Tools for Petrologists

TAS Diagram Plotter

Excel spreadsheet that allows for fast plotting onto a TAS (total alkali silica) diagram for use in naming your volcanic rock by composition. Created using coordinates as given in Le Maitre et al (2002).

Please cite as: Iacovino, Kayla, & Gouard, Cédric. (2021). TAS Diagram Plotter (3.0). Zenodo. https://doi.org/10.5281/zenodo.5907859

Version 3.0 New version by Cédric Gouard. Significant improvements and new features! Logic based on rock composition will now classify your rock type even further than the fields on the TAS diagram. For example, a trachybasalt may be further identified as a hawaiite or potassic trachybasalt; a basaltic trachyandesite may be further identified as a mugearite or shoshonite. The TAS diagram is now drawn in a more sensible way from formulae, and overall user friendliness is improved.
Version 2.0 The user can now resize the TAS diagram chart and keep the region boundaries in tact. Beware that the region labels may still move around relative to their fields, however.

TAS Diagram Plotter version en espanol

Hoja de Excel. Versión en español del trazador de diagramas TAS traducido del inglés por Crescencio Fernandez H.

Please cite as: Iacovino, Kayla, Gouard, Cédric, & Fernandez, Crescencio. (2021). TAS Diagram Plotter version en espanol. Zenodo. https://doi.org/10.5281/zenodo.5907888

Plutonic TAS Diagram Plotter

Excel spreadsheet based on the Volcanic TAS Diagram Plotter (v2.0) with updated parameters and labels for plutonic rocks. Created by Paul Asimow using coordinates and labels as given in E. A. K. Middlemost (1994).

Please cite as: Iacovino, Kayla, & Asimow, Paul. (2018). Plutonic TAS Diagram Plotter (1.0). Zenodo. https://doi.org/10.5281/zenodo.5907892

Version 1.0 Based on Volcanic TAS Diagram Plotter v2.0

DensityX: Glass Density Calc

Excel spreadsheet. Input the composition of a silicate glass/melt in terms of wt% and the H2O content in terms of wt% plus the temperature and pressure of the sample. Spreadsheet outputs the density of your glass/melt in terms of g/cm³ and g/L. User inputs go in blue boxes, output is automatically generated in red boxes.

Please cite as: Iacovino, K. and Till, C. B. (2019) “DensityX: A program for calculating the densities of magmatic liquids up to 1,627 °C and 30 kbar”, Volcanica, 2(1), pp. 1–10. doi: 10.30909/vol.02.01.0110.

References: Iacovino & Till (2019); Lange & Carmichael (1990); Ochs & Lange (1999); Also see Hack & Thompson (2011)

Excel Version 4.1
4.1: Updated molecular weight of H2O from 18 to 18.02 to match python code and web app. Updated 04 Apr 2023.
4.0: Updated to match DensityX python code version 1.1.0, which includes all changes made to the program in response to reviewers of the DensityX manuscript for publication in Volcanica.
3.2: Updated reference list to include all values and reference P and T values used. Updated 10 Apr 2017.
3.1: Minor tweaks to layout to clarify user inputs and program outputs. Fixed typo in reference temperature for H2O. Updated 29 Mar 2017.
3.0: Updated temperature dependence data to refer to correct reference temperature. Calculations now work at high temperature. Updated 26 Jan 2014.

🐍 DensityX Python Library

Github Repository. You can download the DensityX python library locally if you like. It can also be installed via pip “pip install densityx”.

🕸️ DensityX Web Tool

DensityX Web Tool. Online interface to the DensityX python library. Simply upload your file and run it!

Calculate fO2 Buffer

Excel spreadsheet. Tool to calculate oxygen fugacity in terms of the common buffers when logfO2 is known or for translating between fO2 values expressed in terms of various buffers. This is useful for converting calculated oxygen fugacity values into and between delta buffer values (e.g. ΔNNO, ΔQFM…).

Please cite as: Iacovino, Kayla. (2022). Calculate fO2 Buffer (1.5). Zenodo. https://doi.org/10.5281/zenodo.7387196

References: 
B. R. Frost in Mineralogical Society of America “Reviews in Mineralogy” Volume 25.
Campbell, A. J. et al. High pressure effects on the iron–iron oxide and nickel–nickel oxide oxygen fugacity buffers. Earth Planet Sc Lett 286, 556–564 (2009).
French, B. M. & Eugster, H. P. Experimental control of oxygen fugacities by graphite‐gas equilibriums. J Geophys Res 70, 1529–1539 (1965).
Pownceby, M. I. & O’Neill, H. St. C. Thermodynamic data from redox reactions at high temperatures. IV. Calibration of the Re-ReO2 oxygen buffer from EMF and NiO+Ni-Pd redox sensor measurements. Contr. Mineral. And Petrol. 118, 130–137 (1994).
Holzheid, A. & O’Neill, H. St. C. The Cr-Cr203 oxygen buffer and the free energy of formation of Cr203 from high-temperature electrochemical measurements. Geochim Cosmochim Ac 59, 475–479 (1995).
Bygden, J., Du Sichen, and S. Seetharaman. “A thermodynamic study of the molybdenum-oxygen system.” Metallurgical and Materials Transactions B 25.6 (1994): 885-891.

