Age Calibration of Hominid-Bearing Sites in Java, Indonesia

9405320斯威舍现有的古生物数据表明，我们的进化史大部分记录在非洲大陆的岩石中。一个重要的例外是直立人的起源和进化。在爪哇遗址Sangiran、Perning、KedungBrubus、Sambungmacan和Ngongong发现了大量早期原始人的标本。然而，关于分类上的相似性，特别是其中许多发现的年代，相当大的争论仍在继续。关于爪哇原始人年龄的争论集中在两个问题上：一些化石标本的准确地层位置和这些沉积物的准确年龄。该项目由世界上杰出的地质年代学小组负责，将开发一个详细的年代学框架，以便在时间上校准爪哇原始人的进化。目前一些发现的年龄差异很大，从200万多万年前到20万年前。他们将1)使用增量激光和电阻炉加热Ar同位素技术来确定与爪哇原始人遗址有关的含浮石地层的年代，2)直接测定原始人和/或与之相关的哺乳动物化石的年龄，这些化石具有足够数量的火山物质用于Ar同位素测年，以及3)开发和完善目前可用的爪哇上更新世含原始人地层剖面的磁性地层学。由此产生的年表将有助于构建爪哇人的详细时间历史，并首次使爪哇直立人与非洲上更新世的人和动物群的Evets进行精确的时间关联。

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.