Correlations of octahedral cations with OH-, O2-, Cl-, and F- in biotite from volcanic rocks and xenoliths.

Examines the compositional variation in igneous biotite through analyses of a suite of biotites of variable composition from volcanic and xenolith parageneses. Effect of dehydrogenation on the original composition of biotites; Examination of biotite data from mantle samples; Analysis of mantle rocks from Mars.