Ti diffusion in feldspar

2020 ◽  
Vol 105 (7) ◽  
pp. 1040-1051
Author(s):  
D. J. Cherniak ◽  
E. B. Watson
Keyword(s):  
Trace Elements ◽  
Silica Glass ◽  
Rutherford Backscattering Spectrometry ◽  
Chemical Diffusion ◽  
Calcic Plagioclase ◽  
Crustal Rocks ◽  
Temperature Range ◽  
Chemical Signatures ◽  
Order Of Magnitude ◽  
Diffusion Profiles

Abstract Chemical diffusion of Ti has been measured in natural K-feldspar and plagioclase. The sources of diffusant used were TiO2 powders or pre-annealed mixtures of TiO2 and Al2O3. Experiments were run in crimped Pt capsules in air or in sealed silica glass capsules with solid buffers (to buffer at NNO). Rutherford backscattering spectrometry (RBS) was used to measure Ti diffusion profiles. From these measurements, the following Arrhenius relations are obtained for diffusion normal to (001):For oligoclase, over the temperature range 750–1050 °C:DOlig=6.67×10-12exp(-207±31kJ/mol/RT)m2s-1For labradorite, over the temperature range 900–1150 °C:DLab=of4.37×10-14exp(-181±57kJ/mol/RT)m2s-1For K-feldspar, over the temperature range 800–1000 °C:DKsp=3.01×10-6exp(-342±47kJ/mol/RT)m2s-1. Diffusivities for experiments buffered at NNO are similar to those run in air, and the presence of hydrous species appears to have little effect on Ti diffusion. Ti diffusion also shows little evidence of anisotropy. In plagioclase, there appears to be a dependence of Ti diffusion on An content of the feldspar, with Ti diffusing more slowly in more calcic plagioclase. This trend is similar to that observed for other cations in plagioclase, including Sr, Pb, Ba, REE, Si, and Mg. In the case of Ti, an increase of 30% in An content would result in an approximate decrease in diffusivity of an order of magnitude. These data indicate that feldspar should be moderately retentive of Ti chemical signatures, depending on feldspar composition. Ti will be more resistant to diffusional alteration than Sr. For example, Ti zoning on a 50 μm scale in oligoclase would be preserved at 600 °C for durations of ~1 million years, with Sr zoning preserved only for ~70 000 yr at this temperature. These new data for a trace impurity that is relatively slow-diffusing and ubiquitous in feldspars (Hoff and Watson 2018) have the potential to extend the scope and applicability of t-T models for crustal rocks based on measurements of trace elements in feldspars.

scholarly journals Diffusion, Precipitation, and Cavity-Wall Reactions of Ion-Implanted Gold in Silicon

1995 ◽  
Vol 396 ◽  
Author(s):  
S.M. Myers ◽  
G.A. Petersen
Keyword(s):  
Ion Implantation ◽  
Solubility Product ◽  
Rutherford Backscattering Spectrometry ◽  
Rutherford Backscattering ◽  
Cavity Wall ◽  
Temperature Range ◽  
Order Of Magnitude ◽  
Diffusion Precipitation ◽  
Ion Implanted

AbstractThe diffusion of Au in Si and its binding to cavities and to precipitates of the equilibrium Au-Si phase were investigated in the temperature range 1023-1123 K using ion implantation and Rutherford backscattering spectrometry. The diffusivity-solubility product for interstitial Au was found to be about an order of magnitude greater than the extrapolation of previous, indirect determinations at higher temperatures. Chemisorption on cavity walls was shown to be more stable than Au-Si precipitation by 0.1-0.3 eV in the investigated temperature range, indicating that cavities are effective gettering centers for Au impurities.

Trace element behaviour during interaction between basalt and crustal rocks at 0.5–0.8 GPa: an experimental approach

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Silvio Mollo ◽  
Valeria Misiti ◽  
Piergiorgio Scarlato
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Diffusion Coefficients ◽  
Experimental Approach ◽  
Contact Layer ◽  
Major And Trace Elements ◽  
Crustal Rocks ◽  
Basaltic Melt ◽  
Order Of Magnitude ◽  
Diffusive Processes

AbstractWe experimentally investigate the major and trace elements behavior during the interaction between two partially molten crustal rocks (meta-anorthosite and metapelite) and a basaltic melt at 0.5–0.8 GPa. Results show that a hybrid melt is formed at the basalt-crust contact, where plagioclase crystallizes. This contact layer is enriched in trace elements which are incompatible with plagioclase crystals. Under these conditions, the trace element diffusion coefficients are one order of magnitude larger than those expected. Moreover, the HFSE diffusivity in the hybrid melt is surprisingly higher than the REE one. Such a feature is related to the plagioclase crystallization that changes the trace elements liquid-liquid partitioning (i.e. diffusivity) over a transient equilibrium that will persist as long as the crystal growth proceeds.These experiments suggests that the behaviour of the trace elements is strongly dependent on the crystallization at the magma-crust interface. Diffusive processes like those investigated can be invoked to explain some unusual chemical features of contaminated magmatic suites.

