Continued development and application of 40Ar/39Ar dating for archaeometric research

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With National Science Foundation support, Drs. Alan Deino and Paul Renne will initiate a three-year effort to upgrade the 40Ar/39Ar dating facilities at the Berkeley Geochronology Center in Berkeley, California. The 40Ar/39Ar dating method has the broadest temporal range of applicability in archeological and paleoanthropological contexts, and is well established as a highly accurate and precise dating tool that has contributed widely to the study of hominid and hominoid evolution. The planned upgrades will ensure that the Archaeometric community has access to a laboratory exercising the best possible practices in this advanced and powerful dating technique, in order to attain the highest possible levels of precision, accuracy and throughput. The improvements will be in the areas of sample processing and extraction methods for removing argon from samples during analysis. Such advances will permit accurate analysis of difficult materials such as those that are low in potassium, very young, very small, or in the areas of mitigation of certain types of natural geological contamination, thus expanding the scope of problems that can be solved.In order to address these goals over the next three years, expenditures will be focused primarily in three areas: 1) Outfitting of a dedicated laboratory for 40Ar/39Ar sample preparation. The anticipated benefits to Archaeometry are in the area of clean and efficient processing of volume-limited or otherwise difficult samples in a controlled environment with minimal possibility of sample contamination, 2) Construction of a CO2 scanning laser system for better heating control for sample degassing, with the anticipated benefit of improved age resolution and greater accuracy in dating young, small, or low-K samples by enhancing sensitivity and uniformity in the heating process, and 3) NSF funding will also help BGC conduct routine maintenance and the purchase of consumables.Broader impacts of this study are anticipated in three areas: (1) Interdisciplinary stimulus. The research studies enabled by this grant are intrinsically interdisciplinary and foster improved interaction between geological, archaeological, and paleoanthropological scientists; (2) Public outreach. The archaeometric age data produced by BGC are frequently published in high-profile journals that are covered by lay news media, hence receiving broad public dissemination in newspapers, magazines, radio, television, and increasingly, the web; (3) Training early career scientists. Graduate students and postdoctoral fellows, many of whom will continue archaeometric research in the future, will receive direct training in the use of the dating facilities, poised to represent the next generation of 40Ar/39Ar geochronologists. Many other graduate students and postdoctoral fellows will receive archaeometric data in direct support of their field studies.