What is this layer?
Mg# for ultramafic rocks. Geochemical data are derived from the GSWA geochemistry database. Mg# values are calculated using the recommended method of Rollinson (1993): 100 * (MgO% / (MgO% + Fe2O3T%)). Mg# can be used to interpret the degree of fractionation in a melt (Barnes et al., 2012).
Legend
|
Legend |
Range |
Classification |
Description |
Reference |
|---|---|---|---|---|
|
Mg# |
0–30 |
Manual |
A lower degree of fractionation in a melt |
|
|
30–65 |
Manual |
|||
|
65–75 |
Manual |
Mg# >65 likely represents komatiitic basalts and komatiites |
||
|
>75 |
Manual |
A higher degree of fractionation in a melt |
References
Barnes, SJ, Van Kranendonk, MJ and Sonntag, I 2012, Geochemistry and tectonic setting of basalts from the Eastern Goldfields Superterrane: Australian Journal of Earth Sciences, v. 59, no. 5, p. 707–735.
Hayman, PC, Thébaud, N, Pawley, MJ, Barnes, SJ, Cas, RAF, Amelin, Y, Sapkota, J, Squire, RJ, Campbell, IH and Pegg, I 2015, Evolution of a ~2.7 Ga large igneous province: A volcanological, geochemical and geochronological study of the Agnew Greenstone Belt, and new regional correlations for the Kalgoorlie Terrane (Yilgarn Craton, Western Australia): Precambrian Research, v. 270, p. 334–368.
Rollinson, HR 1993, Using geochemical data: Evaluation, presentation, interpretation: Pearson Education Ltd, Harlow, England, 352p.