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

在美国国家科学基金会的支持下，德雷克和柯蒂斯在加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-氩）测年，现在每年可以产生大约250个传统的40K Ar39测年和3000个单晶激光微探针测年，相当于每年大约500个样品测年（通常对同一样品的几个子样品进行测年）。他们的微探针是全自动的，此外，还提供了测定亚毫克单个火山晶体年代的能力。这允许在多年龄组成样本中识别离散年龄人群。超过一半的实验室研究集中在与原始人-类人猿（人类-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，实验室将努力改进这种测年技术，以获得更精确和准确的日期。他们还将继续与古人类学家合作，解决广泛的人类学意义重大的遗址特定问题。钾氩技术可以从火山物质中得出绝对年龄，这一技术彻底改变了人类起源研究领域，因为非洲的许多重要遗址，以前是无法确定的，包含多个火山层。化石只有放在年代框架中才能得到正确的解释，许多难以使用的标本有了新的重要性。德雷克博士和他的同事一直是这项技术发展和应用的领导者。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.