ZINC ISOTOPE ANOMALIES

We have determined the Zn isotope composition in refractory element-rich inclusions of the Allende meteorite. Typical inclusions contain normal Zn. A unique inclusion of the Allende meteorite shows an excess for 66Zn of 16.7 ± 3.7 ∈u (1 ∈u = 0.01%) and a deficit for 70Zn of 21 ± 13 ∈u. These results indicate the preservation of exotic components even for volatile elements in this inclusion. The observed excess 66Zn correlates with excesses for the neutron-rich isotopes of 48Ca, 50Ti, 54Cr, and 58Fe in the same inclusion. These correlated effects provide definitive evidence for material produced in a neutron-rich, nuclear statistical equilibrium process and ejected into the interstellar medium.