Age Calibration of Hominid-Bearing Sites in Java, Indonesia

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9405320 Swisher Available paleontological data indicate that much of our evolutionary history is recorded in rocks on the African continent. An important exception to this, is the origin and evolution of Homo erectus. Numerous specimens of early hominids have been recovered from the Javanese sites of Sangiran, Perning,Kedungbrubus, Sambungmacan, and Ngandong. Considerable debate continues, however, as to the taxonomic affinity and particularly the age of many of these finds. The debate over the age of the Javanese hominids centers around two questions; the precise stratigraphic placemtn of some of the fossil specimens and the precise age of these deposits. This project, by the outstanding geochronology group in the world, will develop a detailed geochronological framework in order to calibrate temporally the evolution of hominids in Java. Current age estaimtes for some finds vary dramatically from slightly over 2 million years ago to as young as 200,000 years ago. They will 1)use incremental laser and resistance furnace heating argon isotope techniques to date pumice-bearing horizons associated with hominid sites in Java, 2) date directly hominids and/or associated mammalian fossils that have sufficient amounts of volcanic material attached for argon isotope dating, and 3) develop and refine the currently available magnetostratigraphies of Plio-Pleistocene hominid-bearing stratigraphic sections of Java. The resultant chronology will permit the construction of a detailed temporal history of Javanese hominids, and allow for the first time, precise temporal correlation of the Javanese Homo erectus with hominid and faunal evets in the Plio-Pleistocene of Africa.