Matches in SemOpenAlex for { <https://semopenalex.org/work/W1836696423> ?p ?o ?g. }
- W1836696423 endingPage "126" @default.
- W1836696423 startingPage "107" @default.
- W1836696423 abstract "Noble gases are ideal probes to study the structure of silicate glasses and melts as the modifications of the silicate network induced by the incorporation of noble gases are negligible. In addition, there are systematic variations in noble gas atomic radii and several noble gas isotopes with which the influence of the network itself on diffusion may be investigated. Noble gases are therefore ideally suited to constrain the time scales of magma degassing and cooling. In order to document noble gas diffusion behavior in silicate glass, we measured the diffusivities of three noble gases (4He, 20Ne and 40Ar) and the isotopic diffusivities of two Ar isotopes (36Ar and 40Ar) in two synthetic basaltic glasses (G1 and G2; 20Ne and 36Ar were only measured in sample G1). These new diffusion results are used to re-interpret time scales of the acquisition of fractionated atmospheric noble gas signatures in pumices. The noble gas bearing glasses were synthesized by exposing the liquids to high noble gas partial pressures at high temperature and pressure (1750–1770 K and 1.2 GPa) in a piston-cylinder apparatus. Diffusivities were measured by step heating the glasses between 423 and 1198 K and measuring the fraction of gas released at each temperature step by noble gas mass spectrometry. In addition we measured the viscosity of G1 between 996 and 1072 K in order to determine the precise glass transition temperature and to estimate network relaxation time scales. The results indicate that, to a first order, that the smaller the size of the diffusing atom, the greater its diffusivity at a given temperature: D(He) > D(Ne) > D(Ar) at constant T. Significantly, the diffusivities of the noble gases in the glasses investigated do not display simple Arrhenian behavior: there are well-defined departures from Arrhenian behavior which occur at lower temperatures for He than for Ne or Ar. We propose that the non-Arrhenian behavior of noble gases can be explained by structural modifications of the silicate network itself as the glass transition temperature is approached: as the available free volume (available site for diffusive jumps) is modified, noble gas diffusion is no longer solely temperature-activated but also becomes sensitive to the kinetics of network rearrangements. The non-Arrhenian behavior of noble gas diffusion close to Tg is well described by a modified Vogel–Tammann–Fulcher (VTF) equation:Da2=A1a2∗exp-B1R(T-T2)-CRTwhere D is the diffusion coefficient, a the diffusion domain size (taken to be the size of the sample), A1 and C are respectively equivalent to the pre-exponential factor and to the activation energy (Ea in J mol−1) of the classical Arrhenius equation, B1 can be interpreted as a “pseudo-activation energy” that reflects the influence of the silicate network relaxation, T2 is the temperature where the diffusion regime switches from Arrhenian to non-Arrhenian, and R is the gas constant (=8.314 J K−1 mol−1). Finally, our step heating diffusion experiments suggest that at T close to Tg, noble gas isotopes may suffer kinetic fractionation at a degree larger than that predicted by Graham’s law. In the case of 40Ar and 36Ar, the traditional assumption based on Graham’s law is that the ratio D40Ar/D36Ar should be equal to 0.95 (the square root of the ratio of the mass of 36Ar over the mass of 40Ar). In our experiment with glass G1, D40Ar/D36Ar rapidly decreased with decreasing temperature, from near unity (0.98 ± 0.14) at T > 1040 K to 0.76 when close to Tg (T = 1003 K). Replicate experiments are needed to confirm the strong kinetic fractionation of heavy noble gases close to the transition temperature." @default.
- W1836696423 created "2016-06-24" @default.
- W1836696423 creator A5019138984 @default.
- W1836696423 creator A5058682258 @default.
- W1836696423 creator A5071973720 @default.
- W1836696423 creator A5077978671 @default.
- W1836696423 creator A5082528777 @default.
- W1836696423 date "2016-01-01" @default.
- W1836696423 modified "2023-10-17" @default.
- W1836696423 title "Multidiffusion mechanisms for noble gases (He, Ne, Ar) in silicate glasses and melts in the transition temperature domain: Implications for glass polymerization" @default.
- W1836696423 cites W1944915281 @default.
- W1836696423 cites W1964828528 @default.
- W1836696423 cites W1969380676 @default.
- W1836696423 cites W1970064559 @default.
