Abstract
Chrome spinel coexisting with fresh olivine in a dunite nodule from tuff shows partial to complete alteration to an opaque, higher reflecting variety of chromite. The spinel has the composition (Fe 0·4 2Mg 0·6) (Fe 0·1 3Cr 0·8Al 1·1)O 4; the chromite is variable: (Fe 0·5 2Mg 0·5) (Fe 0·5−0·6 3Cr 0·8Al 0·5−0·8) 2O 4. The alteration was probably effected at high temperature by a late-magmatic process prior to eruption. Chrome spinel should always be carefully examined optically before drawing petrogenetic inferences based on its chemical composition.
Full Text 
Sign-in/Register to access full text options
Sign-in/Register to access full text options 
Published version (
Free)
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