Ru Self-Diffusion and Ru Diffusion in Al

2005 ◽  
Vol 237-240 ◽  
pp. 402-407 ◽  
Author(s):  
Fanny Dyment ◽  
Silvia Balart ◽  
Constanza Lugo ◽  
Rodolfo A. Pérez ◽  
Nicolás Di Lalla ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Room Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Pure Aluminum ◽  
The Self ◽  
Small Range ◽  
Temperature Range ◽  
Self Diffusion ◽  
Diffusion Parameters ◽  
Order Of Magnitude

The self-diffusion of Ru in the temperature range of (1267-1373) K and the Ru diffusion in pure aluminum in the temperature range of (632-873) K is reported. Difficulties were encountered when working with Ru as matrix (its brittleness at room temperature impeded a good sectioning) and they are the reason why only the order of magnitude of the self-diffusion in the small range of temperature studied is given. For Ru diffusion in aluminum, two experimental techniques were used: the conventional serial sectioning with use of a radiotracer, 103Ru, for the highest temperatures and Heavy Ions Rutherford Backscattering Spectrometry (HIRBS) for the lowest ones. The diffusion parameters are: Q = 199.4 kJ/mol and D0 = 4.1x10-2 m2/s. A comparison is made with Ru diffusion behavior in copper and silver.

Chromium implantation in silica glass

1996 ◽  
Vol 11 (1) ◽  
pp. 229-235 ◽  
Author(s):  
E. Cattaruzza ◽  
R. Bertoncello ◽  
F. Trivillin ◽  
P. Mazzoldi ◽  
G. Battaglin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Photoelectron Spectroscopy ◽  
Silica Glass ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Secondary Ion Mass Spectrometry ◽  
Rutherford Backscattering Spectrometry ◽  
X Ray ◽  
Chromium Silicide ◽  
Secondary Ion

Silica glass was implanted with chromium at the energy of 35 and 160 keV and at fluences varying from 1 × 1016 to 11 × 1016 ions cm−2. In a set of chromium-implanted samples significant amounts of carbon were detected. Samples were characterized by x-ray photoelectron spectroscopy, x-ray-excited Auger electron spectroscopy, secondary ion mass spectrometry, and Rutherford backscattering spectrometry. Chromium silicide and chromium oxide compounds were observed; the presence of carbon in the implanted layers induces the further formation of chromium carbide species. Thermodynamic considerations applied to the investigated systems supply indications in agreement with the experimental evidences.

Rejuvenation events recorded in alkali feldspar from the Tuolumne Intrusive Complex

2021 ◽  
Author(s):  
Susanne Seitz ◽  
Guilherme Gualda ◽  
Luca Caricchi
Keyword(s):  
Trace Elements ◽  
Hierarchical Clustering ◽  
Alkali Feldspar ◽  
Growth Conditions ◽  
Major And Trace Elements ◽  
Sem Analysis ◽  
Intrusive Complex ◽  
Cluster Number ◽  
Chemical Zoning ◽  
Chemical Signatures

<p>Zoned minerals preserve information about their growth conditions, by changing their composition as function of temperature, pressure and melt composition. By carefully looking at a zoned minerals we can determine characteristics of the main stages of the evolution of magmatic systems.</p><p>We study alkali feldspar megacrysts from the Tuolumne Intrusive Complex in California, with the aim of deciphering chemical signatures of rejuvenation events. We characterize the chemical zoning of alkali feldspar using X-ray tomography, BSE imaging, EDS-SEM analysis and LA-ICPMS analysis along profiles. We use hierarchical clustering based on major and trace elements to objectively identify compositional groups for each chemical profile. By reducing the complexity of chemical zoning to one dimension (i.e. cluster number) we can trace the evolution of the conditions of growth and identify rejuvenation events.</p><p>Alkali feldspar megacrysts (up to 20 cm in size) from the Cathedral Peak unit of the Tuolumne Intrusive Complex occur predominantly disperse and only make between 8 - 12 % of the total crystal population. They are mostly homogeneous in major element, and markedly oscillatory zoned in trace elements such as Ba, Sr, and Rb. Using hierarchical clustering we identify four different chemical groups within the alkali feldspar crystals. Each chemical group is repeated multiple times in a single crystal. Overall the crystals show a decreasing trend of Ba towards the rim. Extended alkali feldspar crystallization would lead to a depletion of Ba in the melt and consequently to the growth of low Ba-zones of alkali feldspar. In some crystals the sequence of decreasing Ba is repeated twice. We propose that this reflects melt recharge in a melt-rich magmatic system.</p>

