Archaeological implications of the geology and chronology of the Soa basin, Flores, Indonesia

The timing of arrival of early hominids in Southeast Asia has major implica tions for models of hominid evolution. The majority of evidence for the ear liest appearance of hominids in the region has previously come from Java in western Indonesia. Much of this evidence remains controversial owing to a poor understanding of the stratigraphic and chronologic relationships of th e depositional units from which the material was derived. Before artifacts may be placed into their proper archaeological context, the geologic histor y of archaeological sites must be thoroughly understood, and deposits conta ining artifacts must be properly dated. An extensive investigation has been undertaken on the island of Flores, in eastern Indonesia, to determine the depositional and chronological history of stratigraphic units within the S oa basin; many of the units are associated with stone artifacts attributed to Home erectus, Zircon fission-track dates of tuffaceous deposits within t his lacustrine basin now provide the most reliable data concerning the true time of arrival of Home erectus into Southeast Asia and indicate that thes e early hominids must have successfully begun colonizing eastern Indonesia by ca, 840 ka,