Hoba and Tlacotepec: Two new meteorites with isotopically anomalous Ag

Excesses of ^(107)Ag/^(109)Ag(^(107)Ag^*) of up to 4% relative to terrestrial silver were discovered by Kelly and Wasserburg (1978) in the Santa Clara iron meteorite. Subsequent investigations by Kaiser et al. (1980) (hereafter KKW) revealed much larger ratios of ^(107)Ag/^(109)Ag and showed that the true ^(109)Ag concentration was at a very low level for both the Piñon and Santa Clara iron meteorites. Experiments on other iron meteorites were indicated in order to further clarify the role of extinct ^(107)Pd as the source of the ^(107)Ag excesses compared to other possible sources.