A model for Archean tectonism. Part 2. Numerical models of vertical tectonism in greenstone belts

1980 ◽  
Vol 17 (1) ◽  
pp. 60-71 ◽  
Author(s):  
Jean-Claude Mareschal ◽  
Gordon F. West
Keyword(s):  
Numerical Models ◽  
Volcanic Eruptions ◽  
Crustal Rocks ◽  
Tectonic Model ◽  
Mechanical Evolution ◽  
Accumulated Strain ◽  
Lava Sequence ◽  
Order Of Magnitude ◽  
Greenstone Belts ◽  
Horizontal Temperature Gradients

A tectonic model that attempts to explain common features of Archean geology is investigated. The model supposes the accumulation, by volcanic eruptions, of a thick basaltic pile on a granitoid crust. The thermal blanketing effect of this lava raises the temperature of the granitic crust and eventually softens it enough that gravitational slumping and downfolding of the lava follows.Numerical models of the thermal and mechanical evolution of a granitoid crust covered with a thick lava sequence indicate that such an evolution is possible when reasonable assumptions are made about the temperature dependence of the viscosity in crustal rocks. These models show the lava sinking in relatively narrow regions while wider granite diapirs appear in between. The convection produces strong horizontal temperature gradients that may cause lateral changes in metamoprhic facies. A one order of magnitude drop in accumulated strain occurs between the granite–basalt interface and the center of the granite diaper at a depth of 10–15 km.

scholarly journals SYNTHESIS AND ELECTRICAL CONDUCTIVITY OF SOLID SOLUTIONS OF THE SYSTEM RbF-PbF2-SnF2

2019 ◽  
Vol 85 (5) ◽  
pp. 60-68
Author(s):  
Yuliay Pogorenko ◽  
Anatoliy Omel’chuk ◽  
Roman Pshenichny ◽  
Anton Nagornyi
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Solid Solutions ◽  
Basic Structure ◽  
Elementary Cell ◽  
Initial Structure ◽  
Fluoride Ions ◽  
Temperature Range ◽  
Order Of Magnitude

In the system RbF–PbF2–SnF2 are formed solid solutions of the heterovalent substitution RbxPb0,86‑xSn1,14F4-x (0 < x ≤ 0,2) with structure of β–PbSnF4. At x > 0,2 on the X-ray diffractograms, in addition to the basic structure, additional peaks are recorded that do not correspond to the reflexes of the individual fluorides and can indicate the formation of a mixture of solid solutions of different composition. For single-phase solid solutions, the calculated parameters of the crystal lattice are satisfactorily described by the Vegard rule. The introduction of ions of Rb+ into the initial structure leads to an increase in the parameter a of the elementary cell from 5.967 for x = 0 to 5.970 for x = 0.20. The replacement of a part of leads ions to rubium ions an increase in electrical conductivity compared with β–PbSnF4 and Pb0.86Sn1.14F4. Insignificant substitution (up to 3.0 mol%) of ions Pb2+ at Rb+ at T<500 K per order of magnitude reduces the conductivity of the samples obtained, while the nature of its temperature dependence is similar to the temperature dependence of the conductivity of the sample β-PbSnF4. By replacing 5 mol. % of ions with Pb2+ on Rb+, the fluoride ion conductivity at T> 450 K is higher than the conductivity of the initial sample Pb0,86Sn1,14F4 and at temperatures below 450 K by an order of magnitude smaller. With further increase in the content of RbF the electrical conductivity of the samples increases throughout the temperature range, reaching the maximum values at x≥0.15 (σ573 = 0.34–0.41 S/cm, Ea = 0.16 eV and σ373 = (5.34–8.16)•10-2 S/cm, Ea = 0.48–0.51 eV, respectively). In the general case, the replacement of a part of the ions of Pb2+ with Rb+ to an increase in the electrical conductivity of the samples throughout the temperature range. The activation energy of conductivity with an increase in the content of RbF in the low-temperature region in the general case increases, and at temperatures above 400 K is inversely proportional decreasing. The nature of the dependence of the activation energy on the concentration of the heterovalent substituent and its value indicate that the conductivity of the samples obtained increases with an increase in the vacancies of fluoride ions in the structure of the solid solutions.

