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

在NSF的支持下，德雷克博士和柯蒂斯博士在加利福尼亚州伯克利的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-Ar)测年，现在每年可生产约250个常规40K AR39测年和3000个单晶激光微探针测年，相当于每年约500个样品(同一样品中的几个子样品常规测年)。他们的微型探测器是全自动的，而且还提供了测定亚毫克单个火山晶体年龄的能力。这使得能够识别多年龄成分样本中的离散年龄人口。一半以上的实验室研究集中在与人-人(人-类人猿)进化有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，解决广泛的具有人类学意义的遗址具体问题。钾氩技术允许从火山物质中获得绝对年龄，这给人类起源研究领域带来了革命性的变化，因为非洲许多以前无法确定年代的重要地点包含多个火山层。化石只有放在年代框架内才能得到正确的解释，许多难以使用的标本具有了新的重要性。德雷克博士和他的同事一直是这项技术开发和应用的领导者。因此，支持他们的实验室和他们正在追求的具体研究目标是很重要的。

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.