Version 1.5
1.5 Fixed Re-ReO buffer (previously used log when ln should have been used). Credit Daniel Coulthard for the fix! 1 Dec 2022
1.4: Added equation for Mn-MnO buffer. Also flagged which reactions are calibrated only for 1 bar ( these equations have no pressure dependence). 19 July 2021.
1.3: Added equations for Graphite-CO-CO2 (GCO), Re-ReO, Cr-Cr2O3, and MoMoO2 buffers. Added “Translate from IW” tab. 3 June 2021.
1.2: Added equation for Si-SiO2 buffer. 28 May 2020.
1.1: Added ability to convert from a buffer value to the actual logfO2 value and into other buffers. Useful, for example, in comparing two data sets where one is expressed in terms of ΔNNO and the other in terms of ΔQFM. 6 October 2016.

🐍 Python Script: Oxygen Fugacity (Redox) Buffer Plotter

Python script that plots fO2 buffer values at any given pressure and temperature range. Right click the link above and “Save Target As…” and unzip the .zip file containing a python script and library.  User should edit the file ‘create_plot.py’ and run this script to create a plot.

Please cite as: Iacovino, Kayla. (2021). Oxygen Fugacity (Redox) Buffer Plotter. Zenodo. https://doi.org/10.5281/zenodo.5907875

Update 6 July 2021 Fixed QFM, HM, CoCoO, and QIF equations to use pressure in bars instead of GPa.

Ferric/Ferrous, Fe3+/FeT, fO2 Converter (Kress and Carmichael, 1991)

Excel spreadsheet. Tool for calculating the ferric/ferrous iron ratio in a melt for any given fO2 and vice versa. Also calculates new wt% and mole fraction values for FeO and Fe2O3 in your melt. Useful for determining theoretical iron speciation when total is given as FeOtotal or Fe2O3total and fO2 is known. Can also calculate or recalculate FeO and Fe2O3 wt% from given Fe3+/FeT and FeOT (or existing FeO and Fe2O3 wt%).

Please cite as: Iacovino, Kayla. (2021). Ferric/Ferrous, Fe3+/FeT, fO2 Converter (Kress and Carmichael, 1991) (3.2). Zenodo. https://doi.org/10.5281/zenodo.5907844

References: Kress & Carmichael (1991); B. R. Frost in Mineralogical Society of America “Reviews in Mineralogy” Volume 25.

Version 3.2
3.2: Corrected error in cells J5 and J6, which were previously using an improper conversion coefficient (0.8998 instead of 2). January 2021.
3.1: Added tab for calculating FeO and Fe2O3 from Fe3+/FeT. December 2020.
3.0: Added all parameters for calculations at high pressure. Redesigned user interface. Added conversion from melt comp to fO2. 12 October 2018.
2.2: Fixed bug where dropdown box to choose oxygen fugacity buffer did not work. 11 October 2016.

Hydrous Melts Conversion Tool

Excel spreadsheet with VisualBasic macros. Tool for converting anhydrous composition of a silicate melt in wt% plus known mol fraction of volatiles in the melt (H2O and CO2 mixture) to a hydrous melt composition in terms of both wt% and mol fraction. I created this tool as part of an independent study during my undergrad. Also see the tutorial.

Wtper-to-Molper Conversion Tool

Excel spreadsheet with VisualBasic macros. Tool for converting (hydrous or anhydrous) melt composition from wt% to mol%.

Oxide to Element Conversion Tool

Excel spreadsheet that will convert compositions measured in oxides (SiO2, FeO, K2O, etc) to elements (Si, Fe, K, etc), and vice versa.

Please cite as: Iacovino, Kayla. (2019). Oxide to Element Conversion Tool. Zenodo. https://doi.org/10.5281/zenodo.5907879

Water From Iron Reduction

Excel spreadsheet. Great for experimental petrologists. If a silicate melt is “fused” or “pre-melted” at the same oxygen fugacity that the experiments are ultimately run at, the ratio of ferric to ferrous iron in the melt will remain unchanged. If, however, the melt is fused in air and then run at more reducing conditions, some of the Fe2O3 will be reduced to FeO and will add water to your melt in the process. Use this tool to calculate just how much water was added to your melt due to the reduction of iron during your run. Only works if pre-run fO2 is in air (i.e. all iron is Fe2O3 before run), but calculation can be made for any experimental fO2.

Please cite as: Iacovino, Kayla. (2020). Water From Iron Reduction (1.1). Zenodo. https://doi.org/10.5281/zenodo.5907885

References: Kress & Carmichael (1991); B. R. Frost in Mineralogical Society of America “Reviews in Mineralogy” Volume 25.
Version 1.1