SYNTHESIS OF ALLOY METAL NANOCLUSTERS IN SILICA GLASS BY SEQUENTIAL ION IMPLANTATION

2007 ◽  
Vol 06 (06) ◽  
pp. 423-430 ◽  
Author(s):  
B. JOSEPH ◽  
H. P. LENKA ◽  
P. K. KUIRI ◽  
D. P. MAHAPATRA ◽  
R. KESAVAMOORTHY
Keyword(s):  
Ion Implantation ◽  
Silica Glass ◽  
Metallic Nanoparticles ◽  
Rutherford Backscattering Spectrometry ◽  
Low Frequency ◽  
Peak Position ◽  
Negative Ion ◽  
Metal Nanoclusters ◽  
Cross Sectional ◽  
The Matrix

High fluence low energy negative ion implantation has been used to synthesize embedded metal nanoclusters of Au , Ag and Sb in silica glass. The Au - and Ag -implanted samples showed peaks, corresponding to surface plasmon resonance (SPR) in the optical absorption (OA) spectra, confirming the formation of metallic nanoparticles in the matrix. No SPR peak was observed in case of Sb -implanted samples which is attributed to the absence of pure metallic precipitates which could be detected in the OA spectrum. Low frequency Raman scattering (LFRS) measurements also confirm this. Cross-sectional transmission electron microscopy has been used to infer about the size distribution of the nanoparticles. Sequential implantations of Au and Ag or Au and Sb have been found to result in SPR peaks at locations in between those for nanoparticles of the constituent atoms, indicating the formation of alloy nanoparticles in the system. In case of the Au + Ag system, Rutherford backscattering spectrometry has been used to infer about the composition of the nanoparticles in terms of the concentrations of the metallic constituents. A direct, one-to-one correspondence between the SPR peak position and composition has been observed.

Pzt Interaction with Metal and Oxides Studied by Rutherford Backscattering Spectrometry

1991 ◽  
Vol 243 ◽  
Author(s):  
Peter Revesz ◽  
Jian Li ◽  
Nicholas Szabo ◽  
James W. Mayer ◽  
David Caudillo ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Internal Oxidation ◽  
Rutherford Backscattering Spectrometry ◽  
Metal Electrode ◽  
Rutherford Backscattering ◽  
Annealing Behavior ◽  
Temperature Range ◽  
Pzt Film ◽  
Increasing Temperature

AbstractAnnealing behavior in oxygen ambients of the of the ferroelectric PZT on Hf and Zr electrodes has been studied in the temperature range of 500-800°C using the 3.045MeV O16(∝,∝)O16 resonance in backscattering spectrometry. Internal oxidation of the buried metal electrode was observed. Oxygen concentration of the PZT film decreases with increasing temperature. Pb loss of the PZT film occurred above 700°C.

scholarly journals Trace element geochemistry of carbonates in the Jurassic Lusitanian Basin records mineral-fluid interactions

2019 ◽  
Vol 98 ◽  
pp. 01017
Author(s):  
Mário A. Gonçalves ◽  
Maja Vuckovic ◽  
Alfonso Fiorelli ◽  
Pedro Barrulas ◽  
José Mirão
Keyword(s):  
Trace Elements ◽  
Fluid Flow ◽  
Carbonate Rocks ◽  
Sedimentary Basins ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
Chemical Signatures ◽  
Icp Ms ◽  
Mineral Interaction ◽  
Lusitanian Basin

Carbonate rocks in sedimentary basins are reactive and can record complex histories of events associated with fluid flow in these basins. These include processes of dolomitization and dedolomitization. In this work we provide some preliminary data where distinct calcite and dolomite generations in the Jurassic Lusitanian Basin were analysed by LA-ICP-MS for trace elements in order to characterize chemical signatures of fluid-mineral interaction. It was observed that different carbonate generations can preserve the range of certain trace metal concentrations, but later calcites have distinctly higher contents in REE, Th and U, and Ba. Dolomites also show distinct chemical signatures but lack of analytical and spatial resolution does not allow quantification of the precursor calcite relicts. However, these processes point to the action of basinal fluids triggered by distinct tectonic episodes and associated volcanic activity.

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