Diffusion of Na, K, Rb and Cs in glasses of albite and orthoclase composition

Jambon, Albert; Carron, Jean-Paul

doi:10.1016/0016-7037(76)90138-1

Cited by 85 publications

(45 citation statements)

References 5 publications

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“…Redox diffusivities: PyrLi (squares), PyrNa (circles), Pyrox (triangles). Diffusivity data sources: D O 2 À calculated with Eyring relation from the viscosities of PyrNa, PyrLi and Pyrox (Table 4); D O 2 À : Semkow and Haskin (1985) for diopside composition; D Ca2+ and D Mg 2þ : Jambon and Semet (1978), Roselieb and Jambon (2002) for albite or jadeite compositions; D þ Na þ : Jambon and Carron (1976) for an obsidian composition; D Fe : Koehler and Frischat (1978) for Na 2 O-FeO-Al 2 O 3 -SiO 2 compositions and Henderson et al (1985) for aluminosilicates; D þ M 2 þ: Cooper et al (1996a) and Cook et al (1990) for basalt and Fe-MAS (MAS, MgOAl 2 O 3 -SiO 2 ) compositions. Table 4 Viscosity (Pa s) of oxidized samples and fitted parameters of empirical TVF equations, log g = A + B/(T À T 1 )…”

Section: Redox Mechanismsmentioning

confidence: 99%

Kinetics and mechanisms of iron redox reactions in silicate melts: The effects of temperature and alkali cations

Magnien

Neuville

Cormier

et al. 2008

Geochimica et Cosmochimica Acta

110

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Section: Redox Mechanismsmentioning

confidence: 99%

Kinetics and mechanisms of iron redox reactions in silicate melts: The effects of temperature and alkali cations

Magnien

Neuville

Cormier

et al. 2008

Geochimica et Cosmochimica Acta

110

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“…Decay energy is also important in that low energy radiation has higher backgrounds and/or may dissipate before reaching the detector. Equations are available that take into account radiation which does not escape the sample until sectioned (Jambon and Carron, 1976). Examination of these show that this is not a problem for most gamma decays but can be appreciable for beta radiation.…”

Section: Or Watson (1979)mentioning

confidence: 99%

Strontium and samarium diffusion in diopside

Sneeringer

Hart

Shimizu

1984

Geochimica et Cosmochimica Acta

264

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The volume diffusion of strontium has been measured as a function of temperature, pressure, and crystallographic direction in a synthetic diopside (CaMgSi 2 06), using a Cameca IMS 3f ion microprobe. Temperatures ranged from 1100 to 1300*C for pressures to 20 Kbar. Sr diffusivities were also determined for the c direction of the synthetic crystals by a radiotracer ( 8 5 Sr) and sectioning technique and Rutherford backscattering spectroscopy; and for natural samples by the radiotracer method. The natural sample diffusion coefficients were approximately two orders of magnitude higher than those for the synthetic samples, although the activation energies were similar. The diffusion of samarium in the synthetic crystals was also studied with respect to temperature, pressure, and crystallographic direction using the ion probe. Results for the two cations were comparable (within a factor of 2 at most T's). Values of AVa were negative for strontium diffusion. An empirical relation which adequately described the temperature and pressure dependence of D was calculated for Sr in the c direction of the synthetic samples. The result is:The expression for DSr in the natural samples at one atmosphere is:A single compensation trend for all the data was evident for all values of D and AHa in the synthetic crystals. In the study temperature range at one atmosphere, transport rates for the three crystallographic directions were nearly identical due to compensation with a crossover point at 1111*C and 6 x 10-1 7 cm 2 /sec. Directional compensation was also observed in two other studies Clark and Long, 1971).Comparison of the three analytical techniques yielded excellent agreement in the study range at one atmosphere (D's within a factor of two). The comparison illustrated the fact that technique-generated effects can cause the observed concentration curves to differ from the true diffusion profiles. Treatment for removal of these modifiers was effected through variations in analytical parameters and through empirical data reduction methods. Ion probe depth profiling was proven to be a useful tool for the study of diffusion in crystalline silicates, where extremely slow transport rates limit the applicability of more established techniques such as radiotracer and sectioning.The data were examined in the context of other studies which used similar methods and/or investigated the same variables. Pressure dependence of D in most experiments resulted in positive values of AVa, as opposed to the activation volumes calculated here. The comparisons showed that there are three basic sources of differences between diffusivities for a given phase and element. Sample defect composition, experimental techniques, and analytical methods are all capable of causing variations in the measured D's.A number of models of geologic processes were investigated in light of the present data. Closure temperatures (Tc) were calculated for examples of mineral-mineral age-dating, and major and trace element geothermometry. High values of Tc indicate th...

