Measurement of Cosmogenic sup 36 Cl/Cl in Young Volcanic Rocks: An Application of Accelerator Mass Spectrometry in Geochronology

摘要

We have measured sup 36 Cl/Cl ratios in a number of young volcanic rocks in order to test the feasibility of using sup 36 Cl buildup as a geochronometer for materials less than about 700,000 years old. All of the analyzed rocks have been dated independently using K-Ar or other radiometric dating methods and have exposure histories that are known or can be reasonably assumed. Measured sup 36 Cl/Cl ratios in these rocks are in good agreement with the calculated in-situ sup 36 Cl buildup curve. These analyses indicate that AMS measurement of sup 36 Cl buildup in young rocks is a potentially powerful new method for dating materials that had previously been undatable, and as such will have broad applications in volcanology, tectonics, geophysics, and Quaternary research. (ERA citation 12:032032)