Volcanic Minerals of Victoria

Victoria has some 400 eruption centres dating from the Tertiary. The volcanism consisted of a major basalt province with maar volcanoes, scoria cones and calderas. Many of these eruption centres are preserved in the western district, forming prominent cone and caldera shaped hills. Minerals associated with the volcanism occur spectacularly as megacrysts and within xenoliths, particularly in the scoria cones. The megacrysts and xenoliths both include pyroxenes, olivine, amphiboles and feldspars. They originated within deeper in the crust and were carried to the surface during explosive eruption of the scoria cones. Mt. Franklin, Mt. Shadwell and Mt. Leura contain spectacular specimens filling vesicles in scoria rock. The sides of the old crater at Mt. Franklin, now a camping reserve, are strewn with boulders of scoria rock and many of these contain megacrysts and xenoliths of olivine, pyroxenes, amphiboles and feldspar. Mt. Leura contains xenoliths of lherzolite.