Development and Application of 40k-40 Ar and Laser Microprobe 40Ar/39Ar Dating for Arachaeometric Research

在 NSF 的支持下，博士。德雷克和柯蒂斯在加利福尼亚州伯克利人类起源研究所建立了伯克利地质年代学中心 (BGC)。 BGC 专注于 K-Ar（钾 - 氩）测年，现在每年可生产约 250 个常规 40K Ar39 测年仪和 3000 个单晶激光显微探针测年仪，相当于每年约 500 个样本测年仪（通常会对同一样本的几个子样本进行测年）。他们的微型探针是完全自动化的，此外，还能够测定亚毫克级单火山晶体的年代。这使得可以识别多年龄成分样本中的离散年龄群体。超过一半的实验室研究集中于与原始人类-类人猿（人类-类人猿）进化相关的地质年代学以及相关的考古学和古生物学。在三年的额外支持下，该实验室将致力于改进这种测年技术，以实现更精确和准确的日期。他们还将继续与古人类学家合作，解决一系列具有人类学意义的特定地点问题。钾氩技术可以从火山物质中推导出绝对年龄，它彻底改变了人类起源研究领域，因为非洲许多以前无法确定年代的重要遗址包含多个火山层。只有将化石放入年代顺序框架中才能正确解释，许多难以使用的标本变得具有新的重要性。 Drake 博士和他的同事一直是该技术开发和应用的领导者。因此，支持他们的实验室和他们所追求的具体研究目标非常重要。

With NSF support, Drs. Drake and Curtis have established a Berkeley Geochronology Center (BGC) at the Institute of Human Origins in Berkeley, California. The BGC focuses on K-Ar (potassium - argon) dating and can now produce about 250 conventional 40K Ar39 dates per year and 3000 single-crystal laser microprobe dates which equal about 500 sample dates a year (several subsamples from the same sample are routinely dated). Their microprobe is fully automated and, furthermore, provides the ability to date sub-milligram single volcanic crystals. This permits discrete age populations in multi-age component samples to be identified. More than half the laboratories research is focused on geochronology pertaining to hominid-hominoid (human- great ape) evolution and associated archaeology and paleontology. With three years of additional support, the laboratory will work to improve this dating technique to permit more precise and accurate dates. They will also continue their collaboration with paleoanthropologists and address a wide range of anthropologically significant site specific problems. The potassium argon technique, which allows absolute ages to be derived from volcanic materials has revolutionized the field of human origins studies because many important sites in Africa, which were previously undatable, contain multiple volcanic horizons. Fossils can only be correctly interpreted if put into a chronological framework, and many specimens which were difficult to use have taken on new importance. Dr. Drake and his colleagues have been leaders in the development and application of this technique. It is thus important to support both their laboratory and the specific research goals they are pursuing.