26Al and rare gases in Allende,Bereba and Juvinas: implications for production rates

The ²⁶Al, light rare gas and major and minor element contents of Al-rich and poor samples separated from Allende. Bereba and Junivas have been measured. The production rate of ²¹Ne from Al (²¹P_Al) is $\text{(1.9 ± 0.6) ×}{}^{21}\text{P}{}_{\mathrm{Si}}$ and ${}^{\mathrm{<mtext>22</mtext><mtext>21</mtext>}}\text{P}{}_{\mathrm{Al}}\text{= 1.4 ± 0.4.}$ The ³He, ²¹Ne and ³⁸Ar exposure ages of the eucritic pyroxenes agree suggesting complete cosmogenic gas retention. The eucritic feldspars have lost virtually all ³He and most radiogenic ⁴He. The equation ²⁶Al = 0.42 ± 0.41 Mg + 2.74 ± 0.21 Si + 4.92 ± 0.51 Al + 1.33 S + 0.24 Ca + 0.03 Fe reproduces within 15% our ²⁶Al measurements and the average values measured in ordinary chondrites without recourse to unusual cosmic-ray effects.