SpinMelt v2

Introduction

Models of the SPINMELT family are developed for simulating spinel-melt equilibria in magmatic systems (Ariskin and Nikolaev, 1996). This is a useful petrologic tool allowing for examinations of the effects of oxygen fugacity and chromium contents in the melt on the equilibrium temperature and composition of chrome-aluminous spinels crystallized. The second version of the models (SPINMELT-2.0) is capable to model spinel compositions at variable T-fO2-conditions and elevated pressures (up to 15 kbar) in a wide range of mafic to ultramafic magmas (Nikolaev et al., 2018ab).

System Requirements

• Windows (Windows 10, Windows 8.x, Windows 7, Windows Vista, Windows XP)
• Max OS X (10.8.3+, 10.9+)
• Linux (Debian-based distributive)

Calculation modes

Calculate spinel composition and oxygen fugacity (log fO2) at given silicate melt composition, temperature and pressure

This calculation mode allows one to calculate oxygen fugacity from natural spinel-glass compositions if an independent estimate of the equilibrium temperature is available.

To use this option one should follow next step by step guide:

• Open input data-file using “Load Dataset…” button and wait for loading (see “Input Formats” section for details about input data-file formats)

• Select calculation mode using “Calculate spinel composition and oxygen fugacity (log fO2) at given silicate melt composition, temperature and pressure” button and wait until calculations completed.

• Save results using “Save Results…” button

Calculate spinel composition and temperature at given silicate melt composition, oxygen fugacity and pressure

This calculation mode allows one to calculate of spinel temperature and composition in the equilibrium with a magmatic melt, if oxygen fugacity is known.

To use this option one should follow next step by step guide:

• Open input data-file using “Load Dataset…” button and wait for loading (see “Input Formats” section for details about input data-file formats)

• Select calculation mode using “Calculate spinel composition and temperature at given silicate melt composition, oxygen fugacity and pressure” button and wait until calculations completed

• Save results using “Save Results…” button

Testing mode

The testing mode is designed to compare results of calculations with those obtained in experiments, including the temperature, fO2 and spinel composition. If “Testing Mode” activated using appropriate checkbox from the main screen, source data-file should also contain spinel composition and experimental values for the temperature and oxygen fugacity.

In testing mode there are several additional columns in result table:

• ΔT - Temperature(experimental) - Temperature(calculated)
• ΔlogfO2 - Temperature(experimental) - Temperature(calculated)
• ΔTi, ΔAl, ΔFe3+, ΔFe2+, ΔMg, ΔCr - Spinel composition (experimental) - Spinel composition (calculated)

Input Formats

The application support several input data formats:

• Microsoft Excel (*.xls, *.xlsx)
• Comma and tab separated (*.csv, *.tsv)
• DOS fixed-format (*.dat)

List of available column names:

• for experiments names (alphanumerical values)
  • “Reference”, “Ref.”, “Ref”, “Ref_no”
• for samples names (alphanumerical values)
  • ”#”, “Sample”, “Run”, “No.”, “Run_No”
• for temperate (numerical values)
  • temperature in celsius degree
    • “T”, “Temperature”, “T,C”, “T,°C”, “T(C)”, “T(°C)”, “T_C”, “Temperature,C”
  • temperature in kelvin degree
    • “T,K”, “T,°K”, “T(K)”, “T(°K)”, “T_K”, “Temperature,K”
• for pressure (numerical values)
  • pressure in kilo-bars
    • “Pressure”, “Pressure,kbar”, “Pressure,kb”, “P,kbar”, “P_kbar”, “P(kbar)”, “P,kb”, “P(kb)”, “P_kb”, “P”
  • pressure in gigapascal
    • “Pressure,GPa”, “P,GPa”, “P(GPa)”, “P_GPa”
• for oxygen fugacity (numerical values, oxygen buffers)
  • “log_fO2”, “logfO2”, “lgfO2”, “f_O2”
• for melt composition
  • “SiO2”, “TiO2”, “Al2O3”, and etc.
  • “LQ.SiO2”, “LQ.TiO2”, “LQ.Al2O3”, and etc.
• for spinel composition
  • “SP.TiO2”, “SP.Al2O3”, “SP.Fe2O3”, and etc.
• for comments
  • “Comments”

List of available oxygen buffer names:

• “IW”, “MW”, “FeFeO” - “Myers, Eugster, 1983”
• “WM” - “Myers, Eugster, 1983”
• “IM” - “Huebner J.S., 1971”
• “MH” - “Myers, Eugster, 1983”
• “QFM”, “FMQ” - “Myers, Eugster, 1983”
• “QFM87” - “O’Neill_1987a”
• “IQF” - “Myers, Eugster, 1983”
• “NNO”, “NI-NIO”, “NiNiO” - “Huebner J.S., 1971”
• “CCO” - “Myers, Gunter, 1979”
• “COC>5” - “Woermann et al., 1977”
• “COC<5”, “COC” - “French B.H., 1966”

Example of input data-file

• Example with temperature, fugacity, melt and spinel compositions (xlsx)
• Example with fugacity and melt composition (xlsx)

Output Formats

The application support several output data formats:

• Microsoft Excel (*.xls, *.xlsx)
• Comma and tab separated (*.csv, *.tsv)

List of available column names:

• Ref., Sample - sample name and reference from source data-file
• T, C - temperature - calculated value in case of appropriate mode, or from source data-file
• log fO2 - oxygen fugacity - calculated value in case of appropriate mode, or from source data-file
• P, kb - pressure from source data-file
• ΔQFM - delta between current oxygen fugacity and QFM buffer fugacity
• SP.TiO2 wt.%, SP.Al2O3 wt.%, … - calculated spinel composition in weight percents
• SP.Ti at.%, SP.Al at.%, … - calculated spinel composition in atomic percents
• SP.#mg
• SP.Al/R3
• SP.Cr/R3
• SP.Fe3/R3
• LQ.SiO2 wt.%, LQ.TiO2 wt.%, … - silicate melt composition in weight percents
• Comments - some comments in case of failed calculations

Example of output data-file

Interface

Main Screen Overview

Calculation using “Fugacity” mode

Calculation using “Thermometry” mode

References:

• Nikolaev, G. S., Ariskin, A. A. & Barmina, G. S. (2018). SPINMELT-2.0: Simulation of spinel–melt equilibrium in basaltic systems under pressures up to 15 kbar: I. Model formulation, calibration, and tests. Geochemistry International. 56, 24–45.
• Nikolaev, G. S., Ariskin, A. A. & Barmina, G. S. (2018). SPINMELT-2.0: Simulation of spinel–melt equilibrium in basaltic systems under pressures up to 15 kbar: II. Description of the program package, the topology of the Cr-spinel–melt model system, and petrological implications. Geochemistry International. 56, 125–135.