Muscovite in Darling Range bauxitic laterite

Abstract

Darling Range bauxitic laterite contains 0-17% silt size, Na-rich, 2M1 muscovite which is most abundant in laterite developed from granitic parent rocks. Muscovite grains show evidence of dissolution, but there has been no formation of dioctahedral vermiculite. Muscovite is clearly a much more resistant mineral than the feldspar, biotite and chlorite in the parent materials that have completely altered to secondary minerals. Muscovite is therefore a significant constituent of Darling Range bauxitic laterite and consequently poses problems in bauxite processing.