Stratigraphic relations of australites in the Port Campbell Embayment, Victoria

Abstract

Abstract— In the Port Campbell Embayment of Victoria, australites have been found in situ in channel deposits of the Hanson Plain Sand of Pliocene and Pleistocene age. The large majority of the australites, however, occur as a lag deposit at the basal contact of the Sturgess Sand of late Pleistocene and Holocene age and are spatially correlated with ferruginous sandstone clasts that are derived from the Hanson Plain Sand. Some of the tektites are imbedded in or bonded to the ferruginous sandstone clasts, but most are found as individual tektite fragments. A few percent of the tektites have nearly perfectly preserved, complete aerodynamically shaped forms. The sandstone clasts and associated tektites have been reworked from the much older underlying Hanson Plain and have been locally concentrated in the lag deposit. Some tektites also occur at higher levels in the Sturgess Sand, almost invariably in association with stone flakes, exotic stones transported by the aborigines and, locally, with middens of mollusc shells. Circumstantial evidence indicates that the aborigines transported the tektites found in the upper part of the Sturgess, particularly at Stanhope Bay. As Port Campbell australites unequivocally occur in strata much older than the late Pleistocene and Holocene Sturgess, there is no longer any conflict between the apparent stratigraphic age of the tektites and the middle Pleistocene ages obtained by various chronometric methods.