The association of maghemite and corundum in Darling Range laterites, Western Australia

Abstract

Maghemite in Darling Range lateritic duricrust ranges from 2 to 10% in abundance, contains less than 5 mole % Al and occurs as aggregates of very small ~ 150 A subrounded platy crystals. Corundum is also present, ranging from 1 to 3.5% in abundance, and it contains less than 3 mole % Fe and occurs as rounded (~250 A) crystals. The maghemite and corundum contents are positively correlated (P < 0.01), which may indicate a common origin due to dehydroxylation of Fe and Al oxyhydroxides in bush fires.