THE 21NE PRODUCTION RATE IN QUARTZ REVISITED

Abstract

I have revised our earlier production rate determination of 21Ne in terrestrial quartz [S. Niedermann, Th. Graf, J.S. Kim, C.P. Kohl, K. Marti and K. Nishiizumi (1994) Earth Planet. Sci. Lett. 125, 341-355], taking account of improved knowledge about the exposure age of samples used in that work and applying distinct procedures for scaling to sea level and high latitudes. The corrected value of 19.0+/-3.7 atoms g-1 a-1 is in excellent agreement with expectations based on nuclear properties [J. Masarik and R.C. Reedy (1995) Earth Planet. Sci. Lett. 136, 381-395] and closely corresponds to the present-day production rate. In the case of substantial variations of the geomagnetic field in the past, as proposed by several studies, the revised value can consistently be used with suitable correction methods.