BORON COSMOCHEMISTRY .1. BORON IN METEORITES

Thirty-six fragments of meteorite falls, never touched by water or other possible sources of B contamination, were analyzed for B by prompt gamma-ray neutron activation analysis at McMaster University and at the U.S. National Institute of Standards and Technology. Boron concentrations are close to the sensitivity limit in both laboratories. Results between the two laboratories agree well but with slight systematic differences attributable to blank and background correction factors. The mean B concentrations in different meteorites are similar, from 0.5 to 1.1 ppm. The ranges in different CC, OC and ACH classes overlap, mostly from 0.4 to 1.4 ppm, which is similar to previous measurements on falls. The H, L and LL meteorites overlap in B content with Antarctic chondrites. The solar system abundance, taken as the mean B content of the matrix in all CC, was calculated from seven samples and is 0.69 +/- 0.09 ppm. When normalized, this abundance is 16.9 +/- 2.2 (atoms/10(6)Si). Normalized B and S concentrations show a linear relationship in the CC; the average OC lies on the same line, but individual OCs are dispersed.