Effects of post-cumulus processes on chromite compositions in layered intrusion cumulates and implications for the origins of chromitite layers

In several studies of chromite-rich cumulates in layered intrusions, the Cr/Al ratio of chromite varies significantly within centimetre-to-decimetre scale layering. In the G-H chromitite section of the Stillwater Complex (United States), Cr/Al ratios are consistently higher, by up to relative 20%, in the most chromite-rich rocks compared with immediately adjacent layers. Systematic relationships between Cr/Al ratios and chromite modes are also observed in cumulate rocks of the Bushveld Complex (