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“…As such, interesting comparisons can be made with diffusion coefficients and activation energies calculated from numerous high temperature isotope and tracer diffusion studies (11)(12)(13)(14)(15)(16)(17)(18). Such comparisons for diffusion coefficients for Rb, Cs and Sr are shown in Figure 7.…”

Section: Near-surfacementioning

confidence: 97%

“…The activation energies calculated in the literature (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) for high temperature alkali metal diffusion in crystalline and classy silicates are shown in Figure 8. The wide ranges in apparent energies are in part due to differing compositions and methods of diffusion measurement.…”

Section: Near-surfacementioning

confidence: 99%

Near-Surface Alkali Diffusion into Glassy and Crystalline Silicates at 25°C to 100°C

White

Yee

1987

ACS Symposium Series

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Alkali uptake by obsidian and feldspar was investigated in batch and recirculating column experiments and by XPS profiling using ion sputtering and variable take-off angles. No measurable alkali diffusion occurred in the feldspars. Diffusion coefficients were determined for Rb, Cs and Sr in glass using a one-dimensional model assuming interdiffusion with Na. Activation energies for Rb, Cs and Sr in glass were 50, 83, and 70kJ respectively which were significantly lower than that measured in previous high temperature experiments and indicate diffusion into a hydrated near-surface matrix.The immobilization of dissolved chemical species by adsorption and ion exchange onto mineral surfaces is an important process affecting both natural and environmentally perturbed geochemical systems.However, sorption of even chemically simple alkali elements such as Cs and Sr onto common rocks often does not achieve equilibrium nor is experimentally reversible (1). Penetration or diffusion of sorbed species into the underly ing matrix has been proposed as a concurrent non-equilibration process (2). However, matrix or solid state diffusion is most often considered extremely slow at ambient temperature based on extrapolated data from high tem perature isotopic or tracer diffusion experiments.Only limited attempts have been made to measure matrix diffusion in silicates at lower tempera ture.This paper reports results of alkali diffusion experiments on obsidian and feldspars over a temperature range of 25° to 100°C. The immediate significance of this studv is on potential retardation of radioactive alkali isotopes such as 137 Cs, 90 Sr and ^2 6 Ra during transport in potential reposi tory host rocks such as basalt and tuff which contain glass and feldspar phases. The paper hopefully will also shed light on the more general ques tion of the importance of low temperature diffusion in geological environ ments. Experimental ResultsThe three silicates obtained from Wards Scientific Establishment and employed in this study are obsidian from St. Helena, California, microline from Ontario, Canada and albite from South Dakota. The bujk of the samples were crushed and sieved to between 211 and 423 μτη. Fines were removed by repeated ultrasonic cleaning and décantation. Measured BET

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Diffusion of Na, K, Rb and Cs in glasses of albite and orthoclase composition

Cited by 85 publications

References 5 publications

Kinetics and mechanisms of iron redox reactions in silicate melts: The effects of temperature and alkali cations

Kinetics and mechanisms of iron redox reactions in silicate melts: The effects of temperature and alkali cations

Strontium and samarium diffusion in diopside

Near-Surface Alkali Diffusion into Glassy and Crystalline Silicates at 25°C to 100°C

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