Skip to main content
U.S. flag

An official website of the United States government

Oxide and Cation Compositions of Pyroxene Grains from Drill Core of the Duluth Complex, Minnesota

September 21, 2018

The table contains oxide and cation compositions of pyroxene grains from drill core in the Duluth Complex. The oxides were determined by electron probe microanalysis (EPMA) and are reported in weight percent (we%). The cations were calculated from the oxide concentrations and are reported in mole percent (mol%). Pyroxene minerals are a group of rock-forming inosilicate minerals with calcium (Ca), iron (Fe), and magnesium (Mg) endmembers. Wollastonite (Wo) is the Ca-endmember with the formula Ca2Si2O6. Ferrosilite (Fs) is the Fe-endmember with the formula Fe2Si2O6, and enstatite (En) is the Mg-endmember with the formula Mg2Si2O6. In order to better understand the chemical compositions of the pyroxenes, the percent of Wo, Fs, and En were also determined using the cation compositions Ca, Fe, and Mg.