Acquisition of Advanced Capability 40Ar/39Ar Dating System at the Berkeley Geochronology Center

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With National Science Foundtion support Dr. Paul Renne and his colleagues at the Berkeley Geochronology Center will purchase a high sensitivity gas-source mass spectrometer with an ultra-low background extraction line which will be combined with a CO2 laser to measure 40Ar/39Ar ratios. The entire system will be fully automated to allow 24 hour unattended operation. 40Ar/39Ar dating has proven to be the most versatile means of calibrating the time interval during which anthropoids appeared in the paleontological record and therefore it is widely used by paleoanthropologists, paleontologists, geologists and paleobotanists. At the current time however young samples have proven difficult to date and the lijmitations are imposed by analytical capabilities rather than physical constraints. With the new system the increased sensitivity will permit the Center to date materials as young as 15,000 years and also enable finer grained distal ashes and lower potassium materials to be dated by the single crystal method. The Center is engaged in an active research program and both conducts field research itself and collaborates with many scientists. It dates samples of paleoanthropological interest from sites in Kenya and Ethiopia which are shedding new light on hominid origins. It also is dating localities in Soviet Georgia and Indonesia which have yeilded archaeological and fossil remains. With the new equipment not only will output be increased, but questions dealing, for example with the first appearance and spread of humans in the New World can also be addresed.