Composition and elastic constants of Hortonolite dunite

Mao, Nai-Hsien; Ito, Jun; Hays, J. F.; Drake, Jennifer E.; Birch, Francis

doi:10.1029/jb075i020p04071

Cited by 12 publications

(2 citation statements)

References 14 publications

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“…To validate the mixing calculations and moduli for ultramafic minerals discussed in Section 3.1, we compiled multi-directional seismic wave speed measurements for 40 ultramafic rocks for which modal assemblages are reported (compiled in Table S2 in Supporting Information S1, Babuška, 1972;Birch, 1960Birch, , 1961Christensen, 1966Christensen, , 1974Christensen, , 1978Christensen, , 1979Christensen & Ramananantoandro, 1971;Kono et al, 2004Kono et al, , 2009Kroenke et al, 1976;Mao et al, 1970;O'Reilly et al, 1990;Peselnick & Nicolas, 1978;Prelicz, 2005;Ramana & Rao, 1974). We decompose the minerals into the mineral endmembers following Wood and Banno (1973) and Holland et al (2018) and calculate the seismic wave speed following the same approach as Perple_X.…”

Section: Mixing Theory and Moduli Uncertaintymentioning

confidence: 99%

WISTFUL: Whole‐Rock Interpretative Seismic Toolbox for Ultramafic Lithologies

Shinevar

Jagoutz

Behn

2022

Geochem Geophys Geosyst

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To quantitatively convert upper mantle seismic wave speeds measured into temperature, density, composition, and corresponding and uncertainty, we introduce the Whole‐rock Interpretative Seismic Toolbox For Ultramafic Lithologies (WISTFUL). WISTFUL is underpinned by a database of 4,485 ultramafic whole‐rock compositions, their calculated mineral modes, elastic moduli, and seismic wave speeds over a range of pressure (P) and temperature (T) (P = 0.5–6 GPa, T = 200–1,600°C) using the Gibbs free energy minimization routine Perple_X. These data are interpreted with a toolbox of MATLAB® functions, scripts, and three general user interfaces: WISTFUL_relations, which plots relationships between calculated parameters and/or composition; WISTFUL_geotherms, which calculates seismic wave speeds along geotherms; and WISTFUL_inversion, which inverts seismic wave speeds for best‐fit temperature, composition, and density. To evaluate our methodology and quantify the forward calculation error, we estimate two dominant sources of uncertainty: (a) the predicted mineral modes and compositions, and (b) the elastic properties and mixing equations. To constrain the first source of uncertainty, we compiled 122 well‐studied ultramafic xenoliths with known whole‐rock compositions, mineral modes, and estimated P‐T conditions. We compared the observed mineral modes with modes predicted using five different thermodynamic solid solution models. The Holland et al. (2018, https://doi.org/10.1093/petrology/egy048) solution models best reproduce phase assemblages (∼12 vol. % phase root‐mean‐square error [RMSE]) and estimated wave speeds. To assess the second source of uncertainty, we compared wave speed measurements of 40 ultramafic rocks with calculated wave speeds, finding excellent agreement (Vp RMSE = 0.11 km/s). WISTFUL easily analyzes seismic datasets, integrates into modeling, and acts as an educational tool.

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Section: Mixing Theory and Moduli Uncertaintymentioning

confidence: 99%

WISTFUL: Whole‐Rock Interpretative Seismic Toolbox for Ultramafic Lithologies

Shinevar

Jagoutz

Behn

2022

Geochem Geophys Geosyst

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“…To validate the aforementioned mixing calculations and moduli for ultramafic minerals, we compiled multi-directional seismic wave speed measurements for a variety of ultramafic rocks with reported modal assemblages (Birch, 1960(Birch, , 1961Simmons, 1964;Christensen, 1966Christensen, , 1974Christensen, , 1978Mao et al, 1970;Christensen and Ramananantoandro, 1971;Babuška, 1972;Kroenke et al, 1976;Peselnick and Nicolas, 1978;O'Reilly et al, 1990;Miller and Christensen, 1994;Kono et al, 2004Kono et al, , 2009Prelicz, 2005). For a reported mineral composition, we decompose the minerals into the mineral endmembers following the Jennings & Holland (2015) solution models and calculate the seismic wave speed following the same approach as Perple_X (described above).…”

Section: Calculating Seismic Wave Speedsmentioning

confidence: 99%

Inferring the thermomechanical state of the lithosphere using geophysical and geochemical observables

Shinevar¹

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This thesis focuses on interpreting geophysical and geochemical observables in terms of the thermomechanical state of the lithosphere. In Chapter 1, I correlate lower crustal rheology with seismic wave speed. Compositional variation is required to explain half of the total variability in predicted lower crustal stress, implying that constraining regional lithology is important for lower crustal geodynamics. In Chapter 2, I utilize thermobarometry, diffusion models, and thermodynamic modelling to constrain the ultra-high formation conditions and cooling rates of the Gore Mountain Garnet Amphibolite in order to understand the rheology of the lower crust during orogenic collapse. In Chapter 3, I interpret geophysical data along a 74 Myr transect in the Atlantic to the temporal variability and relationship of crustal thickness and normal faults. In Chapter 4, I constrain the error present in the forward-calculation of seismic wave speed from ultramafic bulk composition. I also present a database and toolbox to interpret seismic wave speeds in terms of temperature and composition. Finally, in Chapter 5 I apply the methodology from Chapter 4 to interpret a new seismic tomographic model in terms of temperature, density, and composition in order to show that the shallow lithospheric roots are density unstable.

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References for 3.1.1 - 3.1.3

Gebrande¹

Landolt-Börnstein - Group v Geophysics

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Composition and elastic constants of Hortonolite dunite

Cited by 12 publications

References 14 publications

WISTFUL: Whole‐Rock Interpretative Seismic Toolbox for Ultramafic Lithologies

WISTFUL: Whole‐Rock Interpretative Seismic Toolbox for Ultramafic Lithologies

Inferring the thermomechanical state of the lithosphere using geophysical and geochemical observables

References for 3.1.1 - 3.1.3

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