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On the basis of the authors’ compiled catalog containing spectroscopic abundances of 14 chemical elements for 90 open star clusters of the Galaxy, we show that in the young clusters not only barium but also three other studied elements of slow neutron-capture, Y, La, and Ce, reveal higher relative abundances than those in the field stars, with differences beyond the error limits. We also find that, at high metallicity ([Fe/H]> −0.1), the relative abundances of the r-process element Eu in the clusters with eccentric, high Zmax orbits are lower, and the relative abundances of primary α-elements O and Mg are higher, than the average values for the field giants. At the same time, at lower metallicity, the [Eu/Fe] ratios in the clusters are, on average, the same as in the field, but with a much larger dispersion, and the [O, Mg/Fe] ratios are lower than in the field giants. Taking into account that both α-elements and r-elements are ejected into the interstellar medium as a result of Type II supernova explosions, and that their yields are dependent on the pre-supernova mass, these properties naturally fit into the assumption that the clusters of different metallicity with eccentric, high Zmax orbits are formed by interaction of two types of high-velocity clouds with the interstellar medium of the Galactic disk. On the one hand, these are low-metallicity high-velocity clouds formed from the “primary” gas; on the other hand, there are more metal-rich intermediate-velocity clouds generated in the Galactic “fountain” process.

Spectroscopic determinations of the relative abundances of chemical elements produced in different nuclear-synthesis processes, [el/Fe], are collected for 90 open star clusters of the Galaxy using data from 109 papers published between 1991 and 2015. Information is gathered on the abundances of α-elements (O, Mg, Si, Ca, and Ti), iron-peak element (Fe), slow neutron capture elements (Y, Ba, La, Ce, Nd, and Zr), rapid neutron capture element (Eu), and elements with an odd number of protons (Na, Al). The weighted averages are calculated for the clusters with more than one determination of the abundances of each studied chemical element. Estimates of metallicities are found for 346 clusters. A compiled catalog of the open cluster parameters contains metallicities, positions, ages, velocities, elements of Galactic orbits, and relative abundances of fourteen chemical elements.

Applying a compilled catalog, we find that the relative abundances of α-elements in open clusters and in field stars of the thin disk of the Galaxy show different dependencies on metallicity, age and parameters of their Galactic orbits. The distinctions are explained by different nature of open clusters and field stars. We confirm the conclusions, reached earlier from the analysis of the parameters of Galactic orbits, that some clusters may have formed from the impact of metal-poor high-velocity clouds on the interstellar matter of the thin disk. Arguments are also adduced in favor of the formation of metal-rich high-velocity clusters from the interaction of metal-rich intermediate-velocity clouds formed from returning gas of the Galactic “fountain” with the interstellar medium of the thin disk.