Location:

Little Broken Hill, New South Wales, Australia

A series of highly metamorphosed iron-rich rocks crop out to the east of the Broken Hill lead-zinc deposit. Quartz-magnetite and iron formations have been recognized lying within quartz-feldspar-biotite-sillimanite-garnet gneisses. The iron formation comprises banded magnetite-garnet-quartz-apatite rocks with accessory gahnite, biotite, amphibole, chlorite and zircon. At outcrop the magnetite has been extensively oxidized to haematite (martite).

Major Minerals:

Magnetite

Minor and Trace Minerals:

Haematite, ilmenite, rutile, gahnite, minerals pyrite, pyrrhotite, chalcopyrite, cubanite, sphalerite, galena, marcasite

Textures:

Magnetite, garnet and quartz are equidimensional with 120' triple junctions. Magnetite-rich layers are interbanded with iron-poor layers. Minor intergrowths of magnetite-ilmenite-rutile-haematite are present. Ilmenite lies between grain boundaries of magnetite or as laths along (111) planes within magnetite. Pyrite has pyrrhotite, chalcopyrite, galena and magnetite inclusions. Pyrrhotite alters to pyrite and marcasite. Surface oxidation of magnetite to haematite to give martite pseudomorphs after magnetite is common in outcrop

References:

Richards, 1966; Stanton, 1976