Neutron activation analysis of silicate spherules from oceanic sediments

A technique of neutron activation analysis was developed for nondestructive analysis of small extraterrestrial grain samples of less than 1 mg. The features of the technique are (1) use of glass standards made from geochemical standard rocks (JB-1 and BHVO-1) and (2) use of a small aluminum plate on which samples and standards are precisely mounted for gamma-ray counting. Twelve silicate spherules obtained from dredged deep-sea sediments were analyzed for trace and major elements by applying the above method of neutron activation and electron microprobe analysis. The results show that most of the silicate spherules analyzed have marine origin except for a 0.7 mm glassy spherule of meteoritic origin reported in the previous paper (NAGASAWA et al., 1979). (author)