Intracrystalline boron isotope partitioning in illite-smectite: Testing the geothermometer
-
Lynda B. Williams
,
Amanda Turner
Abstract
Intracrystalline B-isotope differences of ~40‰, are observed between the interlayer and tetrahedral crystallographic sites of interstratified illite-smectite (I-S). We tested the hypothesis that partitioning of B-isotopes between these sites could provide a low-temperature, single-mineral geothermometer. Samples studied include a metabentonite transected by a dike in the Cretaceous Pierre Shale (200-500 °C), buried mudstones from the Eocene Wilcox Formation (60-125 °C), and I-S products from hydrothermal experiments (300-350 °C). Different reaction kinetics are represented by these different sample sets, therefore results test the equilibrium partitioning of B in the interlayer vs. tetrahedral sites.
In all samples, interlayer δ11B values are isotopically heavier than the tetrahedral δ11B. Because 11B prefers trigonal coordination, we infer that B(OH)3 dominates the interlayer sites. Within each sample set, the intracrystalline differences are greatest (20-40‰) in the most expanded I-S (i.e., smectite-rich), and approach 0 as illitization increases. There is good correlation (R = 0.84) between the interlayer δ11B (calculated by mass balance) and water δ11B indicated by the established maximum temperature of each sample. These results suggest that the interlayer sites of I-S preserve the B isotopic composition of water at the temperature that produced the authigenic illite. Direct measurements of interlayer δ11B equilibrated with water of known δ11B are needed to refine the relationship with temperature, but the existing data indicate the following temperature dependent relationship: T (°C) = (δ11B tetrahedral - δ11B interlayer + 30)/0.05.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Evaluation of image classification routines for determining modal mineralogy of rocks from X-ray maps
- Atomic structure and formation mechanism of (301) rutile twins from Diamantina (Brazil)
- Significance of the depth-related transition montmorillonite-beidellite in the Bouillante geothermal field (Guadeloupe, Lesser Antilles)
- High-pressure infrared spectra of talc and lawsonite
- Proton dynamics in letovicite: Part I. Static 1H and 15N NMR MAS experiments and lineshape simulations
- Proton dynamics in letovicite: Part II. Static 2H NMR experiments and lineshape simulations
- Chemical and structural variations at augite (100) deformation twin boundaries
- Comparative compressibility and structural behavior of spinel MgAl2O4 at high pressures: The independency on the degree of cation order
- Multiple breakdown and chemical equilibrium of silicic clinopyroxene under extreme metamorphic conditions in the Kontum Massif, central Vietnam
- Direct EXAFS evidence for incorporation of As5+ in the tetrahedral site of natural andraditic garnet
- Deformation-controlled cation diffusion in tourmaline: A microanalytical study on trace elements and boron isotopes
- Scandium-45 NMR of pyrope-grossular garnets: Resolution of multiple scandium sites and comparison with X-ray diffraction and X-ray absorption spectroscopy
- Partitioning of trace elements among coexisting crystals, melt, and supercritical fluid during isobaric crystallization and melting
- Thermal diffusivity of aluminous spinels and magnetite at elevated temperature with implications for heat transport in Earth’s transition zone
- High-pressure structure and bonding in CaIrO3: The structure model of MgSiO3 post-perovskite investigated with time-of-flight neutron powder diffraction
- Application of major- and trace-element geochemistry to refine U-Pb zircon, and Sm/Nd or Lu/Hf sampling targets for geochronology of HP and UHP eclogites, Western Gneiss Region, Norway
- Measurement of U-Pb ages of uraninite and davidite by laser ablation-HR-ICP-MS
- A modeling approach to understanding the role of microstructure development on crystalsize distributions and on recovering crystal-size distributions from thin slices
- Neptunium substitution in synthetic uranophane and soddyite
- Coexistence of twisted and untwisted crystals: An impurity/structural order model with implications for agate patterns
- Intracrystalline boron isotope partitioning in illite-smectite: Testing the geothermometer
- Mineralogy of the hardpan formation processes in the interface between sulfide-rich sludge and fly ash: Applications for acid mine drainage mitigation
- Dissolution of radiation-damaged zircon in lateritic soils
- Hydrogen analysis in minerals by continuous-flow mass spectrometry
- Re-examination of berlinite (AlPO4) from the Cioclovina Cave, Romania
- Letter. Valence state partitioning of Cr between pyroxene-melt: Effects of pyroxene and melt composition and direct determination of Cr valence states by XANES. Application to Martian basalt QUE 94201 composition
Articles in the same Issue
- Evaluation of image classification routines for determining modal mineralogy of rocks from X-ray maps
- Atomic structure and formation mechanism of (301) rutile twins from Diamantina (Brazil)
- Significance of the depth-related transition montmorillonite-beidellite in the Bouillante geothermal field (Guadeloupe, Lesser Antilles)
- High-pressure infrared spectra of talc and lawsonite
- Proton dynamics in letovicite: Part I. Static 1H and 15N NMR MAS experiments and lineshape simulations
- Proton dynamics in letovicite: Part II. Static 2H NMR experiments and lineshape simulations
- Chemical and structural variations at augite (100) deformation twin boundaries
- Comparative compressibility and structural behavior of spinel MgAl2O4 at high pressures: The independency on the degree of cation order
- Multiple breakdown and chemical equilibrium of silicic clinopyroxene under extreme metamorphic conditions in the Kontum Massif, central Vietnam
- Direct EXAFS evidence for incorporation of As5+ in the tetrahedral site of natural andraditic garnet
- Deformation-controlled cation diffusion in tourmaline: A microanalytical study on trace elements and boron isotopes
- Scandium-45 NMR of pyrope-grossular garnets: Resolution of multiple scandium sites and comparison with X-ray diffraction and X-ray absorption spectroscopy
- Partitioning of trace elements among coexisting crystals, melt, and supercritical fluid during isobaric crystallization and melting
- Thermal diffusivity of aluminous spinels and magnetite at elevated temperature with implications for heat transport in Earth’s transition zone
- High-pressure structure and bonding in CaIrO3: The structure model of MgSiO3 post-perovskite investigated with time-of-flight neutron powder diffraction
- Application of major- and trace-element geochemistry to refine U-Pb zircon, and Sm/Nd or Lu/Hf sampling targets for geochronology of HP and UHP eclogites, Western Gneiss Region, Norway
- Measurement of U-Pb ages of uraninite and davidite by laser ablation-HR-ICP-MS
- A modeling approach to understanding the role of microstructure development on crystalsize distributions and on recovering crystal-size distributions from thin slices
- Neptunium substitution in synthetic uranophane and soddyite
- Coexistence of twisted and untwisted crystals: An impurity/structural order model with implications for agate patterns
- Intracrystalline boron isotope partitioning in illite-smectite: Testing the geothermometer
- Mineralogy of the hardpan formation processes in the interface between sulfide-rich sludge and fly ash: Applications for acid mine drainage mitigation
- Dissolution of radiation-damaged zircon in lateritic soils
- Hydrogen analysis in minerals by continuous-flow mass spectrometry
- Re-examination of berlinite (AlPO4) from the Cioclovina Cave, Romania
- Letter. Valence state partitioning of Cr between pyroxene-melt: Effects of pyroxene and melt composition and direct determination of Cr valence states by XANES. Application to Martian basalt QUE 94201 composition
