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

在美国国家科学基金会的支持下，Paul Renne博士和他在伯克利地质年代学中心的同事们将购买一台具有超低背景提取线的高灵敏度气源质谱计，该质谱仪将与二氧化碳激光器相结合，测量40Ar/39Ar比率。整个系统将完全自动化，允许24小时无人值守操作。~(40)Ar/~(39)Ar测年已被证明是古生物记录中最通用的校正类人猿出现时间间隔的方法，因此被古人类学家、古生物学家、地质学家和古植物学家广泛使用。然而，目前已证明年轻的样本很难确定日期，而这种怀疑是由分析能力而不是物质限制造成的。有了新的系统，提高的灵敏度将使该中心能够测定早至15,000年前的物质，并使更细粒的远端灰烬和低钾物质能够用单晶法测定年龄。该中心参与了一项积极的研究计划，两人都进行实地研究，并与许多科学家合作。它对肯尼亚和埃塞俄比亚遗址的古人类学兴趣样本进行了年代测定，这为人类起源提供了新的线索。它还在测定苏联、格鲁吉亚和印度尼西亚发现考古和化石遗骸的地点的年代。有了新的设备，不仅产量会增加，而且还可以解决一些问题，例如人类在新大陆的首次出现和传播。

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.