MagmaPandas includes a range of models to calculate fO₂, \({K_{D}}^{Fe-Mg}_{ol-melt}\), Fe³⁺/Fe²⁺, olivine liquidus temperatures, and H₂O-CO₂ saturation pressures. For Fe³⁺/Fe²⁺ and \({K_{D}}^{Fe-Mg}_{ol-melt}\), calibration datasets are (partially) included, and MagmaPandas has built-in functions to access and plot them. Amongst other things, these functions can be used to compare compositions in your own dataset to those in the calibrations in order to select an appropriate model. The example notebooks provide instructions on how to use these functions.

Errors are uncertainties on calibrations, as reported in their original publications. Fe3Fe2 errors are fitted from a validation dataset, please see the Fe3Fe2 error documentation for further explanation. For fO₂ and volatile solubility models, errors are not available

To confirm the accuracy of the models coded in MagmaPandas we performed benchmarks, which can be viewed here

Available models

Models available in MagmaPandas.

Parameter	Model	Equation	Error	MagmaPandas name
fO2 buffer
QFM	O'Neill [1987]	method from		QFM
	Holland and Powell [1990]	van Gerve et al. [2024]
	Holland and Powell [1998]
	Jennings and Holland [2015]
IW	Hirschmann [2021]	eqs. 4 & 17		IW
\({K_{D}}^{Fe-Mg}_{ol-melt}\)	Toplis [2005]	eq. 10	0.02	toplis2005
	Blundy et al. [2020]	eq. 8	Na2O + K2O < 6: 0.019	blundy2020
			Na2O + K2O ≥ 6: 0.04
			Na2O + K2O ≥ 9: 0.063
	Putirka [2016]	eq. 8a	0.04	putirka2016_8a
		eq. 8b	0.04	putirka2016_8b
		eq. 8c	0.04	putirka2016_8c
		eq. 8d	0.04	putirka2016_8d
	Sun and Dasgupta [2020]	eq. 7	0.03	sun2020
	Saper et al. [2022]	eq. 10	0.0141	saper2022
	fixed value	user set	user set	fixed
melt Fe3+/Fe2+	Borisov et al. [2018]	eq. 4	fitted	borisov2018
	Kress and Carmichael [1991]	eq. 7	fitted	kress_carmichael1991
	Jayasuriya et al. [2004]	eq. 6b	fitted	jayasuriya2004
	Putirka [2016]	eq. 6b	fitted	putirka2016_6b
		eq. 6c	fitted	putirka2016_6c
	Deng et al. [2020]	eq. 3	fitted	deng2020
	O'Neill et al. [2006]	eq. 10	fitted	oneill2006
	O'Neill et al. [2018]	eq. 9a	fitted	oneill2016
	Armstrong et al. [2019]	eq. S12	fitted	armstrong2019
	Zhang et al. [2017]	eq. 11	fitted	zhang2017
	Hirschmann [2022]	eq. 21	fitted	hirschmann2022
	Sun and Yao [2024]	eq. 9	fitted	sun2024
	fixed value	user set	user set	fixed
Olivine liquidus	Putirka [2008]	eq. 13	71°	putirka2008_13
temperature		eq. 14	58°	putirka2008_14
		eq. 15	46°	putirka2008_15
		eq. 16	26°	putirka2008_16
	Sun and Dasgupta [2020]	eq. 9	20°	sun2020
	Shea et al. [2022]	eq. 1	13°	shea2022
	Sugawara [2000]	eq. 3	33°	sugawara2000_3
		eq. 6a	30°	sugawara2000_6a
H2O-CO2 saturation	Allison et al. [2022]	eqs. 5 & 6		allison2022
pressure	Iacono-Marziano et al. [2012]	eqs. 12 & 13		iaconomarziano2012
	Shishkina et al. [2010]	eqs. 9 & 13		shishkina2010