Copper and zinc in very metal-poor stars

New high-resolution, low-noise spectroscopic observations have been made of Cu I and Zn I transitions in five bright very metal deficient Population II stars. The Cu I lines are anomalously very weak in all five stars, while the Zn I lines retain reasonable strengths even in the most metal-poor example. A full model atmosphere LTE analysis of Cu and Zn in the program stars, and the inclusion of some results from earlier studies, demonstrate that regular trends exist in the abundances of these elements. First, Zn/Fe retains its solar ratio down to an overall stellar metallicity of Fe/H = -2.5 and even may begin to increase in more extremely metal-poor stars. Second, Cu/Fe declines steadily below Fe/H =-1, reaching less than 1/5 solar by Fe/H =-2.7. The different nucleosynthesis events which may account for the apparent primary origin for Zn and secondary origin for Cu are discussed.