- W1836696423 cites W1970522861 @default.
- W1836696423 cites W1971198291 @default.
- W1836696423 cites W1980845634 @default.
- W1836696423 cites W1982469181 @default.
- W1836696423 cites W1984038258 @default.
- W1836696423 cites W1989705035 @default.
- W1836696423 cites W1994842293 @default.
- W1836696423 cites W1996353420 @default.
- W1836696423 cites W1998453907 @default.
- W1836696423 cites W1999471729 @default.
- W1836696423 cites W2003420763 @default.
- W1836696423 cites W2003711902 @default.
- W1836696423 cites W2003817792 @default.
- W1836696423 cites W2008330590 @default.
- W1836696423 cites W2011492920 @default.
- W1836696423 cites W2018249864 @default.
- W1836696423 cites W2018828056 @default.
- W1836696423 cites W2023360366 @default.
- W1836696423 cites W2024281324 @default.
- W1836696423 cites W2026398600 @default.
- W1836696423 cites W2028777451 @default.
- W1836696423 cites W2033402366 @default.
- W1836696423 cites W2039088836 @default.
- W1836696423 cites W2039322458 @default.
- W1836696423 cites W2041931579 @default.
- W1836696423 cites W2042938286 @default.
- W1836696423 cites W2047320233 @default.
- W1836696423 cites W2051698383 @default.
- W1836696423 cites W2056142610 @default.
- W1836696423 cites W2056910670 @default.
- W1836696423 cites W2057852786 @default.
- W1836696423 cites W2060058980 @default.
- W1836696423 cites W2064071467 @default.
- W1836696423 cites W2068021132 @default.
- W1836696423 cites W2068583036 @default.
- W1836696423 cites W2069364236 @default.
- W1836696423 cites W2071243236 @default.
- W1836696423 cites W2071394561 @default.
- W1836696423 cites W2079190218 @default.
- W1836696423 cites W2083935287 @default.
- W1836696423 cites W2090258675 @default.
- W1836696423 cites W2090627946 @default.
- W1836696423 cites W2091686147 @default.
- W1836696423 cites W2093940739 @default.
- W1836696423 cites W2094408112 @default.
- W1836696423 cites W2107032133 @default.
- W1836696423 cites W2138430630 @default.
- W1836696423 cites W2138666424 @default.
- W1836696423 cites W2138687146 @default.
- W1836696423 cites W2148629092 @default.
- W1836696423 cites W2156370397 @default.
- W1836696423 cites W2167828689 @default.
- W1836696423 cites W2255090554 @default.
- W1836696423 cites W2314788655 @default.
- W1836696423 cites W2319062931 @default.
- W1836696423 cites W2328484096 @default.
- W1836696423 cites W4238453612 @default.
- W1836696423 cites W4242308926 @default.
- W1836696423 cites W4376848192 @default.
- W1836696423 cites W2106646415 @default.
- W1836696423 doi "https://doi.org/10.1016/j.gca.2015.09.027" @default.
- W1836696423 hasPublicationYear "2016" @default.
- W1836696423 type Work @default.
- W1836696423 sameAs 1836696423 @default.
- W1836696423 citedByCount "11" @default.
- W1836696423 countsByYear W18366964232017 @default.
- W1836696423 countsByYear W18366964232018 @default.
- W1836696423 countsByYear W18366964232019 @default.
- W1836696423 countsByYear W18366964232020 @default.
- W1836696423 countsByYear W18366964232021 @default.
- W1836696423 countsByYear W18366964232023 @default.
- W1836696423 crossrefType "journal-article" @default.
- W1836696423 hasAuthorship W1836696423A5019138984 @default.
- W1836696423 hasAuthorship W1836696423A5058682258 @default.
- W1836696423 hasAuthorship W1836696423A5071973720 @default.
- W1836696423 hasAuthorship W1836696423A5077978671 @default.
- W1836696423 hasAuthorship W1836696423A5082528777 @default.
- W1836696423 hasBestOaLocation W18366964232 @default.
- W1836696423 hasConcept C113196181 @default.
- W1836696423 hasConcept C121332964 @default.
- W1836696423 hasConcept C121530826 @default.
- W1836696423 hasConcept C122865956 @default.
- W1836696423 hasConcept C159985019 @default.
- W1836696423 hasConcept C161790260 @default.