The present, time domain study of viscoelasticity contrasts with frequency domain studies in terms of the absolute strains employed. The present study employs relatively large total strains (up to 2). This compares with typical strains of 10−8 in ultrasonic (frequency domain) studies. The stresses used to achieve the strain-rates required to observe viscoelastic behavior in this study approach the tensile strength of the fibers with the result that some of our experiments were terminated by fiber breakage. Although the breakage is unrelated to the observation of non-Newtonian viscosity, their close proximity in this and earlier studies suggests that brittle failure of igneous melts, may, in general, be preceded by a period of non-Newtonian rheology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00199663
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  • 8
    Electronic Resource
    Electronic Resource
    Structural relaxation in silicate melts and non-Newtonian melt rheology in geologic processes (1989)
    Springer
    Physics and chemistry of minerals 16 (1989), S. 508-516 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The timescale of structural relaxation in a silicate melt defines the transition from liquid (relaxed) to glassy (unrelaxed) behavior. Structural relaxation in silicate melts can be described by a relaxation time, τ, consistent with the observation that the timescales of both volume and shear relaxation are of the same order of magnitude. The onset of significantly unrelaxed behavior occurs 2 log10 units of time above τ. In the case of shear relaxation, the relaxation time can be quantified using the Maxwell relationship for a viscoelastic material; τS = ηS/G ∞ (where τS is the shear relaxation time, G ∞ is the shear modulus at infinite frequency and ηS is the zero frequency shear viscosity). The value of G ∞ known for SiO2 and several other silicate glasses. The shear modulus, G ∞, and the bulk modulus, K ∞, are similar in magnitude for every glass, with both moduli being relatively insensitive to changes in temperature and composition. In contrast, the shear viscosity of silicate melts ranges over at least ten orders of magnitude, with composition at fixed temperature, and with temperature at fixed composition. Therefore, relative to ηS, G ∞ may be considered a constant (independent of composition and temperature) and the value of ηS, the relaxation time, may be estimated directly for the large number of silicate melts for which the shear viscosity is known. For silicate melts, the relaxation times calculated from the Maxwell relationship agree well with available data for the onset of the frequency-dependence (dispersion) of acoustic velocities, the onset of non-Newtonian viscosities, the scan-rate dependence of the calorimetric glass transition, with the timescale of an oxygen diffusive jump and with the Si-O bond exchange frequency obtained from 29Si NMR studies. Using data obtained over a range of frequencies and strain-rates we illustrate the significance of relaxed versus unrelaxed behavior in laboratory experiments on silicate melts. Similarly, using strain-rate estimates for magmatic processes we evaluate the significance of the liquid-glass transition in igneous petrogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197020
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  • 9
    Electronic Resource
    Electronic Resource
    The elasticity of the upper mantle orthosilicates olivine and garnet to 3 GPa (1989)
    Springer
    Physics and chemistry of minerals 16 (1989), S. 684-692 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The elastic moduli of single crystals of pyrope-rich garnet and San Carlos olivine have been measured over a 3 GPa pressure range at room temperature. The combination of improved ultrasonic techniques and this large pressure range provide for more reliable characterization of the pressure dependence of acoustic wave velocities than has previously been possible. First and second pressure derivatives of the velocities have been determined within ∼ 1 percent and ∼ 10 percent respectively. The Hashin-Shtrikman bounds for the pressure dependences of the bulk and shear moduli of the garnet used in this study are; K = 173.6 GPa, K′ = 4.93, K″ = −0.28 GPa−1, G= 94.9 GPa, G′ = 1.56, G″ = −0.08 GPa−1 and the Hashin-Shtrikman least-upper bounds and greatestlower bounds for the pressure dependences of the bulk and shear moduli of the San Carlos olivine are K=129.8 GPa, K′ = 4.66, K″= −0.15 GPa−1, G = 77.8 GPa, G′ = 1.93, G″ = −0.11 GPa−1 and K = 129.2 GPa, K′ = 4.63, K″= −0.15 GPa−1 G = 77.3 GPa, G′=1.96, G″ = −0.11 GPa−1 respectively. The determination of the room-pressure elastic moduli of this pyrope-almandine garnet removes the previously observed anomaly in the predictions of systematic treatments of variations of the elastic moduli of garnets with composition. The determination of the second pressure derivatives of the moduli of garnet and olivine illustrates the importance of these terms in extrapolations to higher pressures — with ϱK/ϱP for these crystals being reduced by ∼ 17 percent and ∼ 9 percent respectively over the 3 GPa pressure range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223318
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  • 10
    Electronic Resource
    Electronic Resource
    Low-frequency shear and structural relaxation in rhyolite melt (1992)
    Springer
    Physics and chemistry of minerals 19 (1992), S. 240-245 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The frequency-dependence of the shear viscosity and modulus of rhyolite melt has been determined over a 10–14 log10 Pa s viscosity range and a 0.03–63 rad s−1 angular frequency range. The frequency-dependent viscosity determined at high frequencies is 5 orders of magnitude lower than the Newtonian viscosity. At lower frequencies, a frequency-independent viscosity identical with the Newtonian viscosity is observed. The measured shear modulus increases from zero to 30.5 ± 2.5 GPa with increasing frequency. The viscoelastic regime consists of a maximum in viscous loss centered on the Max-well relaxation time. The width and height of the loss modulus as a function of frequency is inconsistent with a single relaxation-time. The frequency-dependent shear modulus is best described by a distribution of relaxation-times with a sharp cutoff at times slightly longer than the Maxwell relaxation time, and a long tail at shorter times extending up to 5 orders of magnitude less than the Maxwell relaxation time. This distribution of relaxation-times is in contrast with the single-relaxation-time behavior observed in low viscosity silicate melts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202314
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