Mineralogy and origin of the titaniferous deposit at Pluma Hidalgo, Oaxaca, Mexico

Abstract

Ilmenite and rutile, with apatite, are deuteric minerals in gneissic granulite (oligoclase-andesine, minor quartz) with ferro-magnesium bands. Titanium minerals replace feldspar, but are earlier than the abundant chlorite and uralite to which the original augite, hornblende, and olivine are largely altered. Source of the mineralizing solutions is believed to be the residual magma from which the host rock crystallized.