The Development of a Low-Cost and High-Throughput Dating System for Prehistoric Ceramics

California State University-Long Beach Foundation, Long Beach CA

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5) Researchers at the Institute for Integrated Research in Materials, Environments, and Societies (IIRMES), California State University - Long Beach (CSULB) will use NSF Major Research Instrumentation funding to develop a new instrument for dating prehistoric ceramics. Results obtained by materials scientists indicate that low-fired ceramics, such as bricks, tiles, and pottery, gain weight and expand by a process of water absorption that is highly regular on time scales from weeks to millennia. The age of a low-fired ceramic can thus be obtained via highly precise measurement of initial weight, followed by dehydroxylation (firing above 500oC), followed by precise monitoring of weight gain over five to ten days in order to establish the rate of rehydroxylation. The proposed new instrument will automate these steps within a controlled environment to enable large numbers of ceramics to be dated at low cost. In archaeology, determination of the age of artifacts is central to the success of the discipline. Over the years, archaeologists have made use of a wide array of dating techniques: radiocarbon dating, luminescence dating, tree-ring dating, obsidian hydration, electron spin resonance, uranium/thorium series dating and so on. Each technique is best for particular materials and particular time ranges. Ceramic technology was invented independently in multiple world regions during the past 10,000 years, and, since ceramics are durable, archaeologists routinely find broken pieces of pottery, tiles, bricks, and figurines by the thousands (or more) on archaeological sites in many regions of the world. Effective techniques for dating ceramics are thus particularly valuable for the discipline. Unfortunately, however, luminescence, the main technique currently used for dating ceramics, is relatively difficult and expensive. Initial experiments have shown that the rehydroxylation method promises very high precision with relatively simple measurements and instruments. Configured for large numbers of simultaneous measurements, rehydroxylation has the potential to reduce per sample cost dramatically, thus dramatically increasing the number of dates that can be run on any given archaeological project. Moreover, the relative simplicity of the instrumentation means that it could be disseminated to a wide range of laboratory settings. The NSF-supported project being undertaken at IIRMES-CSULB seeks to develop instrumentation and protocols that are optimized for efficient production of rehydroxylation measurements on ceramics. The automated instrument system will retain the precision of the rehydroxylation dating method while dramatically increasing the rate of sample throughput. The project directors anticipate that the new instrumentation will have important, even revolutionary, impacts on archaeological research.